Refrigerant circulating device and method of control

Abstract

To provide a technology for inhibiting dew condensation in a refrigerant circulating device and pressure rise of a primary refrigerant in a flow passage.SOLUTION: A refrigerant circulating device comprises: a common flow passage through which a primary refrigerant flows; first and second flow passages branching from the common flow passage; a third flow passage through which a secondary refrigerant flows; a heat exchanger through which the first and third flow passages pass internally to perform heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that regulates a flow rate of the primary refrigerant through the first flow passage; a second valve that regulates a flow rate of the primary refrigerant through the second flow passage; a sensor unit that detects a secondary temperature which is a temperature of the secondary refrigerant, a device temperature which is a temperature within the device, and a relative humidity within the device; and a change unit that changes a first opening degree, which is an opening degree of the first valve, and a second opening degree, which is an opening degree of the second valve, based on the secondary temperature, the device temperature, and the relative humidity such that a sum of the first and second opening degrees becomes a predetermined value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a refrigerant circulation device and a control method. [Background technology]

[0002] In a refrigerant circulation device as background art, the inflow amount of a primary refrigerant to a heat exchanger is controlled so that the temperature of the secondary refrigerant (hereinafter also referred to as "secondary temperature") does not fall below the dew point in the refrigerant circulation device. Specifically, the opening of a valve provided in the flow path of the primary refrigerant is adjusted so that the secondary temperature falls within the range of dew point +1°C to dew point +1.5°C (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent No. 103115514 Summary of the Invention [Problem to be solved by the invention]

[0004] In the refrigerant circulation device of the related art, the opening of a valve provided in the flow path of the primary refrigerant is adjusted to keep the secondary temperature within the range of dew point +1°C to dew point +1.5°C to prevent condensation. However, there is a concern that such adjustment alone may result in the valve opening being relatively small. As a result, the pressure in the flow path of the primary refrigerant may increase.

[0005] An object of the present disclosure is to provide a technology that can suppress condensation in a refrigerant circulation device and suppress a pressure increase in a flow path of a primary refrigerant. [Means for solving the problem]

[0006] A refrigerant circulation device according to one embodiment of the present disclosure includes a common flow path through which a primary refrigerant flows, first and second flow paths branching from the common flow path, a third flow path through which a secondary refrigerant flows, a heat exchanger through which the first and third flow paths pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant, a first valve that adjusts the flow rate of the primary refrigerant in the first flow path, a second valve that adjusts the flow rate of the primary refrigerant in the second flow path, a sensor unit that detects a secondary temperature that is the temperature of the secondary refrigerant, a device temperature that is the temperature inside the device, and a relative humidity inside the device, and a change unit that changes a first opening degree that is the opening degree of the first valve and a second opening degree that is the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value.

[0007] A refrigerant circulation device according to another aspect of the present disclosure includes a common flow path through which a primary refrigerant flows, first and second flow paths branching from the common flow path, a third flow path through which a secondary refrigerant flows, a heat exchanger through which the first and third flow paths pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant, a first valve that adjusts a first flow rate which is the flow rate of the primary refrigerant in the first flow path, a second valve that adjusts a second flow rate which is the flow rate of the primary refrigerant in the second flow path, a sensor unit that detects a secondary temperature which is the temperature of the secondary refrigerant, a device temperature which is the temperature inside the device, and a relative humidity inside the device, and a change unit that changes a first opening degree which is the opening degree of the first valve and a second opening degree which is the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first flow rate and the second flow rate becomes a predetermined value.

[0008] A control method according to yet another aspect of the present disclosure is a control method for a refrigerant circulation device comprising: a common flow path through which a primary refrigerant flows; first and second flow paths branching from the common flow path; a third flow path through which a secondary refrigerant flows; a heat exchanger through which the first and third flow paths pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; and a second valve that adjusts the flow rate of the primary refrigerant in the second flow path, wherein a secondary temperature that is the temperature of the secondary refrigerant, a device temperature that is the temperature inside the device, and a relative humidity inside the device are detected, and a first opening degree that is the opening degree of the first valve and a second opening degree that is the opening degree of the second valve are changed based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a technique that can suppress condensation in a refrigerant circulation device and suppress a pressure increase in a flow path of a primary refrigerant. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a cooling system 100. As shown in FIG. [Figure 2] FIG. 2 is a block diagram of the CDU 1 according to the embodiment. [Figure 3] FIG. 3 is a flow diagram showing a first part of the processing of the CDU 1 shown in FIG. [Figure 4] FIG. 4 is a flow diagram showing a second part of the processing of CDU 1 shown in FIG. [Figure 5] FIG. 5 is a flow diagram showing a third part of the processing of CDU 1 shown in FIG. [Figure 6] FIG. 6 is a diagram showing the control contents for each condition in the processing of the CDU 1. [Figure 7] FIG. 7 is a block diagram of a CDU 1 according to a first modified example. [Figure 8] FIG. 8 is a flow diagram of the processing of the CDU 1 shown in FIG. [Figure 9] FIG. 9 is a flowchart showing a first part of the processing of the CDU 1 according to the second modified example. [Figure 10] FIG. 10 is a flowchart showing a second part of the processing of the CDU 1 according to the second modified example. [Figure 11] FIG. 11 is a flow diagram showing the 32nd part of the processing of the CDU 1 according to the second modified example. [Figure 12] FIG. 12 is a diagram showing the configuration of a CDU 1 according to the third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0012] [Term definition] Hereinafter, the term "connected" means "connected in a manner that allows fluid flow therethrough."

