Refrigeration system

Abstract

Even when the cooling tower of the refrigeration system is unusable, the cooling performance can be maintained with a simple configuration. [Solution] The refrigeration system of the present invention comprises a first chiller equipped with a first refrigeration cycle in which a refrigerant circulates, and a heat medium circulation path connected to a condenser constituting the first refrigeration cycle, through which a heat medium for heat exchange with the refrigerant circulates. A cooling tower is provided on the heat medium circulation path to release the heat received by the heat medium from the refrigerant in the condenser to the outside. A second air-cooled chiller is also connected in parallel to the cooling tower on the heat medium circulation path. The flow path of the heat medium circulation path is switched by a flow path switching unit so that the heat medium from the condenser is supplied to either the cooling tower or the second chiller.

Description

Technical Field

[0001] The present disclosure relates to a refrigeration system.

Background Art

[0002] There is known a refrigeration system that can cool a cooling load using the heat generated in a refrigeration cycle. The refrigeration cycle is configured such that, for example, a compressor, a condenser, an expansion valve, and an evaporator are arranged as each device constituting the refrigeration cycle on the refrigerant circulation path. Among these components of the refrigeration cycle, the condenser has a function of condensing the refrigerant that has been compressed by the compressor to become high temperature and high pressure by cooling it through heat exchange with a heat medium. For example, in a water-cooled condenser, the heat medium that has become high temperature through heat exchange with the refrigerant is cooled in a cooling tower that constitutes the refrigeration system together with the refrigeration cycle, and can be reused.

[0003] In a cooling tower, the heat medium can be cooled by directly or indirectly exchanging heat with the outside air (specifically, in a closed cooling tower, the cooling water for cooling the heat medium flowing through the heat medium circulation path, which is a closed circuit, is cooled by exchanging heat with the outside air. In an open cooling tower, cooling water or the like is used as the heat medium, and the heat medium itself is cooled by directly exchanging heat with the outside air). In either method, since the cooling water is consumed during the heat exchange with the outside air, in order to maintain the cooling performance of the cooling tower, when the cooling water used in the cooling tower is insufficient, it is necessary to replenish (supply water) from the outside as necessary. Therefore, if the water supply is interrupted due to a natural disaster or the like and the state of inability to supply water continues, the cooling tower becomes unusable, and there is a risk that the operation of the refrigeration system will become difficult. To address such problems, for example, in Patent Document 1, by providing a cold storage water tank capable of storing cooling water in advance, even when water supply is interrupted due to a natural disaster such as an earthquake, the cooling water stored in the cold storage water tank in advance is used to enable the continuous operation of the refrigeration system.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-338648 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the event of a natural disaster, it is anticipated that various infrastructure facilities, such as water supply and power outages, may become unusable simultaneously. For example, if a water supply and power outage occur simultaneously, even if the power is restored first and the water supply pumps for the refrigeration cycle equipment and cooling towers become usable, the cooling towers will remain unusable as long as the water supply is interrupted, and the refrigeration system cannot be restarted. Similarly, even if an emergency backup power source (such as a battery power supply) is provided and the refrigeration cycle equipment and water supply pumps become usable before the power is restored, the refrigeration system cannot be restarted as long as the water supply is interrupted, as water supply from the water source remains interrupted.

[0006] In the aforementioned Patent Document 1, the problem is addressed by installing a cooling water storage tank in the system. However, there is a limit to the amount of cooling water that can be stored in the cooling water storage tank, and this merely extends the lifespan until the cooling water stored in the tank is depleted, without fundamentally solving the problem. Furthermore, adding such a cooling water storage tank increases the overall size of the equipment.

