JP2016142481A - Freezer unit and defrosting method for load cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezer unit and a defrosting method for a load cooler in which defrosting can be carried out without applying any influence against the kinds of cooling refrigerant and temperature and pressure conditions while being adaptable against various operation modes in cooling operation and defrosting operation by improving stability and reliability through simplification of a system.SOLUTION: This invention relates to a freezer unit in which a load cooler 12, a compressor 14, a heat accumulator 16, a capacitor 18, a liquid receiver 17, and an expansion valve 151 are connected in this order by a refrigerant piping in series. Further, there is provided a defrosting circuit 72 that is independent from the cooling circuit so as to circulate between the load cooler and the heat accumulator. The defrosting circuit flows defrosting heat medium in it. The heat accumulator has a heat absorption unit 74 for absorbing heat from heat storage agent. The load cooler has a defrosting unit 76 for radiating heat. The cooling circuit has a heat radiating part 78 for radiating heat to the heat storage agent in the heat accumulator and a cooling part 80 for cooling load fluid in the load cooler.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigeration apparatus and a defrost method for a load cooler. More specifically, while improving reliability by simplifying the system, it is possible to cope with various operation modes of cooling operation and defrost operation. The present invention relates to a refrigeration apparatus capable of defrosting without affecting the type of cooling refrigerant and temperature and pressure conditions, and a defrosting method for a load cooler.

Nowadays, ammonia is toxic to the human body. A natural refrigerant cooling system configured to supply heat to the load cooler by interposing a secondary refrigerant circuit using “)” as a refrigerant is put into practical use.

In such a cooling system, in order to perform defrosting (defrosting) of a cooled load cooler, from the viewpoint of energy saving, a refrigerating apparatus or an air conditioner that performs defrosting using exhaust heat during cooling operation is used. For example, it is disclosed in Patent Document 1 and Patent Document 2.
The refrigeration apparatus of Patent Document 1 is a carbon dioxide circulation / cooling system in which heat exchange between a carbon dioxide refrigerant and an ammonia refrigerant is performed by a cascade condenser to change the carbon dioxide refrigerant into a refrigerant liquid and vaporize the ammonia refrigerant. A hot gas heat exchanger that vaporizes the carbon dioxide refrigerant by heat generated in the ammonia refrigerant in the ammonia refrigerant circuit discharged from the condenser to convert it into hot gas, and sends the carbon dioxide refrigerant into the hot gas heat exchanger, and A defrost circuit is provided for supplying and defrosting hot gas generated in the gas heat exchanger into the load-side cooler.
According to such a defrost circuit, when defrosting (defrost) frost adhering to the load side cooler of the carbon dioxide refrigerant circuit during operation of the cooling system, heat generated in the ammonia refrigerant of the ammonia refrigerant circuit (exhaust heat) Is transferred to the carbon dioxide refrigerant side of the carbon dioxide refrigerant circuit in the hot gas heat exchanger and recovered, the carbon dioxide refrigerant is vaporized by the recovered exhaust heat into hot gas, and the hot gas is supplied to the load side cooler. Thus, it is possible to remove frost adhering to the load side cooler.

In the air conditioner of Patent Document 2, a chemical heat storage device is provided between the compressor and the first four-way switching valve via a second four-way switching valve, and the discharge of the compressor is performed using the chemical heat storage device during heating operation. It absorbs heat from the gas refrigerant, stores heat, and heats the refrigerant on the inlet side of the indoor heat exchanger with the stored heat during the defrost operation.
According to such an air conditioner, the low-temperature and low-pressure liquid refrigerant is heated by the heat stored in the chemical heat storage device on the inlet side of the indoor heat exchanger during the defrost operation and becomes a high-temperature and low-pressure gas refrigerant. Heat is exchanged with the indoor air that is guided to the exchanger and blown by the indoor fan, and warm air is blown into the indoor side, while the high-temperature and low-pressure gas refrigerant becomes low temperature due to heat radiation in the indoor heat exchanger and returns to the compressor.
Therefore, according to such a defrost technique, it is possible to store once the exhaust heat during the cooling operation, and to defrost using the heat.

However, the conventional defrost technique has the following technical problems due to the common use of the cooling refrigerant and the defrost heat medium.
First, it adversely affects the cooling circuit and the cooling refrigerant. More specifically, the hot gas system uses high-temperature and high-pressure compressor discharge gas in the case of a direct expansion refrigeration system, and carbon dioxide, which is a secondary refrigerant, in the case of an ammonia / carbon dioxide refrigeration system as in Patent Document 1. Although it is used after being heated by some heat source, since the heat medium used in the heat source is limited, it is difficult to raise the hot gas temperature as desired with a high pressure heat medium, and as a result, the defrost time becomes longer. If the hot gas temperature needs to be raised, the design pressure of the heat medium system must be higher than the pressure expected in normal cooling operation, which increases the difficulty in designing equipment components or the initial cost. May increase. In particular, in the ammonia / carbon dioxide refrigeration system as disclosed in Patent Document 1, such a problem becomes conspicuous because the pressure of carbon dioxide is high.

Second, when a plurality of air coolers are connected in parallel to a single cooling circuit, the cooling circuit is connected in parallel via an inlet side refrigerant branch pipe and an outlet side refrigerant branch pipe, If the defrost circuit is connected in parallel via the inlet side heat medium branch pipe and the outlet side heat medium branch pipe, at least the inlet side refrigerant branch pipe and the inlet side heat medium branch pipe respectively, Since the switching valve is provided, the system becomes complicated and the reliability deteriorates. More specifically, since the defrost determination is normally performed for a plurality of air coolers, the number of necessary switching valves increases and the switching of the refrigerant flow by the switching valves becomes complicated.

Third, it is difficult to cope with various operation modes of the cooling operation and the defrost operation.
More specifically, regardless of the type of cooling refrigerant, it is desired to use a heat medium suitable for defrosting with hot gas, but the cooling refrigerant is used as it is.
At that time, a plurality of air coolers may be connected in parallel to a single cooling circuit. One of the plurality of air coolers is cooled and one of the remaining air coolers is defrosted. When the cooling refrigerant and the defrosting heat medium are shared, it is complicated to properly adjust the amount of the cooling medium in each system when separating the defrosting operation system from the cooling operation system. In some cases, it is difficult to secure the amount of the defrosting heat medium necessary for the defrosting, or the defrosting time may be prolonged due to a shortage of the defrosting heat medium amount.

