JP2019124369A - Cold water production system - Google Patents

Abstract

To provide a cold water production system which cools a secondary refrigerant such as a brine by a primary refrigerant of a refrigerator and produces cold water by the secondary refrigerant, the cold water production system having safety which is improved by surely preventing mixing of the secondary refrigerant into the cold water.SOLUTION: The secondary refrigerant can be cooled by heat exchange with a primary refrigerant of a refrigerator 2. In a refrigerant circulation path 3(7,8), the secondary refrigerant is circulated to a heat exchanger 6. In a cold water circulation path 4(14,15), water is circulated between a cold water tank 13 and the heat exchanger 6, and the circulated water can be cooled by the secondary refrigerant in the heat exchanger 6. A cold water sending path 14 from the cold water tank 13 to the heat exchanger 6 is provided with circulation pumps 16, 17. Even during circulation stop of the secondary refrigerant in the refrigerant circulation path 3, the cold water is circulated in the cold water circulation path 4 by the circulation pump 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cold water production system in which a secondary refrigerant such as brine is cooled by a primary refrigerant of a refrigerator, and cold water is produced by the secondary refrigerant.

  Conventionally, as disclosed in Patent Document 1 below, a cold water production system for cooling water using a refrigerator is known. Referring to FIG. 3 of the document, the cold water production system includes a double pipe heat exchanger (32), and this heat exchanger (32) is connected to a refrigerator (33) via a refrigerant circuit (33). 31) while being connected to a cold water tank (34) via a cold water circulation path (36, 37). The heat exchanger (32) can exchange heat between the refrigerant of the refrigerator (31) and the circulating water of the cold water tank (34) to cool the stored water in the cold water tank (34).

  In this type of cold water production system, since the heat exchanger exchanges heat between the refrigerant and the water, if the heat exchanger should be damaged, the refrigerant or oil of the refrigerator may be mixed in the cold water. Therefore, depending on the application of cold water (for example, when cold water is used for food cooling), to improve safety, a brine circulation (two) may be provided between the refrigerant circulation (primary refrigerant circulation) and the cold water circulation. It is also conceivable to intervene a secondary refrigerant circulation path). That is, the refrigerator cools the brine, and the brine cools the water.

  However, even when using brine, further safety measures are desired in case the heat exchanger between brine and water is broken. That is, it is preferable if mixing of brine into cold water can be prevented even if the heat exchangers between the brine and water break. In particular, if both the circulation of brine and the circulation of cold water are stopped while the cooling operation is stopped (during the shutdown of the refrigerator), the pressure on the brine side and the water side will be equal, and the heat exchanger should be broken And, there is a risk that the brine will flow into the water side, so measures are desired.

Unexamined-Japanese-Patent No. 9-166339 (Paragraph 0002, FIG. 3)

  The problem to be solved by the present invention is to ensure mixing of the secondary refrigerant into the cold water in a system in which the secondary refrigerant such as brine is cooled by the primary refrigerant of the refrigerator and cold water is produced by the secondary refrigerant. To provide a cold water production system that can be prevented to enhance safety.

  This invention was made in order to solve the said subject, and the invention of Claim 1 can be made to be able to cool a secondary refrigerant by heat exchange with the primary refrigerant of a refrigerator, and the secondary refrigerant can be thermally processed. The cooling water circulation system includes: a refrigerant circulation path to be circulated to an exchanger; and a cold water circulation path that circulates water between a cold water tank and the heat exchanger and can cool the circulating water by the secondary refrigerant in the heat exchanger; A circulation pump is provided in the cold water feed passage from the tank to the heat exchanger, and it is possible to circulate cold water in the cold water circulation passage by the circulation pump even while the secondary refrigerant in the refrigerant circulation passage is stopped. It is a feature cold water production system.

  According to the first aspect of the present invention, it is possible to cool the secondary refrigerant with the primary refrigerant of the refrigerator, cool the circulating water with the secondary refrigerant, and cool the stored water in the cold water tank. Then, even while the secondary refrigerant in the refrigerant circulation path is stopped, cold water is circulated in the cold water circulation path by the circulation pump. Since the circulation pump is provided in the cold water feed path from the cold water tank to the heat exchanger, the pressure on the water side of the heat exchanger can be higher than the pressure on the secondary refrigerant side by the discharge pressure of the circulation pump . Thereby, even if the heat exchanger is damaged, the mixing of the secondary refrigerant into the cold water can be prevented, and the safety can be enhanced.