[0007] At least one embodiment of this disclosure has been made in view of the above circumstances and aims to provide a refrigeration system that can maintain cooling performance with a simple configuration even when the cooling tower of the refrigeration system is unusable. [Means for solving the problem]

[0008] A refrigeration system according to at least one embodiment of this disclosure solves the above problems, A first chiller equipped with a first refrigeration cycle in which a refrigerant circulates, A heat transfer medium circulation path is connected to the condenser constituting the first refrigeration cycle, and through which a heat transfer medium for heat exchange with the refrigerant circulates, A cooling tower provided on the heat transfer medium circulation path for releasing the heat received by the heat transfer medium from the refrigerant in the condenser to the outside, A second air-cooled chiller is connected in parallel to the cooling tower to the heat transfer medium circulation path and is equipped with a second refrigeration cycle for directly or indirectly cooling the heat transfer medium. A flow path switching unit for switching the flow path of the heat transfer medium circulation path so that the heat transfer medium supplied from the condenser is either to the cooling tower or the second chiller, It is equipped with. [Effects of the Invention]

[0009] According to at least one embodiment of this disclosure, a refrigeration system can be provided that can maintain cooling performance with a simple configuration even when the cooling tower of the refrigeration system is unusable. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall configuration diagram of a refrigeration system according to one embodiment. [Figure 2] This figure shows the configuration when the flow path of the heat transfer medium circulation path is switched in the refrigeration system shown in Figure 1. [Modes for carrying out the invention]

[0011] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the configurations described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0012] Figure 1 is an overall configuration diagram of a refrigeration system 1 according to one embodiment. The refrigeration system 1 is a system for cooling a cooling load and comprises a first chiller 2, a cooling tower 4, and a second chiller 6.

[0013] The first chiller 2 has a first refrigeration cycle C1 capable of generating cold energy to cool a cooling load 18. The first refrigeration cycle C1 has a refrigerant circulation path 8 through which the refrigerant M1 circulates. The refrigerant circulation path 8 is equipped with, in order, a compressor 10, a condenser 12, an expansion valve 14, and an evaporator 16 as components of the first refrigeration cycle C1.

[0014] Furthermore, the refrigerant M1 circulating in the first refrigeration cycle C1 can be a variety of refrigerants, including natural refrigerants such as ammonia and carbon dioxide, as well as fluorocarbons.

[0015] The refrigerant M1 circulating in the first refrigeration cycle C1 is first compressed in the compressor 10. The refrigerant M1, which has become high temperature and high pressure after being compressed in the compressor 10, is cooled and condensed in the condenser 12 by heat exchange with the heat transfer medium HM circulating in the heat transfer medium circulation path 20 described later. The refrigerant M1 condensed in the condenser 12 is depressurized in the expansion valve 14 and cools the cooling load 18 in the evaporator 16 (more precisely, the evaporator 16 cools the secondary refrigerant, and the cooling load 18 is cooled via this secondary refrigerant). The refrigerant M1, whose temperature has risen after being used to cool the cooling load 18, is returned to the compressor 10.

[0016] The heat transfer medium HM, which exchanges heat with the refrigerant M1 in the condenser 12, circulates through the heat transfer medium circulation path 20. The heat transfer medium circulation path 20 penetrates the casing 2a of the first chiller 2 and connects to the condenser 12 of the first refrigeration cycle C1 housed in the casing 2a. The heat transfer medium circulation path 20 is also provided with a cooling tower 4 and a second chiller 6 to release the heat received by the heat transfer medium HM from the refrigerant M1 in the condenser 12 to the outside.

[0017] In this embodiment, a closed cooling tower is shown as an example of the cooling tower 4. The heat medium circulation path 20 is configured as a closed circuit, and the heat medium circulation path 20 is connected to the heat exchange unit 5 provided in the cooling tower 4. In the cooling tower 4, the cooling water W supplied from the upper part of the heat exchange unit 5 is dropped downward as sprayed water to expose the heat exchange unit 5 to the cooling water W, whereby the heat medium HM flowing through the heat medium circulation path 20 is cooled. The cooling water W used for cooling the heat medium HM is temporarily stored in a storage tank 4a provided on the lower side in the cooling tower 4. A level sensor 13 for detecting the level (water level) of the cooling water W stored in the storage tank 4a is provided in the storage tank 4a. The cooling water W temporarily stored in the storage tank 4a is circulated through the cooling water circulation path 9 by a cooling water pump 7 and is used again for cooling the heat medium HM in the heat exchange unit 5.

