KR20050103900A - Refrigeration system with bypass subcooling and component size de-optimization - Google Patents

Abstract

A refrigeration system having a primary refrigerant path including a compressor (12), a condenser (24), a primary expansion device (16), and an evaporator (28) connected together to form a closed loop system with a refrigerant circulating therein; and a bypass path (27) coupled to an outlet of the condenser. The bypass path includes a secondary expansion device (23); and a heat exchanger (22) thermally coupled to the primary refrigerant path between the condenser outlet and the primary expansion device inlet to remove heat from the refrigerant discharged from the condenser. The condenser is downsized such that lacks the heat transfer capacity to provide some or all of the required subcooling as provided according to conventional practice, and the heat exchanger provides some or all the required subcooling according to the capacity of the condenser. A pressure differential accommodating device (38) operative to mix two vapors at different pressures may also be provided to connect the outlets of the evaporator and the heat exchanger to an inlet of the compressor.

Description

REFRIGERATION SYSTEM WITH BYPASS SUBCOOLING AND COMPONENT SIZE DE-OPTIMIZATION}

<Cross Reference with Prior Application>

This application entails a priority claim to US Provisional Application No. 60 / 426,073, filed November 11, 2002.

The present invention relates generally to high efficiency refrigeration systems, and more particularly to refrigeration systems that utilize a bypass path for subcooling with the selection of condensers, compressors and evaporators to achieve improved overall system efficiency.

1 is a block diagram of a conventional refrigeration system, indicated entirely by reference numeral 10. The refrigeration system includes a compressor 12, a condenser 14, an expansion device 16 and an evaporator 18. These components are generally connected to each other by a copper tube as indicated by reference numeral 19 to form a circulation system through which R-12, R-22, R-134a, R-407c, R-410c, ammonia Refrigerant, such as carbon dioxide or natural gas, is circulated.

The main stages of the refrigeration cycle include the refrigerant compression step by the compressor 12, the heat dissipation from the refrigerant to the surroundings by the condenser 14, the step of throttling the refrigerant in the expansion device 16, and the evaporator. Endothermic step from the cooling space by the refrigerant of (18). These processes, sometimes referred to as vapor compression refrigeration cycles, work together to cool and dehumidify air in home, commercial and industrial environments, transportation (e.g., cars, airplanes, trains, etc.), refrigeration units, heat pumps and other areas Used for system

Heat is removed from the refrigerant in the condenser, so that when the superheated refrigerant vapor from the compressor 12 reaches the outlet of the condenser, it becomes a liquid refrigerant. In Fig. 1, the condenser is divided into two parts 14a, 14b. The refrigerant vapor superheated in the first portion 14a becomes saturated steam, and after a process called an overheat reduction process, the saturated steam undergoes a phase change from steam to liquid refrigerant. In the second part 14b, the liquid phase refrigerant is further cooled below the saturation temperature at the condenser pressure, which process is known as subcooling.

2 shows the temperature distribution in the condenser. The temperature drops rapidly during the overheat reduction process (point A to point B). During the phase change (point B to point C), which changes from vapor to liquid, the temperature of the refrigerant is kept constant. At the end of the condensation process (point C), 100% liquid refrigerant is present. The temperature of the liquid refrigerant further decreases during the subcooling process (point C to point D) in the second portion of the condenser 14b. During the subcooling process, the temperature difference between the refrigerant and the cooling medium (eg, air or water) decreases, so that subcooling becomes an increasingly inefficient heat transfer process. Therefore, when the cooling capacity is determined, a relatively large condenser is required to cope with inefficient heat transfer due to a small temperature difference.

As is known, the size of the evaporator is determined by the required cooling capacity, and the compressor capacity is defined by the size of the evaporator. Larger compressors improve cooling performance, but cost and energy consumption must also be considered. In addition, since the heat dissipation capacity of the condenser should be equal to the endothermic capacity by the operation of the evaporator and the compressor, increasing the size of the compressor for a predetermined cooling capacity increases the condenser and increases the cost.

There is therefore a trade-off between them, and according to conventional methods there is an acceptable relationship between system cooling capacity (evaporator size) and compressor capacity in a so-called optimized or balanced system. For example, in a conventional one ton system, the evaporator is designed to remove 12 KBTU / Hr, with a corresponding compressor size of 4 KBTU / Hr. Therefore, the condenser must be sized to handle 16 KBTU / Hr.

Many efforts have been made to find ways to improve the efficiency, size and cost of refrigeration systems. Because of the inefficiency of heat transfer during subcooling, this feature of the refrigeration cycle has received considerable attention, but so far no suitable and cost effective technique for reducing or eliminating the size of the subcooling region of the condenser has been found.

For example, a method has been proposed in which a portion of the high pressure refrigerant from the condenser is bypassed into the bypass circuit and expanded through the secondary expansion device, and the resulting cooled refrigerant is used in the heat exchanger to supercool the main flow of the high pressure refrigerant. . The pressure in the bypass circuit remains the same as the pressure in the evaporator. An apparatus of such a configuration is disclosed in US Pat. No. 6,164,086 to Kita et al. 3 shows a schematic of this type of system.

Kita et al. Also proposed an apparatus in which the main expansion valve in the main refrigeration path is shut off when all refrigerant bypasses the bypass path and the refrigerant passes the bypass. The purpose of bypassing the coolant to the bypass line is to form ice in the heat storage vessel and thereby make the ice available for subcooling of the coolant. [Kita et al. Use the term “supercooling” for the subcooling process.] In Kita et al.'S patent, the bypass line is shut off and the main expansion valve is closed in order to meet the usual subcooling requirements. Is opened. Thereafter, all the refrigerant passes through the container filled with ice and the refrigerant is supercooled as the ice removes heat from the refrigerant. The supercooled refrigerant then passes through the main expansion device and eventually flows to the evaporator.

However, it is believed that Kita et al. Suggested that their bypass method is preferred only for mixed (nonazetropic) refrigerant systems such as R-32 / 134a or R-407c due to temperature gradients in the two-phase region. For single phase refrigerant (azeotropic) systems such as R-22 or R-134a, the bypass method does not reduce the temperature at the evaporator inlet.

Kim and Domanski, in the Intracycle Evaporative Cooling in a Vapor Compression Cycle (NISTIR 5873), have described among the bypass methods as described above that "Method 2 ( Method 2) was reviewed for the first method. They also considered another method called "Method 1", which is similar to conventional liquid line / suction line heat exchange where superheated steam is used to supercool the high pressure liquid, but with superheated steam. Instead a liquid vapor mixture from the evaporator is used. This method is shown schematically in FIG. 4.

They did not achieve desirable results for a single refrigerant system in any case, but found that some improvements were made by the first method for non-azeophilic refrigerants. However, no improvement was found for the mixed or single refrigerant system by the second method (the first method of the patent of Kita et al.).

