JP6582102B1 - Cooling system - Google Patents

Abstract

A heat storage device that cools brine using a CO2 refrigerant and a cooling system using the heat storage device are provided. The heat storage device 80 and the cooling system 100 cool a brine using a CO2 refrigerant having a small warming coefficient, and cool cooling loads 50A to 50C using the brine. Thereby, the usage-amount of greenhouse gas with a high global warming potential can be reduced. Further, the cooling system 100 cools the stored brine with high efficiency and stores heat at night when the power rate is relatively cheap and the outside air temperature is lower than that in the daytime. In the daytime operation, the cold energy of the stored brine is used for cooling the cooling loads 50A to 50C. As a result, power consumption during the day can be suppressed, energy costs can be reduced, and surplus power at night can be used effectively, contributing to energy saving. [Selection] Figure 1

Description

The present invention relates to cooling systems that heat storage is cooled brine with CO ₂ refrigerant.

  For example, in stores, commercial facilities, etc., a plurality of temperature management facilities such as a refrigerated showcase and an air conditioning system that maintain and manage the interior (inside the room) at a predetermined temperature are used. Of these cooling devices for temperature management equipment, low-temperature late-night electricity is used to cool the brine (antifreeze) in the heat storage tank for nighttime heat storage. What supplies temperature management equipment and performs temperature maintenance management has high economical efficiency in terms of electric power cost. Examples of such a heat storage system using a heat storage tank include the following [Patent Document 1] and [Patent Document 2].

  Moreover, frost adheres to the cooling load of the temperature management facility or the like by continuous use, and the cooling capacity is reduced. For this reason, a regular defrosting operation is required. In this regard, the following [Patent Document 3] discloses an invention in which defrosting is performed by circulating a relatively high temperature brine used for cooling to a cooling load.

Japanese Patent Laid-Open No. 11-281103 JP 2000-65001 A Japanese Patent Laid-Open No. 2004-77031

In these conventional cooling systems, specific chlorofluorocarbons such as CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon) and alternative chlorofluorocarbons such as HFC (hydrofluorocarbon) have been used as refrigerants. However, at present, international regulations are in place for specific chlorofluorocarbons as ozone-depleting substances and alternative chlorofluorocarbons as greenhouse gases. Therefore, environmental alternative to these CFC alternative to (warming) small CO ₂ refrigerant is demanded.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cooling system using the heat storage equipment for cooling the brine using a CO ₂ refrigerant.