[0013] [Cooling system 100] 1, the cooling system 100 includes, as components, a refrigerant circulation device 1, a distribution manifold 2, a collection manifold 3, at least one cold plate 4, a cooling device 6, and flow paths 7 and 8. These components cool at least one heat source 5 installed in a space A01.

[0014] In addition, when the cooling system 100 is provided with one cold plate 4, the cooling system 100 does not need to include the distribution manifold 2 and the collection manifold 3.

[0015] In the following description, the refrigerant circulation device 1 will also be referred to as "CDU1."

[0016] Among the components, the CDU 1, the distribution manifold 2, the collection manifold 3, and the plurality of cold plates 4 are installed in a space A01. The space A01 is, for example, a server room.

[0017] [Heat source 5, rack 9] A rack 9 is provided in the space A01. A plurality of heat sources 5 are housed in the rack 9. Each heat source 5 is typically an electronic component or an electronic device. The electronic component is a component that constitutes an electronic device, and includes, for example, a central processing unit (so-called CPU), an electrolytic capacitor, a power semiconductor module, or a printed circuit board. The electronic component operates when powered and generates heat. The electronic device is a rack-mounted server or a blade server. The electronic device may also be a projector, a personal computer, or a display.

[0018] [Embodiment (CDU1)] The CDU 1 can be distributed on the market as a cooling system 100. When distributed as the cooling system 100, the cooling device 6 and the flow paths 7 and 8 may be removed from the cooling system 100. The CDU 1 may also be distributed on the market independently. In the embodiment, the CDU 1 is housed in, for example, a rack 9 when in use. However, the present invention is not limited to this, and the CDU 1 may also be installed outside the rack 9 when in use.

[0019] [Primary inlet 11, primary outlet 12, secondary inlet 13, secondary outlet 14] As shown in FIG. 1, the CDU 1 has a primary inlet 11, a primary outlet 12, a secondary inlet 13, and a secondary outlet 14. A low-temperature primary refrigerant C1 flows into the primary inlet 11 through the flow path 7. A high-temperature secondary refrigerant C2 flows into the secondary inlet 13 from the collection manifold 3. The CDU 1 exchanges heat between the primary refrigerant C1 (low temperature) flowing into the CDU 1 through the primary inlet 11 and the secondary refrigerant C2 (high temperature) flowing into the CDU 1 through the secondary inlet 13. As a result, within the CDU 1, thermal energy of the primary refrigerant C1 is transferred to the secondary refrigerant C2. Specifically, the temperature of the secondary refrigerant C2 is lower when it flows out of the CDU 1 than when it flows into the CDU 1. The CDU 1 sends the cooled secondary refrigerant C2 from the secondary outlet 14 toward the distribution manifold 2. The CDU 1 sends the high-temperature primary refrigerant C1 from the primary outlet 12 to the flow path 8.

[0020] [Primary refrigerant C1, secondary refrigerant C2] The primary refrigerant C1 is a fluid such as a coolant. Examples of the coolant include antifreeze and pure water. Typical examples of antifreeze are an ethylene glycol aqueous solution and a propylene glycol aqueous solution. The secondary refrigerant C2 is a fluid of the same or different type as the primary refrigerant C1. At least one of the primary refrigerant C1 and the secondary refrigerant C2 may be a gas refrigerant.