JP 2010-181093 A Japanese Patent Laid-Open No. 05-79731

  In view of the above technical problems, the object of the present invention is to improve the stability and reliability by simplifying the system and to support various operation modes of the cooling operation and the defrost operation. An object of the present invention is to provide a refrigeration apparatus capable of defrosting and a defrosting method for a load cooler without affecting the type of refrigerant and temperature and pressure conditions.

In order to achieve the above object, the refrigeration apparatus of the present invention comprises:
In a refrigeration apparatus that constitutes a cooling circuit in which a cooling refrigerant flows inside by connecting a load cooler, a compressor, a heat accumulator, a condenser, a liquid receiver, and an expansion valve in this order by refrigerant piping,
Furthermore, a defrost circuit independent of the cooling circuit that circulates between the load cooler and the regenerator is provided,
The defrost circuit has a heat medium for defrost flowing therein, and has a heat absorption part that absorbs heat from the heat storage agent in the heat accumulator, and a defrost part that dissipates heat in the load cooler,
The cooling circuit has a heat radiating part that radiates heat to the heat storage agent in the heat accumulator, and a cooling part that cools the load fluid in the load cooler,
Thereby, through the cooling circuit, the load fluid is cooled by the cooling unit and radiated to the heat storage agent through the heat dissipation unit, while the heat absorption unit absorbs heat from the heat storage agent through the defrost circuit, thereby The load cooler is defrosted via a defrost section.

According to the refrigeration apparatus having the above configuration, the load cooler, the compressor, the heat accumulator, the condenser, the liquid receiver, and the expansion valve are sequentially connected by the refrigerant pipe in this order, and the cooling circuit in which the cooling refrigerant flows inside. On the other hand, by providing a defrost circuit independent of the cooling circuit that circulates between the load cooler and the heat accumulator, the reliability of the system can be improved by simplifying the system, and various operations of cooling operation and defrost operation can be performed. While being able to cope with the mode, defrosting is possible without affecting the type of cooling refrigerant and the temperature and pressure conditions.

Further, the heat accumulator is installed at a lower level than the load cooler,
The defrost forward path through which the defrost heat medium heated by the heat radiating section flows from the heat accumulator toward the load cooler, and the defrost cooled by the defrost section from the load cooler toward the heat accumulator A defrost return path through which the heating medium flows is provided, so that a loop-type thermosiphon is preferably configured.
Further, a plurality of the load coolers are provided, and are connected in parallel to the cooling circuit via an inlet side refrigerant branch pipe and an outlet side refrigerant branch pipe, and the inlet side heat medium is connected to the defrost circuit. It is connected in parallel via the branch pipe and the outlet side heat medium branch pipe,
Each of the inlet side refrigerant branch pipes and / or each of the inlet side heat medium branch pipes may be provided with a switching valve.

Furthermore, each of the load coolers is provided with a cooling air inflow opening and a cooling air outflow opening that are disposed to face each other, and a ventilation passage that is directed from the cooling air inflow opening to the cooling air outflow opening therein. A casing provided with,
In the casing, the cooling heat transfer tube is disposed so as to intersect the air flow along the ventilation flow path, and the air cooling refrigerant flows therein,
In the casing, there is provided a defrost heat transfer tube provided independently of the cooling heat transfer tube, in which a defrost heat medium flows,
In the cooling heat transfer tube, one end opening and the other end opening are respectively connected to an air cooling refrigerant inflow opening and an air cooling refrigerant outflow opening provided on a side surface of the casing,
In the heat transfer tube for defrost, one end opening and the other end opening are respectively connected to a defrosting heat medium inflow opening and a defrost heat medium outflow opening provided on a side surface of the casing. Inside the casing, the cooling heat transfer tube is arranged so that it can be defrosted to an external heating type,
An inlet side refrigerant branch pipe and an outlet side refrigerant branch pipe are connected to the air cooling refrigerant inflow opening and the air cooling refrigerant outflow opening, respectively, and the defrosting heat medium inflow opening and the defrosting heat medium outflow opening are respectively The inlet side heat medium branch pipe and the outlet side heat medium branch pipe are preferably connected.

In addition, a drain pan disposed below the casing for receiving a liquid generated during defrosting,
A branch pipe branching upstream of the defrost heat medium inflow opening is provided for the defrost external pipe connected to the defrost heat medium inflow opening, connected to the branch pipe, and connected to the drain pan. In order to conduct heat, a defrost heat transfer tube routed in a downward slope is preferably attached.

In order to achieve the above object, a defrost method for a load cooler according to the present invention comprises:
A cooling circuit in which a plurality of load coolers, compressors, heat accumulators, condensers, liquid receivers, and expansion valves connected in parallel with each other are sequentially connected in this order by the refrigerant pipe, and the cooling refrigerant flows inside, While storing heat through the heat accumulator and cooling the load cooler, the defrost heat medium circulates between each of the plurality of load coolers and the heat accumulator. In the defrosting method of the load cooler that radiates heat through the cooler and defrosts the load cooler,
The step of storing heat in the heat accumulator by performing cooling operation of any of the plurality of load coolers;
And defrosting all or any of the plurality of load coolers.

Further, in the defrosting operation stage, any one of the plurality of load coolers is cooled and operated to store heat in the heat accumulator, and at the same time, any one of the plurality of load coolers is defrosted. You may have the step to do.
Further, the defrosting operation step may include a step of defrosting all or any of the plurality of load coolers while stopping the cooling operation of all the plurality of load coolers.

Furthermore, the plurality of load coolers are installed at different levels,
The regenerator is installed at a lower level than the load cooler installed at the lowest level,
The defrost circuit includes a defrost forward path through which the defrost heat medium heated by the heat accumulator flows from the heat accumulator toward the load cooler, and the load cooler toward the heat accumulator. A defrost return path through which the defrost heat medium cooled by the cooler flows is provided,
Further, the defrost return path is provided with a heat medium receiver that flows through the defrost circuit below the load cooler installed at the lowest level,
In the defrosting operation step, the liquid level of the heat medium in the receiver is set higher than the heat accumulator by a predetermined level difference so that all of the plurality of load coolers are defrosted by a loop thermosyphon system. You may have the stage to drive.

