JP2019074286A - Cooling system and cooling system modification method - Google Patents

Abstract

To provide a non-CFC refrigerant cooling system which achieves low introduction costs.SOLUTION: A cooling system 2 includes: a second evaporator 210 disposed in a cooling device R located in an indoor space; a second refrigerant storage tank 220 which is disposed in an outdoor space and stores a second refrigerant; a second refrigerant circulation mechanism 230 which circulates the second refrigerant between the second refrigerant storage tank 220 and the second evaporator 210; a second refrigerant heat storage tank 240 which is provided at an outdoor space and stores the second refrigerant; and a second heat storage circulation mechanism 250 which circulates the second refrigerant between the second refrigerant storage tank 220 and the second refrigerant heat storage tank 240. Further, the cooling system 2 includes: a first compressor 110 disposed in an outdoor space; a first evaporator 120 disposed in the second refrigerant storage tank 220; and a first refrigerant circulation mechanism 130 which circulates a first refrigerant between the first compressor 110 and the first evaporator 120. The first refrigerant is a combustible refrigerant excluding chlorofluorocarbon, and the second refrigerant is a non-combustible refrigerant excluding chlorofluorocarbon.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling system and a method of remodeling the cooling system.

  Heretofore, fluorocarbon gas has been used as a refrigerant of a freezing / refrigerating apparatus. However, in recent years, environmental issues such as global warming and ozone layer depletion have been closely watched, and the international community has begun working on environmental issues as a united body, such as the 1997 Kyoto Protocol and the 2015 Paris Agreement. From such a background, development of a fluorine-free refrigerant (non-fluorocarbon refrigerant) and research and development of a cooling system using the non-fluorocarbon refrigerant have been advanced (for example, Patent Document 1).

JP, 2017-67393, A

  As non-fluorocarbon refrigerants, carbon dioxide, hydrocarbons such as ammonia and propane, etc. are known. However, in the case of carbon dioxide and ammonia, the cost for introducing a circulation mechanism (such as piping) for circulating the refrigerant becomes high. Moreover, in the case of hydrocarbons such as propane, there was a problem of flammability. Therefore, the spread of non-fluorocarbon refrigerant cooling systems has been delayed.

  SUMMARY OF THE INVENTION In view of such circumstances, the present invention is intended to provide a cooling system for non-fluorocarbon refrigerant and a method for converting the same into a cooling system whose introduction cost is low.

  The cooling system according to the present invention includes a first cooling unit that performs heat exchange using a first refrigerant that is a flammable refrigerant, a second cooling unit that performs heat exchange using a second refrigerant that is a nonflammable refrigerant, The second cooling unit includes a second evaporator disposed in the indoor cooling device, a second refrigerant storage tank disposed outside for accommodating the second refrigerant, and the second refrigerant. And a second refrigerant circulation mechanism for circulating the second refrigerant between the storage tank and the second evaporator, wherein the first cooling unit is provided with a first compressor disposed outside, and the second refrigerant. It is characterized by comprising: a first evaporator disposed in the storage tank; and a first refrigerant circulation mechanism that circulates the first refrigerant between the first compressor and the first evaporator.

  Further, according to the present invention, there is provided a cooling system comprising: an evaporator disposed in an indoor cooling device; a compressor separate from the cooling device; and a circulation mechanism circulating the fluorocarbon in the evaporator and the compressor. A method of remodeling a system, comprising the steps of: providing a refrigerant storage tank storing non-fluorocarbon refrigerant outdoors; connecting the refrigerant storage tank and the evaporator using the circulation mechanism; The method may further comprise the steps of extracting and introducing a non-fluorocarbon refrigerant in the circulation mechanism.

  According to the present invention, since the system of the flammable refrigerant is outdoors, the introduction cost of the non-fluorocarbon refrigerant cooling system can be reduced. As a result, the introduction of cooling systems for non-fluorocarbon refrigerants spreads, resulting in the solution of environmental problems such as global warming and ozone layer depletion.

It is a block diagram which shows the outline | summary of a cooling system. It is a block diagram which shows the outline | summary of an explosion-proof structure. It is a block diagram which shows the outline | summary of the cooling system before remodeling.

  As shown in FIG. 1, the cooling system 2 controls the first cooling unit 100 that performs heat exchange using a first refrigerant, the second cooling unit 200 that performs heat exchange using a second refrigerant, and the respective components. A control unit 300 is provided.