[0018] In addition, at the bottom of the storage tank 4a, a drain pipe 4b is provided for discharging at least a part of the cooling water W to the outside when the cooling water W circulating through the cooling water circulation path 9 becomes excessive or when the cooling water W is exchanged. A valve V5 for adjusting the flow rate of the discharged cooling water W is provided in the drain pipe 4b. Further, a pressure sensor 15 for detecting the pressure of the cooling water W stored in the storage tank 4a is provided in the valve V5 of the drain pipe 4b.

[0019] In the heat exchange unit 5, in order to utilize the heat of vaporization when the cooling water W evaporates by contacting the heat of the heat medium HM or the outside air, the cooling water W circulating through the cooling water circulation path 9 decreases considerably as the operation time elapses. Therefore, the cooling tower 4 includes a replenishment facility 17 for continuously operating the cooling tower 4 by replenishing the decreased cooling water W from the outside.

[0020] In the present embodiment, although the case where a closed cooling tower is adopted as the cooling tower 4 is exemplified, the cooling tower 4 may be an open cooling tower. In this case, the heat medium HM is, for example, cooling water, and in the cooling tower 4, the heat medium HM itself circulated through the heat medium circulation path 20 is cooled by heat exchange with the outside air. Since the heat medium HM is cooled by utilizing the latent heat of vaporization during heat exchange with the outside air, when it decreases to a certain extent with the passage of the operation time, the replenishment facility 17 can replenish the shortage of the cooling water. Note that, as a cold region specification, brine may be used instead of cooling water.

[0021] In FIG. 1, a configuration example of the replenishment facility 17 is simply shown. In the present embodiment, the heat medium HM is cooling water, and the replenishment facility 17 is provided with a water supply source 17a and a water supply pump 17b.

[0022] The water supply source 17a is an infrastructure for supplementing the insufficient cooling water W. When water supply is interrupted due to natural disasters or the like, the water supply from the water supply source 17a is cut off, so that the water supply pump 17b becomes unusable, and the cooling water W consumed with the passage of the operation time cannot be replenished, and thus the cooling tower 4 becomes unusable.

[0023] The heat medium circulation path 20 has a first flow path 22 for supplying the heat medium HM from the first refrigerator 2 (condenser 12) to the cooling tower 4 and a second flow path 24 for supplying the heat medium HM from the cooling tower 4 to the first refrigerator 2 (condenser 12). A valve V1 for adjusting the flow rate of the heat medium HM supplied from the first refrigerator 2 to the cooling tower 4 is provided in the first flow path 22. A valve V2 for adjusting the flow rate of the heat medium HM supplied from the cooling tower 4 to the first refrigerator 2 and a pump device 26 for circulating the heat medium HM in the heat medium circulation path 20 are provided in the second flow path 24.

[0024] The heat transfer medium circulation path 20 also includes a third flow path 30 connecting a first branching point 23 located on the first flow path 22 to the second chiller 6, and a fourth flow path 32 connecting the second chiller 6 to a second branching point 25 located on the second flow path 24. The first branching point 23 is located upstream of the valve V1 in the first flow path 22 with respect to the flow direction of the heat transfer medium HM in the first flow path 22 (in other words, between the condenser 12 and the valve V1 in the first flow path 22). The second branching point 25 is located between the valve V2 and the pump device 26 in the second flow path 24 (i.e., the pump device 26 is located between the second branching point 25 and the first chiller 2 in the second flow path 24). The third flow path 30 is also provided with a valve V3 for adjusting the flow rate of the heat transfer medium HM supplied from the first chiller 2 to the second chiller 6. A valve V4 is provided in the fourth flow path 32 for adjusting the flow rate of the heat transfer medium HM supplied from the second refrigerator 6 to the first refrigerator 2.