  In the invention according to claim 2, the circulation flow rate of the cold water circulation passage during the circulation stop of the refrigerant circulation passage is smaller than the circulation flow rate of the cold water circulation passage during the circulation of the refrigerant circulation passage. It is a cold water manufacturing system of Claim 1 characterized by these.

  According to the second aspect of the present invention, the circulation flow rate of the cold water during the circulation stop of the secondary refrigerant is smaller than the circulation flow rate of the cold water during the circulation of the secondary refrigerant. Therefore, energy saving can be achieved even if the cold water circulation pump is operated during the stop of the cooling operation (during the operation stop of the refrigerator).

  In the invention according to claim 3, a first circulation pump and a second circulation pump having a smaller capacity than the first circulation pump are provided in parallel in the cold water feed path from the cold water tank to the heat exchanger. The first circulation pump is operating or the first circulation pump and the second circulation pump are operating to circulate the refrigerant circulation path, and while the circulation of the refrigerant circulation is stopped, the second circulation pump is circulated. The cold water production system according to claim 2, characterized in that:

  According to the third aspect of the present invention, by using the second circulation pump having a relatively small capacity, it is possible to easily prevent mixing of the secondary refrigerant into cold water with a simple configuration and to enhance safety. As well as being able to save energy.

  The invention according to claim 4 is characterized in that an adjustment mechanism for a flow passage cross-sectional area is provided in the cold water return passage from the heat exchanger to the cold water tank, and the adjustment mechanism is stopped while the circulation of the refrigerant circuit is stopped. The flow path cross-sectional area of the said cold-water return path is made small by this, The cold-water manufacturing system of any one of the Claims 1-3 characterized by the above-mentioned.

  According to the invention described in claim 4, while the circulation of the refrigerant circuit is stopped, the pressure on the water side of the heat exchanger can be reduced by reducing the flow passage cross-sectional area of the chilled water return passage from the heat exchanger to the chilled water tank. It can be enhanced. Thereby, even if the heat exchanger is broken, the mixing of the secondary refrigerant into the cold water can be further reliably prevented, and the safety can be further enhanced.

  Furthermore, in the invention according to claim 5, the secondary refrigerant is a brine, and the refrigerant circuit includes a brine tank for storing brine, and brine is provided between the brine tank and the heat exchanger. It is made to circulate, It is a cold water manufacturing system of any one of the Claims 1-4 characterized by the above-mentioned.

  According to the fifth aspect of the present invention, brine can be used as the secondary refrigerant, and the brine can be circulated between the brine tank and the heat exchanger.

  According to the present invention, in a system in which a secondary refrigerant such as brine is cooled by a primary refrigerant of a refrigerator and cold water is produced by the secondary refrigerant, mixing of the secondary refrigerant into the cold water is reliably prevented. Safety can be enhanced.

It is a schematic diagram showing a cold water production system of one example of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail based on the drawings.
FIG. 1 is a schematic view showing a cold water production system 1 according to an embodiment of the present invention.

  The cold water production system 1 of the present embodiment is a system for cooling a secondary refrigerant with the primary refrigerant of the refrigerator 2 and producing cold water with the secondary refrigerant. The secondary refrigerant is not particularly limited but is typically brine. Hereinafter, although a secondary refrigerant is explained as being brine, the same may be said of the case of other liquids.

  As shown in FIG. 1, the cold water production system 1 of the present embodiment includes a refrigerator 2 for circulating a primary refrigerant, a brine circulation path 3 for circulating brine as a secondary refrigerant, and a cold water circulation path 4 for circulating water. And

  The brine circuit 3 circulates the brine between the brine tank 5 and the heat exchanger 6. The brine tank 5 is a tank storing brine to a set liquid level, and in the present embodiment, the inside is opened under atmospheric pressure. The heat exchanger 6 includes a flow path on the brine side and a flow path on the water side so as to be able to exchange heat without mixing the brine and the water. The heat exchanger 6 may be, for example, a plate type heat exchanger, regardless of its configuration.

  Although the details will be described later, in the heat exchanger 6, the water is cooled by the brine to form cold water. When this cold water is used for food cooling (especially when it is in direct contact with food), it is also acceptable as a food additive (for example, brine) to be safe from brine leakage due to breakage of the heat exchanger 6 It is preferred to use propylene glycol).

