WO2017147299A1

WO2017147299A1 - Active system for improved temperature control and air mixing inside refrigerated truck boxes, trailers and intermodal containers

Info

Publication number: WO2017147299A1
Application number: PCT/US2017/019141
Authority: WO
Inventors: Daniele GALLARDO; David MENICOVICH; Michael Amitay; David John SCHMITZ; Kevin Arthur ZOELLER
Original assignee: Actasys Inc.
Priority date: 2016-02-23
Filing date: 2017-02-23
Publication date: 2017-08-31

Abstract

Systems and methods for using actuators to generate jets of air to improve air mixing and distribution within a refrigerated volume of a refrigerated vehicle and for creating air curtains to minimize heat exchange either at a door to the refrigerated volume when the door is open or at a bulkhead within the refrigerated volume separating portions within that volume which are desired to be kept at differing temperatures. The jets of air are produced using synthetic jet actuators, compressed air actuators or active diffusers.

Description

ACTIVE SYSTEM FOR IMPROVED TEMPERATURE CONTROL AND AIR MIXING INSIDE REFRIGERATED TRUCK BOXES, TRAILERS, AND

INTERMODAL CONTAINERS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority and benefit to U.S. Provisional Patent

Application No. 62/298,799 filed February 23, 2016, the entire contents of which are incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to the control of temperature, air mixing, and heat and cold insulation for refrigerated volumes within refrigerated vehicles and more particularly for refrigerated vehicles such as refrigerated truck boxes, refrigerated trailers, and refrigerated intermodal containers.

BACKGROUND OF THE INVENTION

[0003] Refrigerated vehicles typically use a Truck Refrigeration Unit (TRU) mounted on one of the surfaces of the vehicle, typically the front surface of the trailer for a refrigerated trailer and the upper front surface for truck boxes, to cool a refrigerated volume. Such TRUs include a diesel engine connected to an alternator powering a compressor, which performs a refrigeration cycle.

[0004] The refrigeration cycle used by the TRU is typical of refrigeration cycles used for any generic refrigeration apparatus in the prior art. Specifically, a gas is first liquefied by the compressor in a condenser unit, and is subsequently evaporated into an evaporator. The evaporation of the gas absorbs a significant amount of heat. A fan is normally used to force the hot air inside the refrigerated volume through the evaporator, significantly reducing the temperature of the air itself, which is then forced back into the refrigerated volume to cool the transported goods. The output of the fan is typically directed to the upper portion of the volume being refrigerated, with the intent of exploiting the Coanda effect and keeping the main flow of cooled air at the ceiling of the refrigerated volume itself.

[0005] Theoretically, the cooled air should stay close to the refrigerated volume ceiling and continue its path towards the back of the refrigerated volume, where the cooled air it hits the back door. Upon hitting the back door, the cooled air should change direction and return to the TRU at the front of the refrigerated volume, this time on a lower path closer to the floor of the refrigerated volume.

[0006] The TRU intake is normally located on a lower portion of the refrigerated volume and a TRU bulkhead is often used to prevent what is called "short cycling" in which case the air from the TRU circulates directly from its output to its input without circling through the whole refrigerated volume. The ideal circular air path should provide uniform ventilation and cooling to the transported goods but is heavily dependent on the loading configuration of goods within the refrigerated volume. The goods should be properly distanced from the side walls, back door, and ceiling to allow a proper flow of the cooling air. Very often this configuration is sacrificed to maximize the loading capabilities of the refrigerated volume, compromising the cooling capabilities of the TRU.

[0007] To improve the uniform circulation of the cool air, a device called a "chute'^" is sometimes used in the prior art. Such device consists of a long flexible canvas, often times treated to augment its abrasion resistance, which is connected to the ceiling of the refrigerated volume in a fashion that forms a flexible "U-shaped" channel. The chute is open on the sides to facilitate the flo of the cool air from the TRU to the back of the vehicle.

[0008] Although a chute improves the temperature control and mixing of the air inside refrigerated volumes, the installation space required for it to function properly requires more clearance than would typically be required to allow a proper flow with a basic refrigerated volume (that is, a volume without chute), and for this reason, chutes are often not used in order to maximize the load. Accordingly, there is a need to provide for improved temperature control and mixing of air inside refrigerated volumes that permits the loading of goods within the refrigerated volume to be maximized.

|0009] Another challenge typically affecting refrigerated volumes is related to the loss of cold air from the refrigerated volume associated with the loading and unloading operations of goods from the refrigerated volume. Refrigerated vehicles typically stop multiple times at different locations to deliver refrigerated goods. Each time the door to the refrigerated volume is opened to access the goods, the colder refrigerated air from within the volume, which is heavier than hotter air, flows quickly out of the refrigerated volume through the lower portion of the open door. In a typical refrigerated vehicle, this open door is situated at the back of the refrigerated volume. The cold air is quickly replaced by warmer and oftentimes more humid outside air which flows through the higher upper portion of the open doorway, which is typically the back doorway.

[0010] The replacement of the cold dry air with warmer humid air within the refrigerated volume has very negative effects. The first effect is on the TRU unit, which will have to use more energy to compensate for the higher temperature inside the refrigerated volume. The second effect is caused by the humidity accumulated in the refrigerated volume, which will concentrate on the evaporator unit of the TRU and freeze. The frozen water covering the evaporator will cause it to have a lower heat exchange coefficient and as a result the TRU will function with a lower efficiency.

|00II] in order to mitigate the problem caused by opening the back (or any other) door to the refrigerated volume, the "cold curtain" or "strip doors" were developed in the prior art, consisting of pieces of semi-rigid plastic sheets mounted on the upper edge of the doors to the refrigerated volume or on loading dock entrances which would face the opening to the refrigerated volume. The cold curtains or strip doors allow the passage of machines. personnel, and goods in and out of the refrigerated v olume and at the same time prevent the heat exchange that would normally happen without those units installed. Although cold curtains can indeed help in mitigating the negative effects caused by open doors, in practice they have proven to be extremely prone to breaking due to the frequent passage of goods and workers through them. The high rate of breakages results in high maintenance costs that can nullify the cost savings derived from a more efficient TRU and a more stable temperature control within the refrigerated volume. Moreover, the presence of these curtains negatively impact loading and unloading operations, resulting in lower labor efficiency. Accordingly, there is a need to provide for another way to minimize the escape of cold air through an open door to the refrigerated volume without the use of a physical barrier such as a cold curtain or strip doors.

[0012] Another limit of the current technology to provide uniform circulation of air within the refrigerated volume is the control systems in the prior art on which the operation of the TRU is based. A TRU controller typically has a very simple architecture that relies on a few temperature sensors to activate the TRU when the temperature inside the refrigerated volume goes above a certain set threshold. This simple actuation strategy does not account for the significant temperature change occurring when one or more doors to the refrigerated volume are open and does not detect the presence of air pockets inside the refrigerated vehicle that are not at an optimal temperature. Further, the controller does not take into account the predicted length of the loading or unloading of goods based on a predetermined loading/unloading schedule. Accordingly, there is a need for a more sophisticated control system with a distributed network of sensors to account for the formation of air pockets that are not properly cooled due to uneven and improper loading and for a connection between the controller and the known loading/unloading schedule of the vehicle that will allow the controller to predictively actuate the TRU to minimize the energy lost due to the heat exchange occurring while opening the door or doors to the refrigerated volume.

[0013] In addition to a basic TRU for a refrigerated volume, a number of refrigerated vehicles in the prior art have what is called a "multiple temperatures" control, representing a slight improvement compared to the basic TRU temperature control. These vehicles can transport frozen goods, refrigerated goods, and produce using a single TRU with the functionality to generate, for example, three different temperature zones coupled with two movable bulkheads installed into the refrigerated volume to separate it into different volumes. Each volume can be held at a different temperature. The bulkheads are movable because they should be able to accommodate different types of cargo volumes. While multiple temperature functionality within the refrigerated volumes are extremely convenient for fleet operators that want to ship mixed goods requiring different target temperatures, the bulkheads, due to their movable nature, are very often not perfectly sealed and can put a stress on the TRU due to high heat exchange between the bulkhead compartments. Moreover, the TRU controller is unable to automatically detect the nature of the goods in the different volumes of the cargo. Accordingly, there is a need to provide for an improved multiple temperatures control functionality which minimizes heat exchange between differing temperature control sections and with a TRU controller. Furthermore, there is a need to automatically detect the nature of the goods stored inside each refrigerated bulkhead compartment and automatically adapt TRU operations to maintain a temperature that is optimal for the detected goods.

[0014] It is an object of the present invention to provide for improved temperature control and mixing of air inside refrigerated volumes that permits the loading of goods within the refrigerated volume to be maximized; to provide for another way to minimize the escape of cold air through an open door to the refrigerated volume without the use of a physical barrier such as a cold curtain or strip doors; to pro vide for a more sophisticated control system with a distributed network of sensors to account for the formation of air pockets that are not properly cooled due to uneven and improper loading and for a connection between the controller and the known loading/unloading schedule of the vehicle that will allow the controller to predictively actuate the TRU to minimize the energy lost due to the heat exchange occurring while opening the door or doors to the refrigerated volume; to provide for an improved multiple temperatures control functionality which minimizes heat exchange between differing temperature control sections and with a TRU controller; and to provide a stream of operating data for the TRU operation and of the temperature distribution inside the refrigerated volume to an external logistics database.

SUMMARY OF THE INVENTION

[0015] Systems and methods for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles through the use of actuators for generating jets of air (air jets) are provided. These systems can operate separately or together to maintain a desired uniform air temperature within the refrigerated volume of the refrigerated vehicle.

[0016] In an exemplary embodiment of the present invention, the system comprises at least one actuator for generating a jet of air mounted within the refrigerated volume of the vehicle, remote from the refrigeration unit (the TRU) for enhancing the air mixing and distribution within the refrigerated volume. The system comprises at least one temperature sensor remote from the refrigeration unit configured to capture temperature data within the refrigerated volume of the refrigerated vehicle. In a preferred embodiment, the temperature data is sent to a sensor unit mounted on the refrigerated vehicle. The system also comprises a controller configured to receive the temperature data from the sensor unit or directly from the temperature sensor and to control the at least one actuator based on the received temperature data. [0017] In an exemplary embodiment of the present invention, the system comprises at least one actuator for generating a jet of air mounted within the refrigerated volume of the vehicle proximal to a door which will be used for loading and unloading goods from the refrigerated volume. The actuator is used to generate an air curtain to reduce the heat exchange between the refrigerated volume and the outside air during loading and unloading operations. The system includes a door sensor configured to collect door data which indicates whether the door is open or closed. In a preferred embodiment the door data is sent to a sensor unit mounted on the refrigerated vehicle. The system also comprises a controller configured to receive the door data from the sensor unit or directly from the door sensor and to control the at least one actuator based on the received door data.

[0018] In a preferred embodiment the systems to improve air mixing and distribution and reduce the heat exchange during loading and unloading operations of the refrigerated volume operate within the same refrigerated volume. In such a combined system, only one sensor unit may be used to collect temperature and door data and one controller may be used to control the at least two actuators (one within the refrigerated volume and one specifically proximal to the door) for generating jets of air.

[0019] Either or both of these systems are powered by a power unit which may derive power from an independent power unit (e.g., a battery power pack), the TRU alternator or battery, or the refrigerated vehicle's battery.

[0020] In an exemplary embodiment of the present invention, the method comprises capturing temperature data from at least one temperature sensor remote from the refrigeration unit (the TRU) inside the refrigerated volume of the refrigerated vehicle and controlling at least one actuator for generating a jet of air mounted within the refrigerated volume of the vehicle remote from the refrigeration unit based on the received temperature data to improve air circulation and mixing inside the refrigerated vehicle. [0021] In an exemplary embodiment of the present invention, the method comprises capturing door data from at least one door sensor mounted proximal to a door which will be used for loading and unloading goods from the refrigerated volume and controlling at least one actuator for generating a jet of air mounted proximal to the door based on the received door data to generate an air curtain proximal to the door to minimize the flow of air to and from the refrigerated volume when the door is open.

[0022] In a preferred embodiment, the methods to improve air mixing and distribution and reduce the heat exchange during loading and unloading operations of the refrigerated volume operate within the same refrigerated volume. In such a combined method system, only one controller may be used to control the at least two actuators (one within the refrigerated volume and one specifically proximal to the door) for generating jets of air.

[0023] In an exemplary embodiment of either method, the method further comprises capturing humidity data by at least one humidity sensor mounted on the vehicle and using the controller to adjust operation of the one or more air jets when the captured humidity is different than a reference humidity value.

[0024] Other data which may be captured and sent to the controller for either method include truck refrigeration unit operations data associated with the operating conditions of the truck refrigeration unit which can be used by the controller to adjust operation of the air jets; and delivery data collected from a remote dynamic database containing the loading and unloading schedule of the refrigerated vehicles which can be used by the controller to adjust the air jets based on the predicted future cooling needs of the refrigerated vehicle.

[0025] In another exemplary embodiment of the invention, the controller communicates with an extemal logistics platform and exchanges information regarding the operations of the system. [0026] In an exemplary embodiment of the present invention, the air jets for the system for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles are provided by synthetic jet actuators.

[0027] In an exemplary embodiment based on synthetic jet actuators, the system comprises at least two synthetic jet actuators, with at least one actuator mounted within the refrigerated volume remote from the refrigeration unit and the other mounted proximal to a door within the refrigerated volume that opens to the outside environment when open. The synthetic jet actuators are configured to generate at least two jets of air, one for enhancing the air mixing and distribution, and the other one to generate an air curtain proximal to the door to reduce the heat exchange during loading and unloading operations. At least one temperature sensor is located remote from the refrigeration unit configured to capture temperature data inside the refrigerated volume, and at least one door sensor configured to detect if the vehicle door is closed or open. A controller is configured to receive the temperature and door sensor data and to determine at least one of a drive frequency, phase, and drive amplitude for controlling the at least two synthetic jet actuators, based on received temperature and door data.

[0028] In a preferred embodiment of the present invention, at least one synthetic jet actuator utilized to enhance the air mixing inside the refrigerated volume is mounted on at least one of the lower portion of the TRU output, on the side of the TRU, on the ceiling of the refrigerated vehicle, on the side walls of the refrigerated vehicle, on the doors edges, or on the floor of the refrigerated volume. In other exemplary embodiments of the present invention, the synthetic jet actuators may be placed on some or all of these locations.

[0029] In a preferred embodiment of the present invention, at least one synthetic jet actuator used to generate the air curtain is mounted on at least one of the door edges or edge portions within the refrigerated volume. In other exemplary embodiments of the present invention, the synthetic jet actuators may be placed on some or all of these locations.

[0030] In an exemplary embodiment of the present invention, a sensor unit mounted on the refrigerated vehicle collects temperature and door data from the temperature and door sensors located within the refrigerated volume. The controller may receive the temperature and door data from the sensor unit instead of directly from the temperature and door sensors. The system may further include a humidity sensor which man also be connected to the sensor unit.

[0031] In an exemplary embodiment of the present invention, the system also comprises a main electronic unit coupled to the synthetic jet actuators and which is configured to generate an oscillating voltage signal based on at least one of a drive frequency, drive phase and drive amplitude determined by the controller, wherein the oscillating voltage signal is used to drive the at least two synthetic jet actuators.

[0032] The synthetic jet actuators may be configured to be mounted on a mounting frame which electrically connects the synthetic jet actuators to the main electronic unit. Alternatively, the synthetic jet actuators may be configured to be detachably coupled to the vehicle.

[0033] The sensor unit may include at least two diagnostic sensor configured to capture diagnostic sensor data associated with the at least two synthetic jet actuators, and the controller may be configured to detect a predetermined condition of the synthetic jet actuators based on the diagnostic sensors data. The predetermined condition may include either of a predetermined mechanical condition or a predetermined electrical condition. In an exemplary embodiment, the user interface is coupled to the controller and is configured to provide an indication of the detected predetermined mechanical or electrical condition to an occupant of the vehicle or to the fleet operator. [0034] In embodiments where there are a plurality of synthetic jet actuators positioned at different locations inside the refrigerated volume, operation of each of the synthetic jet actuators may be independently controlled by the controller. In alternative embodiments with a plurality of synthetic jet actuators operation of each of the synthetic jet actuators may be jointly controlled by the controller.

[0035] In another exemplary embodiment, the controller is further connected to a remote dynamic database containing the loading and unloading schedule of the refrigerated vehicles. The controller may also be further connected to the TRU control and can detect its operating condition. The controller may also be connected to an external logistics platform and can send information regarding the operations of the system.