[0025] The heat transfer medium circulation path 20 is provided so as to penetrate the casing 2a between the condenser 12 of the first refrigeration cycle C1, which is housed inside the casing 2a of the first chiller 2, and the cooling tower 4, which is located outside the casing 2a. The second chiller 6, which is connected in parallel with the cooling tower 4 in the heat transfer medium circulation path 20, branches off from the portion of the heat transfer medium circulation path 20 that is outside the casing 2a of the first chiller 2 and connects to the heat transfer medium circulation path 20. Specifically, the first branching point 23 and the second branching point 25 are each provided outside the casing 2a of the first chiller 2.

[0026] If, for example, an ammonia refrigerant requiring advanced leak prevention measures is used as the refrigerant M1 circulating in the first refrigeration cycle C1, and the first branching point 23 and the second branching point 25 where the flow path branches are located inside the casing 2a, measures must be taken to prevent refrigerant M1 leaking from the first refrigeration cycle C1 inside the casing 2a from mixing with the heat transfer medium HM through the first branching point 23 and the second branching point 25, which may lead to increased complexity of the configuration and higher costs. In this embodiment, by providing the first branching point 23 and the second branching point 25 outside the casing 2a, such increased complexity of the configuration and higher costs can be suitably avoided.

[0027] As mentioned above, the second chiller 6 is configured to cool the heat transfer medium HM in place of the cooling tower 4 when the cooling tower 4 becomes unusable due to events such as a water outage, and is connected to the heat transfer medium circulation path 20 in parallel with the cooling tower 4. The second chiller 6 has a second refrigeration cycle C2. The second refrigeration cycle C2 has a refrigerant circulation path 40 through which the refrigerant M2 circulates. The refrigerant circulation path 40 is equipped with a compressor 42, a condenser 44, an expansion valve 46, and an evaporator 48 in that order as components of the second refrigeration cycle C2.

[0028] The refrigerant M2 circulating in the second refrigeration cycle C2 is first compressed in the compressor 42. The refrigerant M2, which has become high temperature and high pressure after being compressed in the compressor 42, is cooled and condensed in the condenser 44 by heat exchange with the outside air. The refrigerant M2 condensed in the condenser 44 is depressurized in the expansion valve 46 and cools the heat transfer medium HM in the evaporator 48. The refrigerant M2, whose temperature has risen after being used to cool the heat transfer medium HM, is returned to the compressor 42. Furthermore, the refrigerant M2 circulating in the second refrigeration cycle C2 can utilize various refrigerants, including natural refrigerants such as ammonia and carbon dioxide, as well as fluorocarbons.

[0029] Here, the condenser 44 in the second refrigeration cycle C2 is an air-cooled condenser capable of cooling (condensing) the refrigerant M2 through heat exchange with the outside air. The cooling tower 4 is unusable in the event of a water outage or power outage until both are restored, and even if only the power is restored, it remains unusable as long as the water outage continues, as mentioned above. In contrast, in the second chiller 6, outside air is used as the medium for heat exchange with the refrigerant M2 in the condenser 44, so as long as the power is restored, operation can be resumed quickly without waiting for the water to be restored. Furthermore, if the second refrigeration cycle C2 is equipped with an emergency backup power source (e.g., battery power), operation can be resumed even earlier without waiting for the restoration of both water and power.

[0030] The aforementioned valves V1 to V4, provided in the heat transfer medium circulation path 20, constitute a flow path switching unit 50 for switching the flow path of the heat transfer medium HM in the heat transfer medium circulation path 20 by switching their open / closed states. The flow path switching by the flow path switching unit 50 is performed based on a control signal from the control device 100.

[0031] The control device 100 is a control unit for controlling the refrigeration system 1 having the above configuration, and is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example, and the CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed in the ROM or other storage medium, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0032] The control device 100 comprises a determination unit 102 and a control unit 104.

[0033] The determination unit 102 is configured to determine the operating status of the cooling tower 4. For example, if a water outage occurs due to a natural disaster, the cooling tower 4 will have difficulty continuing to operate. In other words, if a water outage occurs, the water supply source 17a becomes unusable, so cooling water W cannot be supplied to the cooling tower 4, making it difficult for the cooling tower 4 to continue to operate. The determination unit 102 comprehensively evaluates the operating status of the cooling tower 4 in this way to determine whether or not the refrigeration system 1 using the cooling tower 4 can be operated continuously.