  The brine tank 5 and the heat exchanger 6 are connected by the brine feed passage 7 and the brine return passage 8. A brine pump 9 is provided in the brine feed passage 7 (or the brine return passage 8). When the brine pump 9 is operated, the brine in the brine tank 5 is sent to the heat exchanger 6 via the brine feed passage 7 and returned to the brine tank 5 via the brine return passage 8. Since the brine tank 5 is an open tank as described above, the flow path on the brine side of the heat exchanger 6 is opened to substantially atmospheric pressure while the brine pump 9 is stopped.

  The brine in the brine circulation path 3 can be cooled by the refrigerator 2. In the present embodiment, the brine in the brine tank 5 can be circulated between the refrigerator 2 and cooled. Specifically, the brine tank 5 is connected to the refrigerator 2 by the brine cooling forward passage 10 and the brine cooling return passage 11. The brine cooling forward path 10 (or the brine cooling return path 11) is provided with a brine cooling pump 12. When the brine cooling pump 12 is operated, the brine in the brine tank 5 is sent to the refrigerator 2 via the brine cooling forward path 10 and returned to the brine tank 5 via the brine cooling return path 11.

  The refrigerator 2 is a vapor compression type refrigerator in this embodiment. In this case, the refrigerator 2 is configured by sequentially connecting a compressor, a condenser, an expansion valve, and an evaporator in an annular shape. The compressor compresses the refrigerant into a high temperature, high pressure gas. The condenser condenses and liquefies the refrigerant from the compressor. The expansion valve reduces the pressure and temperature of the refrigerant by passing the refrigerant from the condenser. Then, the evaporator evaporates the refrigerant from the expansion valve. The heat of vaporization at the time of evaporation can cool the brine. That is, the evaporator is a heat exchanger between the brine from the brine tank 5 and the refrigerant of the refrigerator 2.

  The cold water circulation path 4 circulates water between the cold water tank 13 and the heat exchanger 6. The cold water tank 13 is a tank that stores water up to a set water level, and in the present embodiment, the inside is opened to atmospheric pressure. As described above, the heat exchanger 6 is configured to be able to exchange heat without mixing the brine and the water.

  The cold water tank 13 and the heat exchanger 6 are connected by the cold water feed path 14 and the cold water return path 15. A first circulation pump 16 and a second circulation pump 17 are provided in parallel in the cold water feed path 14 from the cold water tank 13 to the heat exchanger 6. Specifically, after the cold water feed path 14 from the cold water tank 13 is branched into the first cold water feed path 14 a and the second cold water feed path 14 b, they join again and are connected to the heat exchanger 6. And while the 1st circulation pump 16 is provided in the 1st cold-water feed path 14a, the 2nd circulation pump 17 is provided in the 2nd cold-water feed path 14b.

  The second circulation pump 17 is a pump having a smaller capacity than the first circulation pump 16. That is, when the first circulation pump 16 is operated, cold water can flow at a larger flow rate than the second circulation pump 17, while when the second circulation pump 17 is operated, the flow rate is smaller than the first circulation pump 16. It can drain cold water.

  The chilled water in the chilled water tank 13 can be optionally supplied to a chilled water demand point (for example, a food machine) via the chilled water extraction passage 18. In the case of the example of illustration, the water pump 20 other than the manual gate valve 19 is provided in the cold-water extraction path 18. The gate valve 19 is normally maintained in the open state. Therefore, the cold water in the cold water tank 13 can be sent to the cold water demand point by operating the water pump 20 according to the demand of the cold water demand point. The cold water tank 13 can be appropriately supplied with water via the ball tap 21 or the like, and the water level in the cold water tank 13 is maintained as desired. By the way, the cold water in the cold water tank 13 can be used, for example, for food cooling, and the cold water itself can also be used as a beverage or a food.

  The cold water production system 1 includes a brine temperature sensor 22 for detecting the temperature of brine, and a cold water temperature sensor 23 for detecting the temperature of cold water. The brine temperature sensor 22 is provided in the brine tank 5 in the illustrated example, but may optionally be provided in the brine feed 7, the brine return 8, the brine cooled outbound 10 or the brine cooled return 11. Moreover, although the cold-water temperature sensor 23 is provided in the cold-water tank 13 in the example of illustration, you may be provided in the cold-water feed path 14 or the cold-water return path 15 depending on the case.