[0021] [Distribution manifold 2] The distribution manifold 2 has a common flow path 21 and a plurality of individual flow paths 22. Note that, in FIG. 1, only two individual flow paths 22 are shown for ease of understanding. Fluid can flow between the common flow path 21 and each individual flow path 22. One end T21 of the common flow path 21 is connected to the secondary outlet 14 and is used as a fluid inlet in the distribution manifold 2. One end T22a of each individual flow path 22 is connected to the common flow path 21. The other end T22b of each individual flow path 22 is used as an outlet for the secondary refrigerant C2 in the distribution manifold 2 and is individually connected to the inlet 41 of the cold plate 4. Therefore, the secondary refrigerant C2 (low temperature) that flows into the inlet (i.e., one end T21) of the distribution manifold 2 first flows within the common flow path 21, is divided into each individual flow path 22, and then flows out from each outlet (i.e., the other end T22b) of the distribution manifold 2.

[0022] [Cold Plate 4] Each cold plate 4 is in thermal contact with at least one heat source 5. A secondary refrigerant C2 (low temperature) flows inside each cold plate 4. Specifically, each cold plate 4 is arranged to be in direct thermal contact with the heat source 5. Each cold plate 4 may be arranged to be in thermal contact with the heat source 5 via, for example, a thermally conductive sheet (not shown). In other words, the term "thermal contact" includes both the meanings of "direct thermal contact" and "indirect thermal contact."

[0023] Each cold plate 4 has an inlet 41, an outlet 42, and an internal flow path 43 for the secondary refrigerant C2. The internal flow path 43 connects the inlet 41 and the outlet 42. The secondary refrigerant C2 (low temperature) flows into the inlet 41 from the individual flow paths 22 connected to the inlet 41. The secondary refrigerant C2 flows through the internal flow path 43 to the outlet 42. Therefore, the thermal energy generated in the heat source 5 is transferred to the secondary refrigerant C2 flowing through the internal flow path 43 of the cold plate 4, which is in thermal contact with the heat source 5. As a result, the heat source 5 is cooled, and the temperature of the secondary refrigerant C2 increases. The secondary refrigerant C2 (high temperature) flows out from the outlet 42 to the individual flow paths 31 of the collection manifold 3.

[0024] [Collection Manifold 3] The collection manifold 3 has a plurality of individual flow paths 31 and a common flow path 32. Note that, for ease of understanding, FIG. 1 shows two individual flow paths 31. Fluid can flow through each individual flow path 31 and the common flow path 32. One end T31a of each individual flow path 31 is connected to an outlet 42 as an inlet for the fluid in the collection manifold 3. The other end T31b of each individual flow path 31 is connected to the common flow path 32. One end T32 of the common flow path 32 is used as an outlet for the fluid in the collection manifold 3 and is connected to the secondary inlet 13. Therefore, the secondary refrigerant C2 that flows from the cold plate 4 into each inlet (i.e., one end T31a) of the collection manifold 3 joins in the common flow path 32 and flows out from one end (i.e., one end T32) of the collection manifold to the secondary inlet 13 of the CDU 1. Thus, the secondary refrigerant C2 circulates through the CDU 1, distribution manifold 2, cold plate 4 and collection manifold 3 in that order.

[0025] [Cooling device 6] The cooling device 6 is installed, for example, outside the space A01. The cooling device 6 may be installed either indoors or outdoors. The cooling device 6 is, for example, a chiller or a cooling tower. The cooling device 6 includes an inlet 61, an outlet 62, and an internal flow path 63 for the primary refrigerant C1, a cooling unit 64, and a pump 65. The internal flow path 63 connects the inlet 61 and the outlet 62. The cooling unit 64 and the pump 65 are each inserted into the internal flow path 63.

[0026] The primary refrigerant C1 that flows into the inlet 61 flows into the cooling unit 64 through a flow path. The cooling unit 64 cools the primary refrigerant C1 that flows into the cooling unit 64. The cooling method in the cooling unit 64 may be either an air-cooling method or a water-cooling method. The primary refrigerant C1 that flows out of the cooling unit 64 flows into the pump 65 through the internal flow path 63. The pump 65 pumps the primary refrigerant C1 that flows into the pump 65 toward the outlet 62. In FIG. 1 , the pump 65 is located between the cooling unit 64 and the outlet 62 in the internal flow path 63. However, the present invention is not limited to this, and the pump 65 may be located between the outlet 62 and the cooling unit 64 in the internal flow path 63.

[0027] [CDU1 configuration] As shown in FIG. 2, the CDU 1 includes a housing 15, a primary flow path 16, a secondary flow path 17, a heat exchanger 18, a sensor unit 19, an operation unit 110, and a control unit 111.

[0028] [Case 15] The housing 15 separates the internal space of the CDU 1 from the external space of the CDU 1. The housing 15 is provided with a primary inlet 11, a primary outlet 12, a secondary inlet 13, and a secondary outlet .