[0036] In an exemplary embodiment based on synthetic jet actuators, the method comprises capturing temperature data from at least one temperature sensor mounted inside the refrigerated volume of the refrigerated vehicle and door position data from at least one door sensor mounted on the vehicle proximal to the door, determining, by a controller, at least one of a drive frequency, drive phase, and drive amplitude for controlling at least two synthetic jet actuators mounted within the refrigerated volume based on the received temperature data and door data, generating at least two air jets by the at least two synthetic jet actuators, based on the at least one of a drive frequency, drive phase, and drive amplitude. At least one of the air jets is used to improve air circulation and mixing inside the refrigerated volume and the other air jet is used to generate an air curtain proximal to the door to minimize the flow of air to and from the refrigerated volume which enhances the heat insulation of the refrigerated vehicle.

[0037] In a preferred embodiment where more than one temperature sensor is mounted inside the refrigerated volume of the refrigerated vehicle, temperature distribution data is captured and used by the controller. [0038] In an exemplary embodiment, the method further comprises capturing humidity data by at least one humidity sensor mounted within the refrigerated volume and using the controller to adjust operation of the at least two synthetic jet actuators when the captured humidity is different than a reference humidity value.

[0039] The method may also further comprise capturing diagnostic sensor data associated with the at least two synthetic jet actuators by at least two diagnostic sensors; and detecting by the controller, a predetermined condition of the at least two synthetic jet actuators based on the diagnostic sensor data, the predetermined condition including at least one of a predetermined mechanical condition or a predetermined electrical condition.

[0040] Other data which may be captured and sent to the controller include truck refrigeration unit operations data associated with the operating conditions of the truck refrigeration unit which can be used by the controller to adjust operation of the at least two synthetic jet actuators; and delivery data collected from a remote dynamic database containing the loading and unloading schedule of the refrigerated vehicles which can be used by the controller to adjust the synthetic jet actuators based on the predicted future cooling needs of the refrigerated vehicle.

[0041] In another exemplary embodiment of the invention, the controller communicates with an external logistics platform and exchanges information regarding the operations of the system.

[0042] In an exemplary embodiment of the present invention, the air jets for the system for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles are provided by compressed air actuators.

[0043] In such an exemplary embodiment the system additionally requires a compressor controlled by a controller and configured to generated compressed air, a manifold, configured to collect the compressed air generated by the compressor and deliver it to at least two compressed air actuators, at least one pressure sensor configured to capture pressure data within the manifold and the controller further configured to receive pressure data from the pressure sensor and to control the compressor to maintain the pressure inside the manifold at a predetermine value.

[0044] In an exemplary embodiment of the present invention, the air jets for the system for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles are provided by active diffusers.

[0045] In such an exemplary embodiment, the system additionally requires a collector box, configured to collect a portion of the airflow generated by the refrigeration unit and at least one duct connecting the collector box to the at least one active diffuser.

[0046] In an exemplary embodiment of the present invention, a system for reducing the heat exchange through insulating bulkheads of a refrigerated volume using synthetic jet actuators is provided wherein the system comprises a refrigeration unit, at least one bulkhead located within the refrigerated volume and at least one synthetic jet actuator for generating a jet of air mounted within the refrigerated volume proximal to the at least one bulkhead to generate an air curtain to reduce the airflow and heat exchange between the portions of the refrigerated volume delimited by the at least one bulkhead.

[0047] The system may further comprise a sensor unit, mounted on the vehicle, having at least one temperature sensor configured to capture temperature distribution inside the refrigerated vehicle, and a controller configured to receive the temperature data from the sensor unit and to determine at least one of a drive frequency, phase, and drive amplitude for controlling the at least one synthetic jet actuator, based on received temperature and door data. [0048] In an exemplary embodiment of the present invention, a method for reducing the heat exchange through insulating bulkheads of a refrigerated volume using synthetic jet actuators is provided wherein the method comprises capturing temperature data from at least one temperature sensor mounted within the refrigerated volume, determining, by a controller, at least one of a drive frequency, drive phase, and drive amplitude for controlling at least one synthetic jet actuator mounted within the refrigerated volume proximal to the at least one bulkhead to generate an air curtain to reduce the airflow and heat exchange between the portions of the refrigerated volume delimited by the at least one bulkhead.

[0049] It is anticipated and within the scope of the invention that the invention is applicable to any desired maintenance of temperature within a contained volume where there is a gradient between the temperature within the volume and the ambient temperature. For example, in one exemplary embodiment the refrigerated volume can be maintained at a temperature warmer than the outside air temperature and can be heated to maintain the desired temperature.

[0050] It is anticipated and within the scope of the invention that the door to the refrigerated volume may be any type of coverable opening such as a window, or any other type of portal that can be covered.

[0051] These and other features of the invention are described in, or apparent from, the following detailed description of various exemplary embodiments of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The features and advantages of the present invention will be more fully understood by reference to the following detailed description of illustrative embodiments of the present invention when taken in conjunction with the following figures, wherein:

[0053] FIG. 1A is a functional block diagram of a system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on synthetic jet actuators in accordance with an exemplary embodiment of the present invention;

[0054] FIG. IB is a functional block diagram of the main electronic unit shown in FIG. 1A;

[0055] FIG. 2A is a perspective view diagram of a refrigerated vehicle including an exemplary system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on synthetic jet actuators, in accordance with an exemplary embodiment of the present invention;

[0056] FIG. 2B is a sectional view of the refrigerated vehicle taken along the line A-A in FIG. 2A in the direction shown by the arrows;

[0057] FIG. 2C is a perspective view diagram of the refrigerated vehicle of FIG. 2A with an open rear door;

[0058] FIG. 3 A is an exploded perspective view diagram of an exemplary synthetic jet actuator, in accordance with an exemplary embodiment of the present invention;

[0059] FIGS. 3B and 3C are perspective view diagrams of the synthetic jet actuator shown in FIG. 3 A;

[0060] FIG. 4A is a cross-sectional diagram of a portion of the synthetic jet actuator of FIG. 3C taken along line B-B, illustrating actuation of the synthetic jet actuator in the closed position;

[0061] FIG. 4B is a cross-sectional diagram of a portion of the synthetic jet actuator of FIG. 3C taken along line B-B, illustrating actuation of the synthetic jet actuator in the open position;

[0062] FIG. 5 is a flow chart of a method for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on synthetic jet actuators in accordance with an exemplary embodiment of the present invention;

[0063] FIG. 6 is a flow chart of a method of performing diagnostic control of the system of FIG. 1A;

[0064] FIG. 7 is a flow chart illustrating a method of performing heat insulation control of the system of FIG. 1A;

[0065] FIG. 8 is a flow chart illustrating a method of performing improved mixing control of the system of FIG. 1A;

[0066] FIG. 9A is a functional block diagram of a system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on compressed air actuators, in accordance with an exemplary embodiment of the present invention;

[0067] FIG. 9B is a functional block diagram of the compressed air actuators shown in FIG. 9A;

[0068] FIG. 1 OA is a perspective view diagram of a refrigerated vehicle including an exemplary system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on compressed air actuators, in accordance with an exemplary embodiment of the present invention;

[0069] FIG. 10B is a sectional view of the refrigerated vehicle taken along the line C-C in FIG. 10A in the direction shown by the arrows;

[0070] FIG. IOC is a perspective view diagram of the refrigerated vehicle of FIG. 10A with an open rear door;

[0071] FIG. 11 is a flow chart of a method for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on compressed air actuators in accordance with an exemplary embodiment of the present invention;

[0072] FIG. 12 is a flow chart of a method of performing diagnostic control of the system of FIG. 9A;

[0073] FIG. 13 is a flow chart illustrating a method of performing heat insulation control of the system of FIG. 9A;

[0074] FIG. 14 is a flow chart illustrating a method of performing improved mixing control of the system of FIG. 9A;

[0075] FIG. 15 is a flow chart illustrating a method of performing compressor control of the system of FIG. 9A;

[0076] FIG. 16A is a functional block diagram of a system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on active diffusers, in accordance with an exemplary embodiment of the present invention;

[0077] FIG. 16B is a functional block diagram of the active diffusers shown in FIG. 16 A;

[0078] FIG. 17A is a perspective view diagram of a refrigerated vehicle including an exemplary system for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on active diffusers, in accordance with an exemplary embodiment of the present invention;

[0079] FIG. 17B is a sectional view of the refrigerated vehicle taken along the line D-D in FIG. 17A in the direction shown by the arrows;

[0080] FIG. 17C is a perspective view diagram of the refrigerated vehicle of FIG. 17A with an open rear door; [0081] FIG. 18 is a flow chart of a method for improved air mixing and distribution in the refrigerated volume and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles based on an active diffuser system in accordance with an exemplary embodiment of the present invention;

[0082] FIG. 19 is a flow chart of a method of performing diagnostic control of the system of FIG. 16A;

[0083] FIG. 20 is a flow chart illustrating a method of performing heat insulation control of the system of FIG. 16A;

[0084] FIG. 21 is a flow chart illustrating a method of performing improved mixing control of the system of FIG. 16A;

[0085] FIG. 22A is a functional block diagram of a system for reducing the heat exchange between volumes insulated by bulkheads in refrigerated vehicles based on synthetic jet actuators, in accordance with an exemplary embodiment of the present invention;

[0086] FIG. 22B is a functional block diagram of the main electronic unit for the system shown in FIG. 22A;

[0087] FIG. 23 is a perspective view diagram of a refrigerated vehicle including an exemplary system for improved heat insulation between volumes insulated by bulkheads based on a synthetic jet actuators, in accordance with an exemplary embodiment of the present invention;

[0088] FIG. 24 is a flow chart of a method for improved heat insulation between volumes insulated by bulkheads in refrigerated vehicles based on synthetic jet actuators in accordance with an exemplary embodiment of the present invention; and

[0089] FIG. 25 is a flow chart illustrating a method of performing bulkheads insulation control of the system of FIG. 22A. [0090] It is emphasized that, according to common practice, various features/elements of the drawings may not be drawn to scale. On the contrary, the dimensions of the various features/elements may be arbitrarily expanded or reduced for clarity. Moreover, in the drawings, common numerical references are used to represent like features/elements.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0091] initially referring to FIG. 1A for the structure of the present invention, symbolic jet actuator system 101 is shown located within the refrigerated volume of refrigerated vehicle 100. One of ordinary skill in the art will appreciate that refrigerated vehicle 100 may comprise any of the following: refrigerated truck box, refrigerated trailer, refrigerated intermodal container, or any other type of structure with a volume for refrigeration.

Refrigeration of the refrigerated volume of refrigerated vehicle 100 can be achieved with ice, utilizing a cooling agent such as, without being limited to, carbon dioxide, or with the use of a mechanical refrigeration system, referred to as truck refrigeration unit (TRU) 112, as shown in the exemplary embodiment of FIG. 1A.

[0092] In an exemplary embodiment, system 101 comprises sensor unit 102, controller 103, main electronic unit 104, one synthetic jet actuator for enhanced mixing 170, one synthetic jet actuator for enhanced insulation 171, data storage unit 106, and user interface 105. At least one synthetic jet actuator for enhanced mixing 170 is used to improve air circulation and mixing inside the refrigerated volume of refrigerated vehicle 100. At least one synthetic jet actuator for enhanced insulation 171 is used to generate an air curtain proximal to the door of the refrigerated volume of refrigerated vehicle 100 to minimize the flow of air to and from the refrigerated volume when the door is open to enhance the heat insulation of the refrigerated vehicle and keep the refrigerated air within the refrigerated volume.

[0093] Both synthetic jet actuators 170 and 171 are operated by main electronic unit 104 which in turn is controlled by controller 103 which receives sensor data from sensor unit 102, TRU operations data from TRU control 108, and deliver}' data from external delivery database 109, in order to perform air mixing control 130, diagnostic control 131 , or heat insulation control 132. In an exemplar}⁷ embodiment of the present invention, controller 103 wdrelessiy connects with fleet logistics platform 178 to exchange operating information. The controller can also interface with user interface 105 and store data on a storage 106.

|0094] in an exemplary embodiment of the present invention, sensor unit 102 comprises one or more temperature sensors 1 20, one or more humidity sensors 121 , one or more diagnostic sensors 122 and one or more door sensors 123.

[0095] Temperature sensor(s) 120 and humidity sensor(s) 121 collect sensor data inside the refrigerated volume of refrigerated vehicle 100. More than one temperature sensor 120 and/or humidity sensor 121 may be positioned inside the refrigerated volume of refrigerated vehicle 100. in embodiments where a plurality of temperature sensors 120 are utilized, they will be uniformly positioned on the mside surfaces of the refrigerated volume to improve the capture of temperature distribution data inside the refrigerated volume of refrigerated vehicle 100. Temperature sensors 120 may consist of any type of commercially available contact temperature sensors such as thermocouples, resistive temperature detectors, thermistors, or bi -metallic thermostats. Humidity sensors 121 (also called hygrometers) may consist of any commercially available type such as capacitive hygrometers, resistive hygrometers, thermal hygrometers, or gravimetric hygrometers.

[0096] Diagnostic sensors 122 are used to identify electrical problems (such as short circuits) and/or mechanical problems with synthetic jet actuators 170 or 171. Diagnostic sensors 122 may consist of any commercially available type of current detectors such as hall effect sensors, current clamp meters, resistors and/or strain gauges or any other type of commercially available sensor to detect the absorbed power such as wattmeter. Electrical and/or mechanical problems of synthetic jet actuators 170 or 171 identified by diagnostic sensors 122 may be communicated to the user (e.g., the operator of refrigerated vehicle 100) via user interface 105. User interface 105 may comprise a screen, LEDs, or other visual means to communicate information to the user, as well as buttons that the user can utilize to check the status of the different components of system 101. in some scenarios, the identified problems may cause system 101 to cease operation. In other scenarios, the identified problems may be automatically corrected (or at least an automatic attempt to correct the problems may be made) during operation of system 101.

[0097] Door sensor(s) 123 detect whether the door to the refrigerated volume of refrigerated vehicle 100 is closed or open. One of ordinary skill in the art will appreciate that numerous types of sensors including force sensors or proximity sensors can be used as door sensor(s) 123.

[0098] in an exemplary embodiment of the present invention, controller 103 may be configured to control operation of one or more sensor unit 102, main electronic unit 104, synthetic jet actuator for enhanced mixing 170, synthetic jet actuator for enhanced insulation 171, storage 106, and user interface 105. Controller 103 may include, for example, a logic circuit, a digital signal processor, a microcontroller or a microprocessor.

[0099] In an exemplary embodiment of the present invention, controller 103 may be configured to perform air mixing control 130, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the main electronic unit 104 to operate synthetic jet actuators 170 or 171, based on the variables related to refrigerated vehicle 100. To determine the variables, controller 103 may use the sensor data received from sensor unit 102 including temperature sensors 120 and humidity sensor 121, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery. To perform air mixing control 130 synthetic jet actuator(s) for enhanced mixing 170 will be utilized. [0100] In an exemplary embodiment of the present invention, air mixing control 130 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, and when the planned delivery is at a certain known point in time. To identify the temperature distribution, controller 103 may use the sensor data received from at least two temperature sensors 120. To identify the TRU operating parameters, the controller 103 may interface with the TRU control 108. To identify the planned deliveries, the controller 103 may interface with the refrigerated vehicle delivery database 109. A description of air mixing control 130 is provided further below with respect to FIG. 8.

[0101] In an exemplary embodiment of the present invention, controller 103 may also be configured to perform diagnostic control 131, to determine whether components of system 101 are operating under normal conditions. For diagnostic control 131, controller 103 compares diagnostic sensor data received from diagnostic sensors 122 to predetermined optimal conditions to determine the presence of an abnormal current absorption and/or the presence of an abnormal power consumption profile and/or the presence of an abnormal load strain gauge values, to identify electrical and/or mechanical problems with components of system 101 or to confirm that system 101 is operating under normal conditions. Depending upon the operating conditions, controller 103 may provide an indication of a normal or faulty condition to user interface 105. Diagnostic control 131 is described further below with respect to FIG. 6.

[0102] In an exemplary embodiment of the present invention, controller 103 may be configured to perform heat insulation control 132, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the main electronic unit 104 to operate synthetic jet actuator(s) for enhanced insulation 171, based on variables related to refrigerated vehicle 100. To determine the variables, controller 103 may use the sensor data received from temperature sensors 120, as well as sensor data from humidity sensor 121, sensor data from door sensor 123, TRU operations data from TRU control 108, and delivery data from refrigerated vehicle delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery.