In addition, there have been few reported improvements for mixed refrigerants, and in some cases practical interest is currently limited because mixed refrigerants are not commercially used and require higher pressure capacity than systems using single refrigerants. It cannot be used for the system.

Although a similar method to the second method proposed by Kita et al. Was used for a very large system (eg 2000 tons), it is unclear whether it can be used for small or medium systems (less than 1000 tons).

Cho and Bai, in US Pat. No. 6,449,964, disclose a method and use of a mixed refrigerant system in a high pressure bypass circuit. They initiated the use of differential pressure control devices to mix two vapors at different pressures.

Thus, there is still a clear need for a cost-effective way to achieve subcooling, particularly without current condenser and large subcooling zones in many systems with small and large cooling capacities. The present invention aims to satisfy this need.

1 shows a block diagram of a conventional refrigeration system.

FIG. 2 shows an example of temperature change in a condenser for the conventional refrigeration system of FIG. 1.

3 shows another refrigeration system according to the prior art in which a portion of the high pressure refrigerant expands to the same pressure at the evaporator outlet through the secondary expansion device in the bypass line.

4 shows an example of a bypass device using a conventional liquid line / suction line heat exchanger.

5 is a block diagram of an embodiment of the present invention in which a subcooled bypass technique is used with conventionally defined deoptimization of the size of a condenser, and a differential pressure regulating device is used to mix the flow of two refrigerants at different pressures. Indicates.

6 is a block diagram of an embodiment according to the present invention in which the evaporator is enlarged to utilize additional subcooling.

7 shows a block diagram of an embodiment according to the present invention using a vortex generator as a differential pressure control device.

8 shows a block diagram of an embodiment according to the invention in which a liquid refrigerant bypasses downstream of the secondary heat exchanger.

9 shows a block diagram of an embodiment according to the present invention in which a thermostatic expansion valve (TXV) is used to maintain a constant suction temperature.

10A and 10B illustrate the structure of a vortex generator that may be used as a differential pressure control device according to the present invention.

11 is a block diagram applying the present invention to a compartment cooling system.

12 is a block diagram applying the present invention to a mixed refrigerant system.

Figure 13 shows a block diagram of an embodiment of the present invention in which a small condenser and a large evaporator are used with a thermostatic expansion valve (TXV) to utilize additional subcooling and the heat exchanger is operated by a refrigerant exiting the evaporator.

Figure 14 shows a block diagram of an embodiment of the invention in which a small condenser and a large evaporator are utilized to utilize additional subcooling and the heat exchanger is operated by refrigerant bypassed from the main expansion device.

According to the present invention, significant improvements have been made using bypass circuits for subcooling in systems where condensers are used that conventionally abandon conventional balancing or optimization relationships between evaporators, compressors and condensers and do not conventionally provide sufficient heat removal capability. It turns out that this can be achieved. That is, in an optimization system, the required capacity determines the evaporator size, the compressor size is defined according to the evaporator size, and the heat input of all of them defines the size of the condenser. On the other hand, according to the present invention, after the evaporator size is determined, the condenser size is "de-optimized" by reducing or eliminating the subcooling capacity, for example bypassing the bypass valve from the main expansion valve into the bypass circuit. Subcooling lost through the use of a heat exchanger operated by This configuration allows the use of smaller compressors, resulting in improved energy efficiency (EER) and system cost. Smaller condensers also reduce the space needed for the system.

Since the condenser is already sufficiently large in the balancing system and the system cannot take advantage of the additional subcooling, a wonderful ability to achieve improved performance beyond that deemed possible using bypass technology is realized. However, in refrigeration systems such as the present invention where the condenser is substantially smaller than the condenser of the optimized size, the bypass method shows significant advantages since the increased subcooling acts as the condenser of the optimized size or the condenser of the oversize. Can be. This significantly increases both cooling capacity and energy efficiency (EER).

Likewise, the present invention makes it possible to manufacture the evaporator substantially larger than the evaporator of the optimum size, thereby increasing the endothermic amount. Thus, by increased subcooling, the bypass method can present a significant advantage since the matched small size condenser acts as an optimal size condenser or an excess size condenser. In such embodiments of the invention, the condenser pressure remains constant despite the increased endothermic action in the evaporator, thus increasing both cooling capacity and energy efficiency (EER) without increasing compressor work.

Generally speaking, according to the present invention, some of the liquid refrigerant from the condenser is reinjected into the primary refrigerant path at a location between the evaporator outlet and the compressor inlet after bypassing into the bypass line. Within the bypass line a secondary expansion device is used to throttle the liquid refrigerant bypassed from the condenser, thus reducing the temperature of the liquid refrigerant to substantially below the condenser outlet temperature.

The cooled refrigerant exiting the secondary expansion valve passes through a heat exchanger connected to the primary refrigerant line between the condenser outlet and the primary expansion device inlet. The heat exchanger removes heat from the refrigerant vapor coming from the condenser and thus reduces the temperature. As a result, the refrigerant enters the primary expansion device at a temperature substantially lower than the saturation temperature. That is, the degree of subcooling increases considerably, for example, from 10 ° C to 15 ° C. This is also achieved even without subcooling part of the condenser.

Since the refrigerant pressure in the bypass line at the heat exchanger outlet is greater than the pressure at the evaporator outlet, a differential pressure control device is used at the intersection of the bypass line outlet and the primary refrigerant line. The differential pressure regulating device may be a vacuum generator or a pressure reducing device.

According to a first aspect of the invention, a refrigerant compression means, a refrigerant condensation means, an expansion means and an evaporation means connected to each other to form a circulation system through which the refrigerant is circulated, and a via attached between the outlet of the condensation means and the inlet of the expansion means. A refrigeration system comprising a pass line is provided, wherein the bypass line comprises a secondary expansion means, heat exchange means for removing heat of the liquid refrigerant discharged from the condenser between an outlet of the condensation means and an inlet of the expansion means, and pressure Differential pressure control means for mixing two different vapors and connecting the outlet of the expansion means and the heat exchange means to the inlet of the compression means.

According to a second aspect of the invention, a primary refrigerant path comprising a compressor, a condenser, a primary expansion device and an evaporator connected to each other to form a circulation system through which the refrigerant circulates, and a via attached between the condenser outlet and the compressor inlet. A refrigeration system comprising a pass line is provided, wherein the bypass line is connected to a primary refrigerant path between the condenser outlet and the primary expansion device inlet to remove heat from the steam discharged from the compressor, the pressure being mutually A differential pressure control device for mixing the other two vapors and connecting the outlets of the evaporator and heat exchanger to the compressor inlet.

Also according to a second aspect of the present invention, a differential pressure control device is a moving member, such as a venturi tube or a so-called "vortex tube," which is commonly used to produce two fluid flows of different temperatures from a single high pressure input flow. It may be a vacuum generator that does not have a.