A first embodiment of a refrigeration apparatus according to the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the refrigeration apparatus 10 includes a load cooler 12, a compressor 14, a heat accumulator 16, a condenser 18, a receiver 17, and an expansion valve 151 that are sequentially connected in this order through a refrigerant pipe, and a cooling refrigerant inside. A defrost circuit 72 that is independent of the cooling circuit 70 and that circulates between the load cooler 12 and the heat accumulator 16 is provided. The defrost circuit 72 includes a defrosting heat medium therein. The heat storage part 16 has a heat absorption part 74 that absorbs heat from the heat storage agent, and the load cooler 12 has a defrost part 76 that radiates heat.
On the other hand, the cooling circuit 70 includes a heat radiating unit 78 that radiates heat to the heat storage agent in the heat accumulator 16, and a cooling unit 80 that cools the load fluid in the load cooler 12.
Thus, the load fluid is cooled by the cooling unit 80 through the cooling circuit 70 and radiated to the heat storage agent through the heat radiating unit 78, while the heat absorption unit 74 absorbs heat from the heat storage agent through the defrost circuit 72, thereby defrosting. The load cooler 12 is defrosted via the section 76.

For the defrost circuit 72, the regenerator 16 is installed at a lower level than the load cooler 12, and the defrost forward path 82 through which the defrost heat medium heated by the heat radiating unit 78 flows from the regenerator 16 toward the load cooler 12, A defrost return path 84 through which the defrost heat medium cooled by the defrost section 76 flows from the load cooler 12 toward the heat accumulator 16 is provided. The defrost return path 84 is provided with a check valve 140, and as will be described later, some load coolers 12 perform cooling operation, and other load coolers 12 connected in parallel perform defrost operation. In this case, the defrosting heat medium is prevented from flowing into the load cooler 12 during the cooling operation.

On the other hand, with respect to the cooling circuit 70, the cooling forward path 155A, B connecting the water cooling type condensing unit 81 and the load cooler 12, and the cooling return path 153A connecting the load cooler 12 and the water cooling type condensing unit 81, B, a heat storage forward path 147A that connects the water-cooled condensing unit 81 and the heat storage unit 16, and a heat storage return path 147B that connects the heat storage unit 16 and the water-cooled condensing unit 81.
Thereby, by using the heat stored during the cooling operation of the load cooler 12 in the heat accumulator 16, the heat medium gas for defrost is sent from the heat accumulator 16 to the load cooler 12, while the heat is accumulated from the load cooler 12. A loop-type thermosiphon is configured to return the defrosting heat transfer fluid generated as a result of defrosting the load cooler 12 to the cooler 16.
The relative installation level difference H with respect to the load cooler 12 of the heat accumulator 16 (more precisely, the liquid level of the heat transfer liquid for defrost in the liquid receiver 20 to be described later) is a viewpoint that constitutes a loop thermosyphon. Therefore, it may be determined as appropriate. The heat storage material of the heat storage device 16 may be a latent heat storage material or a sensible heat storage material. For example, the latent heat storage material is paraffinic, and the sensible heat storage material is water.
The water cooling type condensing unit 81 is provided with a cooling water return pipe 145A and a cooling water supply pipe 145B, and is used for condensing the refrigerant by the condenser 18.

A plurality of load coolers 12 (four in FIG. 1) are provided, and are connected in parallel to the cooling circuit 70 via the inlet-side refrigerant branch pipe 86 and the outlet-side refrigerant pipe 88, and are connected to the defrost circuit 72. On the other hand, they are connected in parallel via the inlet side heat medium branch pipe 90 and the outlet side heat medium branch pipe 92.
As shown in FIG. 1, among the four load coolers 12, the load coolers 12A and 12B are installed on the second floor of the building, for example, and the load coolers 12C and 12D are installed on the first floor of the building, for example. The load coolers 12A and 12B are installed at an upper level than the load coolers 12C and 12D. The load coolers 12A and 12B are installed at the same level, and the load coolers 12C and 12D are installed at the same level.
As described below, each heat medium pipe (the defrost forward path 82 and the defrost return path 84) is provided with a switching valve from the viewpoint of switching between the normal operation mode and the defrost operation mode.
More specifically, the defrosting forward path 82 is provided with switching valves 94A and 94B for switching between the defrosting heat medium to the load coolers 12A and B and the defrosting heat medium to the load coolers 12C and D. In order to switch between the defrosting heat medium for the load cooler 12A and the defrosting heat medium for the load cooler 12B, switching valves 94C and 94D are provided, and the defrosting heat medium and load for the load cooler 12C are provided. In order to switch the heat medium for defrost to the cooler 12 </ b> D, switching valves 94 </ b> E and 94 </ b> F are provided, and a switching valve 94 </ b> G is provided on the upstream side of the heat accumulator 16 in the defrost return path 84.

At the level between the load coolers 12A and 12B and the load coolers 12C and 12D in the defrost return path 84, a liquid receiver 20 having a liquid level gauge 149 is provided. As will be described later, load cooling is performed. When the defrosting operation of the vessel 12 is performed, the defrosting heating medium heats the load cooler 12 as a heating medium gas to become a heating medium liquid. In the heating medium liquid, the defrosting forward path 82 and the defrosting return path 84 respectively. Since the liquid level can fluctuate depending on the state of the heat accumulator 16 and / or the load cooler 12, the liquid receiver 20 is set so that the stability of the defrost operation is not hindered by the fluctuation of the liquid level. Provided. Note that the level of the liquid receiver 20 is lower than the load coolers 12A and 12B from the viewpoint of securing a level difference from the heat accumulator 16 and achieving natural circulation by a loop thermosyphon as will be described later. It should be as close as possible to the level of the load coolers 12A and 12B.