[0103] Heat insulation control 132 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, when the planned delivery is at a certain known point in time, or when there is a certain condition with the door. To identify the temperature distribution, controller 103 may use the sensor data received from at least two temperature sensors 120. To identify the TRU operating parameters, controller 103 may interface with the TRU control 108. To identify the planned deliveries, controller 103 may interface with refrigerated vehicle delivery database 109. To identify the status of the door (Closed or Open) controller 103 may interface with door sensor(s) 123. A description of heat insulation control 130 is provided further below with respect to FIG. 7.

[0104] In an exemplary embodiment of the present invention, User Interface 105 may include any suitable interface to provide visual and/or audio indication of a normal or faulty operating condition. For example, a blinking red LED might signal the presence of a short- circuit, or a blinking yellow LED might signal the presence of a clogged synthetic jet actuator. User Interface 105 may be provided inside the refrigerated volume of refrigerated vehicle 100, or outside the refrigerated volume for the convenience of the user. In an alternative exemplary embodiment of the present invention, user interface 105 may be provided on controller 103 and/or main electronic unit 104. For example, user interface 105 may be an external unit mounted on a component of system 101 or may be formed as part of a component of system 101. Responsive to the indication on user interface 105, the user may operate refrigerated vehicle 100 or may have system 101 inspected for maintenance issues.

[0105] System 101 may include storage 106. Storage 106 may include, for example, a random access memory (RAM), a magnetic disk, an optical disc, flash memory or a hard drive. Storage 106 may store one or more values for sensor unit 102, controller 103, main electronic unit 104, synthetic jet actuators for enhanced mixing 170, synthetic jet actuators for enhanced insulation 171, delivery data from delivery database 109, TRU operations from TRU control 108, and/or user interface 105.

[0106] Main electronic unit 104 may be configured to receive control signals from controller 103 and activate one or more actuators 170 or 171 according to operation parameters (frequency, phase, and voltage amplitude) provided by controller 103 in the control signal. Main electronic unit 104 is described further below with respect to FIG. IB. System 101 may be configured to have multiple main electronic units, each connecting to a group of synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 , and each controlled by controller 103.

[0107] Each synthetic jet actuator for enhanced mixing 170 and each synthetic jet actuator for enhanced insulation 171 may be configured to receive an electrical signal (having an operation frequency, phase, and an operation voltage amplitude) from main electronic unit 104 and may produce an air jet. The air jets produced by synthetic jet actuators for enhanced mixing 170 may be used to control the air mixing and distribution inside the refrigerated volume of refrigerated vehicle 100. The air jets produced by synthetic jet actuators for enhanced insulation 171 may be used to create an air curtain and limit the airflow to and from the refrigerated volume of refrigerated vehicle 100, ultimately reducing the heat exchange between the refrigerated volume and the outside environment. Synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 may be mounted directly to the refrigerated volume of vehicle 100 or may be mounted to vehicle 100 via a mounting frame, such as mounting frame 291 shown in FIG. 2A. In another exemplary embodiment (not shown), synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 may be formed integrally with the vehicle.

[0108] Synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 are described further below with respect to FIGS. 3A-3C and FIGS. 4A and 4B. Synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 are constructed in the same way, the only difference being the purpose of the air jet that each generates. Specifically, synthetic jet actuators for enhanced mixing 170 produce an air jet that is utilized to enhance the air mixing and distribution inside the refrigerated vehicle 100, while synthetic jet actuators for enhanced insulation 171 produce an air jet that is utilized to enhance the insulation between the refrigerated volume and the outside environment by creating an air curtain at the door level that limits the airflow to and from the refrigerated volume.

[0109] One of ordinary skill in the art would recognize that components of one or more of sensor unit 102, controller 103, main electronic unit 104, user interface 105, and storage 106 may be implemented in hardware, software or a combination of hardware and software.

[0110] Referring to FIG. IB, a functional block diagram of an exemplary embodiment of main electronic unit 104 is shown. Main electronic unit 104 may include direct current (DC)/DC converter 142, and one or more amplifiers 144. DC/DC converter 142 may receive a voltage signal from TRU or vehicle battery 140 and convert the voltage to a voltage range suitable for synthetic jet actuators 170 or 171 (as well as being suitable for amplifier(s) 144). Main electronic unit 104 may also receive control signal 148 from controller 103 indicating an operation frequency, operation phase, and operation voltage amplitude for synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171. In FIG. IB, N number of power signals 150 (where N is an integer greater than or equal to 1) having the frequency, phase, and voltage amplitude indicated by control signal 148 are supplied to synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171. The N number of electrical signals 150 may correspond to N/2 number of synthetic jet actuators for enhanced mixing and N/2 number of synthetic jet actuator for enhanced insulation or may correspond to groups of actuators. Each actuator in the group may receive the same electrical signal. Thus, different electrical signals 150 may be provided to different groups of actuators.

[0111] Control signal 148 from controller 103 may also indicate specific synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 for activation with the corresponding operation parameters. Amplifier(s) 144 may amplify the signal from controller 103 according to the voltage amplitude received in control signal 148 from controller 103. Main electronic unit 104 may send a generated electrical signal 150 with the operation frequency, phase, and voltage amplitude to selected synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171.

[0112] Referring next to FIGS. 2A-2C, perspective view diagrams of an exemplary system 101 located within the refrigerated volume of refrigerated vehicle 200 is shown. In particular, FIG. 2A is a perspective view diagram of refrigerated vehicle 200 with its door 212 to the refrigerated volume closed, showing synthetic jet actuator for enhanced mixing 170 in operation to create an enhanced cooling flow throughout the refrigerated volume. For purposes of illustration, door 212 is not visible so that the inside of the refrigerated volume may be illustrated. FIG. 2B is a cross-section diagram of a FIG. 2A along line A- A. FIG. 2C is a perspective view diagram of the refrigerated volume of refrigerated vehicle 200 with its door 212 open, showing synthetic jet actuator for enhanced insulation 171 in operation. [0113] In FIG. 2A, a plurality of synthetic jet actuators for enhanced mixing 170 are disposed in frames 291. In the exemplary embodiment disclosed in FIG. 2A, frames 291 are mounted on refrigerated volume ceiling 210, side walls 211-1 211-2, floor 213, and along the edge of TRU output 281. A plurality of synthetic jet actuators for enhanced insulation 171 are located along the periphery of the back of the refrigerated volume of refrigerated vehicle 200 proximal to door 212. In the example truck refrigeration unit (TRU) 208 is mounted on vehicle 200, and is connected to the refrigerated volume through output 281 and input 282. TRU 208 pushes cold air inside the refrigerated volume through the output 281 and sucks air from the refrigerated volume via input 282. A plurality of temperature sensors 290 are distributed inside the refrigerated volume of refrigerated vehicle 200.

[0114] In the exemplary embodiment disclosed in FIG. 2A synthetic jet actuators for enhanced insulation 171 are not producing an air jet 172 because door 212 is closed and there is no need to create an air curtain between the outside environment and the refrigerated volume of refrigerated vehicle 200. Synthetic jet actuators for enhanced mixing 170 are illustrated producing a plurality of air jets 172 that influence the basic cooling flow 270 that would exist without the enhancement provided by the synthetic jet actuators for enhanced mixing to produce an enhanced cooling flow 271. As illustrated in FIG. 2 A, the enhanced cooling flow 271 produced by the air jets 172 extends to the back of the refrigerated volume whereas the basic cooling flow 270 does not extend throughout the extent of the refrigerated volume.

[0115] FIG. 2B illustrates in detail the configuration of the items on the end of the refrigerated volume opposite door 212. As shown in FIG. 2B, a plurality of synthetic jet actuators for enhanced mixing 170 are installed on frame 291 around the periphery of TRU output 281, each producing an air jet 172, which affects the basic cooling flow 270 and instead produces an enhanced cooling flow 271. In the exemplary embodiment illustrated by FIG. 2B, controller 103, main electronic unit 104 and user interface 105 are each placed on this same wall of the refrigerated volume. Main electronic unit 104 is connected to the synthetic jet actuators for enhanced mixing 170 through electric circuits 110. Main electronic unit 103 is also connected to multiple synthetic jet actuators for enhanced insulation 171 located around the periphery of door 212 (not shown) through electric circuits 110

(connections not shown).

[0116] FIG. 2C illustrates an exemplary embodiment of refrigerated vehicle 200 with door 212 to the refrigerated volume in the open position. In this embodiment, a plurality of synthetic jet actuators for enhanced insulation 171 are each producing an air jet 172. The totality of air jets 172 generates an air curtain that prevents warm humid airflow 272 located outside of the refrigerated volume from going inside the refrigerated volume. At the same time, the air curtain generated by the totality of air jets 172 prevents cold airflow 273 from exiting the refrigerated volume of the refrigerated vehicle.

[0117] Referring to FIGS. 3A-3C, an exemplary synthetic jet actuator for enhanced mixing 170 or for enhanced insulation 171 is shown. In particular, FIG. 3 A is an exploded perspective view diagram of a synthetic jet actuator; and FIGS. 3B and 3C are perspective view diagrams of the synthetic jet actuator.

[0118] The synthetic jet actuator includes outer frame 302-1, 302-2 enclosing actuator cartridge 318. As shown in FIG. 3C, actuator cartridge 318 may be slidably disposed within outer frame 302, for easy access and interchangeability (such as when a problem is detected with a specific synthetic jet actuator). Actuator cartridge 318 may include electrical connector 316 for receiving electrical signal 150 from main electronic unit 104 (not shown).

[0119] Actuator cartridge 318 includes housing 310 having cavity 312 (formed by side wall 320). The housing 310 and cavity 312 may take any suitable geometric configuration, including the configuration shown in FIG. 3 A. Housing 310 also includes jet orifice 314. Housing 310 may be mechanically coupled to plates 306-1 , 306-2, each having respective piezoelectric discs 308-1 , 308-2. Piezoelectric disc 308-1 , side wall 320 and piezoelectric disc 308-2 may define cavity 312 filled with a fluid (such as air). Cavity 312 may be configured to be in fluid communication with jet orifice 314. Jet orifice 314 may be formed of any suitable geometric shape.

[0120] Each piezoelectric disc 308 may include a piezoelectric material and may be electrically connected to main electronic unit 104 (FIG. IB). Main electronic unit 104 may be configured to apply an excitation voltage to each piezoelectric disc 308-1 , 308-2, to displace each piezoelectric disc. The excitation voltage applied to piezoelectric discs 308-1, 308-2 may be an oscillating signal having an oscillation frequency and an amplitude (selected by controller 103 according to several conditions). Thus, piezoelectric discs 308 may be periodically displaced inwardly and outwardly relative to cavity 312, and force fluid in and out of jet orifice 314 thereby creating an air jet.

[0121] Outer frame 302 may include perforated sheet 304. Perforated sheet 304 may permit movement of piezoelectric disc 308 within outer frame 302, while reducing fluid loading on piezoelectric disc 308 (external to actuator cartridge 318). For example, by allowing piezoelectric disc 308 and outer frame 302 to be in fluid communication with ambient fluid through perforated sheet 304, fluid external to actuator cartridge 318 may be more easily displaced by piezoelectric disc 308 into the ambient environment.

[0122] Although FIGS. 3A-3C illustrate a synthetic jet actuator having two piezoelectric discs 308-1, 308-2, in an alternative embodiment, a synthetic jet actuator for use in connection with the present invention may also be configured with one piezoelectric disc 308. For example, in an embodiment with only one piezoelectric disc 308, only plate 306-1 may include piezoelectric disc 308-1 while plate 306-2 may not include a piezoelectric plate, but, rather, may be a rigid structure. In a one piezoelectric disc embodiment, the excitation voltage applied to piezoelectric disc 308-1 may cause piezoelectric disc 308 to be

periodically displaced, to force fluid in and out of jet orifice 314 thereby creating an air jet.

[0123] Referring to FIGS. 4A and 4B, cross-section diagrams of actuator cartridge 318 along line B-B are shown, illustrating operation of actuator cartridge 318 (to form air jet 402). FIG. 4A depicts actuator cartridge 318 as piezoelectric discs 308-1, 308-2 are controlled by electrical signal 150 to move inward into cavity 312, as depicted by arrows 410. Cavity 312 has its volume decreased and fluid is ejected through the jet orifice 314. As the fluid exits cavity 312 throughjet orifice 314, the flow separates at the edges of jet orifice 314 and creates vortex sheets 404 which roll into vortices 406 and begin to move away from jet orifice 314, to form air jet 402.

[0124] FIG. 4B depicts actuator cartridge 318 as piezoelectric discs 308-1, 308-2 are controlled (by electrical signal 150) to move outward with respect to cavity 312, as depicted by arrow 412. Cavity 312 has its volume increased and ambient fluid 400 rushes into cavity 312. When piezoelectric discs 308-1, 308-2 move away from cavity 312, vortices 406 are already removed from the jet orifice edge and thus are not affected by ambient fluid 400 being drawn into cavity 312. In addition, a jet of ambient fluid 402' is synthesized by vortices 406 creating strong entrainment of ambient fluid 400 drawn from large distances away fromjet orifice 314. Air jet 402 produced in the previous phase will continue to move in its original direction, undisturbed by the entrainment of ambient fluid 400.

[0125] Referring generally to FIGS. 3A-3C and FIGS. 4A and 4B, synthetic jet actuator for enhanced mixing 170 and synthetic jet actuator for enhanced insulation 171 may actively use the moving air (ambient air 400) around the vehicle body to generate a controlled pulsating flow of air (air jet 402). Air jet 402 may be used to manipulate the boundary layer around the synthetic jet actuator. Synthetic jet actuator for enhanced mixing 170 and synthetic jet actuator for enhanced insulation 171 operate under electrical signals from power signal 150, using ambient air 400 to generate the pulsating flow of air (by unsteady suction and blow of the air via cavity 312).

[0126] In synthetic jet actuator for enhanced mixing 170 and synthetic jet actuator for enhanced insulation 171 , an isolated air jet is produced by the interactions of a train of vortices 406 that are typically formed by alternating momentary ejection and suction of fluid across jet orifice 314, such that the net mass flux is zero. Because air jet 402 is formed entirely from the working fluid 400, synthetic jet actuator for enhanced mixing 170 and synthetic jet actuator for enhanced insulation 171 can transfer linear momentum to the flow system without net mass injection across the flow boundary.

[0127] Synthetic jet actuator for enhanced mixing 170 and synthetic jet actuator for enhanced insulation 171 may produce air jet 402 over a broad range of length and time scales. For example, a length scale may be between about 6 mm by 1 mm to about 100 mm by 5 mm (for a rectangular jet orifice 314) and between about 1 mm diameter to about 20 mm diameter (for a circular jet orifice 314). The time scale may be, for example, from about 1/2000 second to about 1/10 second.

[0128] Referring to FIG. 5 (and FIG. 1 A), a flow chart is shown for an exemplary embodiment of a method based on synthetic jet actuators for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles. At step 500, components of system 101 are initialized. For example, controller 103 may initiate collection of sensor data from sensor unit 102, may initiate main electronic unit 104 and/or may send an indication to user interface 105 that system 101 is in operation. Furthermore controller 103 may establish preliminary connection with TRU control 108 and wireless connection with refrigerated vehicle delivery database 109 and fleet logistics platform 178. [0129] At step 502, controller 103 performs diagnostic control of components of system 101, to identify any problems that may require maintenance. At step 504, it is determined whether maintenance is necessary (based on step 502).

[0130] When it is determined at step 504 that maintenance is required, step 504 goes to step 506. At step 506, a maintenance indication is presented to the user, for example, via user interface 105. Although, in step 506, a maintenance indication is presented, the system 101 may continue to operate depending on the maintenance required. Accordingly, in some scenarios, step 506 may proceed to step 508. According to other scenarios, step 506 may also include terminating operation of system 101. Examples of diagnostic control (step 502) are described further below with respect to FIG. 6.

[0131] When it is determined, at step 504, that maintenance is unnecessary, step 504 proceeds to step 508. At step 508, it is determined whether the refrigerated vehicle door 212 (FIG. 2A) is open or closed based on input to sensor unit 102 from door sensors 123. An indication may be stored (for example, in storage 105) if it is determined that the door is open. When it is determined at step 508 that the door is open, step 508 goes to step 510. At step 510 the controller 103 performs the heat insulation control to create an air curtain with air jets at open door 212. Examples of heat insulation control (step 510) are described in FIG. 7. So long as door 212 (FIG. 2A) remains open, controller 103 will keep performing heat insulation control (step 510) in a loop.