According to a second aspect of the present invention, the differential pressure regulating device may also be a pressure reducing device without a moving member such as a capillary tube, a defined orifice, a valve or a porous plug. The decompression device is used in a bypass line which is maintained at a higher pressure than the evaporator. The depressurization device equalizes the pressure between the bypass line and the evaporator outlet and includes suitable piping connections such that the equalized pressures can be mixed before returning to the compressor inlet.

According to a third aspect of the present invention, there is provided a method of improving the efficiency of a refrigeration system consisting of a primary refrigerant path comprising a compressor, a condenser, a primary expansion device, and an evaporator connected to each other to form a circulation system through which the refrigerant is circulated, The method includes bypassing a portion of the refrigerant from the condenser to a secondary refrigerant line, and bypassing the bypassed refrigerant between the condenser outlet and the primary expansion device inlet to remove heat from the liquid refrigerant discharged from the condenser. Passing through the heat exchanger connected to the path, and passing the refrigerant from the heat exchanger and the refrigerant from the evaporator to a differential pressure regulating device that mixes two vapors with different pressures, and delivering the refrigerant from the differential pressure regulating device to the compressor inlet. It includes.

The installation of a bypass path for carrying out subcooling improves the efficiency of the condenser, thus reducing the condenser pressure and reducing the pressure rise in the compressor, thereby reducing compressor work. Correspondingly, because subcooling does not have to be done in the condenser, the condenser can be substantially miniaturized and becomes more effective and cost effective. Increased subcooling increases the amount of liquid refrigerant after the throttling process through the first expansion valve. Thus, the endothermic amount (commonly referred to as cooling capacity) in the evaporator increases.

The above-mentioned advantages of subcooling bypass are achieved by bypassing 5% to 15% of the liquid refrigerant outflow from the condenser. By this amount, a reduction in compressor work and an increase in cooling capacity are achieved. Energy efficiency (EER) is defined as the ratio of cooling capacity to compressor work, which increases energy efficiency (EER).

According to a fourth aspect of the present invention, when at least 15%, for example 30%, of the liquid refrigerant from the condenser bypasses the bypass path, the cooling capacity is lowered due to a substantial decrease in the refrigerant flow rate circulating through the evaporator. do. By using a regulating valve in the bypass path, the bypass flow rate and thus cooling capacity can be varied with the heat load, thus making it possible to operate the air conditioning system or the refrigeration system without frequent and inefficient operation of the compressor. As a result, long term energy efficiency (SEER) is improved.

According to a fifth aspect of the invention, multiple evaporators can be used, for example, in compartment cooling systems. Thus, several small evaporators can be provided with one condenser and one compressor in a separate space. If all spaces require cooling, the system can be operated with 5% bypass to provide maximum cooling capacity and maximum efficiency. If less space needs to be cooled and thus the heat load is reduced, the bypass ratio can be increased to reduce the cooling capacity without having to periodically open and close the compressor. This is particularly desirable because repetitive and periodic compressor opening and closing is a very energy inefficient process.

In contrast to the prior art, the idea of the present invention is applicable to conventional single refrigerant systems and mixed refrigerant systems utilizing a combination of refrigerants selected to provide the desired combination of thermal and flammable properties. Such mixed refrigerant systems also include heat storage characteristics that provide high efficiency of the condenser by increasing the fraction of liquid in the refrigerant as the refrigerant flows into the condenser. Regenerative mixed refrigerant systems are disclosed, for example, in US Pat. Nos. 6,250,086 and 6,293,108, which are incorporated herein by reference.

According to another aspect of the present invention, the size of the condenser can be further reduced by employing a bypass circuit for reducing overheating as well as overcooling. The use of the overheat reduction bypass is disclosed in U.S. Patent Application No. 10 / 253,000 (Atty Docket 3474-21), filed and pending on September 23, 2002, in this U.S. patent. The application is incorporated herein by reference.

 It is therefore an object of the present invention to provide an apparatus and method for removing subcooled regions in a condenser of a refrigeration system.

It is also an object of the present invention to increase the efficiency of known refrigeration systems by providing a more cost effective method of providing subcooling of the refrigerant in the refrigeration system.

Another object of the present invention is to improve the cooling capacity and energy efficiency (EER) of known refrigeration systems by providing an efficient method of providing subcooling of a refrigerant.

It is yet another object of the present invention to provide a system with improved cooling capacity and energy efficiency (EER) by using bypass subcooling techniques with deoptimization of the size of the condenser conventionally used for a given cooling capacity.

It is an object of the present invention to provide a cost-effective method of providing subcooling of a refrigerant, thereby enabling the use of smaller condensers in known refrigeration systems.

It is yet another object of the present invention to provide energy efficiency (EER) or cooling capacity while allowing the use of condensers and compressors smaller than the current optimal size and size ratio of components of known cooling systems that do not use bypass subcooling technology. It does not deteriorate.

It is another object of the present invention to provide a method and apparatus for subcooling refrigerants that can be used in regenerative and non-regenerative single refrigerant systems and mixed refrigerant systems.

It is a further object of the present invention to provide an improved refrigeration system in which the evaporator pressure is substantially lowered by the use of a vacuum generator and thus the evaporator capacity is improved.

It is yet another object of the present invention to provide an improved refrigeration system in which a vacuum generator is used to mix two refrigerant flows at different pressures to increase the suction pressure of the compressor, thereby reducing the required pressure rise for the compressor. Reduces compressor work and increases energy efficiency (EER).

It is a further object of the present invention to provide an improved refrigeration system which mixes two vapors at different pressures using a vacuum generator so that the pressure in the bypass line can be maintained at a higher pressure than the condenser pressure.

It is yet another object of the present invention to provide an improved refrigeration system which mixes two vapors at different pressures using a pressure reducing device so that the pressure in the bypass line can be maintained at a higher pressure than the evaporator pressure.

It is still another object of the present invention to satisfy various conditions related to temperature by performing subcooling outside the condenser, i.e., by performing subcooling in a bypass where the refrigerant from the condenser bypasses, and controlling the amount of refrigerant bypassed. It is to provide an improved cooling system capable of adjusting the cooling capacity so that the system can be operated without the need for periodic compressor opening and closing which is energy inefficient.

It is yet another object of the present invention to provide a method and apparatus for improving cooling capacity and energy efficiency (EER) of conventional refrigeration systems by employing bypass technology with deoptimization of condenser sizes for both subcooling and overheating reduction. It is.

Throughout the drawings, like elements have been given the same reference numerals.