The load cooler 12 is installed in, for example, a refrigerator such as a freezer, a refrigerated warehouse, and a shipping room.
As shown in FIG. 2, each of the load coolers 12 is, for example, a unit cooler that is fixed to a ceiling in a warehouse with suspension bolts and nuts via suspension fittings 117, and is provided with cooling air inflow openings that are arranged to face each other. And a cooling air outflow opening, and a casing 102 provided with a ventilation channel 100 from the cooling air inflow opening toward the cooling air outflow opening. A blower 101 is provided on a pair of opposite side surfaces of the casing 102. Reference numeral 103 denotes a terminal box to which a terminal of the blower 101 is wired.
The casing 102 is arranged so as to intersect the air flow along the ventilation channel 100, and the cooling heat transfer tube 104 in which the air cooling refrigerant flows, and the casing 102, independently of the cooling heat transfer tube 104. The defrost heat transfer tube 106 through which the defrost heat medium flows is provided in a non-contact manner and is provided in parallel with each other, and each of the cooling heat transfer tube 104 and the defrost heat transfer tube 106 will be described later. A U-shaped pipe portion disposed outside each of the opposing partition plates 120 of the casing 102 and a straight pipe portion extending between the opposing partition plates 120 are connected.

In the cooling heat transfer pipe 104, the cooling forward path 155 is connected to the downstream side of the expansion valve 151 via the flow divider 141 and the inlet side refrigerant branch pipe 86 that branches from the flow divider 141, while the cooling backward path 153 is connected via an outlet side refrigerant pipe 88.
In the defrost heat transfer pipe 106, the defrosting forward path 82 is connected to the downstream side of the switching valve 94 via the inlet side heat medium branch pipe 90, while the outlet side heat medium branch is connected to the defrost return path 84. Connection is made via a pipe 92.

As shown in FIG. 3, each of the opposing partition plates 120 of the casing 102 is provided with a large number of through-holes 123, and the defrosting heat transfer tube 106 is a straight line for defrosting that extends between the opposing partition plates 120 in the casing 102. It has the pipe part 124 and the defrost U-shaped pipe part 126 which connects the defrost straight pipe parts 124 through the through-hole 123 outside the casing 102.
The cooling heat transfer tube 104 is a cooling straight pipe portion 128 that extends between the opposing partition plates 120 in the casing 102 and a cooling straight pipe portion 128 that connects the cooling straight pipe portions 128 to each other through the through-hole 122 outside the casing 102. And a U-shaped tube portion 130.
More specifically, as shown in FIG. 3, the heat medium in the defrost pipe is collected in the inlet header 107, and is branched from there by a branch pipe (four branches in the figure). The defrost U-shaped bend pipe 126 provided on one partition plate of the plate 120, the defrost straight pipe portion 124 extending between the opposing partition plates 120, and the defrost U provided on the other partition plate of the opposing partition plate 113. The defrosting U is formed so as to be connected in a vertical direction (two in the drawing) with respect to the through-holes that are formed by the bent pipes 126 and are provided in each partition plate 120 and arranged in the vertical and horizontal directions. Bend pipe 126 is provided, and each branch pipe is collected at outlet header 109 and connected to pipe 84 therefrom.
On the other hand, the refrigerant in the cooling pipe is collected in the flow divider 141, and is branched from there by the inlet-side refrigerant branch pipe 86 (six branches in the figure). In each branch pipe, one partition plate of the opposing partition plate 120 is opposed. A cooling U-bend pipe 130 provided between the opposing partition plates 120 and a cooling U-bend pipe 130 provided on the other partition plate of the opposing partition plate 120. Each of the partition plates 120 is provided with a cooling U-bend pipe 130 so that the through holes arranged in the vertical direction and the horizontal direction are connected to each other in some cases. And connected to the cooling return path 153 from there.

Plate-like fins 132 for the cooling heat transfer tubes 104 are further provided in the casing 102, and the plate-like fins 132 are provided with a plurality of through holes 122 and 123 at the same positions as the partition plate 113. A plurality of plate-like fins 132 are provided in parallel to each other so as to be orthogonal to the ventilation channel 100.
In this case, the plate-like fins 132 having the function of expanding the heat transfer area of the cooling heat transfer tube 104 are used to support the defrosting heat transfer tube 106 together with the cooling heat transfer tube 104.
Each of the straight tube portions of the cooling heat transfer tube 104 and each of the straight tube portions of the defrost heat transfer tube 106 are fixed to the plate-like fins 132 so as to pass through the through holes 122 and 123, whereby the defrost heat transfer tube 106. The plate-like fins 132 and the cooling heat transfer tube 104 are defrosted in the form of heat radiation or heat conduction.

  The cooling refrigerant temperature is, for example, −10 ° C., whereby the air is cooled from room temperature to −5 ° C., while the defrosting heat medium temperature is 20 ° C. The frost formed is defrosted (described later).

As shown in FIG. 3, the defrosting heat transfer tube 106 is disposed below the casing 102 and is connected to the drain pan 134 for receiving the liquid generated at the time of defrosting and the defrosting forward path 82 connected to the defrosting heat transfer tube 106. And a defrosting heat transfer pipe 135 that is connected to the branch pipe 136 and routed in a descending gradient so as to contact the bottom surface 137 of the drain pan 134. Through the heat transfer tube 135, the entire bottom surface 137 of the drain pan 134 is heated in a heat conductive form so that it can be defrosted. The defrost heat transfer tube 135 is connected to the defrost return path 84 downstream of the outlet header 109.
The defrost heat transfer pipe 106 and the cooling refrigerant pipe 104 are both preferably copper pipes from the viewpoint of heat transfer and cost, and may be aluminum pipes or stainless steel pipes depending on the case, and the plate-like fins 132 are made of heat. In order to give priority to transmission, aluminum is preferable, and copper or stainless steel may be used in some cases, and the casing is, for example, galvanized steel sheet and the drain pan is SUS.

As a modification, an electric heater for defrosting in which a heating coil is wired inside the casing 102 is provided, and a through-hole (not shown) through which the heating coil passes is provided in the facing partition plate 120 of the casing 102. When remodeling the air cooler based on the air cooler, the defrosting heat transfer tube 106 may be provided in place of the defrosting electric heater using a through hole through which the heating coil passes.
Accordingly, it is possible to avoid an increase in the size of the air cooler by providing a defrost heat transfer tube separately.