[0029] [Primary flow path 16] The primary flow path 16 includes joints 16a and 16b, valves 16c and 16d, pipes 16e to 16k, and a flow path 18e (described later) of the heat exchanger 18. The primary flow path 16 is installed inside the housing 15. The primary flow path 16 is a pipe for the primary refrigerant C1 in the CDU 1.

[0030] Each of the joints 16a and 16b is a so-called Tee joint. Specifically, each of the joints 16a and 16b is T-shaped and has connection ports on three sides (i.e., a first connection port, a second connection port, and a third connection port). In this embodiment, each of the valves 16c and 16d is a two-way valve whose flow rate can be adjusted under the control of the control unit 111, and includes a valve body, a valve element, a valve seat, a first connection port, and a second connection port. The opening of the valves 16c and 16d (i.e., the valve seat) is adjusted under the control of the control unit 111.

[0031] Pipe 16e connects the primary inlet 11 and the first connection port of fitting 16a. Pipe 16f connects the second connection port of fitting 16a and the first connection port of valve 16c. Pipe 16g connects the second connection port of valve 16c and the inlet 18a of heat exchanger 18. Pipe 16h connects the third connection port of fitting 16a and the first connection port of valve 16d. Pipe 16i connects the second connection port of valve 16d and the first connection port of fitting 16b. Pipe 16j connects the outlet 18b of heat exchanger 18 and the second connection port of fitting 16b. Pipe 16k connects the third connection port of fitting 16b and the primary outlet 12.

[0032] Pipe 16e is an example of a "common flow path" in the present disclosure. The combination of joint 16a, pipe 16f, valve 16c, pipe 16g, flow path 18e, pipe 16j, and joint 16b is an example of a "first flow path" in the present disclosure. Valve 16c is also an example of a "first valve" in the present disclosure, and adjusts the flow rate of the primary refrigerant C1 in the first flow path in the present disclosure.

[0033] The combination of joint 16a, pipe 16h, valve 16d, pipe 16i, and joint 16b is an example of a "second flow path" of the present disclosure. Valve 16d is an example of a "second valve" of the present disclosure, and adjusts the flow rate of the secondary refrigerant C2 in the second flow path of the present disclosure.

[0034] When the opening degrees of valves 16c and 16d are the same, the flow rate of the flow path from joint 16a to joint 16b via valve 16c (i.e., the "first flow path" in the present disclosure) is the same as the flow rate of the flow path from joint 16a to joint 16b via valve 16d (i.e., the "second flow path" in the present disclosure). This makes it easy for the change unit 111a, described below, to change the first opening degree D1 and the second opening degree D2.

[0035] [Secondary flow path 17] Secondary flow path 17 includes joints 17a and 17b, pumps 17c and 17d, and pipes 17e to 17k. Secondary flow path 17 is installed inside housing 15. Secondary flow path 17 is a pipe for secondary refrigerant C2 in CDU 1. Secondary flow path 17 is an example of the "third flow path" of the present disclosure.

[0036] Each of the joints 17a and 17b is, for example, a Tee joint, similar to the joint 16a. Each of the pumps 17c and 17d has a housing, a pump rotor, an inlet, and an outlet. The pump rotor rotates within the housing by driving force from a pump motor. As a result, each of the pumps 17c and 17d pumps fluid that has flowed in through its inlet out of its outlet.

[0037] Pipe 17e connects the secondary inlet 13 and the inlet 18c of the heat exchanger 18. Pipe 17f connects the outlet 18d of the heat exchanger 18 and the first connection port of the fitting 17a. Pipe 17g connects the second connection port of the fitting 17a and the inlet of the pump 17c. Pipe 17h connects the outlet of the pump 17c and the first connection port of the fitting 17b. Pipe 17i connects the third connection port of the fitting 17a and the inlet of the pump 17d. Pipe 17j connects the outlet of the pump 17d and the second connection port of the fitting 17b. Pipe 17k connects the third connection port of the fitting 17b and the secondary outlet 14.

[0038] [Heat exchanger 18] The heat exchanger 18 is, for example, a plate-type heat exchanger. The heat exchanger 18 has a plurality of heat transfer plates stacked in the same direction (i.e., a stack of heat transfer plates), an inlet 18a and an outlet 18b for the primary refrigerant C1, and an inlet 18c and an outlet 18d for the secondary refrigerant C2. The inlets 18a, 18c and the outlets 18b, 18d are each located, for example, in a heat transfer plate located at one end of the stack. The stack also has a flow path 18e through which the primary refrigerant C1 flows from the inlet 18a to the outlet 18b. The stack also has a flow path 18f through which the secondary refrigerant C2 flows from the inlet 18c to the outlet 18d.