  The first refrigerant is a flammable refrigerant excluding fluorocarbon, and the second refrigerant is a nonflammable refrigerant excluding fluorocarbon. The first refrigerant is preferably a gas, and the second refrigerant is preferably a liquid. The flammable refrigerant is a refrigerant classified as flammable in the high pressure method as of February 2014, and includes, for example, ammonia and hydrocarbons (propylene, propane, butane and the like). Non-flammable refrigerants include brine liquid and carbon dioxide.

  The second cooling unit 200 includes a second evaporator 210 disposed in the indoor cooling device R, a second refrigerant storage tank 220 disposed outside and containing the second refrigerant, a second refrigerant storage tank 220 and a second A second refrigerant circulation mechanism 230 for circulating the second refrigerant between the evaporators 210, a second refrigerant storage tank 240 provided outdoors and containing the second refrigerant, a second refrigerant storage tank 220 and a second refrigerant storage tank And a second heat storage circulation mechanism 250 for circulating the second refrigerant between 240.

  The cooling device R includes, for example, a showcase for storing a refrigerated item and a frozen item, a refrigerator, a freezer, an air conditioner, and the like. The second refrigerant circulation mechanism 230 includes a pipe H2, a pump P2 provided in the pipe H2, and a valve B2 provided in the pipe H2. The second heat storage and circulation mechanism 250 includes pipes H2 for feed and return, and a pump P2 and a valve (not shown) provided in each pipe H2.

  The first cooling unit 100 is provided between the first compressor 110 disposed outdoors, the first evaporator 120 disposed in the second refrigerant storage tank 220, and the first compressor 110 and the first evaporator 120. A first refrigerant circulation mechanism 130 for circulating the first refrigerant, a first heat storage system compressor 150 disposed outside, a first heat storage system evaporator 160 disposed in the second refrigerant heat storage tank 240, and a first heat storage And a first heat storage system refrigerant circulation mechanism that circulates the first refrigerant between the system compressor and the first heat storage system evaporator. Each of the first refrigerant circulation mechanism 130 and the first heat storage system refrigerant circulation mechanism 170 includes a pipe H1 and a pump P1 provided in the pipe H1 and promoting circulation of the first refrigerant.

The control unit 300 individually controls each compressor, each evaporator, each pump, and the like. Thereby, the operation | movement and the stop of operation | movement of the following (1)-(4) can be switched.
(1) Supply the cold generated by the first compressor 110 to the second refrigerant storage tank 220 (2) Supply the cold of the second refrigerant storage tank 220 to the second evaporator 210 (3) first heat storage The cold heat generated by the system compressor 150 is accumulated in the second refrigerant storage tank 240 (4) The cold heat accumulated in the second refrigerant storage tank 240 is supplied to the second refrigerant storage tank 220

  Next, how to use the cooling system 2 will be described.

  The control unit 300 individually controls each compressor, each evaporator, each pump, and the like. At this time, the first refrigerant circulation mechanism 130 and the second refrigerant circulation mechanism 230 are in the operating state. Therefore, the cold generated by the first compressor 110 is supplied to the second refrigerant storage tank 220, and the cold of the second refrigerant storage tank 240 is supplied to the second refrigerant storage tank 220. Thereby, the cooling device R can cool the target using the cold generated by the first compressor 110 (cold supply state).

  Further, the control unit 300 causes the first heat storage system refrigerant circulation mechanism 170 to be in the operation state, and the second heat storage circulation mechanism 250 is in the stop state. At this time, the cold generated by the first heat storage system compressor 150 is stored in the second refrigerant storage tank 240 (heat storage state).

  Furthermore, the first refrigerant circulation mechanism 130 and the first heat storage system refrigerant circulation mechanism 170 are stopped by the control unit 300, and the second refrigerant circulation mechanism 230 and the second heat accumulation circulation mechanism 250 are in the operating state. Thereby, the cold generated by the first heat storage system compressor 150 is supplied to the second evaporator 210 (heat storage supply state).

  Therefore, the running state can be suppressed by transitioning to the heat storage state in a time zone where the power cost is low, and transitioning to the heat storage supply state when the power cost is high.