[0132] When it is determined, at step 508, that the vehicle door 212 (FIG. 2A) is closed, step 508 proceeds to step 512. At step 512 it is determined whether the temperature distribution inside the vehicle is optimal. Controller 103 will determine the temperature distribution by gathering temperature data from sensor unit 102. An indication might be stored (for example, in storage 105) if it is determined that the temperature distribution is not optimal. When it is determined at step 512 that the temperature distribution is not optimal, step 512 goes to step 514. At step 514 the controller 103 performs the improved mixing control. Examples of improved mixing control (step 514) are described in FIG. 8. Until the temperature distribution is not optimal, the controller 103 will keep performing improved mixing control (step 514) in a loop.

[0133] When it is determined, at step 512 that the temperature distribution is optimal, step 512 goes to step 502, which starts again the cycle by performing a diagnostic control. In an alternative embodiment of the method, controller 103 will also perform air mixing control when the vehicle door 212 is open and the controller 103 is performing heat insulation control.

[0134] Referring to FIG. 6 and FIG. 1 A a flow chart is shown of an exemplary method of performing diagnostic control (step 502). At step 600, connected synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 (FIG. 2A) are detected, for example, by one or more current detectors (an example of diagnostic sensor 122) electrically coupled to synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171 via an electrical conduit. At step 602, it is determined, for example, by controller 103, whether the current absorbed is within predetermined current limits, based on the value of the current detector(s). For example, for a power of about 10 W to about 20 W per piezoelectric disk 308 and a voltage amplitude of about 200 V, the typical absorbed current should be between 0.05A and 0.1 A.

[0135] When it is determined, at step 602, that the absorbed current is outside of the predetermined current limits, step 602 proceeds to step 604. At step 604, controller 103 performs a short-circuit analysis of the electrical circuit (of synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhanced insulation 171) based on the sensor data from the current detector(s). At step 606, a location of a short-circuit in the electrical circuit is determined by controller 103, based on the analysis in step 604. At step 608, a maintenance indication is prompted by controller 103. The maintenance indication may also be stored in storage 106. The stored maintenance indication may include information regarding the short-circuit condition, including the identified location of the short-circuit. The maintenance indication may also be provided to the user through the user interface 105.

[0136] At step 610, responsive to the short-circuit condition, controller 103 may terminate operation of system 101.

[0137] When it is determined, at step 602, that the absorbed current is within the predetermined current limits, step 602 proceeds to step 612. At step 612, it is determined whether current absorption profiles of syntheticjet actuators for enhanced mixing 170 and syntheticjet actuators for enhanced insulation 171 are within predetermined tolerances. For example, controller 103 may monitor the absorption profile of synthetic jet actuators for enhanced mixing 170 and synthetic jet actuators for enhance insulation 171 (such as an amplitude of the profile) via one or more current detectors (an example of diagnostic sensor 122) coupled to syntheticjet actuators for enhanced mixing 170 and syntheticjet actuators for enhanced insulation 171.

[0138] When it is determined, at step 612, that the absorption profiles are outside of the predetermined tolerances, step 612 proceeds to step 614. At step 614, one synthetic jet actuator for enhanced mixing 170 or a syntheticjet actuator for enhanced insulation 171 is identified, by controller 103, as having a clogged jet orifice 314 (FIG. 5 A). At step 616, controller performs a jet de-clogging cycle for the identified synthetic jet actuator for enhanced mixing 170 or synthetic jet actuator for enhanced insulation 171 (in step 614). For example, controller 103 may cause main electronic unit 104 to operate the identified actuator according to a predetermined operation frequency, phase, and/or voltage amplitude, in an attempt to de-clog the jet orifice. Step 616 proceeds to step 612. [0139] When it is determined, at step 612, that the absorption profiles are within the predetermined tolerances, step 612 proceeds to step 618. At step 618, it is determined whether strain gauge signals of one or more synthetic jet actuator for enhanced mixing 170 or synthetic jet actuator for enhanced insulation 171 are within predetermined tolerances. For example, controller 103 may monitor strain gauge signals of strain gauges (examples of diagnostic sensor 122) mounted on piezoelectric discs 308 FIG. 5A) of synthetic jet actuator for enhanced mixing 170 or synthetic jet actuators for enhanced insulation 171. For example, when a piezoelectric disc 308 is operating normally, the strain gauge signal may exhibit a sinusoidal shape. If piezoelectric disc 308 is cracked or broken, the strain gauge signal may still be somewhat sinusoidal with a reduced amplitude or the signal may be a flat line.

[0140] When it is determined, at step 618, that the strain gauge signals are within the predetermined tolerances, step 618 proceeds to step 504.

[0141] When it is determined, at step 618, that the strain gauge signals are outside of the predetermined tolerances, step 618 proceeds to step 620. At step 620, controller 103 determines that a piezoelectric disc 308 is broken. At step 622, controller 103 stores an indication, such as in storage 106, that the identified actuator cartridge 318 should be replaced. At step 624, controller 103 regulates operation of the remaining functional actuators to compensate for the broken actuator. Step 624 proceeds to step 504.

[0142] Referring to FIG. 7, and FIG. 1 A a flow chart is shown of an exemplary method for performing heat insulation control by using synthetic jet actuators for enhanced insulation 171 (FIG. 2A) (step 510). At step 710 controller 103 determines the temperature distribution inside the refrigerated vehicle through sensor unit 102. The information on temperature distribution can be stored in storage 106. At step 712 the controller 103 connects with TRU control 108 and analyzes the TRU operations. The TRU operations data can be stored in storage 106. In step 716 controller 103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 150 (FIG. 2 A)) to be applied to synthetic jet actuators for enhanced heat insulation 171 based on the information regarding the door status, the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 718 such operating parameters are applied to the synthetic j et actuators for enhanced heat insulation 171 to generate an air curtain. In step 720 the controller 103 determines whether door 212 is still open or whether it is closed. If the door is determined to be open, step 720 goes to step 710 and a new cycle of heat insulation control is performed. If the door is determined to be closed, step 720 goes to step 512 (FIG. 8).

[0143] In general, the operation frequency, phase, and amplitude for the oscillating voltage signal may be determined according to one or more predetermined relationships between temperature distribution, door status, TRU operations, and output air jet characteristics. The predetermined relationship may be based on physical characteristics of synthetic jet actuator for enhanced heat insulation 171 (such as a size and/or shape of cavity 312, material properties of piezoelectric disc 308 as well as the properties of the fluid itself). In an exemplary embodiment, the operation frequency and amplitude may be determined from a look up table according to the temperature and/or the relative humidity. In another exemplary embodiment, controller 103 may use a mathematical model that may correlate the optimal frequency and amplitude with temperature and/or relative humidity data received from sensor unit(s) 102. In general, there is an empirical relationship between

temperature/humidity and frequency/amplitude. The relationship may be a function of the piezoelectric disc material and the diameter of the piezoelectric disc 308.

[0144] Referring to FIG. 8, and FIG. 1 A a flow chart is shown of an exemplary method for performing improved mixing control by using synthetic jet actuators for enhanced mixing 170 (FIG. 1A) (step 514). In step 800 controller 103 detects the temperature distribution inside the refrigerated volume of refrigerated vehicle 200 by detecting temperature data from at least two temperature sensor(s) 120 of sensor unit(s) 102. Step 801 determines whether the temperature distribution is optimal or not. If the temperature distribution is optimal, step 801 goes to step 502 (FIG. 5). If the temperature distribution is not optimal, step 801 goes to step 802. In step 802 the controller 103 detects the TRU operations by connecting to the TRU control 108. In step 803 the controller 103 connects to a refrigerated vehicle delivery database 109 and determines the closest next delivery. Step 804 determines whether door 212 (FIG. 2A) of the vehicle is going to open within a certain time interval. Since it is inefficient to perform air mixing control when the door is open, in a preferred embodiment only heat insulation control is performed when the door is open. Thus, if the door is going to open in a time interval below a reference value, step 804 goes to step 510 to perform heat insulation control. If the door is going to open in a time interval above a reference value, step 804 goes to step 805. In step 805 the controller 103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 150 (FIG. 2A)) to be applied to synthetic jet actuators for enhanced mixing 170 (FIG. 2A) based on the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 806 such operating parameters are applied to the synthetic jet actuators for enhanced mixing 170 and generate multiple air jet that will increase the air mixing and enhance the air distribution inside the refrigerated volume of the refrigerated vehicle. Step 806 goes to step 800 to detect the temperature distribution and a new cycle of the control starts. The air mixing control cycle will be looped until an optimal temperature distribution inside the vehicle is achieved. In an alternative embodiment (not shown) door status is not taken into account when performing air mixing control, and instead air mixing continues whether the door is open or closed.

[0145] Initially referring to FIG. 9A compressed air actuators system 90101 is shown located within the refrigerated volume of refrigerated vehicle 100. One of ordinary skill in the art will appreciate that refrigerated vehicle 100 may comprise any of the following:

refrigerated truck box, refrigerated trailer, refrigerated intermodal container, or any other type of structure with a volume for refrigeration. Refrigeration of the refrigerated volume of refrigerated vehicle 100 can be achieved with ice, utilizing a cooling agent such as, without being limited to, carbon dioxide, or with the use of a mechanical refrigeration system, referred to as truck refrigeration unit (TRU) 12, as shown in the exemplary embodiment of FIG. 9A.

[0146] in an exemplar)_'- embodiment, system 90101 comprises sensor unit 90102, controller 90103, compressor 90104, one compressed air actuator for enhanced mixing 90170, one compressed air actuator for enhanced insulation 90171 , data storage unit 90106, one manifold 90107, and user interface 90105. A least one compressed air actuator for enhanced mixing 90170 is used to improve air circulation and mixing inside the refrigerated volume of refrigerated vehicle 100. At least one compressed air actuator for enhanced insulation 90171 is used to generate an air curtain proximal to the door of th e refri gerated volume of refrigerated vehicle 100 to minimize the flow of air to and from the refrigerated volume when the door is open to enhance the heat insulation of the refrigerated vehicle and keep the refrigerated air within the refrigerated volume.

[0147] Both compressed air actuators 90170 and 90171 are operated by controller 90103 which receives sensor data from sensor unit 90102, TRU operations data from TRU control 108, and delivery data from external delivery database 109, in order to perform air mixing control 90130, diagnostic control 90131, or heat insulation control 90132. in an exemplary embodiment of the present invention, controller 90103 wirelessly connects with fleet logistics platform 178 to exchange operating information. The controller can also interface with user interface 90105 and store data on a storage 90106. [0148] In an exemplary embodiment of the present invention, sensor unit 90102 comprises one or more temperature sensors 90120, one or more humidity sensors 90121 ,one or more pressure sensors 90124, one or more diagnostic sensors 90122, and one or more door sensors 90123.

[0149] Temperature sensor(s) 90120 and humidity sensor(s) 9012! collect sensor data inside the refrigerated volume of refrigerated vehicle 100. More than one temperature sensor 90120 and/or humidity sensor 90121 may be positioned on vehicle 100. In embodiments where a plurality of temperature sensors 90120 are utilized, they will be uniformly positioned on the refrigerated volume to capture temperature distribution inside the refrigerated vehicle 100. Temperature sensors 90120 may consist of contact temperature sensors such as thermocouples, resistive temperature detectors, thermistors, or bi-metallic thermostats.

Humidity sensors 90121 (also called hygrometers) may consist of capacitive hygrometers, resistive hygrometers, thermal hygrometers, or gravimetric hygrometers.

[0150] Diagnostic sensor(s) 90122 are used to identify electrical problems (such as short circuits) and/or mechanical problems with compressed air actuators 90170 or 90171 , Diagnostic sensors 90122 may consist of any commercially available type of current detectors such as hall effect sensors, current clamp meters, resistors and/or strain gauges or any other type of commercially available sensor to detect the absorbed power such as wattmeter. Identified electrical and/or mechanical problems of actuators may be

communicated to the user via user interface 90105. User interface 90105 may comprise a screen, LEDs, or other visual means to communicate information to the user, as well as buttons that the user can utilize to check the status of the different components of system 90101. In some scenarios, the identified problems may cause system 90101 to cease operation. In other scenarios, the identified problems may be automatically corrected (or at least an automatic attempt to correct the problems may he made) during operation of system 90101.

[0151] Door sensor(s) 90123 detect whether the door to the refrigerated volume of refrigerated vehicle 100 is closed or open. One of ordinary skill in the art will appreciate that numerous types of sensors including force sensors or proximity sensors can be used as door sensor(s) 90123.

[0152] Pressure sensor(s) 90124 detect the pressure existing inside the manifold 90107. More than one pressure sensor 90124 may be positioned inside manifold 90107. In embodiments where a plurality of pressure sensors 90124 are utilized, they will be uniformly positioned inside the manifold to capture pressure distribution. Pressure sensor(s) 90124 may consist of pi ezoresi stive strain gauge pressure sensor, capacitive pressure sensor, electromagnetic pressure sensor, piezoelectric pressure sensor, potentiometric pressure sensors, or optical pressure sensors.

[0153] in an exemplary embodiment of the present invention, controller 90103 may be configured to control operation of one or more sensor unit 90102, compressor 90104, compressed air actuator for enhanced mixing 90170, compressed air actuator for enhanced insulation 90171, storage 90106, and user interface 90105. Controller 90103 may include, for example, a logic circuit, a digital signal processor, a microcontroller or a microprocessor.

[0154] In an exemplary embodiment of the present invention, controller 90103 may be configured to perform air mixing control 90130, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the compressed air actuators 90170 and 90171, based on the variables related to refrigerated vehicle 100. To determine the variables, controller 90103 may use the sensor data received from temperature sensors 90120, as well as sensor data from humidity sensor 90121, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery. To perform air mixing control 90130 compressed air actuators for enhanced mixing 90170 will be utilized.

[0155] In an exemplary embodiment of the present invention, air mixing control 90130 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, and when the planned delivery is at a certain known point in time. To identify the temperature distribution, controller 90103 may use the sensor data received from temperature sensor 90120. To identify the TRU operating parameters, the controller 90103 may interface with the TRU control 108. To identify the planned deliveries, the controller 90103 may interface with the refrigerated vehicle delivery database 109. A description of air mixing control 90130 is provided further below with respect to FIG. 14.

[0156] In an exemplary embodiment of the present invention, controller 90103 may also be configured to perform diagnostic control 90131, to determine whether components of system 90101 are operating under normal conditions. For diagnostic control 90131 , controller 90103 compares sensor data received from diagnostic sensors 90122 to predetermine conditions, to identify electrical and/or mechanical problems with components of system 90101 or to confirm that system 90101 is operating under normal conditions. Depending upon the operating conditions, controller 90103 may provide an indication of a normal or faulty condition to user interface 90105. Diagnostic control 90131 is described further below with respect to FIG. 12.

[0157] In an exemplary embodiment of the present invention, controller 90103 may be configured to perform heat insulation control 90132, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the compressed air actuators 90170 and 90171, based on the variables related to refrigerated vehicle 100. To determine the variables, controller 90103 may use the sensor data received from temperature sensors 90120, as well as sensor data from humidity sensor 90121, sensor data from door sensor 90123, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery. To perform heat insulation control 90132 compressed air actuators for enhanced insulation 90171 will be utilized.

[0158] Heat insulation control 90132 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, when the planned delivery is at a certain known point in time, and when the door is open. To identify the temperature distribution, controller 90103 may use the sensor data received from at least two temperature sensors 90120. To identify the TRU operating parameters, controller 90103 may interface with the TRU control 108. To identify the planned deliveries, controller 90103 may interface with refrigerated vehicle delivery database 109. To identify the status of the door (Closed or Open) controller 90103 may interface with door sensor(s) 90123. A description of heat insulation control 90132 is provided further below with respect to FIG. 13.

[0159] In an exemplary embodiment of the present invention, controller 90103 may be configured to perform compressor control 90133, to control the pressure inside the manifold

90107, based on the pressure detected through the pressure sensor 90124. The compressor can be turned on or off according to a predetermined relationship between the pressure detected through the pressure sensors 90124 and an optimal value of pressure established depending on the configuration of system 90101. [0160] in an exemplary embodiment of the present invention control 90103 may be configured to perforin compressor control 90133, to control the operations of the compressor 90104 (turning it on or off) to regulate the pressure inside the manifold 90107 with respect to a reference optimal pressure. To identify the pressure inside the manifold 90107, controller 90103 may use the sensor data received from pressure sensor(s) 90123. A description of compressor control 90133 is provided further below with respect to FIG. 15.