The operation of the refrigeration apparatus 10 having the above configuration will be described below with reference to FIGS. 4 to 8 through the description of the operation method of the refrigeration apparatus 10.
The operation method of the refrigeration apparatus 10 is divided into a normal cooling operation mode (heat storage stage) (FIG. 4) and a defrost operation mode (FIG. 6) as operation modes.
A case where the normal cooling operation mode (heat storage stage) is performed for all of the load coolers 12A to 12D and then the defrost operation mode is performed for the load coolers 12C and 12D located at the lower level will be described.

First, as shown in FIG. 4, in the normal cooling operation mode (heat storage stage), among the switching valves 94A to 94G, the switching valves 94A, 94B and 94G are closed in the normal cooling operation mode (heat storage stage), and the others are opened. Then, the compressor 14 is operated.
The refrigerant flows into the compressor 14 from the load cooler 12 through the cooling return path 153A, is compressed here, and further flows into the heat accumulator 16 from the compressor 14 through the heat storage forward path 147A, where the refrigerant is The heat is dissipated and stored in the regenerator 16, and further flows into the condenser 18 from the regenerator 16 via the heat storage return path 147B, where it is condensed or supercooled, and further from the condenser 18 via the cooling forward path 155A, the expansion valve 151. The degree of superheat of the refrigerant is adjusted by adjusting the opening degree of the expansion valve 151 and then returns to the load cooler 12 from the expansion valve 151 via the flow divider 141 to form a cooling circuit. I have to.

As described above, the refrigerant flows as indicated by the arrows in FIG. 4, and is in a gas state between the load cooler 12 and the heat accumulator 16 through the compressor 14, particularly the load cooler 12 and the compressor 14. Between the compressor 14 and the heat accumulator 16, while between the compressor 14 and the regenerator 16, a liquid or wet steam state between the regenerator 16 and the load cooler 12 via the expansion valve 151. It is.

Next, as shown in FIG. 6, in the defrost operation mode, the compressor 14 is stopped, and in FIG. 5, only the switching valve 94A among the switching valves 94A to 94G is closed.
More specifically, the refrigerant gas evaporated (heat absorption) by the heat storage of the heat accumulator 16 flows from the defrost forward path 82 to the load coolers 12C and 12D, where the refrigerant gas is condensed (heat radiation), thereby cooling the load. The defrosting of the coolers 12C and 12D is performed, the defrosting attached to the load coolers 12C and 12D is performed, and the refrigerant liquid returns to the heat accumulator 16 through the defrost return path 84, and repeats this natural circulation, thereby loop thermostat A siphon is comprised and defrost is performed about the load coolers 12C and D.
More specifically, as shown in FIG. 7, the plate-like fins 132, and further the plate-like fins 132, are heated by the heat medium flowing through the defrosting heat transfer tube 106 through the defrosting heat transfer tube 106. Then, the heat is transferred to the cooling refrigerant pipe 104 and is also transferred to the plate-like fins 132 and the outer peripheral surface 160 of the cooling heat transfer pipe 104 through the defrost heat transfer pipe 106 in the form of heat radiation.

In the case of the latter heat radiation mode, the defrosting heat transfer tube 106 has a plate-like fin according to the heat conduction mode because the cooling refrigerant does not flow inside and the frosting on the outer peripheral surface of the pipe is difficult to form compared to the cooling heat transfer tube 104. 132, and the liquid defrosted from the cooling heat transfer tube 104 is separated from the plate-like fins 132 and the outer peripheral surface 160 of the cooling heat transfer tube 104, and is effectively prevented from being recooled and refreezing. It is possible.
More specifically, as in the prior art, the cooling heat transfer tube 104 is shared for cooling and defrosting, and when the defrosting heat medium flows inside, the cooling refrigerant flows inside when defrosting. As a result, frost is formed on the outer peripheral surface 160 of the cooling heat transfer tube 104. Therefore, unless the frost formed on the outer peripheral surface 160 is melted, heat is emitted outward from the outer peripheral surface 160 of the cooling heat transfer tube 104. It is difficult to effectively transfer heat in the form, and the liquid defrosted by the heat conduction form is re-cooled by moving away from the plate-like fins 132 and the outer peripheral surface 106 of the cooling heat transfer tube 104 and re-frozen in an ice column shape. It becomes difficult to prevent it. As a result, between the adjacent plate-like fins 132 constitutes the ventilation channel 100 for air to be cooled, the channel area of the ventilation channel 100 is narrowed, and the cooling capacity is deteriorated.

In this regard, as in this time, in the air cooler, a defrost heat transfer tube 106 is provided separately from the cooling heat transfer tube 104, and the outer peripheral surface 105 of the cooling heat transfer tube 104 and the outer peripheral surface 162 of the defrost heat transfer tube 106 are provided. By setting the predetermined distance D1, as shown by the arrow in FIG. 7, the defrosting heat medium flowing inside the defrosting heat transfer tube 106 transfers heat in the form of heat conduction through the plate-like fins 132 and is attached. By transferring heat in the form of heat radiation outward from the outer peripheral surface 162 of the defrost heat transfer tube 106 with a low degree of frost, it is possible to effectively prevent refreezing of the defrosted liquid.
From this point of view, the distance D1 between the outer peripheral surface 160 of the cooling heat transfer tube 104 and the outer peripheral surface 162 of the defrosting heat transfer tube 106 is determined based on the temperature of the outer peripheral surface 160 of the cooling heat transfer tube 104 and the outer periphery of the defrosting heat transfer tube 106. What is necessary is just to determine suitably according to the temperature of the surface 162, a heat-medium flow volume, and the space | interval D2 of the adjacent plate-shaped fin 132. FIG.
When the defrosting of the load cooler 12 is completed by this defrost operation, the normal cooling operation mode is restored and heat storage is resumed in preparation for the next defrost operation.

  The timing of switching between the normal cooling operation mode (FIG. 4) and some defrost operation modes (FIG. 6) of the load coolers 12 </ b> A to 12 </ b> D depends on the frost generation state in the load cooler 12. It may be switched manually as appropriate, or when the load in the load cooler 12 is relatively constant and the progress of frost is relatively regular, a timer is set in advance to switch automatically. Alternatively, the temperature of the heat transfer tube (not shown) of the load cooler 12 may be detected and set according to the detected temperature.