The present invention
(1) A heat storage tank 30 for storing brine obtained by diluting the antifreeze liquid with water to a predetermined concentration, a storage brine cooling means 32A for cooling the brine in the heat storage tank 30, and a cooling load 50A for the brine in the heat storage tank 30 The storage brine cooling unit 32A heat-exchanges the CO ₂ refrigerant compressed by the compression unit 20a and liquefies the CO ₂ refrigerant compressed by the compression brine 20a. a heat exchange portion 21a for the expansion portion 24a for liquefied adiabatic expansion of CO ₂ refrigerant in the heat exchanging portion 21a, the brine of the heat storage tank 30 by heat exchange with the CO ₂ refrigerant expanded by the expansion part 24a a reservoir brine heat exchanger unit 26 for cooling, a heat storage device 80 have a,
Cooling loads 50A to 50C connected to the supply pipe 40, pump means 42 for pumping the brine in the heat storage tank 30 to the cooling loads 50A to 50C via the supply pipe 40, and heat generated by the cooling loads 50A to 50C The falling brine cooling means 32B for cooling the exchanged brine, the second compression section 20b that constitutes the falling brine cooling means 32B and compresses the CO ₂ refrigerant, and the falling brine cooling means 32B constitutes the second compression. a second heat exchanging portion 21b, the CO ₂ refrigerant cooled by said constitutes a falling brine cooling unit 32B and the second heat exchanging portion 21b thermally insulating the CO ₂ refrigerant compressed in parts 20b liquefied by cooling The heat is exchanged between the _second expansion part 24b to be expanded and the CO ₂ refrigerant constituting the falling brine cooling means 32B and expanded in the second expansion part 24b. A downstream brine heat exchanger 28 that cools the brine that has been heat exchanged with the cooling loads 50A to 50C, and a downstream side of the downstream brine heat exchanger 28, the discharge side branches into the heat storage tank 30 side and the supply pipe 40 side. The above-described problem is solved by providing a cooling system 100 including the three-way valve 44.
(2) The problem is solved by providing the cooling system 100 according to the above (1), further including an air agitating means 36 for agitating brine by discharging bubbles into the heat storage tank 30.
( 3 ) During night operation, the flow path of the three-way valve 44 is set to the supply pipe 40 side, the storage brine cooling means 32A and the falling brine cooling means 32B perform the cooling operation, and the storage brine cooling means 32A is the heat storage tank. 30 and cooling the brine flowing down in the supply pipe 40, the cooling brine cooling means 32B.
During daytime operation, the three-way valve 44 changes the amount of brine recirculated to the heat storage tank 30 and the amount of brine recirculated to the supply piping 40 according to the temperature of the brine flowing down in the supply piping 40. By providing the cooling system 100 according to the above (1) or (2) , the above problem is solved.
( 4 ) At the time of defrosting operation for the heat exchanger 52 of the cooling loads 50A to 50C , the flowing-down brine cooling means 32B is stopped and the flow path of the three-way valve 44 is set to the supply pipe 40 side (1) ) To (3) to provide the cooling system 100 according to any one of the above problems.

Cooling system Ru engaged to the present invention performs a brine cooled with a smaller CO ₂ refrigerant global warming potential, to cool the cooling load using this brine. Thereby, the usage-amount of greenhouse gas with a high global warming potential can be reduced.
In addition, the cooling system according to the present invention cools the stored brine with high efficiency and stores heat at night when the power rate is relatively cheap and the outside air temperature is lower than that in the daytime. In the daytime operation, the cold energy of the stored brine is used for cooling the cooling load. Thereby, power consumption during the day can be suppressed, and energy costs can be reduced. In addition, it is possible to effectively use surplus power at night, which can contribute to energy saving.

The present invention is a schematic diagram of a nighttime operation of the engaging Ru cooling system. A daytime schematic diagram during operation of the engagement Ru cooling system according to the present invention. The present invention is a schematic diagram of a defrosting during operation of the engaging Ru cooling system. It is a figure which shows the example of the storage brine heat exchange part of the thermal storage apparatus of the cooling system which concerns on this invention. It is a figure which shows the other example of the storage brine heat exchange part of the heat storage apparatus of the cooling system which concerns on this invention.

For engagement Ru cooling system 100 of the present invention will be described with reference to the drawings. Here, FIG. 1 is a schematic configuration diagram of a nighttime operation of the engaging Ru cooling system 100 of the present invention. FIG. 2 is a schematic configuration diagram during daytime operation. FIG. 3 is a schematic configuration diagram during the defrosting operation. In addition, the solid line arrow in FIGS. 1 to 3 shows the flow direction of the CO ₂ refrigerant and brine, and the broken line arrow shows a simplified control signal path.