[0034] In one embodiment, the determination unit 102 may determine the operating state of the cooling tower 4 based on the measurement value of a level sensor 13 provided in the storage tank 4a of the cooling tower 4. In this case, if the measurement value of the level sensor 13 falls below a preset reference value, it can be determined that the insufficient cooling water W has not been properly replenished and that continuous operation of the refrigeration system 1 using the cooling tower 4 is difficult.

[0035] In another embodiment, the determination unit 102 may determine the operating state of the cooling tower 4 based on the measurement value of a pressure sensor 15 installed in the drain pipe 4b of the storage tank 4a of the cooling tower 4. In this case, if the measurement value of the pressure sensor 15 falls below a preset reference value, it can be determined that the insufficient cooling water W has not been properly replenished and that continuous operation of the refrigeration system 1 using the cooling tower 4 is difficult.

[0036] The control unit 104 is configured to control the flow path switching unit 50 based on the determination result of the determination unit 102. Specifically, if the determination unit 102 determines that the operating state of the cooling tower 4 is normal, the control unit 104 controls the flow path switching unit 50 so that the heat transfer medium HM containing heat received from the refrigerant M1 is supplied to the cooling tower 4. Specifically, as shown in Figure 1, the flow path switching unit 50 is controlled so that valves V1 and V2 are switched to the open state and valves V3 and V4 are switched to the closed state, thereby selecting the cooling tower 4 as the destination for the heat transfer medium HM (at this time, the heat transfer medium HM is not supplied to the second chiller 6, and the second chiller 6 is stopped, thus avoiding unnecessary energy consumption).

[0037] On the other hand, if the determination unit 102 determines that the operating state of the cooling tower 4 is not normal, the control unit 104 controls the flow path switching unit 50 so that the heat transfer medium HM, which contains heat received from the refrigerant M1, is supplied to the second chiller 6 instead of the cooling tower 4. Specifically, as shown in Figure 2, the flow path switching unit 50 is controlled so that valves V1 and V2 are switched to the closed state and valves V3 and V4 are switched to the open state, thereby selecting the second chiller 6 as the destination for the heat transfer medium HM (at this time, the heat transfer medium HM is not supplied to the cooling tower 4, and the cooling tower 4 is stopped, thus avoiding unnecessary energy consumption).

[0038] As described above, according to the above embodiment, the heat transfer medium HM can be cooled by either the cooling tower 4 or the second chiller 6 by switching the flow path of the heat transfer medium circulation path 20 using the flow path switching unit 50 based on the operating state of the cooling tower 4. As a result, even if a water outage occurs for an extended period due to a natural disaster or the like, the heat transfer medium HM can be cooled by the second chiller 6 instead of the cooling tower 4, thus enabling the operation of the refrigeration system 1 to continue smoothly.

[0039] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of this disclosure, and the above-described embodiments may also be combined as appropriate.

[0040] The contents described in each of the above embodiments can be understood, for example, as follows:

[0041] (1) A refrigeration system according to one embodiment is: A first chiller equipped with a first refrigeration cycle in which a refrigerant circulates, A heat transfer medium circulation path is connected to the condenser constituting the first refrigeration cycle, and through which a heat transfer medium for heat exchange with the refrigerant circulates, A cooling tower provided on the heat transfer medium circulation path for releasing the heat received by the heat transfer medium from the refrigerant in the condenser to the outside, A second air-cooled chiller is connected in parallel to the cooling tower to the heat transfer medium circulation path and is equipped with a second refrigeration cycle for directly or indirectly cooling the heat transfer medium. A flow path switching unit for switching the flow path of the heat transfer medium circulation path so that the heat transfer medium supplied from the condenser is either to the cooling tower or the second chiller, It is equipped with.