5 illustrates the concept of a bypass technique in which a portion of the liquid refrigerant is bypassed along the bypass line or bypass path 27. As the refrigerant in the bypass path flows through the secondary expansion device 23, the pressure and the temperature are lowered. The low temperature refrigerant mixture behind the secondary expansion device receives heat energy from the hot liquid refrigerant discharged from the condenser and flows through the primary refrigerant line to further supercool the liquid refrigerant. By further subcooling by the bypass method, there is no need for the subcooling process in the condenser. Thus, a smaller condenser 14b is shown in FIG. 5 with the subcooled region removed, and the subcooled region removed is shown by a rectangular dotted box.

FIG. 6 illustrates a bypass technique in which an evaporator is utilized that is larger than the evaporator of an optimal system without the bypass technique. Because of the increased degree of subcooling by the bypass technology, a larger evaporator can be utilized. If the supercooling degree is increased, a larger amount of liquid refrigerant is produced at a lower temperature behind the main expansion device, thereby improving the endothermic action of the evaporator. The increased size of the evaporator is shown by a rectangular dotted box 18a. The increased sized evaporator is shown at 28 in FIG. 6. The size of the evaporator directly affects the capacity of the refrigeration system. In this embodiment, the technique of utilizing a larger evaporator than the evaporator of an optimal system without bypass is very important, because using the bypass technology of the present invention increases the capacity of the system without increasing the size of the condenser and compressor. Because you can. Increasing the size of the evaporator while keeping the size of the other components constant will not only increase the cooling capacity, but additional bypass will also be needed to reduce the size of the condenser and the size of the compressor. It is possible to meet the predetermined evaporator capacity. For example, a refrigeration system may be constructed in which the size of the condenser and the size of the compressor are smaller than the optimum system while maintaining the size of the evaporator and the cooling capacity. It is particularly desirable to reduce the size of the compressor, because the current compressor cost is about half of the total cost of the refrigeration system.

FIG. 7 illustrates a bypass technique with an evaporator 28 larger than the evaporator of a refrigeration system without bypass and a condenser 24 smaller than the condenser of the refrigeration system. For example, in the case of a one ton air conditioning system without bypass, as shown in FIG. 1, the condenser 14 corresponding to one ton (i.e., 15 KBtu / hr), the evaporator 18 corresponding to one ton (Ie 12 KBtu / hr), and a compressor 12 configured to be applied to one ton is required. In the case of a one ton air conditioning system with a bypass, a smaller condenser 24 (ie 10 KBtu / hr), a larger evaporator 28 (ie 15 KBtu / hr), and as shown in FIG. 6, and The same compressor 12 formed to be applied to one tonne is required.

6 illustrates a bypass technique utilizing the differential pressure control device 38. The pressure of the bypass path 27 is higher than the pressure of the evaporator. Thus, there is a need for a differential pressure control device to control the different pressures of the two vapors behind the evaporator. The differential pressure regulating device may be a vacuum generating device such as a vortex generator or a venturi tube or a pressure reducing device such as a capillary tube, a defined small orifice, a valve or a porous plug. In the case of a decompression device, the pressure of the refrigerant flow discharged from the bypass path is reduced by friction to match the evaporator pressure. In addition, the decompression device may be provided with appropriate piping and the like so that steam having a uniform pressure may be mixed before returning to the compressor inlet.

FIG. 7 illustrates a bypass technique in which a vortex generator 29 is used as a differential pressure regulator to generate a vacuum and mix two refrigerant flows of different pressures.

According to the embodiment shown in FIGS. 5 to 7, the refrigerant is diverted to the secondary path before the primary refrigerant flow is subcooled in the heat exchanger 22. 8 shows yet another embodiment bypassed after a subcooling process. A differential pressure control device 38 is provided between the evaporator and the compressor to mix the two vapors at different pressures.

Figure 9 illustrates one embodiment of the present invention employing a thermostatic expansion valve (TXV) 16a with bypass technology. The thermostatic expansion valve (TXV) 16a monitors the degree of superheat by measuring the refrigerant flow entering the evaporator 28 using the temperature sensing element 41. The thermostatic expansion valve (TXV) 16a is opened and closed in response to the thermosensitive element 41. A thermostatic expansion valve (TXV) 16a keeps the superheat of evaporator 28 constant. The use of a thermostatic expansion valve (TXV) 16a with bypass technology allows the use of a smaller evaporator than any other evaporator. As the endothermic action of the evaporator 28 increases, the degree of superheat also increases. Therefore, when the thermostatic expansion valve (TXV) 16a is opened, the mass flow rate of the circulating refrigerant is increased to keep the degree of superheat constant. Using a larger evaporator with a thermostatic expansion valve (TXV) 16a can significantly increase the endothermic action of the evaporator when the thermostatic expansion valve (TXV) 16a increases the mass flow rate of the circulating refrigerant. Will be.

In the absence of a bypass, the use of larger evaporators results in increased condenser pressure with increased endothermic action, thereby increasing compressor work. In general, since the amount of increase in the compressor work is greater than the amount of increase in the endothermic action, the energy efficiency (EER) is lowered. However, according to the bypass technique of the present invention, the supercooling after the condenser 24 is sufficiently formed so that the endothermic action of the evaporator 28 does not increase even if the endothermic action is increased, because the bypass condenser 24 is formed by the bypass. ) Can behave as if its size is enlarged. Therefore, the energy efficiency EER is increased when the bypass is provided.

The structure of the vortex generator is shown in FIGS. 10A and 10B. The structure of the vortex generator, generally indicated at 40, is derived from a so-called vortex tube, which is a known device, which allows the inlet flow of compressed gas to flow through two outlet streams, i.e., the temperature of the gas supplied to the vortex tube. And lower cold flows. The vortex tube does not contain any moving parts. Such a device is disclosed in US Pat. No. 6,250,086, which is incorporated herein by reference.

As shown in FIGS. 10A and 10B, a vortex generator 40 is used to mix two vapors of different pressures into one flow. In the present invention, the vortex generator 40 is used as the mixing means. This vortex generator consists of a tubular body 60 having an axial inlet 52, a tangential inlet 54 at the inlet end 62 and an outlet 58 at the opposite outlet end 64. The internal structure of the tube 60 at the inlet end is formed such that the high pressure gas flow entering the tangential inlet 54 is moved towards the outlet 58 along the helical path. As a result, a strong vortex flow is formed in the tube 60, and the steam is pressurized radially outward in accordance with the radial differential pressure caused by the centrifugal force generated by the vortex flow, thereby forming a high pressure on the outer circumference and a low pressure on the shaft. Will be. This low pressure causes fluid to enter the axial inlet 52 and mix with the high pressure spiral flow and then exit through the outlet 58.

Referring to the system shown in FIG. 7 and the structure of the vortex generator 40 shown in FIGS. 10A and 10B, the high pressure tangential flow through the tube 54 from the secondary heat exchanger 22 and the bypass path 27 is shown. Is formed and a flow is formed which flows from the outlet of the evaporator 28 to the axial inlet 52. By using a vacuum generator based on a vortex generator, the refrigerant discharged from the evaporator 28 and the high pressure refrigerant discharged from the secondary heat exchanger 22 can be removed without using an expensive pump with moving parts. You can mix.