First, the brine used in the present invention is prepared by diluting a known antifreeze such as ethylene glycol or propylene glycol with water, and is prepared to a concentration at which freezing of the water component starts at a predetermined temperature (for example, −6 ° C.). The heat storage device 80 of the cooling system 100 according to the present invention includes a heat storage tank 30 for storing the brine, a stored brine cooling means 32A for cooling the brine in the heat storage tank 30, and a brine for cooling the brine in the heat storage tank 30. And a supply pipe 40 to be supplied to the 50A to 50C side. Further, the reservoir brine cooling means 32A includes a compression section 20a for compressing the CO ₂ refrigerant, a heat exchange portion 21a for liquefying CO ₂ refrigerant compressed in the compression portion 20a is cooled, liquefied in the heat exchange section 21a and known expansion portion 24a, such as an expansion valve for adiabatically expanding the CO ₂ refrigerant that has, stored brine heat to cool the brine (reservoir brine) in the heat storage tank 30 by heat exchange with the expanded CO ₂ refrigerant by the expansion portion 24a And an exchange unit 26. Further, the reservoir brine cooling means 32A preferably has a CO ₂ refrigerant that has liquefied in the heat exchange portion 21a, the liquid-gas heat exchanger section 22a which performs heat exchange between the CO ₂ refrigerant used in the cooling of the reservoir brine . The compression portion 20a and the heat exchanger 21a, it is preferable to use the outdoor unit 34a of the known refrigerating apparatus using CO ₂ refrigerant.

The stored brine cooling means 32A may have a known dryer 10 for removing moisture mixed in the CO ₂ refrigerant between the heat exchange unit 21a and the liquid gas heat exchange unit 22a. It may also have a known suction filter 12 for removing contaminants mixed in CO ₂ refrigerant between the liquid-gas heat exchanger section 22a and the compression portion 20a. Moreover, you may provide the well-known accumulator 14 between the storage brine heat exchange part 26 and the liquid gas heat exchange part 22a.

  The storage brine heat exchanging unit 26 is installed in the heat storage tank 30 to cool the stored brine to a predetermined set temperature, and a plurality of coil-shaped cooling pipes 25 are provided in the heat storage tank 30 as shown in FIG. Arranged ones or other shapes may be used. In particular, as shown in FIG. 5, it is particularly preferable that the folded pipelines 23 folded at a predetermined interval are connected in parallel to fill the inside of the heat storage tank 30. 4A is a top view of the stored brine heat exchange section 26 using the coil-shaped cooling pipe 25, and FIG. 4B is a front view. FIG. 5A is a front view of the stored brine heat exchanging portion 26 using the folded pipe 23, and FIG. 5B is a side view. The heat storage tank 30 is provided with a temperature sensor S2 for acquiring the temperature of the stored brine and a water level acquiring means S1 for acquiring the water level of the stored brine. In addition, although the water level acquisition means S1 may use what acquires the water level of a storage brine directly, you may calculate and acquire a water level from the pressure of a storage brine using a pressure sensor.

  When the storage brine in the heat storage tank 30 is cooled and reaches the freezing temperature, the water component in the brine is frozen, and the latent heat at this time is also stored. At this time, by optimizing the settings of the storage brine cooling means 32A and the air stirring means 36 described later, the water component in the brine is frozen as fine ice, and the storage brine is made up of fine ice and liquid antifreeze. A mixed sherbet-like ice slurry may be used. In this configuration, the supply pipe 40, the pump means 42, and the like can cope with ice slurry pressure feeding, so that the cooling loads 50A to 50C can be cooled by the ice slurry of the stored brine. In this case, in addition to the sensible heat of the stored brine, the latent heat when the ice slurry is melted can be used directly for cooling the cooling loads 50A to 50C, so that higher cooling efficiency can be obtained.

  Furthermore, it is preferable that the heat storage device 80 has the air stirring means 36. The air agitating means 36 is provided on the bottom surface side in the heat storage tank 30 and agitates the stored brine by discharging the air supplied from the air pump 36a as bubbles from the bottom side. According to this configuration, the stored brine can be cooled as a whole, and efficient heat storage with little waste can be performed. Further, when performing load cooling, the stored cold energy can be used without waste. In particular, when ice is present in the storage brine, the latent heat of the ice can be quickly conducted to the entire storage brine and used effectively for cooling the load.