[0039] The primary refrigerant C1 flows from inlet 18a into flow path 18e in the stack body and circulates through the stack body toward outlet 18b. The secondary refrigerant C2 flows from inlet 18c into flow path 18f in the stack body and circulates through the stack body toward outlet 18d. That is, the first flow path and the third flow path of the present disclosure pass through the heat exchanger 18.

[0040] Furthermore, within the stack of heat transfer plates, the high-temperature secondary refrigerant C2 and the low-temperature primary refrigerant C1 flow while being physically isolated from each other. Each heat transfer plate is made of a material with relatively low heat transfer resistance. Therefore, within the stack, heat exchange occurs between the primary refrigerant C1 (low temperature) and the secondary refrigerant C2 (high temperature). That is, the heat exchanger 18 exchanges heat between the primary refrigerant C1 and the secondary refrigerant C2. As a result of the heat exchange, the thermal energy of the secondary refrigerant C2 is transferred to the primary refrigerant C1. That is, the secondary refrigerant C2 is at a lower temperature when it flows out of the outlet 18d than when it flows into the inlet 18c.

[0041] [Sensor part 19] The sensor unit 19 detects a secondary temperature T2o, which is the temperature of the secondary refrigerant C2, a device temperature Td, which is the temperature inside the CDU 1, and a relative humidity Hd inside the CDU 1. In detail, the sensor unit 19 includes temperature sensors 19a and 19b and a humidity sensor 19c.

[0042] Specifically, the temperature sensor 19a detects the secondary temperature T2o between the outlet 18d and the secondary outlet 14 in the secondary flow path 17, and outputs information indicating the secondary temperature T2o to the control unit 111.

[0043] Specifically, the temperature sensor 19b detects the device temperature Td near the heat exchanger 18, and outputs information indicating the device temperature Td to the control unit 111.

[0044] Specifically, the humidity sensor 19c detects the relative humidity Hd near the heat exchanger 18 and outputs information indicating the relative humidity Hd to the control unit 111.

[0045] Hereinafter, information indicating the secondary temperature T2o, the device temperature Td, and the relative humidity Hd may be simply referred to as "secondary temperature T2o," "device temperature Td," and "relative humidity Hd," respectively.

[0046] The sensor unit 19 may include a flow rate sensor in each of the pipes 16g and 16j. The sensor unit 19 may also include a pressure sensor.

[0047] [Operation unit 110] The CDU 1 further includes an operation unit 110. The operation unit 110 is, for example, a touch screen. The touch screen includes a display and a touch sensor.

[0048] [Control unit 111] The control unit 111 includes electronic circuits such as a microcomputer and memory (not shown). The control unit 111 is located above the primary flow path 16 and the secondary flow path 17 in the vertical direction of the housing 15 of the CDU 1. This prevents the electronic circuits from being submerged in the leaked primary refrigerant C1 or secondary refrigerant C2, even if the primary refrigerant C1 leaks from the primary flow path 16 or the secondary refrigerant C2 leaks from the secondary flow path 17.

[0049] The microcomputer, in accordance with a program stored in the memory, controls the components of the CDU 1. In detail, the control unit 111 functions as a change unit 111a and a setting unit 111b when the program is executed.

[0050] The change unit 111a changes the first opening degree D1 of the valve 16c and the second opening degree D2 of the valve 16d based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd so that the sum of the first opening degree D1 and the second opening degree D2 becomes a predetermined value Vp. A pressure increase of the primary refrigerant C1 in the joint 16a, the pipes 16e and 16f, and the valve 16c is suppressed.

[0051] Specifically, the valves 16c and 16d have the same specifications. The opening degrees of the valves 16c and 16d represent the ratio of the opening area of the valve seat at a given displacement of the valve disc to the total opening area. The valve seat is the part that receives the valve disc when it is in the fully closed position.

[0052] In the embodiment, the opening degree is expressed as a percentage for ease of understanding. In this case, the predetermined value Vp is generally 100% or more. Examples of the predetermined value Vp include 100% or 120%. The predetermined value Vp may be a fixed value or a variable value as long as it is 100% or more. Furthermore, the predetermined value Pv may be 100% or less as long as the pressure increase of the primary refrigerant C1 is suppressed. For example, the predetermined value Pv may be 80%. Even if the change unit 111a reduces the first opening degree D1 to prevent condensation in the heat exchanger 18, the change unit 111a increases the second opening degree D2, thereby suppressing the pressure increase of the primary refrigerant C1 in the joint 16a, the pipes 16e and 16f, and the valve 16c.