[0161] In an exemplary embodiment of the present invention, user interface 90105 may include any suitable interface to provide visual and/or audio indication of a normal or faulty operating condition, such as a blinking red LED might signal the presence of a short-circuit, or a blinking yellow LED might signal the presence of a leak in the manifold 90107. User interface 90105 may be provided inside the refrigerated volume of refrigerated vehicle 100, or outside the refrigerated volume for the convenience of the user. In an alternative exemplary embodiment of the present invention, user interface 90105 may be provided on controller 90103. For example, user interface 90105 may be an external unit mounted on a component of system 90101 or may be formed as part of a component of system 90101. Responsive to the indication on user interface 90105, the user may operate refrigerated vehicle 100 or may have system 90101 inspected for maintenance issues.

[0162] System 90101 may include storage 90106. Storage 90106 may include, for example, a random access memory (RAM), a magnetic disk, an optical disc, flash memory or a hard drive. Storage 90106 may store one or more values for sensor unit 90102, controller 90103, compressed air actuators for enhanced mixing 90170, compressed air actuators for enhanced insulation 90171, delivery data from delivery database 109, TRU operations from TRU control 108, and/or user interface 90105.

[0163] Compressor 90104 may be configured to receive compressor control signals from controller 90103 to activate or deactivate. Compressor 90104 is connected to a manifold 90107 and is regulated by controller 90103 to maintain manifold 90107 pressure at a predetermined value through a compressor control 90133 algorithm.

[0164] Manifold 90107 is configured to store compressed air, and connect the compressor 90104 to the at least one compressed air actuator for enhanced mixing 90170 and to the at least one compressed air actuator for enhanced heat insulation 90171. Hie pressure inside manifold 90107 is detected by the at least one pressure sensor 90124 that is mounted inside the manifold 90107.

[0165] Each compressed air actuator for enhanced mixing 90170 and each compressed air actuator for enhanced insulation 90171 may be configured to receive an electrical signal (having an operation frequency, phase, and an operation voltage amplitude) from controller 90103 and may produce an air jet. The air jets produced by compressed air actuators for enhanced mixing 90170 may be used to control the air mixing and distribution inside the refrigerated vehicle 100. The air jets produced by compressed air actuators for enhanced insulation 90171 may be used to create an air curtain and limit the airflow to and from the refrigerated vehicle 100, ultimately reducing the heat exchange between the refrigerated volume and the outside environment. Compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 may be mounted directly to vehicle 100 or may be mounted to vehicle 100 via a mounting frame, such as mounting frame 10291 shown in FIG. 10A. In another embodiment (not shown) compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 may be formed integral with the vehicle.

[0166] Compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 are each made of a flow electro-valve 90111 and of a nozzle 90112 as shown in FIG. 9B. Compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 are constructed in the same way, the only difference being the purpose of the air jet that each generates. Specifically, compressed air actuators for enhanced mixing 90170 produce an air jet that is utilized to enhance the air mixing and distribution inside the refrigerated vehicle 100, while compressed air actuators for enhanced insulation 90171 produce an air jet that is utilized to enhanced the insulation between the refrigerated volume and the outside environment by creating an air curtain at the door level that limits the airflow to and from the refrigerated volume.

[0167] One of ordinary skill in the art would recognize that that components of one or more of sensor unit 90102, controller 90103, compressed air actuator for enhanced mixing 90170, compressed air actuator for enhanced heat insulation 90171 , user interface 90105, compressor 90104, and storage 90106 may be implemented in hardware, software or a combination of hardware and software.

[0168] Referring to FIG. 9B, a functional block diagram of an exemplary embodiment of compressed air actuator for enhanced mixing 90170 and compressed air actuator for enhanced heat insulation 90171 is shown. Actuators 90170 or 90171 include at least one flow electro-valve 90111 and at least one nozzle 90112. Flow electro-valve 90111 may receive control signal 90148 from controller 90103 indicating an operation frequency, operation phase, and operation voltage amplitude for opening and/or closing its connection between the manifold 90104 and the nozzle 90112. The manifold 90104 is connected to the flow electro-valve 90111 through a pressurized line 90114, while the flow electro-valve 90111 is connected to the nozzle 90112 through a regulated pressure line 90113. In FIG. 9B, N number of signals 90148 (where N is an integer greater than or equal to 1) having the frequency, phase, and voltage amplitude indicated by controller 90103 are supplied to compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171. Each actuator in the group may receive the same electrical signal. Thus, different electrical signals 90148 may be provided to different groups of actuators.

[0169] The control signal 90148 from controller 90103 may also indicate specific compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90 S 71 for activation with the corresponding operation parameters.

[0170] Referring next to FIGS. 1 OA- IOC, perspective view diagrams of an exemplary system 90101 located within the refrigerated volume of refrigerated vehicle 200 is shown. In particular, FIG. 10A is a perspective view diagram of refrigerated vehicle 200 with its door 100212 to the refrigerated volume closed, showing compressed air actuator for enhanced mixing 90170 in operation to create an enhanced cooling flow throughout the refrigerated volume. FIG. 10B is a cross-section diagram of a FIG. 10A along line C-C (FIG. 10A). FIG. IOC is a perspective view diagram of refrigerated vehicle 200 with its door 100212 closed, showing compressed air actuator for enhanced insulation 90171 in operation.

[0171] In FIG. 10A a plurality of compressed air actuators for enhanced mixing 90170 are disposed in a frame 100291. In the exemplary embodiment disclosed in FIG. 10A, frames 100291 are mounted on refrigerated volume ceiling 100210, side walls 100211-1 100211-2, floor 100213, and along the edge of TRU output 281. A plurality of compressed air actuators for enhanced insulation 90171 are located along the periphery of the back of the refrigerated volume of refrigerated vehicle 200 proximal to door 100212. Truck refrigeration unit (TRU) 208 is mounted on the refrigerated vehicle 200, and is connected to the refrigerated volume through an output 281 and an input 282. The TRU 208 pushes cold air inside the refrigerated volume through the output 281 and sucks air from its input 282. A plurality of temperature sensors 100290 are distributed inside the refrigerated volume of the refrigerated vehicle 200. Compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced heat insulation 90171 are connected to a manifold 100107, which is connected to compressor 100104.

[0172] In the exemplary embodiment disclosed in FIG. 10A compressed air actuators for enhanced insulation 90171 are not producing an air jet 100172 because the door 100212 is closed and there is no need to create an air curtain between the outside environment and the refrigerated volume of the refrigerated vehicle 200. Compressed air actuators for enhanced mixing are illustrated producing a plurality of air jets 100172 that influence the basic cooling flow 100270 that would exist without the enhancement provided by the compressed air actuators for enhanced mixing to produce an enhanced cooling flow 100271. As illustrated in FIG. 10A, the enhanced cooling flow 100271 produced by the air jets 100172 extends to the back of the refrigerated volume whereas the basic cooling flow 100270 does not extend throughout the extent of the refrigerated volume.

[0173] FIG. 10B illustrates in detail the configuration of the items on the end of the refrigerated volume opposite door 100212. As shown in FIG. 10B, a plurality of compressed air actuators for enhanced mixing 90170 are installed on a framel00291 around the periphery of TRU output 281, each producing air jet 100172, which affects the basic cooling flow 100270 and instead produces an enhanced cooling flow 100271. In the exemplary embodiment illustrated by FIG. 2B, controller 90103, manifold 100107, compressor 100104, and user interface 100105 can be placed on the same wall of the refrigerated volume.

Manifold 100107 is also connected to the multiple compressed air actuators for enhanced insulation 90171 located around the periphery of the door 100212 (not shown) through electric circuits (connections not shown).

[0174] FIG. IOC illustrates an exemplary embodiment of refrigerated vehicle 200 with door 100212 to the refrigerated volume in the open position. In this embodiment a plurality of compressed air actuators for enhanced insulation 90171 are each producing air jet 100172. The totality of air jet 100172 generates an air curtain that prevents warm humid airflow 100272 located outside of the refrigerated volume from going inside the refrigerated volume. At the same time, the air curtain generated by the totality of air jets 100172 prevents cold airflow 100273 from exiting the refrigerated volume of the refrigerated vehicle. Compressor 100104 and manifold 100107 connected to the compressed air actuator for enhanced insulation 90171 are also represented.

[0175] Referring to FIG. 1 1 (and FIG. 9A), a flow chart is shown for an exemplary embodiment of a method based on compressed air actuators for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles. At step 1 1500, components of the system 90101 are initialized. For example, controller 90103 may initiate collection of sensor data from sensor unit 90102, may initiate compressed air actuator 90170 or 90171 and/or may send an indication to user interface 90105 that system 90101 is in operation. Furthermore controller 90103 may establish preliminary connection with TRU control 108 and wireless connection with refrigerated vehicle delivery database 109 and fleet logistics platform 178.

[0176] At step 1 1502, controller 90103 may perform diagnostic control of components of system 90101, to identify any problems that may require maintenance. At step 1 1504, it is determined whether maintenance is necessary (based on step 11502).

[0177] When it is determined at step 11504 that maintenance is required, step 1 1504 goes to step 11506. At step 1 1506, a maintenance indication is presented to the user, for example, via user interface 90105. Although, in step 1 1506, a maintenance indication is presented, the system 90101 may continue to operate depending on the maintenance required. Accordingly, in some scenarios, step 1 1506 may proceed to step 1 1508. According to other scenarios, step 11506 may also include terminating operation of system 90101. Examples of diagnostic control (step 11502) are described further below with respect to FIG. 12.

[0178] When it is determined, at step 11504, that maintenance is unnecessary, step 11504 proceeds to step 11508. At step 11508, it is determined whether the refrigerated vehicle door 100212 (FIG. 10A) is open or closed. An indication may be stored (for example, in storage 90105) if it is determined that the door is open. When it is determined at step 11508 that the door is open, step 11508 goes to step 11510. At step 11510 the controller 90103 performs the heat insulation control. Examples of heat insulation control (step 11510) are described in FIG. 13. So long as door 100212 (FIG. 10A) remains open, controller 90103 will keep performing heat insulation control (step 11510) in a loop.

[0179] When it is determined, at step 11508, that the vehicle door 100212 (FIG. 10A) is closed, step 11508 proceeds to step 11512. At step 11512 it is determined whether the temperature distribution inside the vehicle is optimal. Controller 90103 will determine the temperature distribution by gathering temperature data from the sensor unit 90102. An indication might be stored (for example, in storage 90105) if it is determined that the temperature distribution is not optimal. When it is determined at step 11512 that the temperature distribution is not optimal, step 11512 goes to step 11514. At step 11514 the controller 90103 performs the improved mixing control. Examples of improved mixing control (step 11514) are described in FIG. 14. Until the temperature distribution is not optimal, the controller 90103 will keep performing improved mixing control (step 11514) in a loop.

[0180] When it is determined, at step 11512 that the temperature distribution is optimal, step 11512 goes to step 11502, which starts again the cycle by performing a diagnostic control. In an alternative embodiment of the method, controller 90103 will also perform air mixing control when the vehicle door 100212 is open and the controller 90103 is performing heat insulation control.

[0181] Referring to FIG. 12 and FIG. 9 A a flow chart is shown of an exemplary method of performing diagnostic control (step 11502). At step 12600, connected compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 (FIG. 9A) are detected, for example, by one or more current detectors (an example of diagnostic sensor 90122) electrically coupled to compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 via an electrical circuit. At step 12602, it is determined, for example, by controller 90103, whether the current absorbed is within predetermined current limits, based on the value of the current detector(s).

[0182] When it is determined, at step 12602, that the absorbed current is outside of the predetermined current limits, step 12602 proceeds to step 12604. At step 12604, controller 90103 performs a short-circuit analysis of the electrical circuit (of compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171) based on the sensor data from the current detector(s). At step 12606, a location of a short- circuit in the electrical circuit is determined by controller 90103, based on the analysis in step 12604. At step 12608, a maintenance indication is prompted, by controller 90103. The maintenance indication may also be stored in storage 90106. The stored maintenance indication may include information regarding the short-circuit condition, including the identified location of the short-circuit. The maintenance indication may also be provided to the user through the user interface 90105.

[0183] At step 12610, responsive to the short-circuit condition, controller 90103 may terminate operation of system 90101.

[0184] When it is determined, at step 12602, that the absorbed current is within the predetermined current limits, step 12602 proceeds to step 12612. At step 12612, it is determined whether current absorption profiles of compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 are within predetermined tolerances. For example, controller 90103 may monitor the absorption profile of compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171 (such as an amplitude of the profile) via one or more current detectors (an example of diagnostic sensor 90122) coupled to electro-valve 90111 of compressed air actuators for enhanced mixing 90170 and compressed air actuators for enhanced insulation 90171.

[0185] When it is determined, at step 12612, that the absorption profiles are outside of the predetermined tolerances, step 12612 proceeds to step 12614. At step 12614, one compressed air actuator for enhanced mixing 90170 or a compressed air actuator for enhanced insulation 90171 is identified, by controller 90103, as having a clogged nozzle 90112 (FIG. 9B). At step 12616, controller performs a jet de-clogging cycle for the identified compressed air actuator for enhanced mixing 90170 or compressed air actuator for enhanced insulation 90171 (in step 12614). For example, controller 90103 may cause the identified actuators to operate according to a predetermined operation frequency, phase, and/or voltage amplitude, in an attempt to de-clog the nozzle 90112. Step 12616 proceeds to step 12612.

[0186] When it is determined, at step 12612, that the absorption profiles are within the predetermined tolerances, step 12612 proceeds to step 12618. At step 12618, it is determined whether the pressure inside the manifold 90107 is constant and within predetermined values while compressed air actuators 90170 or 90171 are not operating. For example, controller 90103 may detect pressure from pressure sensor(s) in manifold 90107 and compare it with predetermined optimal values of pressure.

[0187] When it is determined, at step 12618, that the pressure inside manifold 90107 is constant and within predetermined limits, step 12618 proceeds to step 11504. [0188] When it is determined, at step 12618, that the pressure inside manifold 90107 is not constant or lower than the predetermined limits, step 12618 proceeds to step 12620. At step 12620, controller 90103 determines that a there is a leak in the pressurized line. At step 12622, controller 90103 stores an indication, such as in storage 90106, that the system 90101 has a leak in one of the pressurized lines and stops operations of system 90101.

[0189] Referring to FIG. 13, and FIG. 9A a flow chart is shown of an exemplary method for performing heat insulation control by using compressed air actuators for enhanced insulation 90171 (FIG. 10A). At step 13710 controller 90103 determines the temperature distribution inside the refrigerated vehicle through sensor unit 90102. The information on temperature distribution can be stored in storage 90106. At step 13712 controller 90103 connects with e TRU control 108 and analyzes TRU operations. The TRU operations data can be stored in the storage 90106. In step 13716 controller 90103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 90148 (FIG. 10B)) to be applied to compressed air actuators for enhanced heat insulation 90171 based on the information regarding the door status, the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 13718 such operating parameters are applied to the compressed air actuators for enhanced heat insulation 90171 to generate an air curtain. In step 13720 the controller 90103 determines whether the door 100212 is still open or whether it is closed. If the door is determined to be open, step 13720 goes to step 13710 and a new cycle of heat insulation control is performed. If the door is determined to be closed, step 13720 goes to step 11512 (FIG. 11).

[0190] In general, the operation frequency, phase, and amplitude for the oscillating voltage signal may be determined according to one or more predetermined relationships between temperature distribution, door status, TRU operations, and output air jet characteristics. The predetermined relationship may be based on physical characteristics of compressed air actuator for enhanced heat insulation 90171 (such as a size and/or shape of nozzle 90112 (FIG. 9B) as well as the properties of the fluid itself). In an exemplary embodiment, the operation frequency and amplitude may be determined from a look up table according to the temperature and/or the relative humidity. In another exemplary

embodiment, controller 90103 may use a mathematical model that may correlate the optimal frequency and amplitude with temperature and/or relative humidity data received from sensor unit(s) 90102. In general, there is an empirical relationship between temperature/humidity and frequency/amplitude.