  Further, the cooling system 100 according to the present invention includes the heat storage device 80, the cooling loads 50 </ b> A to 50 </ b> C connected to the supply pipe 40 of the heat storage device 80, and the stored brine in the heat storage tank 30 via the supply pipe 40. Pump means 42 for pumping to the cooling loads 50A to 50C side, falling brine cooling means 32B for cooling the brine exchanged by the cooling loads 50A to 50C, and the discharge side branch to the heat storage tank 30 side and the supply piping 40 side 3 It has the direction valve 44 and the control part which is not shown in figure which controls these each part.

Also, falling brine cooling means 32B, similarly to the reservoir brine cooling means 32A, CO ₂ refrigerant compressing section 20b for compressing (second compression unit), cooling the CO ₂ refrigerant compressed in the compression section 20b A heat exchanging part 21b (second heat exchanging part) that is liquefied and a well-known expansion part 24b (second expansion part) such as an expansion valve that adiabatically expands the CO ₂ refrigerant cooled by the heat exchanging part 21b; And a brine heat exchanging section 28 for cooling the brine exchanged with the cooling loads 50A to 50C by heat exchange with the CO ₂ refrigerant expanded in the expansion section 24b. A three-way valve 44 is located downstream of the brine heat exchange unit 28. Also, falling brine cooling unit 32B includes a CO ₂ refrigerant that has liquefied in the heat exchanger 21b, the liquid-gas heat exchanger section 22b that performs heat exchange between the CO ₂ refrigerant heat exchange in the brine heat exchanger unit 28 It is preferable. The compression unit 20b and the heat exchanger section 21b, similarly to the reservoir brine cooling means 32A, it is preferable to use the outdoor unit 34b of the known refrigerating apparatus using CO ₂ refrigerant. Further, like the stored brine cooling means 32A, it is preferable to provide the dryer 10, the suction filter 12, etc. on the refrigerant path.

  The cooling loads 50A to 50C are, for example, refrigerated showcases, refrigerated warehouses, other refrigeration facilities, air conditioning units, etc., and cool by cooling heat between the brine from the supply pipe 40 and the air in the room (indoor). Each has a heat exchanger 52 to be operated. A three-way valve 54 is provided upstream of each heat exchanger 52, and one discharge side of the three-way valve 54 is connected to each heat exchanger 52. A bypass pipe 56 that joins downstream of the heat exchanger 52 is connected to the other discharge side of the three-way valve 54. Further, each of the cooling loads 50A to 50C is provided with a temperature sensor S4 that measures and outputs the temperature in the cabinet.

  The cooling loads 50A to 50C may be configured as a single unit, but basically a plurality of cooling loads are connected and used. At this time, the cooling loads 50A to 50C are connected in series, and for example, a refrigerated showcase for meat and fish and shellfish, which is required to be refrigerated at a low temperature, is arranged on the upstream side (cooling load 50A). For example, a refrigerated showcase for vegetables and beverages, a cooling air-conditioning facility (cooling loads 50B, 50C), etc., which are allowed to be refrigerated at a high temperature, are sequentially arranged on the downstream side. In this configuration, low-temperature brine (or ice slurry) is supplied to the cooling load 50A on the upstream side, and the interior is cooled by heat exchange with this brine. Further, the brine used for this cooling is sequentially supplied to the cooling loads 50B and 50C on the downstream side, and heat exchange is performed in the respective heat exchangers 52 to cool the interior (inside the room). In this configuration, the coldest brine is supplied to the cooling load 50A that requires a low cooling temperature to cool the inside of the cabinet, and the cooling loads 50B and 50C that do not require much cooling temperature are used at the preceding cooling load. Cool with the brine. Thus, efficient cooling of the cooling loads 50A to 50C can be performed by using the cold heat of the brine in a cascade manner without waste. The brine used for cooling the cooling loads 50 </ b> A to 50 </ b> C flows down to the three-way valve 44 side via the return pipe 46.