[0053] A relief valve is sometimes used in a fluid circuit. However, because a typical relief valve simply releases excess pressure, it is unsuitable for the CDU 1, which must prevent condensation. Therefore, in this embodiment, the CDU 1 is equipped with flow-controllable valves 16c and 16d, and the change unit 111a changes the first opening D1 and the second opening D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd so that the sum of the first opening D1 and the second opening D2 becomes a predetermined value Vp.

[0054] The change unit 111a periodically determines a change amount ΔD between the first opening degree D1 and the second opening degree D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, and then changes the first opening degree D1 and the second opening degree D2 by the change amount ΔD. This makes it possible to lower the temperature of the secondary refrigerant C2 in a relatively short time.

[0055] The setting unit 111b sets a target temperature Tt for the secondary temperature T2o. The changing unit 111a changes the first opening D1 and the second opening D2 so that the secondary temperature T2o approaches the target temperature Tt. The cooling performance of the primary refrigerant C1 by the secondary refrigerant C2 is maintained.

[0056] The change unit 111a changes the first opening degree D1 and the second opening degree D2 so that the secondary temperature T2o does not become equal to or lower than the dew point based on the device temperature Td and the relative humidity Hd while the target temperature Tt is equal to or lower than the dew point based on the device temperature Td and the relative humidity Hd. This suppresses the occurrence of condensation inside the CDU 1.

[0057] Next, the processing of the control unit 111 will be described in more detail with reference to FIGS.

[0058] As shown in FIGS. 3 to 5, the processing of the control unit 111 includes steps S101 to S127.

[0059] In step S101, the control unit 111 displays an input screen on the touch screen of the operation unit 110. The input screen is a screen for allowing the user of the CDU 1 to input a target temperature Tt. The operation unit 110 transmits information indicating the target temperature Tt specified by a user operation (hereinafter also simply referred to as "target temperature Tt") to the control unit 111.

[0060] In step S102, the control unit 111 functions as the setting unit 111b, which sets the target temperature Tt received from the operation unit 110 in, for example, a memory.

[0061] In step S103, the control unit 111 operates the pumps 17c and 17d. At this time, the pump 65 also operates on the cooling device 6 side. The fluids and discharge rates of the pumps 17c, 17d, and 65 are determined appropriately. As a result, the primary refrigerant C1 flows into the primary inlet 11. The primary refrigerant C1 circulates within the primary flow path 16. The primary refrigerant C1 flows out from the primary outlet 12. The secondary refrigerant C2 flows into the secondary inlet 13. The secondary refrigerant C2 circulates within the secondary flow path 17. The secondary refrigerant C2 flows out from the secondary outlet 14. The primary refrigerant C1 and the secondary refrigerant C2 are subject to heat exchange in the heat exchanger 18.

[0062] In steps S104 to S127, the control unit 111 functions as a change unit 111a.

[0063] In step S104, the change unit 111a determines the first opening degree D1 to be a first initial value D10, and determines the second opening degree D2 to be a second initial value D20. The change unit 111a changes the first opening degree D1 of the valve 16c to the first initial value D10, and changes the second opening degree D2 of the valve 16d to the second initial value D20.

[0064] Immediately after the CDU 1 starts operating, the secondary temperature T2o is expected to be relatively high. In order to lower the secondary temperature T2o relatively quickly, the first initial value D10 and the second initial value D20 are set to satisfy, for example, the following conditions (a) and (b). The condition (a) is that the sum of the first initial value D10 and the second initial value D20 is a predetermined value Vp. The condition (b) is that the first initial value D10 is greater than the second initial value D20. By satisfying the conditions (a) and (b), a large amount of low-temperature primary refrigerant C1 flows through the flow path 18e relatively quickly. Therefore, the change unit 111a changes the first opening D1 and the second opening D2 so that the secondary temperature T2o approaches the target temperature Tt. Note that the condition (b) may also be that the first initial value D10 is equal to or less than the second initial value D20.

[0065] In step S105, the change unit 111a starts counting time from an initial value t0 using a timer (not shown) provided inside the control unit 111.

[0066] In step S106, the change unit 111a determines whether the timer has measured the specific time tp. If it is determined that the specific time tp has not been measured (No in step S106), the process returns to step S106. If it is determined that the specific time tp has been measured (Yes in step S106), the process proceeds to step S107.

[0067] By repeating the processing loop defined by steps S105 to S127, the change unit 111a can periodically determine the change amount ΔD between the first opening degree D1 and the second opening degree D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, and then change the first opening degree D1 and the second opening degree D2 by the change amount ΔD.

[0068] In step S107, the change unit 111a acquires the secondary temperature T2o, the device temperature Td, and the relative humidity Hd from the sensor unit 19. In step S107, the change unit 111a further obtains the dew-point temperature DP from the device temperature Td and the relative humidity Hd using a known technique.