[0191] Referring to FIG. 14, and FIG. 9A a flow chart is shown of an exemplary method for performing improved mixing control by using compressed air actuators for enhanced mixing 90170. In step 14800 controller 90103 detects the temperature distribution inside the refrigerated volume of refrigerated vehicle 200 by detecting temperature data from the temperature sensor(s) 90120 of sensor unit(s) 90102. Step 14801 determines whether the temperature distribution is optimal or not. If the temperature distribution is optimal, step 14801 goes to step 11502 (FIG. 11). If the temperature distribution is not optimal, step 14801 goes to step 14802. In step 14802 the controller 90103 detects TRU operations by connecting to TRU control 108. In step 14803 controller 90103 connects to a refrigerated vehicle delivery database 109 and determines the closest next delivery. Step 14804 determines whether the door 100212 (FIG. 10A) of the vehicle is going to open within a certain time interval. Since it is inefficient to perform air mixing control when the door is open, in a preferred embodiment only heat insulation control is performed when the door is open. Thus, if the door is going to open in a time interval below a reference value, step 14804 goes to step 11510 (FIG. 11) to perform heat insulation control. If the door is going to open in a time interval above a reference value, step 14804 goes to step 14805. In step 14805 the controller 90103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 90148 (FIG. 9B)) to be applied to compressed air actuators for enhanced mixing 90170 (FIG. 1A) based on the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 14806 such operating parameters are applied to the compressed air actuators for enhanced mixing 90170 and generate multiple air jets that will increase the air mixing and enhance the air distribution inside the refrigerated volume of the refrigerated vehicle. Step 14806 goes to step 14800 to detect the temperature distribution and a new cycle of the control starts. The air mixing control cycle will be looped until an optimal temperature distribution inside the vehicle is achieved. In an alternative embodiment (not shown) door status is not taken into account when performing air mixing control, and instead air mixing continues whether the door is open or closed.

[0192] Referring to FIG. 15, and FIG. 9A a flow chart is shown of an exemplary method for performing compressor control of system 90101. In step 15710 controller 90103 detects the pressure inside manifold 90107 through pressure sensor(s) 90124 installed inside the manifold 90107. In step 15712 controller 90103 compares the detected pressure with a reference pressure. If the detected pressure is below the reference pressure, step 15712 goes to step 15716. In step 15716 controller 90103 activates compressor 90104, which fills manifold 90107 with more air, raising the pressure inside manifold 90107. Step 15716 proceeds at the beginning of the compressor control loop at step 16710. If the detected pressure is equal to the reference pressure, step 15716 goes to step 15714. At step 15714 controller 90103 stops the compressor and step 15714 goes to step 11508 (FIG. 11).

[0193] Initially referring to FIG. 16A for the structure of the present invention, active diffuser system 160101 is shown located within the refrigerated volume of refrigerated vehicle 100. One of ordinary skill in the art will appreciate that refrigerated vehicle 100 may comprise any of the following: refrigerated truck box, refrigerated trailer, refrigerated intermodal container, or any other type of structure with a volume for refrigeration.

Refrigeration of the refrigerated volume of refrigerated vehicle 100 can be achieved with ice, utilizing a cooling agent such as, without being limited to, carbon dioxide, or with the use of a mechanical refrigeration system, referred to as truck refrigeration unit (TRU) 112, as shown in the exemplary embodiment of FIG. 16 A

[0194] in an exemplary embodiment, system 160101 comprises sensor unit 160102, controller 160103, collector box 160104, one active diffuser for enhanced mixing 160170, one active diffuser for enhanced insulation 160171 , data storage unit 160106, and user interface 160105. At least one active diffuser for enhanced mixing 160170 is used to improve air circulation and mixing inside the refrigerated volume of refrigerated vehicle 100. At least one active diffuser for enhanced insulation 160171 is used to generate an air curtain proximal to the door of the refrigerated volume of refrigerated vehicle 100 to minimize the flow of air to and from the refrigerated volume when the door is open to enhance the heat insulation of the refrigerated vehicle and keep the refrigerated air within the refrigerated volume.

[0195] Both active diffusers 160170 and 160171 are operated by controller 160103, which receives sensor data from sensor unit 160102, TRU operations data from TRU control 108, and delivery data from external deliver}' database 109, in order to perform air mixing control 160130, diagnostic control 160131, or heat insulation control 160132. In an exemplary embodiment of the present invention, controller 160103 wirelessly connects with fleet logistics platform 178 to exchange operating information. The controller can also interface with user interface 160105 and store data on a storage 160106.

[0196] In an exemplary embodiment of the present invention, sensor unit 160102 comprises one or more temperature sensors 160120, one or more humidity sensors 160121, one or more diagnostic sensor(s) 160122, and one or more door sensor(s) 160123. [0197] Temperature sensor(s) 160120 and humidity sensor(s) 160121 collect sensor data inside the refrigerated volume of refrigerated vehicle 100. More than one temperat ure sensor 160120 and/or humidity sensor 160121 may be positioned on vehicle 100. In embodiments where a plurality of temperature sensors 160120 are utilized, they will be uniformly positioned on the inside surfaces of the refrigerated volume to improve the capture of temperature distribution data inside the refrigerated volume of refrigerated vehicle 100. Temperature sensors 160120 may consist of contact temperature sensors such as

thermocouples, resistive temperature detectors, thermistors, or bi-metaliic thermostats.

Humidity sensors 160121 (also called hygrometers) may consist of capacitive hygrometers, resistive hygrometers, thermal hygrometers, or gravimetric hygrometers.

[0198] Diagnostic sensors 160122 are used to identify electrical problems (such as short circuits) and/or mechanical problems with active diffusers 160170 or 160171. Diagnostic sensors 160122 may consist of any commercially available type of current detectors such as hall effect sensors, current clamp meters, resistors and/or strain gauges or any other type of commercially available sensor to detect the absorbed power such as wattmeter. Electrical and/or mechanical problems of actuators 160170 or 160171 may be communicated to the user (e.g. the operator of refrigerated vehicle 100) via user interface 160105. User interface 160105 may comprise a screen, LEDs, or other visual means to communicate information to the user, as well as buttons that the user can utilize to check the status of the different components of system 160101. In some scenarios, the identified problems may cause system 160101 to cease operation. In other scenarios, the identified problems may be automatically corrected (or at least an automatic attempt to correct the problems may be made) during operation of system 160101.

[0199] Door sensors 160123 detect whether the door to the refrigerated volume of refrigerated vehicle 100 is closed or open. One of ordinary skill in the art will appreciate that numerous types of sensors including force sensors or proximity sensors can be used as door sensor(s) 160123.

[0200] In an exemplary embodiment of the present invention, controller 160103 may be configured to control operation of one or more sensor unit 160102, active diffuser for enhanced mixing 160170, active diffuser for enhanced insulation 160171, storage 160106, and user interface 160105. Controller 160103 may include, for example, a logic circuit, a digital signal processor, a microcontroller or a microprocessor. Controller 160103 may be connected to the vehicle or TRU battery 140 to power the whole system or altematively have its own battery.

[0201] In an exemplary embodiment of the present invention, controller 160103 may be configured to perform air mixing control 160130, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the active diffusers 160170 and 160171, based on the variables related to refrigerated vehicle 100. To determine the variables, controller 160103 may use the sensor data received from sensor unit 160102 including temperature sensors 160120 and humidity sensor 160121, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery. To perform air mixing control 160130, active diffuser(s) for enhanced mixing 160170 will be utilized.

[0202] In an exemplary embodiment of the present invention, air mixing control 160130 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, and when the planned delivery is at a certain known point in time. To identify the temperature distribution, controller 160103 may use the sensor data received from at least two temperature sensors 160120. To identify the TRU operating parameters, the controller 160103 may interface with the TRU control 108. To identify the planned deliveries, the controller 160103 may interface with the refrigerated vehicle delivery database 109. A description of air mixing control 160130 is provided further below with respect to FIG. 21.

[0203] In an exemplary embodiment of the present invention, controller 160103 may also be configured to perform diagnostic control 160131, to determine whether components of system 160101 are operating under normal conditions. For diagnostic control 160131 , controller 160103 compares diagnostic sensor data received from diagnostic sensors 160122 to predetermined optimal conditions, to determine the presence of an abnormal current absorption and/or the presence of an abnormal power consumption profile to identify electrical and/or mechanical problems with components of system 160101 or to confirm that system 160101 is operating under normal conditions. Depending upon the operating conditions, controller 160103 may provide an indication of a normal or faulty condition to user interface 160105. Diagnostic control 160131 is described further below with respect to FIG. 19.

[0204] In an exemplary embodiment of the present invention, controller 160103 may be configured to perform heat insulation control 160132, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the active diffusers 160170 and 160171 , based on the variables related to refrigerated vehicle 100. To determine the variables, controller 160103 may use the sensor data received from temperature sensors 160120, as well as sensor data from humidity sensor 160121 , sensor data from door sensor 160123, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery. [0205] Heat insulation control 160132 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volume, when certain TRU operating parameters are in effect, when the planned delivery is at a certain known point in time, or when there is a certain condition with the door. To identify the temperature distribution, controller 160103 may use the sensor data received from at least two temperature sensors 160120. To identify the TRU operating parameters, controller 160103 may interface with the TRU control 108. To identify the planned deliveries, controller 160103 may interface with refrigerated vehicle delivery database 109. To identify the status of the door (Closed or Open) controller 160103 may interface with door sensor(s) 160123. A description of heat insulation control 160132 is provided further below with respect to FIG. 20.

[0206] In an exemplary embodiment of the present invention, user interface 160105 may include any suitable interface to provide visual and/or audio indication of a normal or faulty operating condition. For example, a blinking red LED might signal the presence of a short- circuit, or a blinking yellow LED might signal the presence of a leak in the duct 17107 (FIG. 17A) or collector box 160104. User interface 160105 may be provided inside the refrigerated volume of refrigerated vehicle 100, or outside the refrigerated volume for the convenience of the user. In an alternative exemplary embodiment of the present invention, user interface 160105 may be provided on controller 160103. For example, user interface 160105 may be an external unit mounted on a component of system 160101 or may be formed as part of a component of system 160101. Responsive to the indication on user interface 160105, the user may operate refrigerated vehicle 100 or may have system 160101 inspected for maintenance issues.

[0207] System 160101 may include storage 160106. Storage 160106 may include, for example, a random access memory (RAM), a magnetic disk, an optical disc, flash memory or a hard drive. Storage 160106 may store one or more values for sensor unit 160102, controller 160103, active diffusers for enhanced mixing 160170, active diffusers for enhanced insulation 160171, delivery data from delivery database 109, TRU operations from TRU control 108, and/or user interface 160105.

[0208] In an embodiment of the present invention, collector box 160107 is configured to collect the airflow from the TRU output 281 and deliver the airflow to the at least two active diffusers 160170 and 160171.

[0209] Each active diffuser for enhanced mixing 160170 and each active diffuser for enhanced insulation 160171 may be configured to receive an electrical signal (having an operation frequency, phase, and an operation voltage amplitude) from controller 160103 and may produce an air jet. The air jets produced by active diffusers for enhanced mixing

160170 may be used to control the air mixing and distribution inside the refrigerated vehicle 100. The air jets produced by active diffusers for enhanced insulation 160171 may be used to create an air curtain and limit the airflow to and from the refrigerated vehicle 100, ultimately reducing the heat exchange between the refrigerated volume and the outside environment. Active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation

160171 may be mounted directly to vehicle 100 or may be mounted to vehicle 100 via a mounting frame, such as mounting frame 170291 shown in FIG. 17 A. In another exemplary embodiment (not shown), active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 may be formed integral with the vehicle.

[0210] Active diffusers for enhanced mixing 160170 and active diffusers for enhanced heat insulation 160171 constructed in the same way, the only difference being the purpose of the air jet that each generates. Specifically, active diffusers for enhanced mixing 160170 produce an air jet that is utilized to enhance the air mixing and distribution inside the refrigerated vehicle 100, while active diffusers for enhanced insulation 160171 produce an air jet that is utilized to enhance the insulation between the refrigerated volume and the outside environment by creating an air curtain at the door level that limits the airflow to and from the refrigerated volume.

[0211] One of ordinary skill in the art would recognize that components of one or more of sensor unit 160102, controller 160103, active diffusers for enhanced mixing 160170, active diffusers for enhanced heat insulation 160171, user interface 160105, and storage 160106 may be implemented in hardware, software or a combination of hardware and software.

[0212] Referring to FIG. 16B, a functional block diagram of an exemplary embodiment of active diffuser for enhanced mixing 160170 and active diffuser for enhanced heat insulation 160171 is shown. Each one of the actuators 160170 or 160171 include at least one motorized duct damper 1601 11 and at least one diffuser 90112. Motorized duct damper 1601 11 may receive control signal 160148 from controller 160103 indicating an operation frequency, operation phase, and operation voltage amplitude for opening and/or closing its connection between the collector box 160104 and the nozzle 160112. The collector box 160104 is connected to the motorized duct damper 1601 11 through a duct 161 14, while the motorized duct damper 1601 11 is connected to the diffuser 1601 12 through a regulated flow duct 160113. In FIG. 16B, The N number of electrical signals 160148 may correspond to N/2 number of active diffusers for enhanced mixing 160170 and N/2 number of active diffusers for enhanced insulation 160171 or may correspond to groups of actuators. Each actuator in the group may receive the same electrical signal. Thus, different electrical signals 160148 may be provided to different groups of actuators.

[0213] The control signal 16048 from controller 160103 may also indicate specific active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 for activation with the corresponding operation parameters. [0214] Referring next to FIGS. 17A-17C, perspective view diagrams of an exemplary system 160101 located within the refrigerated volume of refrigerated vehicle 200 is shown. In particular, FIG. 17A is a perspective view diagram of refrigerated vehicle 200 with its door 170212 to the refrigerated volume closed, showing active diffusers for enhanced mixing 160170 in operation to create an enhanced cooling flow throughout the refrigerated volume. For purposes of illustration, door 170212 is not visible so that the inside of the refrigerated volume may be illustrated. FIG. 17B is a cross-section diagram of a FIG. 17A along line D-D (FIG. 17 A). FIG. 17C is a perspective view diagram of refrigerated vehicle 200 with its door 170212 open, showing active diffusers for enhanced insulation 160171 in operation.

[0215] In FIG. 17A a plurality of active diffusers for enhanced mixing 160170 and of active diffusers for enhanced insulation 160171 are disposed in a frame 170291. In the exemplary embodiment disclosed in FIG. 17A frame 170291 is mounted on refrigerated volume ceiling 170210, side walls 170211-1 170211-2, floor 170213, and along the edge of TRU output 281. A plurality of active diffusers for enhanced insulation 160171 are located along the periphery of the back of the refrigerated volume of refrigerated vehicle 200 proximal to door 170212. In the exemplary embodiment disclosed in FIG. 17A the truck refrigeration unit (TRU) 208 is mounted on the refrigerated vehicle 200, and it is connected to the refrigerated volume through output 281 and input 282. TRU 208 pushes cold air inside the refrigerated volume through the output 281 and sucks air from the refrigerated volume via input 282. A plurality of temperature sensors 170290 are distributed inside the refrigerated volume of refrigerated vehicle 200. Active diffusers for enhanced mixing 160170 and active diffusers for enhanced heat insulation 160171 are connected to collector box 170104 through ducts 17107. Collector box 100104 is connected to the TRU output 281.

[0216] In the exemplary embodiment disclosed in FIG. 17A active diffusers for enhanced insulation 160171 are not producing an air jet 172 because door 170212 is closed and there is no need to create an air curtain between the outside environment and the refrigerated volume of refrigerated vehicle 200. Active diffusers for enhanced mixing 160170 are illustrated producing a plurality of air jets 170172 that influence the basic cooling flow 170270 that would exist without the enhancement provided by the active diffusers for enhanced mixing to produce an enhanced cooling flow 170271. As illustrated in FIG. 17A the enhanced cooling flow 170271 produced by the air jets 170172 extends to the back of the refrigerated volume whereas the basic cooling flow 170270 does not extend throughout the extent of the refrigerated volume.

[0217] FIG. 17B illustrates in detail the configuration of the items on the end of the refrigerated volume opposite to door 170212. As shown in FIG. 17B, a plurality of active diffusers for enhanced mixing 160170 are installed on a framel70291 around the periphery of TRU output 281, each producing an air jet 170172, which affects the basic cooling flow 170270 and instead produces an enhanced cooling flow 170271. In the exemplary

embodiment illustrated by FIG. 17B , controller 160103, ducts 170107, collector box 160104, and the user interface 160105 are each placed on the same wall of the refrigerated volume. Collector box 160104 is connected to the multiple active diffusers for enhanced insulation 160171 located around the periphery of the door 170212 through duct(s) 170107 (not shown).