  Further, the supply pipe 40 is provided with a temperature sensor S3 for acquiring the temperature of the brine flowing down, and in the daytime operation, the opening ratio on the discharge side of the three-way valve 44 according to the temperature of the brine acquired by the temperature sensor S3. Is controlled. Further, before and after the downstream brine heat exchange section 28, a temperature sensor S5 that acquires the temperature of the brine after heat exchange by the cooling loads 50A to 50C and the temperature of the brine after heat exchange by the downstream brine heat exchange section 28 are acquired. The temperature sensor S6 is provided, and the discharge amount of the pump means 42 is controlled in accordance with the brine temperature acquired by the temperature sensor S5. Further, the on / off of the falling brine cooling means 32B is controlled according to the brine temperature acquired by the temperature sensor S6.

Next, the operation during night driving engagement Ru cooling system 100 of the present invention will be described with reference to FIG. The switching between the daytime operation, the nighttime operation, and the defrosting operation of the cooling system 100 is performed by a timer set in the control unit, for example.

First, in the night operation, the control unit sets the flow path of the three-way valve 44 to the supply pipe 40 side. Thereby, the flow path of the brine flowing down on the cooling loads 50A to 50C side and the heat storage tank 30 are separated. Then, the control unit operates the stored brine cooling means 32A. As a result, the compression unit 20a operates to compress the CO ₂ refrigerant and discharge it in a high temperature and high pressure state. Next, the high-temperature and high-pressure CO ₂ refrigerant is cooled and liquefied by heat exchange with the outside air or water in the heat exchange section 21a. Next, after the unnecessary moisture mixed inside the CO ₂ refrigerant is removed by the dryer 10, heat exchange is performed between the CO ₂ refrigerant and the CO ₂ refrigerant used for cooling the stored brine in the liquid gas heat exchange unit 22 a. Done and further cooling. Next, the CO ₂ refrigerant is adiabatically expanded in the expansion section 24a and becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant. Then, the CO ₂ refrigerant heat exchange is performed by flowing down the reservoir brine heat exchanger unit 26 provided in the heat storage tank 30 with the reservoir brine in the heat storage tank 30 to vaporize. Then, the temperature of the reservoir brine is reduced by the heat absorption of the CO ₂ refrigerant at this time. The temperature of the storage brine is acquired by the temperature sensor S2 and output to the control unit. Next, the vaporized CO ₂ refrigerant flows into the liquid gas heat exchange section 22a via the accumulator 14, and heat exchange is performed with the upstream CO ₂ refrigerant (liquid phase). Next, after unnecessary impurities are removed by the suction filter 12, the CO ₂ refrigerant is sucked into the compression unit 20a and discharged again as a high-temperature and high-pressure CO ₂ refrigerant.

  In addition, the control unit operates the air pump 36a when the temperature of the storage brine acquired via the temperature sensor S2 falls within a specific temperature range set in advance or when a preset time zone is reached. Thereby, air bubbles are discharged from the air agitating means 36 and the stored brine is agitated. Thereby, the heat exchange by the storage brine heat exchange part 26 is performed uniformly, and the temperature of the storage brine falls entirely. When the temperature of the storage brine reaches the freezing temperature, the water in the storage brine is frozen. This freezing increases the volume of the stored brine and raises the water level. The change in the water level of the stored brine is acquired by the water level acquisition means S1 and output to the control unit. Then, the control unit stops the stored brine cooling means 32A when the water level of the stored brine reaches the preset upper limit water level. Thereby, excessive freezing (heat storage) of the storage brine is prevented. Further, the control unit stops the stored brine cooling means 32A when the temperature of the stored brine acquired via the temperature sensor S2 reaches a preset lower limit temperature. Thereby, brine of a predetermined temperature is stored in the heat storage tank 30. Even if the storage brine does not reach the upper limit water level and the lower limit temperature, the control unit stops the storage brine cooling means 32A when the preset time zone is exceeded.