[0042] According to the embodiment of (1) above, the first chiller is equipped with a first refrigeration cycle in which a refrigerant circulates. The refrigerant circulating in the first refrigeration cycle can exchange heat with a heat transfer medium in a condenser that constitutes the first refrigeration cycle. The heat transfer medium can be cooled in a cooling tower or a second chiller by switching the flow path by a flow path switching unit. By providing a cooling tower and a second chiller as a configuration for cooling the heat transfer medium in this way, even if the cooling tower becomes unusable due to a natural disaster or the like, the heat transfer medium can be cooled by using the second chiller, and the cooling performance of the refrigeration system can be suitably maintained.

[0043] (2) In other embodiments, in the embodiment of (1) above, The first refrigerator has a casing that houses the first refrigeration cycle, including the condenser. The heat transfer medium circulation path is provided between the condenser located inside the casing and the cooling tower located outside the casing. The second chiller branches off from the heat transfer medium circulation path in the area outside the casing and connects to the heat transfer medium circulation path.

[0044] According to the embodiment of (2) above, the second chiller, which can cool the heat transfer medium instead of the cooling tower, is connected by branching off from the heat transfer medium circulation path, which is located outside the casing housing the first refrigeration cycle. If a refrigerant such as ammonia, which requires advanced leakage prevention measures, is used as the refrigerant circulating in the first refrigeration cycle, then if the branching point is located inside the casing housing the first refrigeration cycle, measures must be taken to prevent refrigerant leaking into the casing from mixing with the heat transfer medium from the branching point, which may lead to increased complexity of the configuration and higher costs. In this embodiment, by providing the branching point outside the casing, such increased complexity of the configuration and higher costs can be suitably avoided.

[0045] (3) In other embodiments, in the embodiment of (1) or (2) above, The aforementioned heat transfer medium circulation path is A first flow path for supplying the heat transfer medium from the first chiller to the cooling tower, A second flow path for supplying the heat transfer medium from the cooling tower to the first refrigerator, A third flow path connecting a first branch point provided on the first flow path to the second refrigerator, A fourth flow path connecting the second refrigerator and a second branching point provided on the second flow path, Includes, A pump device for pressurizing the heat transfer medium is provided between the second branching point and the first refrigerator in the second flow path.

[0046] According to the embodiment of (3) above, the above configuration can suitably realize a configuration in which either a cooling tower or a second chiller can be selected as the configuration for cooling the heat transfer medium by switching the flow path of the heat transfer medium circulation path.

[0047] (4) In other embodiments, in any one embodiment of (1) to (3) above, The flow path switching section includes at least one switching valve provided on the heat transfer medium circulation path.

[0048] According to the embodiment of (4) above, a flow path switching unit can be suitably realized that allows for selective switching between a cooling tower or a second chiller as a configuration for cooling the heat medium by switching at least one switching valve provided on the heat medium circulation path.

[0049] (5) In other embodiments, in any one embodiment of (1) to (4) above, A determination unit for determining the operating state of the cooling tower, Based on the determination result of the determination unit, a control unit controls the flow path switching unit, It is equipped with.

[0050] According to the embodiment of (5) above, by controlling the flow path switching unit based on the determination result regarding the operating state of the cooling tower, it is possible to selectively switch between the cooling tower and the second chiller as the configuration for cooling the heat transfer medium.

[0051] (6) In other embodiments, in the embodiment of (5) above, The control unit, If it is determined that the operating state of the cooling tower is normal, the flow path switching unit is controlled so that the heat transfer medium containing the heat received from the refrigerant is supplied to the cooling tower. If the operating state is determined to be abnormal, the flow path switching unit is controlled so that the heat transfer medium, which includes the heat received from the refrigerant, is supplied to the second refrigerator.

[0052] According to the embodiment of (6) above, if it is determined that the cooling tower is operating normally, the flow path of the heat transfer medium circulation path is switched so that the cooling tower is selected as the configuration for cooling the heat transfer medium. On the other hand, if it is determined that the cooling tower is not operating normally, the flow path of the heat transfer medium circulation path is switched so that the second chiller is selected as the configuration for cooling the heat transfer medium.