[0069] In step S108, the change unit 111a determines whether the target temperature Tt is equal to or lower than the dew-point temperature DP. If it is equal to or lower than the dew-point temperature DP (Yes in step S108), the process proceeds to step S109. If it is not equal to or lower than the dew-point temperature DP (No in step S108), the process proceeds to step S119.

[0070] In step S109, the change unit 111a determines whether the secondary temperature T2o is equal to or lower than the dew-point temperature DP. If it is determined that the secondary temperature T2o is equal to or lower than the dew-point temperature DP (Yes in step S109), it is determined that condensation will occur around the heat exchanger 18, and the process proceeds to step S110. If it is determined that the secondary temperature T2o is not equal to or lower than the dew-point temperature DP (No in step S109), it is determined that condensation will not occur, and the process proceeds to step S115 (see FIG. 4).

[0071] In step S110, the change unit 111a obtains the absolute value of the difference between the secondary temperature T2o and the dew-point temperature DP as the temperature difference ΔT1.

[0072] Next, in step S111, the change unit 111a determines whether the temperature difference ΔT1 is equal to or greater than a reference value V1.

[0073] If it is determined that the secondary temperature T2o is equal to or greater than the reference value V1 (Yes in step S111), it is determined that the secondary temperature T2o is significantly lower than the dew-point temperature DP, and the process proceeds to step S112. Step S112 is executed when conditions (c1), (d1), and (e1) are satisfied, as shown in the dotted-line box W1 in FIG. 6. The condition (c1) is that the target temperature Tt is equal to or less than the dew-point temperature DP (see step S108). The condition (d1) is that the secondary temperature T2o is equal to or less than the dew-point temperature DP (see step S109). The condition (e1) is that the temperature difference ΔT1 is equal to or greater than the reference value V1 (see step S111).

[0074] On the other hand, if it is determined that the temperature difference ΔT1 is not equal to or greater than the reference value V1 (No in step S111), it is assumed that the secondary temperature T2o is near the dew-point temperature DP, and the process proceeds to step S113. Step S113 is executed when condition (e2) is met in addition to the above-mentioned conditions (c1) and (d1), as shown in the dashed-line box W2 in Fig. 6. Condition (e2) is that the temperature difference ΔT1 is less than the reference value V1 (see step S111).

[0075] In step S112, the change unit 111a determines the change amount ΔD to be the change amount ΔD1 (see also box W1 in FIG. 6). In the same step, the change unit 111a further reduces the first opening D1 by the change amount ΔD1 compared to the current opening. The change unit 111a further increases the second opening D2 by the change amount ΔD1 compared to the current opening.

[0076] The sum of the first initial value D10 and the second initial value D20 is the predetermined value Vp. After step S112 is executed, the sum of the first opening D1 and the second opening D2 is the predetermined value Vp. Furthermore, after steps S113, S117, S118, S126, and S127 (described later) are executed, the sum of the first opening D1 and the second opening D2 is the predetermined value Vp.

[0077] In step S113, the change unit 111a determines the change amount ΔD to be the change amount ΔD2 (see also box W2 in FIG. 6). In the same step, the change unit 111a further reduces the first opening D1 by the change amount ΔD2 compared to the current opening amount. The change unit 111a further increases the second opening D2 by the change amount ΔD2 compared to the current opening amount.

[0078] The change amount ΔD2 is smaller than the change amount ΔD1. Therefore, the flow rate of the primary refrigerant C1 in the flow path 18e is smaller when step S112 is performed than when step S113 is performed. Therefore, when step S112 is performed, the secondary temperature T2o can be significantly increased, thereby enabling early prevention of condensation around the heat exchanger 18. On the other hand, when step S113 is performed, the secondary temperature T2o can be made slightly higher than the dew-point temperature DP. Therefore, the heat source 5 is cooled well while preventing condensation from occurring inside the CDU 1.

[0079] When the target temperature Tt is equal to or lower than the dew-point temperature DP, the change unit 111a executes steps S108 to S113 while the secondary temperature T2o is equal to or lower than the dew-point temperature DP. That is, in the CDU 1, rather than setting the secondary temperature T2o to the target temperature Tt, the first opening D1 and the second opening D2 are changed so that the secondary temperature T2o quickly exceeds the dew-point temperature DP. This achieves both suppression of condensation inside the CDU 1 and cooling performance of the heat source 5.

[0080] After step S112 or step S113, in step S114, the change unit 111a starts timing from an initial value t0 using a built-in timer (not shown), after which the process returns to step S106.

[0081] As shown in FIG. 4, in step S115, the change unit 111a calculates the temperature difference ΔT1 described in step S110 (see FIG. 3).