  In parallel with this, the control unit acquires the temperature of the brine flowing down the return pipe 46 via the temperature sensor S5, and operates the pump means 42 in accordance with the temperature. The pump means 42 can adjust the discharge amount by well-known inverter control, and the control unit increases the discharge amount of the pump means 42 when the brine temperature is high, and the pump when the brine temperature is low. The discharge amount of the means 42 is reduced.

Further, the control unit acquires the temperature of the brine on the downstream side of the flowing-down brine heat exchanging unit 28 via the temperature sensor S6, and operates the flowing-down brine cooling means 32B when the temperature exceeds a preset temperature. . As a result, the compression unit 20b of the falling brine cooling means 32B operates to compress the CO ₂ refrigerant and discharge it in a high temperature and high pressure state. Next, this high-temperature and high-pressure CO ₂ refrigerant is cooled and liquefied by heat exchange with the outside air or water in the heat exchange section 21b. Next, after the unnecessary moisture mixed inside is removed by the dryer 10, the CO ₂ refrigerant is exchanged with the CO ₂ refrigerant used in the heat exchange of the brine heat exchange section 28 in the liquid gas heat exchange section 22b. Heat exchange takes place and further cooling. Next, the CO ₂ refrigerant is adiabatically expanded in the expansion section 24b and becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant. Next, the CO ₂ refrigerant is vaporized by performing heat exchange with the brine flowing down through the falling brine heat exchanging section 28 and flowing down through the return pipe 46. Then, the temperature of the brine by the heat absorption of the CO ₂ refrigerant at this time is reduced. The temperature of the brine after the heat exchange is acquired by the temperature sensor S6 and output to the control unit. Next, the vaporized CO ₂ refrigerant flows into the liquid gas heat exchange unit 22b, and heat exchange is performed with the upstream CO ₂ refrigerant (liquid phase). Next, after unnecessary impurities are removed by the suction filter 12, the CO ₂ refrigerant is sucked into the compression unit 20b and discharged again as a high-temperature and high-pressure CO ₂ refrigerant.

  Further, the brine cooled by the falling brine heat exchange section 28 flows into the supply pipe 40 through the three-way valve 44 and is pumped to the cooling loads 50A to 50C by the pump means 42. Although the temperature sensor S3 acquires the temperature of the brine flowing down the supply pipe 40, special control based on the temperature sensor S3 is not performed during nighttime operation.

  Then, the brine pumped by the pump means 42 reaches the three-way valve 54 of the cooling load 50A located at the uppermost stream. At this time, the control unit sets the discharge direction of the three-way valve 54 to the heat exchanger 52 side when the internal temperature acquired via the temperature sensor S4 of the cooling load 50A is higher than a preset temperature. In this case, the brine flows down the heat exchanger 52 to exchange heat with the air in the warehouse, and lowers the temperature in the warehouse of the cooling load 50A. And it flows down to the cooling load 50B side of a back | latter stage. Further, when the temperature in the chamber of the cooling load 50A is lower than a preset temperature, the control unit assumes that the cooling state of the cooling load 50A is sufficient and sets the discharge direction of the three-way valve 54 to the bypass pipe 56 side. In this case, the brine flows down directly to the cooling load 50B side through the bypass pipe 56 without passing through the heat exchanger 52. Then, the brine flowing down to the cooling load 50B side flows down to the cooling load 50C side through the heat exchanger 52 or the bypass pipe 56 in exactly the same manner as the cooling load 50A. Similarly, the brine that has flowed down to the cooling load 50 </ b> C flows down to the return pipe 46 through the heat exchanger 52 or the bypass pipe 56. And after cooling in the falling brine heat exchange part 28, it is supplied to cooling of cooling load 50A-50C again through the supply piping 40. FIG. Further, the control unit stops the flowing-down brine cooling means 32B when the temperature of the brine acquired via the temperature sensor S6 becomes equal to or lower than a preset temperature. Thereby, freezing of the brine in the flowing-down brine heat exchange part 28 by excessive cooling can be prevented.