  As shown in FIG. 5, when only the load cooler 12A is defrosted, among the switching valves 94A to 94G, the switching valves 94B and 94D are closed, and the others are opened, and only the load cooler 12B is opened. In the case of defrosting, among the switching valves 94A to 94G, the switching valves 94B and 94C are closed and the others are opened, and when only the load cooler 12C is defrosted, the switching valves 94A to 94G are switched. When the valves 94A and 94F are closed and the others are opened, and only the load cooler 12D is defrosted, the switching valves 94A and 94E among the switching valves 94A to 94G are closed, and the others are opened and loaded. When defrosting only the cooler 12A and the load cooler 12B, only the switching valve 94B is closed among the switching valves 94A to 94G. , Otherwise, open, in the case of defrosting only the load condenser 12C and load cooler 12D, of 94G to no switching valves 94A, only to close switch valve 94A, otherwise, may be opened. In this case, in the switching valves 94A to 94G, in order to prevent the possibility of liquid sealing, the switching valves 94A to 94G are opened when there is no problem in both opening and closing.

As a modification of the operation method, in the present embodiment, heat storage is performed for all four air coolers while cooling operation is performed, and then, the load coolers 12C and D located at the lower level are defrosted. As described above, without being limited thereto, as long as the heat storage amount necessary for the defrost operation is ensured in the heat storage, any of the four air coolers are stored while performing the cooling operation, and the remaining heat storage is performed. About an air cooler, you may perform what is called a chasing operation which performs a defrost operation | movement simultaneously.
Specifically, as shown in FIG. 8, among the switching valves 94A to 94G, the switching valve 94A is closed, and the load coolers 12A and 12B are cooled by the cooling circuit 70, and the heat accumulator 16 stores heat. On the other hand, the defrost circuit 72 defrosts the load coolers 12C and 12D.
In addition, by operating the switching valve, the defrosting is performed only on one of the load coolers 12C and 12D by the defrost circuit 72 while cooling only one of the load coolers 12A and 12B by the cooling circuit 70. But you can. In this case, the other of the load coolers 12A and 12B is in a stopped state, but the other of the load coolers 12C and 12D may be in a cooling operation or a stopped state.

According to the refrigeration apparatus 10 having the above configuration, the refrigerant gas evaporated by cooling the load cooler 12 during the cooling operation is compressed by the compressor 14 and dissipated in the heat accumulator 16, and as a result, heat is stored. The refrigerant gas or the refrigerant liquid is condensed or supercooled by the condenser 18, and the refrigerant liquid is received by the receiver 17, and the cooling circuit is configured to cool the load cooler 12 again through the expansion valve 151. The cooler 12 is cooled.

On the other hand, during the defrosting operation of the load cooler 12, the heat stored in the heat accumulator 16 during the cooling operation of the load cooler 12 is used to pass the defrosting from the heat accumulator 16 to the load cooler 12 via the defrost forward path 82. Thus, while the refrigerant gas is sent, the refrigerant liquid generated as a result of defrosting the load cooler 12 is returned from the load cooler 12 to the heat accumulator 16 via the defrost return path 84, thereby the hot-side heat accumulator located below. 16 and a cold-side load cooler 12 positioned above constitute a loop-type thermosiphon by natural circulation, which enables defrosting with the compressor 14 stopped, as well as the conventional single unit. It is possible to defrost while achieving energy saving without causing the problem of heat transport limit due to flooding in a tubular thermosyphon. .

Furthermore, according to the refrigeration apparatus 10 having the above-described configuration, the load cooler 12, the compressor 14, the heat accumulator 16, the condenser 18, the receiver 17, and the expansion valve 151 are sequentially connected in this order through the refrigerant pipe, and cooled inside. By providing a defrost circuit 72 independent of the cooling circuit 70 that circulates between the load cooler 12 and the heat accumulator 16 with respect to the cooling circuit 70 in which the refrigerant for refrigerant flows, reliability is improved by simplifying the system. However, while being able to cope with various operation modes of the cooling operation and the defrost operation, the defrost can be performed without affecting the type of the cooling refrigerant and the temperature and pressure conditions.

According to the defrosting (defrosting) method of the load cooler 12 having the above configuration, a plurality of load coolers 12, a compressor 14, a heat accumulator 16, a condenser 18, a receiver 17, and an expansion valve 151 connected in parallel with each other are provided. In this order, the refrigerant pipes are connected in order, and the cooling circuit in which the cooling refrigerant flows inside stores heat through the heat accumulator 16 and cools the load cooler 12, while the defrosting heat medium has a plurality of loads. In the defrosting method of the load cooler 12 that circulates between each cooler 12 and the heat accumulator 16 and radiates heat through the heat accumulator 16 and defrosts the load cooler 12 by a defrost circuit independent of the cooling circuit 12. The step of storing heat in the heat accumulator 16 by performing cooling operation of any of the plurality of load coolers 12 and the plurality of load coolers 1 One of and a step of operating defrost.
In this case, in the defrosting operation stage, any one of the plurality of load coolers 12 is cooled and stored in the heat accumulator 16, and in parallel therewith, any of the remaining load coolers 12 is defrosted. It may have a stage to operate, or a defrost operation stage carries out a defrost operation of one of a plurality of load coolers 12 in parallel with stopping a cooling operation of all of a plurality of load coolers 12 There may be stages, and it is possible to cope with various operation modes of the cooling operation and the defrost operation, and it is possible to defrost without affecting the type of cooling refrigerant and the temperature and pressure conditions.

As a modification, during the cooling operation, a step of bypassing the heat accumulator 16 may be provided after the heat storage step.
More specifically, since the refrigerant gas discharged from the compressor 14 flows to the condenser 18 through the heat accumulator 16, pressure loss in the heat accumulator 16 is inevitably generated. Therefore, such pressure loss is eliminated. Therefore, a regenerator bypass pipe connecting between the heat storage forward path 147A and the heat storage return path 147B may be provided, and the heat accumulator 16 may be bypassed via a heat accumulator bypass pipe (not shown).
In particular, in the normal cooling operation, after sufficient heat storage is performed by the regenerator 16, only the cooling operation may be performed by bypassing the regenerator 16 via the regenerator bypass pipe.