[0053] (7) In other embodiments, in the embodiment of (5) or (6) above, The cooling tower is a closed-type cooling tower in which a heat exchange section connected to the heat transfer medium circulation path, which is a closed circuit through which the heat transfer medium circulates, can be cooled by sprayed water. The determination unit determines the operating state based on the measurement value of a level sensor installed in a storage tank for storing the sprayed water used to cool the heat exchange unit within the cooling tower.

[0054] According to the embodiment of (7) above, if the cooling tower is a closed-type cooling tower, the operating state of the cooling tower can be suitably determined based on the level of spray water (cooling water) in a storage tank for storing spray water (cooling water) to cool the heat exchange section inside the cooling tower.

[0055] (8) In other embodiments, in the embodiment of (5) or (6) above, The cooling tower is a closed-type cooling tower in which a heat exchange section connected to the heat transfer medium circulation path, which is a closed circuit through which the heat transfer medium circulates, can be cooled by sprayed water. The determination unit determines the operating state based on the measurement value of a pressure sensor installed in a drain pipe provided in a storage tank for storing the sprayed water used to cool the heat exchange unit within the cooling tower.

[0056] According to the embodiment of (8) above, if the cooling tower is a closed-type cooling tower, the operating state of the cooling tower can be suitably determined based on the pressure in the drain pipe provided in the storage tank for storing the spray water (cooling water) used to cool the heat exchange section within the cooling tower.

[0057] (9) In other embodiments, in the embodiment of (5) or (6) above, The cooling tower is an open-type cooling tower in which the heat transfer medium can be cooled by heat exchange with the outside air. The determination unit determines the operating state based on the measurement value of a level sensor installed in a storage tank for storing the heat transfer medium after heat exchange with the outside air within the cooling tower.

[0058] According to the embodiment of (9) above, if the cooling tower is an open-type cooling tower, the operating state of the cooling tower can be suitably determined based on the level of the heat transfer medium (e.g., cooling water) in a storage tank for storing the heat transfer medium that exchanges heat with the outside air inside the cooling tower.

[0059] (10) In other embodiments, in the embodiment of (5) or (6) above, The cooling tower is an open-type cooling tower in which the heat transfer medium can be cooled by heat exchange with the outside air. The determination unit determines the operating state based on the measurement value of a pressure sensor installed in a drain pipe provided in a storage tank for storing the heat transfer medium after heat exchange with the outside air inside the cooling tower.

[0060] According to the embodiment of (10) above, if the cooling tower is an open-type cooling tower, the operating state of the cooling tower can be suitably determined based on the pressure in the drain pipe provided in the storage tank for storing the heat transfer medium (e.g., cooling water) that exchanges heat with the outside air inside the cooling tower.

[0061] (11) In other embodiments, in any one embodiment of (1) to (10) above, The aforementioned refrigerant is ammonia refrigerant.

[0062] According to the embodiment of (11) above, in a refrigeration system using ammonia refrigerant, cooling performance can be suitably maintained with a simple configuration even when the cooling tower is unusable. [Explanation of Symbols]

[0063] 1. Refrigeration System 2. First Refrigeration Unit 2a Casing 4 cooling tower 4a storage tank 4b Drain pipe 5 Heat exchange section 6. Second Refrigeration Unit 8 Refrigerant circuit 10 Compressor 12 Condenser 13 Level Sensor 14 Expansion valve 15 Pressure sensor 16 Evaporator 17 Supply equipment 17a Water supply source 17b Water supply pump 18 Cooling load 20 Heat medium circulation path 22 First flow path 24 Second flow path 30 Third flow path 32 Fourth flow path 23 First branch point 25 Second branch point 26 Pump device 40 Refrigerant circulation path 42 Compressor 44 Condenser 46 Expansion valve 48 Evaporator 50 Flow path switching unit 100 Control device 102 Judgment unit 104 Control unit C1 First refrigeration cycle C2 Second refrigeration cycle HM Heat medium M1, M2 Refrigerant