Other devices based on fluid mechanics and geometry can also be used to generate a vacuum to mix refrigerant flows exiting evaporator 18 and heat exchanger 22. For example, devices that operate according to the principle of venturi tubes can also be used.

Referring again to FIG. 7, the liquid refrigerant discharged from the condenser 24 in operation is bypassed to the bypass path 27 by an appropriate valve (not shown), for example. The bypassed refrigerant flows through the secondary expansion device (23) and then through the heat exchanger (22), where the heat exchanger performs the subcooling function that was conventionally performed downstream of the condenser. Appropriate selection of the system variable, in particular the mass flow rate of the refrigerant bypassed in the bypass path, allows the refrigerant to be discharged from the condenser 24 to a saturation temperature or to a temperature close to the saturation temperature and to heat transfer to the outside. This allows phase change to be carried out along the entire flow path through the condenser to achieve maximum condenser efficiency. For this purpose, it has been found that only 5% to 15% of the liquid refrigerant discharged from the condenser needs to be bypassed in the bypass path.

Specifically, the provision of a bypass path for subcooling makes the condenser 24 more efficient and reduces the condenser pressure. When the condenser pressure is reduced, the pressure rise in the compressor 12 is lowered, thereby reducing the work of the compressor. Let's go. The coefficient of performance ("COP") of the refrigeration system, sometimes referred to as energy efficiency (EER), is defined as Qv / Wc, where Qv represents the endothermic amount absorbed by the system's evaporator, and Wc is the work performed by the compressor. Indicates. As can be seen from the equation, decreasing Wc increases coefficient of performance (COP) and energy efficiency (EER).

Therefore, since the subcooling process does not need to be performed inside the condenser 24, the condenser becomes more efficient, and the degree of subcooling in front of the main expansion device 16 is increased. Thus, the amount of liquid refrigerant is increased after the throttling process through the main expansion valve 16. Accordingly, the endothermic amount (commonly referred to as cooling capacity) of the evaporator 28 is also increased.

Referring to FIG. 7, by appropriately configuring a vacuum generator such as the vortex generator 40 or the venturi tube shown in FIGS. 10A and 10B, the pressure at the low pressure inlet 52 is lower than the inlet pressure of the main evaporator 28. can do. As a result, a pressure drop phenomenon may occur across the evaporator 28. This is very desirable as the evaporator outlet pressure is lowered because the evaporator temperature difference is increased and the evaporator capacity is increased.

More importantly, after mixing the two vapor flows exiting heat exchanger 22 and evaporator 28, the pressure of the mixed flow may be higher than the evaporator inlet pressure. This means that the required pressure rise of the compressor 12 is reduced by increasing the suction pressure at the compressor inlet. Reduced compressor work results in increased energy efficiency (EER), which is highly desirable.

In FIG. 11, a compartment air conditioning system, implemented in accordance with the principles of the present invention, is shown at 110. The compartment air conditioning system differs from the system 50 shown in FIG. 5 in that the bypass path 92 includes an adjustable control valve 94 and is also positioned to operate in different rooms and open and close respectively. The evaporator 96 is formed by several parallel-connected evaporator units 98a, 98b connected to the main expansion device 16 by valves 100a, 100b. Thus, the system 110 is configured to form two separate cooling zones, but, as can be expected, may form a larger number of cooling zones as needed.

The pressures of the outlets of the evaporator units 98a and 98b are the same, which outlets are commonly connected to the inlet of the differential pressure control device 38.

In operation, when it is desired to cool both cooling zones, valves 100a and 100b are opened so that refrigerant flows through both evaporators 98a and 98b. In order to achieve maximum cooling efficiency, the valve 94 is adjusted to bypass 10% to 60% of the refrigerant discharged from the condenser 24 to the bypass path. Accordingly, all of the advantages for bypass subcooling described in connection with FIGS. 5, 6, and 7 are also established in the case of the present system 110.

According to an additional feature of the present system 110, in the case where cooling is required only in the region where the evaporator unit 98a is located, for example, the valve 100a is opened and the valve 100b is closed and the valve 94 is closed. In other cases, is adjusted to bypass the refrigerant flowing through the evaporator 98b to the bypass path 92 together with the refrigerant required for subcooling.

In order to vary the bypass mass flow rate, the valve 94 of the bypass path 92 must be continuously or adjustable in several steps to provide the desired amount of different flow rate. For example, 5% to 15% of refrigerant may be bypassed to achieve maximum performance, and 20%, 30%, 40%, 50% and 60% of refrigerant may be required if the required cooling capacity is lowered. It may be bypassed. Valves that can provide this capacity are currently on the market, and any suitable valve or any valve of this type may be used.

As described above, maximum efficiency and cooling capacity are achieved by diverting 5% to 15% of the coolant mass flow to the bypass path 92. If the amount of bypassed coolant is increased by more than 15% to, for example, 30% or more, the coolant mass flow rate circulated through the evaporator 96 is significantly reduced to lower the cooling capacity. Thus, by bypassing the refrigerant that is not needed in the stopped evaporator, it is possible to change the cooling capacity according to the heat load without repeating the operation and shutdown cycles of the compressor or providing an expensive variable speed compressor.

This is very desirable in that large amounts of energy are consumed by the compressor's actuation and shutdown cycles. This elimination of inefficiency significantly improves long-term energy efficiency, sometimes measured as SEER, taking into account the effect of compressor operation and shutdown on the efficiency of the system. The energy efficiency SEER is the ratio of the sum multiplied by the operating time times Qv (the endothermic amount absorbed by the evaporator) to the sum multiplied by the operating time times Wc (compressor days).

As can be appreciated from the above description, the cooling capacity can be varied in the single zone system shown in FIGS. At this time, additional coolant is bypassed to the bypass path 27 by an appropriate control valve (not shown) in order to control the desired reduction in cooling capacity, and the refrigeration system needs to repeat the compressor's operation and shutdown cycles frequently. Can be operated without.

In the configuration described above, it is assumed that a single refrigerant circulates through the system. To achieve very desirable advantages, subcooling bypass may be used in refrigeration systems with mixed refrigerants.

FIG. 12 shows one embodiment of the present invention as a mixed refrigerant system using a mixture of refrigerants R-32, R-125 and R-134a as an example. This mixture is commonly used as a very desirable mixture because R-32 is flammable but has very good thermal properties, and R-125 and R-134a are less flammable than R-32 but are non-flammable. Because it is safer. For simplicity of illustration, changes in the heat storage paths disclosed in US Pat. Nos. 6,293,108 and 6,449,964 are omitted from the system of FIG.