  Next, an operation example of the cold water production system 1 of the present embodiment will be described. The operation described below is automatically performed by a controller (not shown). That is, the controller is connected to the refrigerator 2, the brine pump 9, the brine cooling pump 12, the first circulation pump 16, the second circulation pump 17, the brine temperature sensor 22 and the cold water temperature sensor 23, etc. The refrigerator 2 and the pumps 9, 12, 16, 17 and the like are controlled based on detection signals of the sensors 22, 23.

  When an operation start instruction is issued, such as when the start button is pressed, the controller starts the operation of the cold water production system 1. On the other hand, when an operation stop instruction is issued, such as when the stop button is pressed, the controller stops the operation of the cold water production system 1.

  During the operation of the cold water production system 1, the brine is cooled so as to maintain the temperature detected by the brine temperature sensor 22 at the set temperature (for example, -3.degree. C.). Specifically, the brine cooling pump 12 is operated in a state where the refrigerator 2 is operated to circulate the brine in the brine tank 5 to the refrigerator 2 to cool and maintain the brine at the set temperature. . At this time, the refrigerator 2 and the brine cooling pump 12 are operated when the detected temperature of the brine temperature sensor 22 exceeds the set upper limit, and the refrigerator 2 and the brine cooling pump 12 are stopped when the detected temperature falls below the set lower limit. You may

  During operation of the cold water production system 1, the cold water is cooled so as to maintain the detected temperature of the cold water temperature sensor 23 at a target temperature (for example, 1.5 ° C. to 3 ° C.). Specifically, when the temperature detected by the cold water temperature sensor 23 is equal to or higher than the upper limit temperature (for example, 3 ° C.), the brine is operated with the first circulation pump 16 (or the first circulation pump 16 and the second circulation pump 17) operated. The pump 9 is operated. Thus, the water in the cold water tank 13 circulates with the heat exchanger 6, and the brine in the brine tank 5 circulates with the heat exchanger 6. Therefore, in the heat exchanger 6, cooling of the circulating water (and hence the water in the cold water tank 13) is achieved by the brine.

  While both the water and the brine are circulating in the heat exchanger 6, it is preferable to maintain the water side circulation pressure at a pressure higher than the brine side circulation pressure. That is, during operation of the first circulation pump 16 (or the first circulation pump 16 and the second circulation pump 17) and the brine pump 9, the pressure on the water side in the heat exchanger 6 is higher than the pressure on the brine side. , Installation of each pump 9, 16 (17) and piping and setting of flow rate are performed. Thereby, even if the heat exchanger 6 is broken, it is possible to prevent the mixing of the brine into the cold water circulation path 4 (thus, the cold water tank 13 and the cold water demand point) and to enhance the safety.

  On the other hand, when the temperature detected by the cold water temperature sensor 23 falls below the lower limit temperature (which is lower than the upper limit temperature, for example 1.5 ° C.), the second circulation pump 17 is operated with the brine pump 9 stopped. Let At this time, it is preferable to stop the first circulation pump 16.

  Thus, in the cold water production system 1 of the present embodiment, the cold water is circulated to the cold water circulation path 4 by the second circulation pump 17 even when the circulation of brine in the brine circulation path 3 is stopped. Since the second circulation pump 17 is provided in the cold water feed path 14 from the cold water tank 13 to the heat exchanger 6, the discharge pressure of the second circulation pump 17 makes the water side pressure in the heat exchanger 6 the brine side. The pressure of the can be raised. Thereby, even if the heat exchanger 6 is broken, it is possible to prevent the mixing of the brine into the cold water circulation path 4 (thus, the cold water tank 13 and the cold water demand point) and to enhance the safety. Moreover, since the second circulation pump 17 operated during the circulation stop of the brine circulation path 3 has a smaller capacity than the first circulation pump 16 operated during the circulation of the brine circulation path 3, energy saving can be achieved. it can. The second circulation pump 17 is sufficient as long as cold water can be circulated in the cold water circulation passage 4, and energy saving can be achieved as the capacity is smaller.