[0218] FIG. 17C illustrates an exemplary embodiment of refrigerated vehicle 200 with door 170212 to the refrigerated volume in the open position. In this embodiment, a plurality of active diffusers for enhanced insulation 160171 are each producing an air jet 170172. The totality of the active diffusers 160171 generates an air curtain that prevents warm humid airflow 170272 located outside of the refrigerated volume of the refrigerated vehicle from going inside the refrigerated volume. At the same time, the air curtain generated by the totality of air jets 170172 prevents cold airflow 170273 from exiting the refrigerated volume of the refrigerated vehicle. Collector box 160104 and duct(s) 170107 connected to the active diffusers for enhanced insulation 160171 are also represented.

[0219] Referring to FIG. 18 (and FIG. 16A), a flow chart is shown for an exemplary embodiment of a method based on active diffusers for improved air mixing and distribution in the refrigerated volume of refrigerated vehicles and for reducing the heat exchange during loading and unloading operations of refrigerated vehicles. At step 18500, components of the system 160101 are initialized. For example, controller 160103 may initiate collection of sensor data from sensor unit 160102, may initiate active diffusers 160170 or 160171 and/or may send an indication to user interface 160105 that system 160101 is in operation.

Furthermore controller 160103 may establish preliminary connection with TRU control 108 and wireless connection with refrigerated vehicle delivery database 109 and fleet logistics platform 178.

[0220] At step 18502, controller 160103 performs diagnostic control of components of system 160101, to identify any problems that may require maintenance. At step 18504, it is determined whether maintenance is necessary (based on step 18502).

[0221] When it is determined at step 18504 that maintenance is required, step 18504 goes to step 18506. At step 18506, a maintenance indication is presented to the user, for example, via user interface 160105. Although, in step 18506, a maintenance indication is presented, the system 160101 may continue to operate depending on the maintenance required. Accordingly, in some examples, step 18506 may proceed to step 18508. According to other examples, step 18506 may also include terminating operation of system 160101. Examples of diagnostic control (step 18502) are described further below with respect to FIG. 19.

[0222] When it is determined, at step 18504, that maintenance is unnecessary, step 18504 proceeds to step 18508. At step 18508, it is determined whether the refrigerated vehicle door 170212 (FIG. 17A) is open or closed based on input to sensor unit 160102 from door sensor 160123. An indication may be stored (for example, in storage 160105) if it is determined that the door is open. When it is determined at step 18508 that the door is open, step 18508 goes to step 18510. At step 18510 the controller 160103 performs the heat insulation control. Examples of heat insulation control (step 18510) are described in FIG. 20. So long as door 170212 (FIG. 17A) remains open, the controller 160103 will keep performing heat insulation control (step 18510) in a loop.

[0223] When it is determined, at step 18508, that the vehicle door 170212 (FIG. 17A) is closed, step 18508 proceeds to step 18512. At step 18512 it is determined whether the temperature distribution inside the vehicle is optimal. Controller 160103 will determine the temperature distribution by gathering temperature data from the sensor unit 160102. An indication might be stored (for example, in storage 160105) if it is determined that the temperature distribution is not optimal. When it is determined at step 18512 that the temperature distribution is not optimal, step 18512 goes to step 18514. At step 18514 the controller 160103 performs the improved mixing control (step 18514). Examples of improved mixing control (step 18514) are described in FIG. 21. Until the temperature distribution is not optimal, the controller 160103 will keep performing improved mixing control (step 18514) in a loop.

[0224] When it is determined, at step 18512 that the temperature distribution is optimal, step 18512 goes to step 18502, which starts again the cycle by performing a diagnostic control. In an alternative embodiment of the method, controller 160103 will also perform air mixing control when the vehicle door 170212 is open and the controller 103 is performing heat insulation control.

[0225] Referring to FIG. 19 and FIG. 16A a flow chart is shown of an exemplary method of performing diagnostic control (step 18502). At step 19600, connected active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 (FIG. 16A) are detected, for example, by one or more current detectors (an example of diagnostic sensor 160122) electrically coupled to active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 via an electrical circuit. At step 19602, it is determined, for example, by controller 160103, whether the current absorbed is within predetermined current limits, based on the value of the current detector(s).

[0226] When it is determined, at step 19602, that the absorbed current is outside of the predetermined current limits, step 19602 proceeds to step 19604. At step 19604, controller 160103 performs a short-circuit analysis of the electrical circuit (of active diffuser for enhanced mixing 160170 and active diffusers for enhanced insulation 160171) based on the sensor data from the current detector(s). At step 19606, a location of a short-circuit in the electrical circuit is determined by controller 160103, based on the analysis in step 19604. At step 19608, a maintenance indication is prompted, by controller 160103. The maintenance indication may also be stored in storage 160106. The stored maintenance indication may include information regarding the short-circuit condition, including the identified location of the short-circuit. The maintenance indication may also be provided to the user through the user interface 160105.

[0227] At step 19610, responsive to the short-circuit condition, controller 160103 may terminate operation of system 160101.

[0228] When it is determined, at step 19602, that the absorbed current is within the predetermined current limits, step 19602 proceeds to step 19612. At step 19612, it is determined whether current absorption profiles of active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 are within predetermined tolerances. For example, controller 160103 may monitor the absorption profile of active diffusers for enhanced mixing 160170 and active diffusers for enhanced insulation 160171 (such as an amplitude of the profile) via one or more current detectors (an example of diagnostic sensor 160122) coupled to the motorized duct damper 1601 11 of the active diffusers for enhanced mixing 160170 and of the active diffusers for enhanced insulation 160171.

[0229] When it is determined, at step 19612, that the absorption profiles are outside of the predetermined tolerances, step 19612 proceeds to step 19614. At step 19614, one active diffuser for enhanced mixing 160170 or an active diffuser for enhanced insulation 160171 is identified, by controller 160103, as having a clogged diffuser 1601 12. At step 19616, controller performs a jet de-clogging cycle for the identified active diffuser for enhanced mixing 160170 or active diffuser for enhanced insulation 160171 (in step 19614). For example, controller 160103 may cause the active diffusers 160170 or 160171 to operate according to a predetermined operation frequency, phase, and/or voltage amplitude, in an attempt to de-clog the diffuser 160112. Step 19616 proceeds to step 19612.

[0230] When it is determined, at step 19612, that the absorption profiles are within the predetermined tolerances, step 19612 proceeds to step 18504.

[0231] Referring to FIG. 20, and FIG. 16A a flow chart is shown of an exemplary method for performing heat insulation control by using active diffusers for enhanced insulation 160171 (step 18510). At step 20710 the controller 160103 determines the temperature distribution inside the refrigerated vehicle through the sensor unit 160102. The information on temperature distribution can be stored in storage 160106. At step 20712 controller 160103 connects with the TRU control 108 and analyzes the TRU operations. The TRU operations data can be stored in storage 160106. In step 20716 controller 160103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 160148 (FIG. 16B)) to be applied to active diffusers for enhanced heat insulation 160171 based on the information regarding the door status, the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 20718 such operating parameters are applied to the active diffusers for enhanced heat insulation 160171 to generate an air curtain. In step 20720 controller 160103 determines whether the door is still open or whether it is closed. If the door is determined to be open, step 20720 goes to step 20710 and a new cycle of heat insulation control is performed. If the door is determined to be closed, step 20720 goes to step 18512 (FIG. 18).

[0232] In general, the operation frequency, phase, and amplitude for the oscillating voltage signal may be determined according to one or more predetermined relationships between temperature distribution, door status, TRU operations, scheduled delivery and output air jet characteristics. The predetermined relationship may be based on physical

characteristics of active diffusers for enhanced heat insulation 160171 (such as a size and/or shape of diffuser 160112 (FIG. 16B) as well as the properties of the fluid itself). In another exemplary embodiment, the operation frequency and amplitude may be determined from a look up table according to the temperature and/or the relative humidity. In another exemplary embodiment, controller 160103 may use a mathematical model that may correlate the optimal frequency and amplitude with temperature and/or relative humidity data received sensor unit(s) 160102. In general, there is an empirical relationship between

temperature/humidity and frequency/amplitude.

[0233] Referring to FIG. 21, and FIG. 16A a flow chart is shown of an exemplary method for performing improved mixing control by using active diffusers for enhanced mixing 160170. In step 21800 controller 160103 detects the temperature distribution inside the refrigerated volume of the refrigerated vehicle 200 by detecting temperature data from at least two temperature sensor(s) 160120 of sensor unit(s) 160102. Step 21801 determines whether the temperature distribution is optimal or not. If the temperature distribution is optimal, step 21801 goes to step 18502 (FIG. 18). If the temperature distribution is not optimal, step 21801 goes to step 21802. In step 21802 the controller 160103 detects the TRU operations by connecting to the TRU control 108. In step 21803 the controller 160103 connects to a refrigerated vehicle delivery database 109 and determines the closest next delivery. Step 21804 determines whether door 170212 (FIG. 17A) of the vehicle is going to open within a certain time interval. Since it is inefficient to perform air mixing control when the door is open, in a preferred embodiment only heat insulation control is performed when the door is open. Thus if the door is going to open in a time interval below a reference value, step 21804 goes to step 18510 (FIG. 18). If the door is going to open in a time interval above a reference value, step 21804 goes to step 21805. In step 21805 the controller 160103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 160148 (FIG. 16B)) to be applied to active diffusers for enhanced mixing 160170 (FIG. 16A) based on the temperature distribution inside the refrigerated vehicle, and operations data from the TRU. In step 21806 such operating parameters are applied to the active diffusers for enhanced mixing 160170 and generate multiple air jets that will increase the air mixing and enhance the air distribution inside the refrigerated volume of the refrigerated vehicle. Step 21806 goes to step 21800 to detect the temperature distribution and a new cycle of the control starts. The air mixing control cycle will be looped until an optimal temperature distribution inside the vehicle is achieved. In an alternative embodiment (not shown) door status is not taken into account when performing air mixing control, and instead air mixing control continues whether the door is open or closed.

|0234] Initially referring to FIG. 22A, synthetic jet actuator system 22101 located within the refrigerated volume of refrigerated vehicle 100 is shown. In an exemplary embodiment, which provides for a system for reducing the heat exchange between volumes insulated by bulkheads in refrigerated vehicles based on synthetic jet actuators, system 220101 comprises sensor unit 220102, controller 220103, mam electronic unit 220104, one synthetic jet actuator 220170, data storage unit 220106, and user interface 220105. The at least one synthetic jet actuator 220170 is used to generate an air curtain proximal to the door of the refrigerated volume of refrigerated vehicle 100 to minimize the flow between the different refrigerated bulkheads volumes to enhance their heat insulation.

[0235] Synthetic jet actuators 220170 are operated by main electronic unit 220104 which in turn is controlled by controller 220103, which receives sensor data from sensor unit 220! 02, TRU operations data from TRU control 220108, and delivery data from external delivery database 220109, in order to perform enhanced heat insulation control 220132 and diagnostic control 220131. In an embodiment of the present invention, controller 220103 wireless!y connects with logistics platform 178 to exchange operating information. Controller 220103 can also interface with user interface 220105 and store data on storage 220106.

[0236] in an exemplar)' embodiment of the present invention, sensor unit 220102 comprises one or more temperature sensors 220120, one or more humidity sensors 220121, one or more diagnostic sensors 220122, and one or more RFID sensors 220123. More than one temperature sensor 220120, humidity sensor 220121, and/or RFID sensor may be positioned within the refrigerated volume of refrigerated vehicle 100. In enibodinients where a plurality of temperature sensors 220120 are utilized, they will be uniformly positioned on the inside surfaces of the refrigerated volume to improve the capture of the temperature distribution data inside the refrigerated volume of the refrigerated vehicle 100. Temperature sensors 220120 may consist of any type of commercially available contact temperature sensors such as thermocouples, resistive temperature detectors, thermistors, or bi-metallic thermostats. Humidity sensors 220121 (also called hygrometers) may consist of capacitive hygrometers, resistive hygrometers, thermal hygrometers, or gravimetric hygrometers.

[0237] Diagnostic sensors 220122 are used to identify electrical problems (such as short circuits) and/or mechanical problems with air jet 22170. Diagnostic sensors 220122 may consist of any commercially available type of current detectors such as hall effect sensors, current clamp meters, resistors and/or strain gauges or any other type of commercially available sensor to detect the absorbed power such as a wattmeter. Electrical and/or mechanical problems of synthetic jet actuators 220170 may be communicated to the user (e.g. the operator of refrigerated vehicle 100) via user interface 220105. User interface 220105 may comprise a screen, LEDs, or other visual means to communicate information to the user, as well as buttons that the user can utilize to check the status of the different components of system 220101 . In some scenarios, the identified problems may cause system 220101 to cease operation. In other scenarios, the identified problems may be automatically corrected (or at least an automatic attempt to correct the problems may be made) during operation of system 220101,

[0238] Door sensor(s) 220123 detect whether the door to the refrigerated volume of refrigerated vehicle 100 is closed or open. One of ordinary skill in the art will appreciate that numerous types of sensors including force sensors or proximity sensors can be used as door sensor(s) 220123.

[0239] In an exemplary embodiment of the present invention, controller 220103 may be configured to control operations of one or more sensor unit 220102, main electronic unit 220104, synthetic jet actuator 220170, storage 220106, and user interface 220105. Controller 220103 may include, for example, a logic circuit, a digital signal processor, a microcontroller or a microprocessor.

[0240] In an exemplary embodiment of the present invention, controller 230103 may be configured to perform diagnostic control 220131, to determine whether components of system 220101 are operating under normal conditions. For diagnostic control 220131, controller 220103 compares diagnostic sensor data received from diagnostic sensors 220122 to predetermined conditions to determine the presence of an abnormal current absorption and/or the presence of an abnormal power consumption profile and/or the presence of an abnormal load strain gauge values, to identify electrical and/or mechanical problems with components of system 220101 or to confirm that system 220101 is operating under normal conditions. Depending upon the operating conditions, controller 220103 may provide an indication of a normal or faulty condition to user interface 220105. Diagnostic control 220131 for system 220101 is performed in the same fashion as diagnostic control 131 performed for system 101 described above with respect to FIG. 6.

[0241] In an exemplary embodiment of the present invention, controller 220103 may be configured to perform heat insulation control 220132, to control the operating frequency, operating phase, and operating voltage amplitude of the electrical signal provided to the main electronic unit 220104, based on the variables related to refrigerated vehicle 100. To determine the variables, controller 220103 may use the sensor data received from temperature sensors 220120, as well as sensor data from humidity sensor 220121, RFID data from RFID sensor 220123, TRU operations data from TRU control 108, and delivery data from refrigerated delivery database 109. The operating frequency, phase, and voltage amplitude may be determined according to a predetermined relationship between temperature and humidity conditions, TRU operating parameters, and planned delivery.

[0242] Heat insulation control 220132 may be performed when refrigerated vehicle 100 has a certain temperature distribution inside the refrigerated volumes, when the RFID determines the presence of certain goods that require a certain level of refrigeration, when certain TRU operating parameters are in effect, when the planned delivery is at a certain known point in time, or when there is a certain condition with the door. To identify the temperature distribution, controller 220103 may use the sensor data received from at least two temperature sensors 220120. To identify the TRU operating parameters, controller 220103 may interface with the TRU control 108. To identify the planned deliveries, controller 220103 may interface with refrigerated vehicle delivery database 109. To identify the nature of the goods stored in each refrigerated volume and to determine the ideal refrigeration temperature for each refrigerated volume the controller 220103 may interface with the RFID sensors 220123. A description of heat insulation control 220130 is provided further below with respect to FIG. 25.

[0243] In an exemplary embodiment of the present invention, User Interface 220105 may include any suitable interface to provide visual and/or audio indication of a normal or faulty operating condition. For example, a blinking red LED might signal the presence of a short-circuit, or a blinking yellow LED might signal the presence of a clogged synthetic jet actuator. User Interface 220105 may be provided inside the refrigerated volume of refrigerated vehicle 100, or outside the refrigerated volume for the convenience of the user. In an alternative exemplary embodiment of the present invention, user interface 220105 may be provided on controller 220103 and/or main electronic unit 220104. For example, user interface 220105 may be an external unit mounted on a component of system 220101 or may be formed as part of a component of system 220101. Responsive to the indication on user interface 220105, the user may operate refrigerated vehicle 100 or may have system 220101 inspected for maintenance issues.