The system, denoted by reference numeral 120, is a bypass path as in compressor 12, expansion device 16a, evaporator 28, heat exchanger 22, and system 50 (see FIG. 5). 27 is composed of a differential pressure regulating device 38. However, the condenser of the system 120 shown in FIG. 12 is divided into two condensers 24a, 24b, and any suitable or predetermined type of gas-liquid (LV) separator 108 is provided between the two condensers. .

The gas-liquid (LV) separator 108 flows the inlet vapor flow discharged from the condenser 24a into the first vapor component flowing into the inlet of the condenser 24b, and a portion of it flows into the bypass path 27 to open the valve 112. The second liquid component of low temperature flowing through the inlet of the heat exchanger (22).

The R-134a refrigerant is enriched in the second component discharged by the gas-liquid (LV) separator 108 and passed through the valve 112 because the refrigerant has a different condensation point and boiling point than that of the R-134a refrigerant. It is because it is higher than a component. In addition to the benefit of performing the overheating reduction step outside of the condenser 24a as described above, additional benefits are provided that can reduce the condenser pressure by allowing R-134a to enrich in the refrigerant in the bypass path in liquid form.

As described above, the system shown in FIG. 12 is a representative system in which the principles of the present invention are applied to a mixed refrigerant heat storage system. However, the bypass can also be applied to other mixed refrigerant storage systems.

FIG. 13 shows an embodiment in which the present invention is applied to a conventional liquid line / suction line heat exchange system, in which superheated vapor or gas-liquid mixture discharged from an evaporator is deoptimized in size compared to the size of the condenser disclosed in the prior art. It is used to supercool the high pressure liquid discharged from the condenser. Since the suction temperature increases in front of the compressor 212, the present invention uses the thermostatic expansion device 216 together with a thermostatic bulb 241 to monitor the suction temperature to increase the circulating mass flow rate of the refrigerant. The thermostatic expansion device 216 increases the mass flow rate of the circulating refrigerant, whereby the suction temperature is kept constant in the present invention. The present invention uses a condenser 214 that is much smaller than the condenser in the optimization system. The present invention also uses an evaporator 218 of much larger size than the evaporator in the optimization system. In an optimization system, conventional liquid line / suction line heat exchange does not improve the efficiency of the system. The present invention using large evaporator 218 enables refrigeration systems to be manufactured with condensers and small compressors smaller than the size in an optimization system that does not use a bypass method.

FIG. 14 shows the invention as applied to a system configuration similar to the system shown in FIG. 4, and here also does not employ optimization of the condenser size as defined by conventional techniques. In FIG. 14, a portion of the liquid refrigerant bypasses the second expansion device 223 and the heat exchanger 222 to supercool the high pressure liquid coming from the condenser. The present invention uses a condenser 224 that is much smaller than the condenser in the optimization system. The present invention also uses an evaporator 228 that is much larger than the evaporator in the optimization system.

In the description of the invention, specific terminology has been used for the sake of clarity. However, it is not intended that the present invention be limited to specific descriptive terms, and each specific term should be understood to include all terms that exhibit technically equivalent effects in similar ways to achieve similar purposes.

Likewise, the described and illustrated embodiments are representative, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the present invention and other embodiments are possible with reference to the present disclosure. Accordingly, the scope of the invention is defined and defined only by the appended claims and not by the description of the specification.

Claims (80)