  By the way, the 1st cooling unit 100 performs heat exchange using the 1st refrigerant (flammable refrigerant). For this reason, it is necessary to reduce the risk of ignition and explosion due to leakage of the first refrigerant. Therefore, the circulation path of the first refrigerant (the flammable refrigerant) is set indoors, not indoors. At this time, it is preferable to set in a well-ventilated place. Furthermore, the cooling system 2 preferably comprises an explosion proof structure 400. The explosion-proof structure 400 is preferably provided to a specific portion (for example, the first compressor 110 or the first heat storage system compressor 150) in the circulation path of the first refrigerant (flammable refrigerant). Hereinafter, although the details of the explosion-proof structure 400 will be described, the common portion of the first compressor 110 and the first heat storage system compressor 150 will be described by taking as an example a case where it is provided to the first compressor 110.

  As shown in FIGS. 1 and 2, the explosion-proof structure 400 includes a housing 410 that accommodates the first compressor 110, a first exhaust fan 420 provided above the first compressor 110 in the housing, and a first exhaust fan 420. A second exhaust fan 430 provided below the first compressor 110, a first refrigerant leak detection sensor 440 that detects a leak of the first refrigerant, and a shutoff valve 450 that shuts off the flow of the first refrigerant .

  In the housing 410, an opening 410X is formed between the first exhaust fan 420 and the second exhaust fan 430 in the height direction. The first refrigerant leak detection sensor 440 is provided below the first compressor 110 (FIG. 2), and is provided in the pipe H1 of the first refrigerant circulation mechanism 130 (FIG. 1). The shutoff valve 450 is provided in the pipe H1 of the first refrigerant circulation mechanism 130.

  The control unit 300 determines whether or not the first refrigerant leaks from the sensing signal from the first refrigerant leak detection sensor 440. Then, when the leak of the first refrigerant is not detected, the control unit 300 opens the shutoff valve 450, operates the pump P1 and the first exhaust fan 420, and stops the second exhaust fan 430. As a result, external air can be supplied to the first compressor 110, so that heat can be dissipated from the first compressor 110. On the other hand, when a leak of the first refrigerant is detected, the control unit 300 closes the shutoff valve 450 and stops the pump P1 and the first exhaust fan 420 while operating the second exhaust fan. This makes it possible to deliver the leaked first refrigerant to the outside of the housing 410. As a result, it is possible to prevent the ignition and the like due to the flammable first refrigerant.

  The second refrigerant storage tank 220 preferably has an airtight structure. The first heat storage system refrigerant circulation mechanism 170 is preferably immersed in the second refrigerant in the second refrigerant storage tank 220. According to these structures, when the first refrigerant leaks in the second refrigerant storage tank 220, it can be detected as a bubble. Therefore, such a structure functions as a first refrigerant leak detection structure. Therefore, it is preferable that the normal second refrigerant storage tank 220 be filled with the second refrigerant. If necessary, a camera for photographing the second refrigerant storage tank 220 and an image analysis apparatus capable of detecting the presence or absence of air bubbles by image analysis of a camera image may be provided.

  In addition, when the existing cooling system is shifted from the existing cooling system using fluorocarbon as the refrigerant to the cooling system for non-fluorocarbon refrigerant, when the existing facility is discarded, the disposal cost and the introduction cost of new construction become enormous. Therefore, in the cooling system of non-fluorocarbon refrigerant, it is desirable to maximize the existing diversion and minimize the remodeling cost.

  As shown in FIG. 3, the existing cooling system includes an evaporator EX disposed in the indoor cooling device R, a compressor CP separate from the cooling device R, and a refrigerant between the evaporator EX and the compressor CP. In the case of including the circulation mechanism CR that circulates, it is preferable to convert the non-fluorocarbon refrigerant into the cooling system as follows.

  First, a new installation step of providing the second refrigerant storage tank 220 and the first cooling unit 100 (at least the first compressor 110, the first evaporator 120 and the first refrigerant circulation mechanism 130) outdoors, and the existing circulation mechanism CR. A connection step of connecting the second evaporator 210 (existing evaporator EX) and the second refrigerant storage tank 220 using as the second refrigerant circulation mechanism 230, extracting fluorocarbon in the existing circulation mechanism CR, and removing non-fluorocarbon refrigerant It is preferable to provide the refrigerant | coolant substitution step which introduce | transduces (2nd refrigerant | coolant). In addition, a heat storage tank new construction step for newly forming a first heat storage system compressor 150, a first heat storage system evaporator 160, a first heat storage system refrigerant circulation mechanism 170, a second refrigerant heat storage tank 240, and a second heat storage circulation mechanism 250; Preferably, When the existing circulation mechanism CR is used as the second refrigerant circulation mechanism 230, a part of the closed structure (O-shaped) circulation mechanism CR is cut and used as an open structure (C-shaped). Is preferred. Thereby, the heat exchange efficiency in the 2nd evaporator 210 (existing evaporator EX) and the 2nd refrigerant storage tank 220 can be raised. In addition, the existing compressor CP may be used as the first compressor 110 or the first heat storage system compressor 150.