[0244] System 220101 may include storage 220106. Storage 220106 may include, for example, a random access memory (RAM), a magnetic disk, an optical disc, flash memory or a hard drive. Storage 220106 may store one or more values for sensor unit 220102, controller 220103, main electronic unit 220104, synthetic jet actuators 220170, delivery data from delivery database 109, TRU operations from TRU control 108, and/or user interface 220105.

[0245] Main electronic unit 220104 may be configured to receive control signals from controller 220103 and activate one or more actuators 220170 according to operation parameters (frequency, phase, and voltage amplitude) provided by controller 220103 in the control signal. Main electronic unit 220104 is described further below with respect to FIG. 22B. System 220101 may be configured to have multiple main electronic units, each connecting to a group of synthetic jet actuators 220170 and each controlled by controller 220103.

[0246] Each synthetic jet actuator 22170 may be configured to receive an electrical signal (having an operation frequency, phase, and an operation voltage amplitude) from main electronic unit 220104 and may produce a air jet. The air jets produced by synthetic jet actuators 220170 may be used to create an air curtain and limit the airflow to and from the different refrigerated volumes insulated by the bulkheads, ultimately reducing the heat exchange between the different refrigerated volumes. Air jet 220170 may be mounted directly to vehicle 100 or may be mounted to vehicle 100 via a mounting frame, such as mounting frame 230291 shown in FIG. 23. As another example, Synthetic jet actuators 220170 may be formed integral with the vehicle.

[0247] Synthetic jet actuators 220170 are described above with respect to FIGS. 3A-3C and FIGS. 4A and 4B. Synthetic jet actuators 220170 are constructed in the same way of synthetic jet actuators 170 and 171, the only differentiating factor is the purpose of the air jet that they generate: synthetic jet actuators for enhanced mixing 170 produce an air jet that is utilized to enhance the air mixing and distribution inside the refrigerated vehicle 100, and synthetic jet actuators for enhanced insulation 171 produce an air jet that is utilized to enhance the insulation between the refrigerated volume and the outside environment by creating an air curtain at the door level that limits the airflow to and from the refrigerated volume, while synthetic jet actuator 22170 produce an air jet that is utilized to enhance the insulation between refrigerated volumes insulated by the by creating an air curtain at the bulkhead level that limits the airflow between the refrigerated volumes. [0248] One of ordinary skill in the art would recognize that components of one or more of sensor unit 220102, controller 220103, main electronic unit 220104, user interface 220105, and storage 220106 may be implemented in hardware, software or a combination of hardware and software.

[0249] Referring to FIG. 22B, a functional block diagram of an exemplar ' embodiment of main electronic unit 220104 is shown. Main electronic unit 220104 may include direct current (DC)/DC converter 220142, and one or more amplifiers 220144. DC/DC converter 220142 may receive a voltage signal from TRU or vehicle battery 140 and convert the voltage to a voltage range suitable for synthetic jet actuators 220170 (as well as being suitable for amplifier(s) 220144). Main electronic unit 220104 may also receive control signal 220148 from controller 220103 indicating an operation frequency, operation phase, and operation voltage amplitude for synthetic jet actuators 220170. In FIG. 22B, N number of power signals 220150 (where N is an integer greater than or equal to 1) having the frequency, phase, and voltage amplitude indicated by control signal 220148 are supplied to synthetic jet actuators 220170. Each actuator in the group may receive the same electrical signal. Thus, different electrical signals 220150 may be provided to different groups of actuators.

[0250] Control signal 220148 from controller 220103 may also indicate specific synthetic jet actuators 220170 for activation with the corresponding operation parameters. Amplifier(s) 220144 may amplify the signal from controller 220103 according to the voltage amplitude received in control signal 220148 from controller. Main electronic unit 220104 may send a generated electrical signal 220150 with the operation frequency, phase, and voltage amplitude to selected synthetic jet actuators 220170.

[0251] Referring next to FIG. 23, a perspective vie diagram of an exemplary system 220101 located within the refrigerated volume of refrigerated vehicle 200 is shown. In particular, FIG. 23 is a perspecti ve view diagram of refrigerated vehicle 200 with its door 230212 to the refrigerated volume closed, showing a plurality of synthetic jet actuators 220170 mounted on bulkheads 230180 in operation to create an enhanced insulation between the refrigerated volumes. For purposes of illustration, door 230212 is not visible so that the inside of the refrigerated volume may be illustrated In the exemplary embodiment of FIG. 23 a plurality of synthetic jet actuators for enhanced mixing 220170 are disposed in frames 230291, which is installed along the edges of bulkheads. In an alternative embodiment frames 230291 can be installed on refrigerated vehicle ceiling 230210, side walls 230211-1 230211-2, or floor 230213 In the exemplary embodiment of FIG. 23 the truck refrigeration unit (TRU) 208 is mounted on the refrigerated vehicle 200, and it is connected to the refrigerated volume through an output 281 and an input 282. The TRU pushes cold air inside the refrigerated volume through the output 281 and sucks air from the refrigerated volume via input 282. A plurality of temperature sensors 230290 that are distributed inside the refrigerated vehicle 200.

[0252] Synthetic jet actuators 22070 are represented producing a plurality of air jets 230172 that create air curtains along the edges of bulkhead(s) 230180, limiting the air flow between the different refrigerated volumes 230270, practically enhancing the heat insulation between refrigerated volumes 230270. In the example controller 22103, main electronic unit 22104, and user interface 22015 are represented in a exemplary location, and are connected to the synthetic jet actuators 220170 through an electric circuit 230110.

[0253] Referring to FIG. 24 (and FIG. 22A), a flow chart is shown for an exemplary method based on synthetic jet actuators for reducing the heat exchange between refrigerated volumes delimited by insulating bulkheads of multi-temperatures loading vehicles. At step 24500, components of the system 220101 are initialized. For example, controller 220103 may initiate collection of sensor data from sensor unit 220102, may initiate main electronic unit 220104 and/or may send an indication to user interface 220105 that system 220101 is in operation. Furthermore controller 220103 may establish preliminary connection with TRU control 108 and wireless connection with refrigerated vehicle delivery database 109 and fleet logistics platform 178.

[0254] At step 24502, controller 220103 may perform diagnostic control of components of system 220101, to identify any problems that may require maintenance. At step 24504, it is determined whether maintenance is necessary (based on step 24502).

[0255] When it is determined at step 24504 that maintenance is required, step 24504 goes to step 24506. At step 24506, a maintenance indication is presented to the user, for example, via user interface 220105. Although, in step 24506, a maintenance indication is presented, the system 220101 may continue to operate depending on the maintenance required. Accordingly, in some scenarios, step 24506 may proceed to step 24508. According to other scenarios, step 24506 may also include terminating operation of system 220101. Examples of diagnostic control (step 24502) are provided above with respect to FIG. 6. The structure of diagnostic control 24502 is the same as the diagnostic control structure described for system 101 in step 502.

[0256] When it is determined, at step 24504, that maintenance is unnecessary, step 24504 proceeds to step 24508. At step 24508, it is determined whether the heat insulation between the refrigerated volumes 230270 is optimal. An indication may be stored (for example, in storage 220105) if it is determined that the insulation is not optimal. When it is determined at step 24508 that the insulation is not optimal, step 24508 goes to step 24510. At step 24510 the controller 220103 performs the bulkheads insulation control. Examples of bulkheads insulation control (step 24510) are described in FIG. 25. [0257] When it is determined, at step 24508, that the heat insulation between refrigerated volumes is optimal, step 24508 proceeds to step 24502, which starts again the cycle by performing a diagnostic control.

[0258] Referring to FIG. 25, and FIG. 22A a flow chart is shown of an exemplary method for performing bulkhead insulation control by using synthetic jet actuators 220170 (FIG. 22A). At step 25710 controller 220103 determines the temperature distribution inside the refrigerated volumes through the sensor unit 220102. The information on temperature distribution can be stored in storage 220106. At step 25711 the controller 220103 connects with the RFID sensors to detect RFID signals coming from the goods stored in the refrigerated volumes. Controller 220103 will determine the kind of good stored in each refrigerated volume 23270 (FIG. 23) and determine an optimal temperature at which they should be stored. At step 255712 the controller 220103 connects with the TRU control 108 and analyze the TRU operations. The TRU operations data can be stored in the storage 220106. At step 25714 the controller 220103 analyzes the delivery schedule by connecting to a refrigerated vehicle delivery database 109. The delivery data can be stored into storage 220106. In step 25716 controller 220103 selects an operation frequency, phase, and a voltage amplitude for the operational signals (electrical signals 220150 (FIG. 22A)) to be applied to synthetic jet actuators 220170 based on the information regarding the temperature distribution inside the refrigerated vehicle, RFID signals coming from stored goods, operations data from the TRU, and the next scheduled delivery. In step 25718 such operating parameters are applied to the synthetic jet actuators 220170 and generate at least an air curtain. In step 25720 the controller 220103 determines whether the heat insulation between the refrigerated volumes is optimal. If the insulation is determined to be not optimal, step 25720 goes to step 25710 and a new cycle of bulkhead insulation control is performed. If the insulation between refrigerated volumes is determined to be optimal, step 25720 goes to step 24502 (FIG. 24).

[0259] In general, the operation frequency, phase, and amplitude for the oscillating voltage signal may be determined according to one or more predetermined relationships between temperature distribution, RFID signals, TRU operations, scheduled delivery and output air jet characteristics. The predetermined relationship may be based on physical characteristics of synthetic jet actuator 220170 (such as a size and/or shape of cavity 312 (FIG. 3), material properties of piezoelectric disc 308 (FIG. 3) as well as the properties of the fluid itself). In an exemplary embodiment, the operation frequency and amplitude may be determined from a look up table according to the temperature and/or the relative humidity. In another exemplary embodiment, controller 220103 may use a mathematical model that may correlate the optimal frequency and amplitude with temperature and/or relative humidity data received sensor unit(s) 220102. In general, there is an empirical relationship between temperature/humidity and frequency/amplitude. The relationship may be a function of the piezoelectric disc material and the diameter of the piezoelectric disc 308 (FIG. 3).

[0260] Now that embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. The spirit and scope of the present invention is to be construed broadly.

Claims

What is Claimed:

1. A system to improve air mixing and distribution within a refrigerated volume, the system comprising:

a refrigeration unit;

at least one actuator for generating a jet of air, mounted within the refrigerated volume remote from the refrigeration unit for enhancing the air mixing and distribution within the refrigerated volume;

at least one temperature sensor remote from the refrigeration unit configured to capture temperature data within the refrigerated volume;

a controller configured to receive the temperature data to control the at least one actuator, based on the received temperature data.

2. A system to reduce the heat exchange during loading and unloading operations of a refrigerated volume, the system comprising:

at least one door within the refrigerated volume that opens to the outside environment when open;

at least one actuator for generating a jet of air mounted proximal to the at least one door to generate an air curtain at the door opening when the door is open to reduce the heat exchange during loading and unloading operations;

at least one door sensor configured to collect door data indicating whether the door is open or closed;

a controller configured to receive the door data and to control the at least one actuator based on the received door data.

3. A method to improve air mixing and distribution within a refrigerated volume wherein the temperature is conditioned by a refrigeration unit, the method comprising: capturing temperature data from at least one temperature sensor mounted inside the refrigerated volume remote from the refrigeration unit;

controlling at least one actuator for generating a jet of air mounted within the refrigerated volume remote from the refrigeration unit based on the received temperature data to improve air circulation and mixing inside the refrigerated volume.

4. A method to reduce the heat exchange during loading and unloading operations of a refrigerated volume with a door, the method comprising:

capturing door data from at least one door sensor mounted proximal to the door indicating whether the door is open or closed;

controlling at least one actuator for generating a jet of air mounted proximal to the door based on the received door data;

generating an air curtain proximal to the door using the actuator to minimize the flow of air to and from the refrigerated volume when the door is open.

5. The system of claim 1 further comprising:

at least one humidity sensor remote from the refrigeration unit configured to capture humidity data within the refrigerated volume; and wherein

the controller is further configured to actuate the actuator when the humidity data differs from a predetermined humidity value.

6. The system of claim 1, wherein the actuator is a synthetic jet actuator.

7. The system of claim 6 wherein the controller is further configured to determine at least one of a drive frequency, phase, and drive amplitude for controlling the at least one synthetic jet actuator based on the received temperature data.

8. The system of claim 7, further comprising a main electronic unit coupled to the at least one synthetic jet actuator; wherein the main electronic unit is configured to generate an oscillating voltage signal based on the at least one of a drive frequency, drive phase and drive amplitude determined by the controller, and the oscillating voltage signal is used to drive the at least one synthetic jet actuator.

9. The system of claim 8, further comprising at least one mounting frame attached to an inside surface within the refrigerated volume;

wherein the at least one synthetic jet actuator is configured to be coupled to the mounting frame; the mounting frame electrically connecting the at least one synthetic jet actuator to the main electronic unit.

10. The system of claim 9, further comprising a user interface coupled to the controller, the user interface configured to provide an indication of a detected predetermined condition.

11. The system of claim 6 wherein there is a plurality of synthetic j et actuators positioned at different locations within the refrigerated volume; and

operation of each of the synthetic jet actuators is independently controlled by the controller.

12. The system of claim 6 wherein there is a plurality of synthetic jet actuators positioned at different locations within the refrigerated volume; and

operation of each of the synthetic jet actuators is jointly controlled by the controller.

13. The system of claim 1 , wherein the actuator is a compressed air actuator and the system further comprises:

a compressor controlled by the controller and configured to generate compressed air; a manifold, configured to collect the compressed air generated by the compressor and deliver it to the at least one compressed air actuator;

at least one pressure sensor configured to capture pressure data within the manifold; the controller further configured to receive pressure data from the pressure sensor and to control the compressor to maintain the pressure inside the manifold at a predetermine value.

14. The system of claim 1 , wherein the actuator is an active diffuser and the system further comprises:

a collector box, configured to collect a portion of the airflow generated by the refrigeration unit;

at least one duct connecting the collector box to the at least one active diffuser.

15. The system of claim 2, wherein the actuator is a synthetic jet actuator.

16. The system of claim 15 wherein the controller is further configured to determine at least one of a drive frequency, phase, and drive amplitude for controlling the at least one synthetic jet actuator based on the received temperature data.

17. The system of claim 16, further comprising

a main electronic unit coupled to the at least one synthetic jet actuator, wherein the main electronic unit is configured to generate an oscillating voltage signal based on the at least one of a drive frequency, drive phase and drive amplitude determined by the controller, and the oscillating voltage signal is used to drive the at least one synthetic jet actuator.

18. The system of claim 17, further comprising at least one mounting frame attached to an inside surface within the refrigerated volume proximal to the door;

and wherein the at least one synthetic jet actuator is configured to be coupled to the mounting frame;

the mounting frame electrically connecting the at least one synthetic jet actuator to the main electronic unit.

19. The system of claim 18, further comprising a user interface coupled to the controller, the user interface configured to provide an indication of a detected predetermined condition.

20. The system of claim 15 wherein there is a plurality of synthetic jet actuators positioned at different locations within the refrigerated volume; and

21. The system of claim 15 wherein there is a plurality of synthetic jet actuators positioned at different locations within the refrigerated volume; and

22. The system of claim 2, wherein the actuator is a compressed air actuator and the system further comprises:

23. The system of claim 2, wherein the actuator is an active diffuser and the system further comprises:

24. A system to reduce the heat exchange through insulating bulkheads of a refrigerated volume, the system comprising: a refrigeration unit;

at least one bulkhead located within the refrigerated volume;

at least one synthetic jet actuator for generating a jet of air mounted within the refrigerated volume proximal to the at least one bulkhead to generate an air curtain to reduce the airflow and heat exchange between the portions of the refrigerated volume delimited by the at least one bulkhead.

25. The system of claim 24 further comprising:

a controller configured to receive the temperature data to control the at least one synthetic jet actuator, based on the received temperature data.

26. The system of claim 25 wherein

the controller is further configured to determine at least one of a drive frequency, phase, and drive amplitude for controlling the at least one synthetic jet actuator based on the received temperature data.

27. The system of claim 26 further comprising:

at least one RFID sensor mounted in each portion of the refrigerated volume delineated by the bulkhead configured to capture RFID data of any goods located within each portion of the refrigerated volume which have RFID tags associated with them; and wherein the controller is further configured to receive the RFID data to control the at least one synthetic jet actuator to maintain each portion of the refrigerated volume at a predetermined desired temperature determined based on the RFID data associated with the goods located within the portion of the refrigerated volume.

28. The system of claim 27 wherein the at least one synthetic jet actuator is mounted on the at least one bulkhead.