A primary refrigerant path having refrigerant compression means, refrigerant condensation means, expansion means and evaporation means connected together to form a circulation system through which the refrigerant is circulated; A bypass path connected to the outlet of the condensation means, the second expansion means and a heat exchange means connected to the primary refrigerant path between the inlet of the expansion means and the outlet of the condensation means to remove heat of the liquid refrigerant discharged from the condenser, And a bypass path comprising a differential pressure regulating device connecting the outlet of the evaporation means and the outlet of the heat exchange means with the inlet of the compression means to mix two vapors of different pressures. The method of claim 1, The heat transfer capacity of the condensation means is insufficient to subcool the refrigerant as necessary, and the refrigerant is entirely subcooled as necessary by the heat exchange means. The method of claim 1, A refrigeration system, characterized in that the heat exchange means and the condensation means are configured to subcool the refrigerant as much as necessary by the heat exchange means. A primary refrigerant path having a compressor, a condenser, a primary expansion device and an evaporator connected together to form a circulation system through which the refrigerant is circulated; A bypass path connected to the outlet of the condenser, the secondary expansion device, a heat exchanger connected to the primary refrigerant path between the primary expansion device inlet and the condenser outlet to remove heat from the refrigerant discharged from the condenser, And a bypass path comprising a differential pressure regulator connecting the outlet of the evaporator and the outlet of the heat exchanger with the inlet of the compressor to mix the two vapors. The method of claim 4, wherein The heat transfer capacity of the condenser is insufficient to subcool the refrigerant as needed, and the refrigerant is entirely subcooled as needed by the heat exchanger. The method of claim 4, wherein And the heat exchanger and the condenser are configured such that the refrigerant is substantially subcooled by the heat exchanger. The method of claim 4, wherein The bypass path is connected to the condenser outlet downstream of the heat exchanger. The method of claim 4, wherein The evaporator consists of a number of parallel connected evaporator parts located in each part of the space cooled by the refrigeration system; A plurality of on / off valves each connecting the primary expansion device to the evaporator component to stop the operation of each evaporator component by blocking the flow of refrigerant into each evaporator component when cooling at a particular location is not required at any given time. Open and close valve, An adjustable valve in the bypass path, which is capable of regulating the refrigerant flow in the bypass path such that refrigerant mass flow that is not needed in the primary refrigerant path flows into the bypass path when certain evaporator components are deactivated. Refrigeration system, characterized in that it further comprises. The method of claim 8, The compressor is configured and regulated to operate continuously regardless of changes in heat load when the refrigeration system is in operation. The method of claim 8, Differential pressure regulator, A low pressure inlet commonly connected to the outlets of the evaporator components, A high pressure inlet connected to the bypass path, And an outlet connected to the inlet of the compressor. The method of claim 8, The valve in the bypass path bypasses about 5% to about 15% of the refrigerant to the bypass path when all evaporator components are running, requiring maximum cooling capacity, and about 60 when the heat load is reduced by stopping operation of certain evaporator components. A refrigeration system, characterized in that it is operable to bypass up to% refrigerant to the bypass path. The method of claim 4, wherein Further comprising a valve in the bypass path, wherein the valve bypasses from about 5% to about 15% of the refrigerant to the bypass path when the maximum cooling capacity is required due to high heat load and up to about 60% when the heat load is reduced. And a refrigeration system operable to bypass the refrigerant in the bypass path. The method of claim 12, The compressor is configured and regulated to operate continuously regardless of changes in heat load when the refrigeration system is in operation. The method of claim 4, wherein The expansion device of the primary refrigerant path is operated in a thermosensitive manner in response to a temperature sensor connected to the inlet of the compressor, so that the overheating state of the evaporator can be kept constant. The method of claim 14, Evaporator, characterized in that the evaporator is reduced in size compared to the size previously required to increase the cooling capacity without increasing the compressor work. The method of claim 15, The condenser is reduced in size compared to the size previously required for large evaporators selected to achieve the desired cooling capacity. The method of claim 14, The condenser is reduced in size compared to the size previously required for the evaporator selected to achieve the desired cooling capacity. The method of claim 4, wherein The condenser is reduced in size compared to the size previously required for the evaporator selected to achieve the desired cooling capacity. The method of claim 4, wherein Refrigerant system, characterized in that the refrigerant circulated in the refrigeration system consists of a single component. The method of claim 4, wherein Refrigerant system, characterized in that the refrigerant circulated in the refrigeration system is a mixed refrigerant containing various components selected to provide the desired thermal and flammable properties together. The method of claim 20, In order to improve evaporator efficiency, the apparatus further includes a gas-liquid separator that can selectively bypass at least one component of the mixed refrigerant to the bypass path to increase the liquid ratio of the mixed refrigerant as it enters the evaporator. Refrigerating system, characterized in that. The method of claim 21, The bypassed refrigerant has a high condensation temperature and a high boiling temperature relative to the remainder of the refrigerant. A primary refrigerant path having a compressor, a condenser, a primary expansion device and an evaporator connected together to form a circulation system through which the refrigerant is circulated; A bypass path connected between the outlet of the condenser and the inlet of the compressor, the bypass path comprising a secondary expansion device and a heat exchanger connected to the primary refrigerant path between the primary expansion device inlet and the condenser outlet to supercool the refrigerant discharged from the condenser. And a bypass path, wherein the heat transfer capacity of the condenser is insufficient to subcool the refrigerant as needed. The method of claim 23, And the heat exchanger and the condenser are configured such that the refrigerant is completely cooled by the heat exchanger. The method of claim 23, The vapor pressure of the refrigerant discharged from the heat exchanger is higher than the vapor pressure of the refrigerant discharged from the evaporator, And a differential pressure regulating device connecting the outlet of the evaporator and the outlet of the heat exchanger with the inlet of the compressor. The method of claim 25, The differential pressure control device is a refrigeration system, characterized in that the vacuum generator having an inlet connected to the outlet of the evaporator and the outlet of the heat exchanger and an outlet connected to the inlet of the compressor. The method of claim 25, The differential pressure control device is a refrigeration system, characterized in that the venturi tube or vortex tube. The method of claim 25, The differential pressure control device comprises a decompression device connected to an outlet of a heat exchanger, and a mixing device connecting the outlet of the evaporator and the inlet of the compressor with the inlet of the compressor. The method of claim 28, Refrigeration system, characterized in that the pressure reducing device is a capillary tube, a defined orifice, a valve or a porous plug. The method of claim 23, The bypass path is connected to the condenser outlet downstream of the heat exchanger. The method of claim 23, The evaporator consists of a number of parallel connected evaporator parts located in each part of the space cooled by the refrigeration system; A plurality of on / off valves each connecting the primary expansion device to the evaporator component to stop the operation of each evaporator component by blocking the flow of refrigerant into each evaporator component when cooling at a particular location is not required at any given time. Open and close valve, An adjustable valve in the bypass path, which is capable of regulating the refrigerant flow in the bypass path such that refrigerant mass flow that is not needed in the primary refrigerant path flows into the bypass path when certain evaporator components are deactivated. Refrigeration system, characterized in that it further comprises. The method of claim 31, wherein The compressor is configured and regulated to operate continuously regardless of changes in heat load when the refrigeration system is in operation. The method of claim 31, wherein And a differential pressure control device having a low pressure inlet commonly connected to the outlets of the evaporator components, a high pressure inlet connected to the bypass path, and an outlet connected to the inlet of the compressor. The method of claim 31, wherein The valve in the bypass path bypasses about 5% to about 15% of the refrigerant to the bypass path when all evaporator components are running, requiring maximum cooling capacity, and about 60 when the heat load is reduced by stopping operation of certain evaporator components. A refrigeration system, characterized in that it is operable to bypass up to% refrigerant to the bypass path. The method of claim 23, Further comprising a valve in the bypass path, wherein the valve bypasses from about 5% to about 15% of the refrigerant to the bypass path when the maximum cooling capacity is required due to high heat load and up to about 60% when the heat load is reduced. And a refrigeration system operable to bypass the refrigerant in the bypass path. 36. The method of claim 35 wherein The compressor is configured and regulated to operate continuously regardless of changes in heat load when the refrigeration system is in operation. The method of claim 23, The expansion device of the primary refrigerant path is operated in a thermosensitive manner in response to a temperature sensor connected to the inlet of the compressor, so that the overheating state of the evaporator can be kept constant. The method of claim 37, Evaporator, characterized in that the evaporator is enlarged compared to the size previously