Claims

1. A first chiller equipped with a first refrigeration cycle in which a refrigerant circulates, A heat transfer medium circulation path is connected to the condenser constituting the first refrigeration cycle, and through which a heat transfer medium for heat exchange with the refrigerant circulates, A cooling tower provided on the heat transfer medium circulation path for releasing the heat received by the heat transfer medium from the refrigerant in the condenser to the outside, A second air-cooled chiller is connected in parallel to the cooling tower to the heat transfer medium circulation path and is equipped with a second refrigeration cycle for directly or indirectly cooling the heat transfer medium. A flow path switching unit for switching the flow path of the heat transfer medium circulation path so that the heat transfer medium supplied from the condenser is either to the cooling tower or the second chiller, A refrigeration system equipped with the following features.

2. The first refrigerator has a casing that houses the first refrigeration cycle, including the condenser. The heat transfer medium circulation path is provided between the condenser located inside the casing and the cooling tower located outside the casing. The refrigeration system according to claim 1, wherein the second refrigerator branches off from the heat transfer medium circulation path in a portion located outside the casing and is connected to the heat transfer medium circulation path.

3. The aforementioned heat transfer medium circulation path is A first flow path for supplying the heat transfer medium from the first refrigerator to the cooling tower, A second flow path for supplying the heat transfer medium from the cooling tower to the first refrigerator, A third flow path connecting a first branching point provided on the first flow path to the second refrigerator, A fourth flow path connecting the second refrigerator and a second branching point provided on the second flow path, Includes, The refrigeration system according to claim 1 or 2, wherein a pump device for pressurizing the heat transfer medium is provided between the second branching point and the first refrigerator in the second flow path.

4. The refrigeration system according to claim 1 or 2, wherein the flow path switching section includes at least one switching valve provided on the heat transfer medium circulation path.

5. A determination unit for determining the operating state of the cooling tower, Based on the determination result of the determination unit, a control unit controls the flow path switching unit, A refrigeration system according to claim 1 or 2, comprising:

6. The control unit, If it is determined that the operating state of the cooling tower is normal, the flow path switching unit is controlled so that the heat transfer medium containing the heat received from the refrigerant is supplied to the cooling tower. The refrigeration system according to claim 5, wherein if it is determined that the operating state is not normal, the flow path switching unit is controlled so that the heat transfer medium containing the heat received from the refrigerant is supplied to the second refrigerator.

7. The cooling tower is a closed-type cooling tower in which a heat exchange section connected to the heat transfer medium circulation path, which is a closed circuit through which the heat transfer medium circulates, can be cooled by sprayed water. The refrigeration system according to claim 5, wherein the determination unit determines the operating state based on the measured value of a level sensor installed in a storage tank for storing the sprayed water used to cool the heat exchange unit within the cooling tower.

8. The cooling tower is a closed-type cooling tower in which a heat exchange section connected to the heat transfer medium circulation path, which is a closed circuit through which the heat transfer medium circulates, can be cooled by sprayed water. The refrigeration system according to claim 5, wherein the determination unit determines the operating state based on the measured value of a pressure sensor installed in a drain pipe provided in a storage tank for storing the sprayed water used to cool the heat exchange unit within the cooling tower.

9. The cooling tower is an open-type cooling tower in which the heat transfer medium can be cooled by heat exchange with the outside air. The refrigeration system according to claim 5, wherein the determination unit determines the operating state based on the measured value of a level sensor installed in a storage tank for storing the heat transfer medium after heat exchange with the outside air in the cooling tower.

10. The cooling tower is an open-type cooling tower in which the heat transfer medium can be cooled by heat exchange with the outside air. The refrigeration system according to claim 5, wherein the determination unit determines the operating state based on the measured value of a pressure sensor installed in a drain pipe provided in a storage tank for storing the heat transfer medium after heat exchange with the outside air in the cooling tower.

11. The refrigeration system according to claim 1 or 2, wherein the refrigerant is ammonia refrigerant.

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