  When the operation of the cold water production system 1 is stopped, the refrigerator 2, the brine pump 9, the brine cooling pump 12, and the first circulation pump 16 are stopped, but the operation of the second circulation pump 17 is continued. Thereby, the pressure by the side of water in heat exchanger 6 can be raised rather than the pressure by the side of brine. Therefore, even if the heat exchanger 6 is broken, it is possible to prevent the mixing of brine into the cold water circulation path 4 (and consequently the cold water tank 13 and the cold water demand point), thereby enhancing the safety. Moreover, since the second circulation pump 17 has a smaller capacity than the first circulation pump 16, energy can be saved.

  As described above, according to the cold water production system 1 of the present embodiment, the brine pump 9 and the first circulation pump 16 are operated during the circulation of the brine circulation path 3, but the pressure on the water side in the heat exchanger 6 Can be prevented from mixing the brine into the cold water circulation passage 4 even if the heat exchanger 6 is broken. In addition, the first circulation pump 16 is stopped during the circulation stop of the brine circulation path 3 (in other words, during the operation stop of the cold water production system 1 or the suspension of the cooling water cooling operation by the brine even during the operation). By operating the second circulation pump 17 in the above state and raising the pressure on the water side of the heat exchanger 6 above the pressure on the brine side, even if the heat exchanger 6 is broken, to the cold water circulation path 4 Can be prevented from being mixed with Thus, regardless of the operating conditions, always increase the pressure on the water side higher than the pressure on the brine side to ensure that the mixing of the brine into the cold water is prevented even if the heat exchanger 6 breaks. Can. Therefore, for example, even when the operation is stopped at night, the pressure on the water side can always be increased to prevent the adverse effect of the heat exchanger 6 from being damaged. Moreover, energy can be saved by using the second circulation pump 17 with a relatively small capacity.

  By the way, in the cold water return passage 15 from the heat exchanger 6 to the cold water tank 13, it is preferable to provide an adjustment mechanism (not shown) for the flow passage cross sectional area. A valve (for example, a motor valve) whose opening degree can be adjusted can be used as the adjustment mechanism of the flow path cross-sectional area. Alternatively, small-diameter sub-passages may be provided in parallel in a part of the main flow path of the cold water return path 15, and switching of the valves provided in these respective flow paths may be switched. In any case, while the circulation of the brine circulation passage 3 is stopped due to the stop of the brine pump 9, the adjustment mechanism reduces the flow passage cross-sectional area of the cold water return passage 15. As a result, the pressure on the water side of the heat exchanger 6 can be increased, and even if the heat exchanger 6 is broken, the mixing of brine into the cold water can be further reliably prevented to further enhance the safety. Can.

  The chilled water production system 1 of the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. In particular, (a) the refrigerant circulation path 3 which can cool the secondary refrigerant by heat exchange with the primary refrigerant of the refrigerator 2 and circulates the secondary refrigerant to the heat exchanger 6, (b) the cold water tank 13 and Water circulation with the heat exchanger 6 and a cold water circulation passage 4 capable of cooling the circulating water by the secondary refrigerant in the heat exchanger 6; (c) cold water from the cold water tank 13 to the heat exchanger 6 The circulation pump 17 is provided in the feed passage 14, and even if the circulation pump 17 circulates cold water to the cold water circulation passage 4 even while the circulation of the secondary refrigerant in the refrigerant circulation passage 3 is stopped, the other configuration is appropriate. It can be changed to Further, the circulation flow rate of the cold water circulation passage 4 during the circulation stop of the refrigerant circulation passage 3 is preferably smaller than the circulation flow rate of the cold water circulation passage 4 during circulation of the refrigerant circulation passage 3. The appropriate means can also be changed appropriately.

  For example, in the above embodiment, the cold water tank 13 is opened under atmospheric pressure, and when the cold water circulation pumps 16 and 17 are stopped, the cold water circulation passage 4 and the heat exchanger 6 (water side) are opened under atmospheric pressure. Although an example has been shown, the cold water circuit 4 and the heat exchanger 6 may be held at a pressure above atmospheric pressure. In that case, an opening / closing valve is provided at the inlet / outlet of the cold water tank 13 (the cold water feed passage 14 (downstream from the junction of the first cold water feed passage 14a and the second cold water feed passage 14b) and the cold water return passage 15) While the circulation of brine in the brine circulation path 3 is stopped, the water side flow path of the heat exchanger 6 is maintained in a pressurized state. Specifically, when stopping the circulation of brine in the brine circulation path 3, first, after closing the on-off valve of the cold water return path 15, the water side flow path of the heat exchanger 6 is passed through the first circulation pump 16 (and / Alternatively, in the state pressurized by the second circulation pump 17), the on-off valve of the cold water feed passage 14 may be closed and the circulation pump 16 (17) may be stopped. As a result, even when the circulation pumps 16 and 17 are stopped, the pressure on the water side of the heat exchanger 6 can be maintained higher than the pressure on the brine side. Then, if the pressure in the cold water circulation passage 4 is lower than a predetermined pressure, the second circulation pump 17 may be operated by opening the on-off valve.