A second embodiment of the refrigeration apparatus according to the present invention will be described below in detail with reference to the drawings.
In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the characteristic portions of the present embodiment will be described in detail.
The feature of the second embodiment of the present invention resides in the installation level of the liquid receiver 20 installed in the defrost return path 84, thereby expanding the diversity of the defrost operation.
More specifically, the liquid receiver 20 installed in the defrost return path 84 is, as shown in FIG. 1, between the load coolers 12A and 12B and the load coolers 12C and 12D in the first embodiment. However, in this embodiment, as shown in FIG. 8, it is installed at a level between the load coolers 12C and 12D and the heat accumulator 16 located at the lowermost level, thereby defrosting operation. At this time, in the first embodiment, it was difficult to defrost all four load coolers 12A to 12D simultaneously. In this embodiment, all four load coolers 12A to 12D are At the same time, defrost operation is possible.

The level difference H between the liquid level of the defrosting heat medium in the liquid receiver 20 and the heat accumulator 16 may be determined from such a viewpoint, and is preferably directly below the load coolers 12A to 12D.
The cooling operation is the same as that of the first embodiment, and the defrosting operation is the same as that of the first embodiment in that natural circulation by the loop thermosyphon is achieved.
About the mode of defrost operation, it has a step of storing heat in a heat accumulator by carrying out cooling operation of any of a plurality of load coolers, and a step of defrosting all or any of a plurality of load coolers, The operation stage includes a stage in which any one of the plurality of load coolers is defrosted while being stored in the heat accumulator by performing a cooling operation, and in parallel with the heat accumulator. Well, the defrost operation step may include a step of defrosting all or any of the plurality of load coolers in parallel with stopping the cooling operation of all of the plurality of load coolers.

More specifically, as shown in FIG. 9, after storing heat in the heat accumulator by the cooling operation of the load coolers 12A to 12D, the compressor 14 is stopped, all the switching valves 94A to 94G are opened, and load cooling is performed. The defrosting operation may be performed for all of the devices 12A to 12D, and, as shown in FIG. 10, after the heat is accumulated in the heat accumulator by the cooling operation of the load coolers 12A to 12D, While cooling the load coolers 12A and 12B located at the level, defrosting the load coolers 12C and 12D located at the lower level, or cooling the load coolers 12C and 12D located at the lower level, Even if the so-called chasing operation is performed by defrosting the load coolers 12A and 12B located at the upper level. There. Alternatively, after storing heat in the heat accumulator by the cooling operation of the load coolers 12A to 12D, the compressor 14 is stopped, and only the load coolers that require defrosting are selected from the load coolers 12A to 12D. You may drive.
In this case, when the defrost operation is performed for all of the load coolers 12A to 12D, the defrosting heat medium forward path to the load coolers 12A and 12B is performed to ensure the defrost operation of the upper level load coolers 12A and 12B. It is also possible to reduce the flow path resistance by increasing the diameter of the heat transfer path of the defroster to the load coolers 12C and 12D.
As described above, the present embodiment expands the diversity in the case where the defrost operation is performed by the loop thermosyphon compared to the first embodiment.

The embodiments of the present invention have been described in detail above, but various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, as long as sufficient heat storage is performed by the heat accumulator 16, only the load cooler 12 that requires defrosting may be performed individually, and in that case, a plurality of load coolers 12 that require defrosting may be performed. In some cases, a so-called chasing operation in which a defrost operation is performed simultaneously with heat storage while performing a cooling operation may be performed.
For example, in the present embodiment, the heat accumulator 16 has been described. However, the heat accumulator 16 is not limited thereto, and may be a heat accumulating tank as long as heat can be stored from the refrigerant. For example, heat may be stored using exhaust heat.
For example, in the first embodiment and the second embodiment, in the case where there are a plurality of load coolers 12, the liquid receiver 20 is installed in the defrost return path 84. If all the units 12 are installed at the same level and the load fluctuation on the load cooler 12 side or the heat storage unit 16 side is not large, the loop type sir can also be naturally circulated stably by the siphon. The liquid container 20 may be omitted.

1 is a configuration diagram of a refrigeration apparatus 10 according to a first embodiment of the present invention. 1 is a perspective view of an air cooler of a refrigeration apparatus 10 according to a first embodiment of the present invention. It is the schematic which shows the surroundings of the air cooler of the freezing apparatus 10 which concerns on 1st Embodiment of this invention. In the refrigerating apparatus 10 which concerns on 1st Embodiment of this invention, it is a figure similar to FIG. 1 which shows the normal cooling driving | operation during heat storage. It is a table | surface which shows the opening / closing state of the switching valve according to the defrost driving | operation of the refrigeration apparatus 10 which concerns on 1st Embodiment of this invention. In refrigeration equipment 10 concerning a 1st embodiment of the present invention, it is the same figure as Drawing 1 showing defrost operation. It is a conceptual diagram which shows the defrost situation in the air cooler of the refrigeration apparatus 10 which concerns on 1st Embodiment of this invention. In the refrigerating apparatus 10 which concerns on 1st Embodiment of this invention, it is a figure similar to FIG. 1 which shows the driving | running state of a modification. In the refrigeration apparatus 10 which concerns on 2nd Embodiment of this invention, it is a figure similar to FIG. In the refrigeration apparatus 10 which concerns on 2nd Embodiment of this invention, it is a figure similar to FIG. 6 which shows an operating condition.