  Thereby, when transitioning from the existing cooling system using fluorocarbon as the refrigerant to the cooling system of non-fluorocarbon refrigerant, the existing diversion can be maximized, so that the remodeling cost can be minimized.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

100 first cooling unit 110 first compressor 120 first evaporator 130 first refrigerant circulation mechanism 150 first heat storage system compressor 160 first heat storage system evaporator 170 first heat storage system refrigerant circulation mechanism 200 second cooling unit 210 2 evaporator 220 second refrigerant storage tank 230 second refrigerant circulation mechanism 240 second refrigerant storage tank 250 second heat storage circulation mechanism 300 control unit 400 explosion-proof structure 410 housing 410 X opening 420 first exhaust fan 430 second exhaust fan 440 detection Sensor 450 shut off valve

Claims (5)

A first cooling unit that performs heat exchange using a first refrigerant that is a flammable refrigerant;
A second cooling unit that performs heat exchange using a second refrigerant that is a nonflammable refrigerant;
It has a control unit that controls each part,
The second cooling unit is
A second evaporator arranged in the indoor cooling system,
A second refrigerant storage tank disposed outdoors and containing a second refrigerant;
A second refrigerant circulation mechanism that circulates the second refrigerant between the second refrigerant storage tank and the second evaporator;
The first cooling unit is
A first compressor disposed outdoors,
A first evaporator disposed in the second refrigerant storage tank;
A first refrigerant circulation mechanism that circulates the first refrigerant between the first compressor and the first evaporator. The second cooling unit is
A second refrigerant storage tank provided outdoors and containing the second refrigerant;
A second heat storage circulation mechanism for circulating the second refrigerant between the second refrigerant storage tank and the second refrigerant storage tank;
The first cooling unit is
A first heat storage system compressor disposed outside,
A first heat storage system evaporator disposed in the second refrigerant heat storage tank;
A first heat storage system refrigerant circulating mechanism for circulating the first refrigerant between the first heat storage system compressor and the first heat storage system evaporator;
The control unit
A heat storage state in which cold heat generated by the first heat storage system compressor is stored in the second refrigerant heat storage tank;
A cold heat supply state in which cold heat generated by the first heat storage system compressor is supplied to the second evaporator;
The cooling system according to claim 1, wherein the cooling system is switchable between the two. A housing for housing the first compressor;
A first exhaust fan provided above the first compressor in the housing;
A second exhaust fan provided below the first compressor;
A first refrigerant leak detection sensor that detects a leak of the first refrigerant;
The first refrigerant is a gas,
An opening is formed in the housing between the first exhaust fan and the second exhaust fan in the height direction,
The first refrigerant leak detection sensor is provided below the first compressor, and is provided in the first refrigerant circulation mechanism.
The control unit operates the first exhaust fan when the leak of the first refrigerant is not detected, and stops the second exhaust fan while the leak of the first refrigerant is detected. The cooling system according to claim 1 or 2, wherein the first exhaust fan is stopped while the second exhaust fan is operated. It further comprises a first refrigerant leak detection structure,
The first refrigerant leak detection structure is
An airtight structure of the second refrigerant storage tank;
In the second refrigerant storage tank, a structure in which the first heat storage system refrigerant circulating mechanism is immersed in the second refrigerant,
The cooling system according to any one of claims 1 to 3, wherein the first refrigerant is a gas, and the second refrigerant is a liquid. An evaporator arranged in the indoor cooling system,
A compressor separate from the cooling device;
A method of remodeling a cooling system, comprising: the evaporator and a circulation mechanism that circulates fluorocarbon with the compressor,
Providing a refrigerant storage tank containing non-fluorocarbon refrigerant outdoors;
Connecting the refrigerant storage tank and the evaporator using the circulation mechanism;
Removing the fluorocarbon in the circulation mechanism;
Introducing the non-fluorocarbon refrigerant in the circulation mechanism.

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