  Here, at night, the loads of the cooling loads 50A to 50C are smaller than those during the day. And each part of the flowing-down brine cooling means 32B is designed by the capability which can supplement the load amount of the cooling loads 50A-50C at night.

Next, the operation of the daytime during operation of the engaging Ru cooling system 100 of the present invention will be described with reference to FIG. First, in the daytime operation, the stored brine cooling means 32A basically stops. However, when the temperature of the stored brine acquired by the temperature sensor S2 exceeds the preset upper limit temperature, the control unit operates the stored brine cooling means 32A to cool the stored brine in the same way as during night operation. Do.

  Further, the control unit controls the falling brine cooling means 32B and each three-way valve 54 in the same manner as during night operation. Moreover, a control part adjusts the opening degree of the supply piping 40 side of the three-way valve 44, and the thermal storage tank 30 side according to the temperature of the brine of the supply piping 40 which temperature sensor S3 acquires. That is, when the temperature of the temperature sensor S3 is equal to or lower than the set temperature, the control unit controls the opening ratio of the three-way valve 44 on the supply pipe 40 side to be large and the opening ratio on the heat storage tank 30 side to be small. Thereby, the recirculation | reflux amount to the supply piping 40 of brine increases, and the recirculation | reflux amount to the thermal storage tank 30 decreases. In this case, cooling of the cooling loads 50A to 50C is mainly performed by the falling brine cooling means 32B side.

  In addition, when the temperature of the temperature sensor S3 is higher than the set temperature, that is, when the load amount of the cooling loads 50A to 50C increases and exceeds the capacity of the falling brine cooling means 32B, the control unit performs the heat storage tank 30 of the three-way valve 44. The opening ratio on the side is increased and the opening ratio on the supply pipe 40 side is controlled to be smaller. In this case, the recirculation amount of the brine to the heat storage tank 30 increases, and the recirculation amount to the supply pipe 40 decreases. Thereby, the low-temperature storage brine flows from the heat storage tank 30 into the supply pipe 40 and is supplied to the cooling of the cooling loads 50A to 50C. Moreover, the brine discharged into the heat storage tank 30 is cooled by the stored brine. As a result, the load on the falling brine cooling means 32B is reduced, and the power consumption during the day can be suppressed.

Next, the operation during defrosting operation of the engaging Ru cooling system 100 of the present invention will be described with reference to FIG. The defrosting operation is for melting and removing frost adhering to the heat exchangers 52 of the cooling loads 50A to 50C, and is periodically performed at predetermined intervals regardless of whether the operation is nighttime operation or daytime operation. .

  In the defrosting operation in the cooling system 100, the control unit sets the discharge direction of the three-way valve 44 to the supply pipe 40 side. Thereby, the flow path of the brine flowing down on the cooling loads 50A to 50C side and the heat storage tank 30 are separated. Further, the control unit sets all the discharge directions of the three-way valves 54 of the cooling loads 50A to 50C to the heat exchanger 52 side. Then, the control unit stops the falling brine cooling means 32B. Thereby, the brine subjected to heat exchange with the cooling loads 50 </ b> A to 50 </ b> C circulates in all the heat exchangers 52 without being cooled. And by performing this for a certain period of time, the frost adhering to the heat exchanger 52 is melted and removed. When the defrosting operation for a specified time is completed, the falling brine cooling means 32B returns to the night operation or daytime operation described above. The stored brine cooling means 32A does not perform any special operation even during the defrosting operation, and maintains the operation during the night operation and the daytime operation as it is.

As described above, cooling system 100 Ru engaged to the present invention performs a brine cooled with a smaller CO ₂ refrigerant global warming potential, to cool the cooling load 50A~50C with this brine. Thereby, the usage-amount of greenhouse gas with a high global warming potential can be reduced.