H Level difference D1 Distance between the outer peripheral surface of the heat transfer tube for cooling and the outer peripheral surface of the heat transfer tube for defrost D2 Distance between adjacent plate fins 10 Refrigeration unit 12 Load cooler 14 Compressor 16 Heat accumulator 17 Receiver 18 Condenser 20 Liquid receiving 70 Cooling circuit 72 Defrost circuit 74 Heat absorption section 76 Defrost section 78 Heat radiation section 80 Cooling section 81 Condensing unit 82 Defrost forward path 84 Defrost return path 86 Inlet side refrigerant branch pipe 88 Outlet side refrigerant branch pipe 90 Inlet side heat medium branch pipe 92 Outlet side heat medium branch pipe 94 Switching valve 100 Ventilation flow path 101 Blower 102 Casing 103 Terminal box 104 Cooling heat transfer pipe 105 Refrigerant header 106 Defrost heat transfer pipe 107 Defrost inlet header 109 Defrost outlet header 112 Air cooling refrigerant Inflow opening 113 Partition plate 117 Suspension bracket 118 Defrost heat medium outlet opening 120 Partition plate 122 Refrigerant tube through hole 123 Defrost tube through hole 124 Defrost straight tube portion 126 Defrost U tube portion 128 Cooling straight tube portion 130 Cooling U shape Pipe portion 132 Plate-like fin 134 Drain pan 135 Defrost heat transfer pipe 136 Branch pipe 137 Bottom face 140 Check valve 141 Divider 143 Check valve 145A Cooling water supply pipe 145B Cooling water return pipe 147A Heat storage forward path 147B Heat storage return path 149 Liquid level Total 151 Expansion valve 153 Cooling return path 155 Cooling outbound path 160 Outer peripheral surface 162 Outer peripheral surface

Claims (9)

In a refrigeration apparatus that constitutes a cooling circuit in which a cooling refrigerant flows inside by connecting a load cooler, a compressor, a heat accumulator, a condenser, a liquid receiver, and an expansion valve in this order by refrigerant piping,
Furthermore, a defrost circuit independent of the cooling circuit that circulates between the load cooler and the regenerator is provided,
The defrost circuit has a heat medium for defrost flowing therein, and has a heat absorption part that absorbs heat from the heat storage agent in the heat accumulator, and a defrost part that dissipates heat in the load cooler,
The cooling circuit has a heat radiating part that radiates heat to the heat storage agent in the heat accumulator, and a cooling part that cools the load fluid in the load cooler,
Thereby, through the cooling circuit, the load fluid is cooled by the cooling unit and radiated to the heat storage agent through the heat dissipation unit, while the heat absorption unit absorbs heat from the heat storage agent through the defrost circuit, thereby A refrigeration apparatus, wherein the load cooler is defrosted through a defrosting unit. The regenerator is installed at a lower level than the load cooler;
The defrost forward path through which the defrost heat medium heated by the heat radiating section flows from the heat accumulator toward the load cooler, and the defrost cooled by the defrost section from the load cooler toward the heat accumulator And a defrost return path through which the heating medium flows,
Furthermore, the defrost return path is provided with a liquid receiver for the defrost heat medium at a level above the heat accumulator,
The refrigeration apparatus according to claim 1, thereby constituting a loop thermosyphon. A plurality of the load coolers are provided, and are connected in parallel to the cooling circuit via an inlet side refrigerant branch pipe and an outlet side refrigerant branch pipe, and to the defrost circuit, the inlet side heat medium branch pipe And connected in parallel via the outlet side heat medium branch pipe,
The refrigeration apparatus according to claim 1 or 2, wherein a switching valve is provided in each of the inlet side refrigerant branch pipes and / or each of the inlet side heat medium branch pipes. Each of the load coolers is provided with a cooling air inflow opening and a cooling air outflow opening that are arranged to face each other, and a ventilation passage is provided in the interior from the cooling air inflow opening to the cooling air outflow opening. A casing,
In the casing, the cooling heat transfer tube is disposed so as to intersect the air flow along the ventilation flow path, and the air cooling refrigerant flows therein,
In the casing, there is provided a defrost heat transfer tube provided independently of the cooling heat transfer tube, in which a defrost heat medium flows,
In the cooling heat transfer tube, one end opening and the other end opening are respectively connected to an air cooling refrigerant inflow opening and an air cooling refrigerant outflow opening provided in the casing,
In the defrosting heat transfer tube, one end opening and the other end opening are respectively connected to a defrosting heat medium inflow opening and a defrosting heat medium outflow opening provided in the casing, and the defrosting heat transfer tube is disposed in the casing. In, the cooling heat transfer tube is arranged so that it can be defrosted to an external heating type,
An inlet side refrigerant branch pipe and an outlet side refrigerant branch pipe are connected to the air cooling refrigerant inflow opening and the air cooling refrigerant outflow opening, respectively, and the defrosting heat medium inflow opening and the defrosting heat medium outflow opening are respectively The refrigeration apparatus according to claim 3, wherein the inlet side heat medium branch pipe and the outlet side heat medium branch pipe are connected. A drain pan disposed below the casing for receiving liquid generated during defrosting;
A branch pipe branching upstream of the defrost heat medium inflow opening is provided to the defrost external pipe connected to the defrost heat medium inflow opening, and connected to the branch pipe to heat the drain pan. The refrigeration apparatus according to claim 4, further comprising a defrost heat transfer tube routed downward. A cooling circuit in which a plurality of load coolers, compressors, heat accumulators, condensers, liquid receivers, and expansion valves connected in parallel with each other are sequentially connected in this order by the refrigerant pipe, and the cooling refrigerant flows inside, While storing heat through the heat accumulator and cooling the load cooler, the defrost heat medium circulates between each of the plurality of load coolers and the heat accumulator. In the defrosting method of the load cooler that radiates heat through the cooler and defrosts the load cooler,
The step of storing heat in the heat accumulator by performing cooling operation of any of the plurality of load coolers;
And defrosting all or any one of the plurality of load coolers.         The defrost operation step is a step of defrosting any one of the plurality of load coolers while accumulating heat in the heat accumulator by performing a cooling operation of any of the plurality of load coolers. The defrost method for a load cooler according to claim 6, wherein:         The defrost operation step includes a step of defrosting all or any of the plurality of load coolers in parallel with stopping the cooling operation of all of the plurality of load coolers. Load cooler defrost method. The plurality of load coolers are installed at different levels;
The regenerator is installed at a lower level than the load cooler installed at the lowest level,
The defrost circuit includes a defrost forward path through which the defrost heat medium heated by the heat accumulator flows from the heat accumulator toward the load cooler, and the load cooler toward the heat accumulator. A defrost return path through which the defrost heat medium cooled by the cooler flows is provided,
Further, the defrost return path is provided with a heat medium receiver that flows through the defrost circuit below the load cooler installed at the lowest level,
In the defrosting operation step, the liquid level of the heat medium in the receiver is set higher than the heat accumulator by a predetermined level difference so that all of the plurality of load coolers are defrosted by a loop thermosyphon system. The method of defrosting a load cooler according to claim 6, comprising a step of operating.

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