required to increase the cooling capacity without increasing the compressor work. The method of claim 38, The condenser is reduced in size compared to the size previously required for large evaporators selected to achieve the desired cooling capacity. The method of claim 37, The condenser is reduced in size compared to the size previously required for the evaporator selected to achieve the desired cooling capacity. The method of claim 23, The condenser is reduced in size compared to the size previously required for the evaporator selected to achieve the desired cooling capacity. The method of claim 23, The heat exchanger is connected such that an opposing flow of refrigerant is formed in the heat exchanger and the refrigerant sensitive to temperature is provided in the primary refrigerant path. The method of claim 23, Refrigerant system, characterized in that the refrigerant circulated in the refrigeration system consists of a single component. The method of claim 23, Refrigerant system, characterized in that the refrigerant circulated in the refrigeration system is a mixed refrigerant containing various components selected to provide the desired thermal and flammable properties together. The method of claim 44, In order to improve evaporator efficiency, the apparatus further includes a gas-liquid separator that can selectively bypass at least one component of the mixed refrigerant to the bypass path to increase the liquid ratio of the mixed refrigerant as it enters the evaporator. Refrigerating system, characterized in that. The method of claim 45, The bypassed refrigerant has a high condensation temperature and a high boiling temperature relative to the remainder of the refrigerant. A method of improving the efficiency of a refrigeration system consisting of a primary refrigerant path comprising a compressor, a condenser, a primary expansion device and an evaporator connected together to form a circulation system through which the refrigerant is circulated, Bypassing a portion of the refrigerant discharged from the condenser into a secondary refrigerant path comprising a secondary expansion device and a heat exchanger connected to the primary refrigerant path between the primary expansion device inlet and the condenser outlet; Flowing the bypassed refrigerant through a heat exchanger to remove heat from the refrigerant flowing in the primary refrigerant path; Flowing the refrigerant discharged from the heat exchanger and the refrigerant discharged from the evaporator through a differential pressure regulating device for mixing two vapors having different pressures; And delivering the refrigerant discharged from the differential pressure control device to the inlet of the compressor. The method of claim 47, And the refrigerant is diverted to the bypass path at a location downstream of the heat exchanger. The method of claim 47, About 5% to about 15% of the liquid refrigerant discharged from the condenser is diverted to the bypass path. The method of claim 47, Adjusting the amount of refrigerant exiting the condenser and bypassing the bypass path to adjust the cooling capacity of the refrigeration system according to the heat load; Further comprising continuously operating the compressor when the refrigeration system is in operation to improve long term energy efficiency. The method of claim 47, The primary refrigerant path comprises a plurality of evaporators located at each location to be cooled individually, Bypassing a predetermined minimum amount of refrigerant into the bypass path when a maximum cooling capacity is needed to cool all locations; And bypassing the increased amount of refrigerant in the bypass path when the heat load is reduced. The method of claim 51, And continuously operating the compressor regardless of the required cooling capacity when the refrigeration system is in operation. The method of claim 52, wherein Stopping the operation of the evaporator by blocking the flow of refrigerant entering the evaporator for a particular evaporator at a location that does not require cooling at a given time; Bypassing the refrigerant typically delivered to the particular evaporator that is shut down into a bypass path. The method of claim 47, The refrigerant circulating in the refrigeration system is a method of improving the efficiency of the refrigeration system, characterized in that consisting of a single component. The method of claim 47, The refrigerant circulated in the refrigeration system is a mixed refrigerant comprising a variety of components selected to provide the desired thermal and flammable properties together. The method of claim 55, To improve the evaporator efficiency, further comprising selectively bypassing at least one component of the mixed refrigerant into the bypass path to increase the liquid ratio of the mixed refrigerant as it enters the evaporator. To improve the efficiency of refrigeration systems. The method of claim 56, wherein The bypassed refrigerant has a high condensation temperature and a high boiling temperature relative to the remainder of the refrigerant. The method of claim 47, Sensing the temperature of the refrigerant at the inlet of the compressor; In order to maintain the superheated state of the refrigerant discharged from the evaporator at a constant level, the efficiency of the refrigeration system further comprises the step of adjusting the mass flow rate of the refrigerant through the expansion device of the primary refrigerant path according to the sensed temperature Way. The method of claim 58, A method of improving the efficiency of a refrigeration system, characterized in that the evaporator is enlarged relative to the size previously required to increase the cooling capacity without increasing the compressor work. The method of claim 59, The condenser is reduced in size compared to conventionally required sizes for large evaporators selected to achieve the desired cooling capacity. The method of claim 58, The condenser is reduced in size relative to the size previously required for the selected evaporator to achieve the desired cooling capacity. The method of claim 47, The condenser is reduced in size relative to the size previously required for the selected evaporator to achieve the desired cooling capacity. As a method of improving the efficiency of the refrigeration system, Flowing refrigerant through a primary refrigerant path comprising a compressor, a condenser, a primary expansion device, and an evaporator connected together to form a circulation system, wherein the heat transfer capacity of the condenser is insufficient to overcool the circulation refrigerant as needed; ; Bypassing a portion of the refrigerant discharged from the condenser into a secondary refrigerant path comprising a secondary expansion device and a heat exchanger connected to the primary refrigerant path between the primary expansion device inlet and the condenser outlet; Flowing the bypassed refrigerant through a heat exchanger to supercool the refrigerant flowing in the primary refrigerant path. The method of claim 63, wherein Flowing the refrigerant discharged from the heat exchanger and the refrigerant discharged from the evaporator through a differential pressure regulating device for mixing two vapors having different pressures; And passing the refrigerant discharged from the differential pressure control device to the inlet of the compressor. The method of claim 63, wherein And the refrigerant is diverted to the bypass path at a location downstream of the heat exchanger. The method of claim 63, wherein The refrigerant is all subcooled as necessary by the heat transfer of the heat exchanger efficiency improvement method of the refrigeration system. The method of claim 63, wherein About 5% to about 15% of the liquid refrigerant discharged from the condenser is diverted to the bypass path. The method of claim 63, wherein Adjusting the amount of refrigerant exiting the condenser and bypassing the bypass path to adjust the cooling capacity of the refrigeration system according to the heat load; Further comprising continuously operating the compressor when the refrigeration system is in operation to improve long term energy efficiency. The method of claim 63, wherein The primary refrigerant path comprises a plurality of evaporators located at each location to be cooled individually, Bypassing a predetermined minimum amount of refrigerant into the bypass path when a maximum cooling capacity is needed to cool all locations; And bypassing the increased amount of refrigerant in the bypass path when the heat load is reduced. The method of claim 69, wherein And continuously operating the compressor regardless of the required cooling capacity when the refrigeration system is in operation. The method of claim 70, Stopping the operation of the evaporator by blocking the flow of refrigerant entering the evaporator for a particular evaporator at a location that does not require cooling at a given time; Bypassing the refrigerant typically delivered to the particular evaporator that is shut down into a bypass path. The method of claim 63, wherein The refrigerant circulating in the refrigeration system is a method of improving the efficiency of the refrigeration system, characterized in that consisting of a single component. The method of claim 63, wherein The refrigerant circulated in the refrigeration system is a mixed refrigerant comprising a variety of components selected to provide the desired thermal and flammable properties together. The method of claim 73, To improve the evaporator efficiency, further comprising selectively bypassing at least one component of the mixed refrigerant into the bypass path to increase the liquid ratio of the mixed refrigerant as it enters the evaporator. To improve the efficiency of refrigeration systems. The method of claim 74, wherein The bypassed refrigerant has a high condensation temperature and a high boiling temperature relative to the remainder of the refrigerant. The method of claim 63, wherein Sensing the temperature of the refrigerant at the inlet of the compressor; In order to maintain the superheated state of the refrigerant discharged from the evaporator at a constant level, the efficiency of the refrigeration system further comprises the step of adjusting the mass flow rate of the refrigerant through the expansion device of the primary refrigerant path according to the sensed temperature Way. 77. The method of claim 76, A method of improving the efficiency of a refrigeration system, characterized in that the evaporator is enlarged relative to the size previously required to increase the cooling capacity without increasing the compressor work. 78. The method of claim 77 wherein The condenser is reduced in size compared to conventionally required sizes for large evaporators selected to achieve the desired cooling capacity. 77. The method of claim 76, The condenser is reduced in size relative to the size previously required for the selected evaporator to achieve the desired cooling capacity. The method of claim 63, wherein The condenser is reduced in size relative to the size previously required for the selected evaporator to achieve the desired cooling capacity.