  Further, in the above embodiment, the first circulation pump 16 and the second circulation pump 17 are provided in parallel in the cold water circulation path 4, and among the circulation pumps 16 and 17 according to the start and stop of the brine pump 9, Whether to operate only the first circulation pump 16 (or both the first circulation pump 16 and the second circulation pump 17) or to operate only the second circulation pump 17 was switched. Good. That is, only one circulation pump 16 is provided in the chilled water feed passage 14 from the chilled water tank 13 to the heat exchanger 6 (the installation of the second chilled water feed passage 14 b and the second circulation pump 17 is omitted). The rotational speed of the pump 16 may be controlled (inverter control). In this case, while the brine pump 9 is stopped, the rotational speed of the cold water circulation pump 16 may be reduced to a predetermined level.

  Moreover, in the said Example, in order to cool brine, although brine was circulated between the brine tank 5 and the refrigerator 2, you may comprise as follows. That is, the evaporator of the refrigerator 2 may be provided in the brine tank 5 or in the brine feed path 7 or the like. In this case, when the refrigerator 2 is operated, the refrigerant (primary refrigerant) of the refrigerator 2 is supplied to the evaporator and exchanges heat with the brine of the brine tank 5 or the brine feed passage 7 to cool the brine.

  In addition, the cold water production system 1 can also be used, for example, to cool and cool a beverage, besides cooling water to produce cold water.

Reference Signs List 1 cold water production system 2 refrigerator 3 brine circulation path 4 cold water circulation path 5 brine tank 6 heat exchanger 7 brine feed path 8 brine return path 9 brine pump 10 brine cooling return path 11 brine cooling return path 12 brine cooling pump 13 cold water tank 14 cold water Feed path (14a: first cold water feed path, 14b: second cold water feed path)
15 cold water return passage 16 first circulation pump 17 second circulation pump 18 cold water extraction passage 19 gate valve 20 water supply pump 21 ball tap 22 brine temperature sensor 23 cold water temperature sensor

Claims (5)

A refrigerant circulation path which makes it possible to cool the secondary refrigerant through heat exchange with the primary refrigerant of the refrigerator and circulates the secondary refrigerant to the heat exchanger;
Water is circulated between a cold water tank and the heat exchanger, and a cold water circulation path capable of cooling the circulating water by the secondary refrigerant in the heat exchanger;
A circulating pump is provided in the cold water feed path from the cold water tank to the heat exchanger, and the circulating pump circulates the cold water in the cold water circulation path even while the secondary refrigerant in the refrigerant circulation path is stopped. A cold water production system characterized by The circulation flow rate of the cold water circulation path during the circulation stop of the refrigerant circulation path is smaller than the circulation flow rate of the cold water circulation path during the circulation of the refrigerant circulation path. Cold water production system. A first circulation pump and a second circulation pump having a smaller capacity than the first circulation pump are provided in parallel in the cold water feed path from the cold water tank to the heat exchanger,
The refrigerant circulation path is circulated while the first circulation pump is in operation or the first circulation pump and the second circulation pump are in operation, and the second circulation is performed while the refrigerant circulation path is stopped. The cold water production system according to claim 2, wherein the pump is operated. An adjustment mechanism for a flow passage cross-sectional area is provided in the cold water return path from the heat exchanger to the cold water tank,
The cooling water production system according to any one of claims 1 to 3, wherein the adjustment mechanism makes the flow passage cross-sectional area of the cooling water return passage small while the circulation of the refrigerant circulation passage is stopped. The secondary refrigerant is brine.
The cold water according to any one of claims 1 to 4, wherein the refrigerant circuit includes a brine tank for storing brine, and the brine is circulated between the brine tank and the heat exchanger. Manufacturing system.

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