  In addition, the cooling system 100 according to the present invention cools the stored brine with high efficiency and stores heat at night when the power rate is relatively cheap and the outside air temperature is lower than the daytime. In the daytime operation, the cold energy of the stored brine is used for cooling the cooling loads 50A to 50C. Thereby, the load of the falling brine cooling means 32B in the daytime operation is reduced, and the power consumption during the day can be suppressed. As a result, energy costs can be reduced, and surplus power at night can be effectively used, contributing to energy savings.

  Furthermore, the cooling system 100 according to the present invention stops the falling brine cooling means 32B and defrosts the heat exchanger 52 by circulating the brine. As a result, further energy cost reduction and energy saving can be achieved.

  In addition, since the structure, mechanism, shape, dimension, piping route, operation, etc. of each part of the heat storage device 80, the heat storage tank 30, and the cooling system 100 shown in this example are examples, they are not limited to this example. The present invention can be modified and implemented without departing from the scope of the present invention.

20a Compression unit
20b (second) compression unit
21a Heat exchange section
21b (second) heat exchange section
24a Expansion part
24b (second) expansion part
26 Storage brine heat exchanger
28 Downstream brine heat exchanger
30 heat storage tank
32A storage brine cooling means
32B Flowing brine cooling means
36 Air stirring means
40 Supply piping
42 Pump means
44 3-way valve
50A-50C Cooling load
80 heat storage device
100 cooling system

Claims (4)

A heat storage tank for storing brine in which the antifreeze is diluted to a predetermined concentration with water, storage brine cooling means for cooling the brine in the heat storage tank, supply piping for supplying the brine in the heat storage tank to the cooling load side, The storage brine cooling means includes a compression unit that compresses the CO ₂ refrigerant, a heat exchange unit that exchanges heat to liquefy the CO ₂ refrigerant compressed by the compression unit, and CO ₂ that is liquefied by the heat exchange unit an expansion unit for refrigerant adiabatically expanded, and the heat storage device have a, a reservoir brine heat exchanger unit for cooling the brine of the heat storage tank by the heat exchange with the expanded CO ₂ refrigerant by the expansion unit,
A cooling load connected to the supply pipe;
Pump means for pumping the brine in the heat storage tank to the cooling load side via the supply pipe;
A falling brine cooling means for cooling the brine subjected to heat exchange with the cooling load;
A _second compression section that configures the downstream brine cooling means and compresses the CO ₂ refrigerant; and a second compression section that configures the downstream brine cooling means and cools and liquefies the CO ₂ refrigerant compressed by the second compression section . A second expansion part that constitutes the falling brine cooling means and adiabatic expansion of the CO ₂ refrigerant cooled by the second heat exchange part, and constitutes the falling brine cooling means. A falling brine heat exchange section for cooling the brine heat-exchanged with the cooling load by heat exchange with the CO ₂ refrigerant expanded in the expansion section ;
A cooling system comprising a three-way valve located downstream of the downflow brine heat exchange section and having a discharge side branched into the heat storage tank side and the supply piping side. The cooling system according to claim 1, further comprising an air agitating means for agitating the brine by discharging bubbles into the heat storage tank. During night operation, the flow path of the three-way valve is on the supply pipe side, the storage brine cooling means and the falling brine cooling means perform a cooling operation, and the storage brine cooling means cools the brine in the heat storage tank, The falling brine cooling means cools the brine flowing down in the supply pipe;
The daytime during operation, claims, characterized in that changing the recirculation amount of the brine to the reflux amount and the supply pipe side of the brine to the 3-way valve the heat storage tank side according to the temperature of the brine flowing down the supply pipe The cooling system according to claim 1 or 2 . During defrosting operation for the heat exchanger of the cooling load, stops the falling brine cooling means, according to 3-way valve flow paths to one of claims 1 to 3, characterized in that the feed pipe side Cooling system.

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