[0082] Next, in step S116, the change unit 111a determines whether the temperature difference ΔT1 is equal to or greater than a reference value V2.

[0083] If it is determined that the secondary temperature T2o is equal to or greater than the reference value V2 (Yes in step S116), it is determined that the secondary temperature T2o is significantly higher than the dew-point temperature DP, and the process proceeds to step S117. Step S117 is executed when conditions (d2) and (f1) are met in addition to the above-mentioned condition (c1), as shown in the dotted-line box W3 in FIG. 6. The condition (d2) is that the secondary temperature T2o exceeds the dew-point temperature DP (see step S109). The condition (f1) is that the temperature difference ΔT1 is equal to or greater than the reference value V2 (see step S116).

[0084] On the other hand, if it is determined that the temperature difference ΔT1 is not equal to or greater than the reference value V2 (No in step S116), it is assumed that the secondary temperature T2o is near the dew-point temperature DP, and the process proceeds to step S118. Step S118 is executed when condition (f2) is met in addition to the above-mentioned conditions (c1) and (d2), as shown in the dashed-line box W4 in Fig. 6. Condition (f2) is that the temperature difference ΔT1 is less than the reference value V2 (see step S116).

[0085] In step S117, the change unit 111a determines the change amount ΔD to be a change amount ΔD3 (see also box W3 in FIG. 6). In the same step, the change unit 111a further increases the first opening D1 by the change amount ΔD3 from the current opening amount. The change unit 111a further decreases the second opening D2 by the change amount ΔD3 from the current opening amount.

[0086] In step S118, the change unit 111a determines the change amount ΔD to be a change amount ΔD4 (see also box W4 in FIG. 6). In the same step, the change unit 111a further increases the first opening D1 by the change amount ΔD4 from the current opening amount. The change unit 111a further decreases the second opening D2 by the change amount ΔD4 from the current opening amount.

[0087] The secondary temperature T2o decreases regardless of whether step S117 or S118 is performed. However, the change amount ΔD4 is smaller than the change amount ΔD3. Therefore, when step S117 is performed, the secondary temperature T2o approaches the dew-point temperature DP relatively quickly. When step S118 is performed, the secondary temperature T2o is maintained near the dew-point temperature DP.

[0088] After step S117 or step S118, the process proceeds to step S114 (see FIG. 3).

[0089] 5, in step S119, the change unit 111a determines whether the secondary temperature T2o is equal to or higher than the target temperature Tt. If it is determined that the secondary temperature T2o is equal to or higher than the target temperature Tt (Yes in step S119), the process proceeds to step S120. If it is determined that the secondary temperature T2o is not equal to or higher than the target temperature Tt (No in step S119), the process proceeds to step S124.

[0090] In step S120, the change unit 111a obtains the absolute value of the difference between the secondary temperature T2o and the target temperature Tt as the temperature difference ΔT2.

[0091] Next, in step S121, the change unit 111a determines whether the temperature difference ΔT2 is equal to or greater than the reference value V3. If it is determined that the temperature difference ΔT2 is equal to or greater than the reference value V3 (Yes in step S121), it is determined that the secondary temperature T2o is significantly higher than the target temperature Tt, and the process proceeds to step S122. Step S122 is executed when conditions (c2), (f1), and (g1) are satisfied, as shown in a dotted-line box W5 in FIG. 6. The condition (c2) is that the target temperature Tt exceeds the dew-point temperature DP (see step S108). The condition (f1) is that the secondary temperature T2o is equal to or greater than the target temperature Tt (see step S119). The condition (g1) is that the temperature difference ΔT2 is equal to or greater than the reference value V3 (see step S121).

[0092] On the other hand, if it is determined that the temperature difference ΔT2 is not equal to or greater than the reference value V3 (No in step S121), it is assumed that the secondary temperature T2o is near the target temperature Tt, and the process proceeds to step S123. Step S123 is executed when condition (g2) is met in addition to the above conditions (c2) and (f1), as shown in a dashed-line box W6 in Fig. 6. Condition (g2) is that the temperature difference ΔT2 is less than the reference value V3 (see step S121).

[0093] In step S122, the change unit 111a determines the change amount ΔD to be a change amount ΔD5. In the same step, the change unit 111a further increases the first opening D1 by the change amount ΔD5 from the current opening amount. The change unit 111a further decreases the second opening D2 by the change amount ΔD5 from the current opening amount.

[0094] In step S123, the change unit 111a determines the change amount ΔD to be a change amount ΔD6. In the same step, the change unit 111a further increases the first opening D1 by the change amount ΔD6 from the current opening amount. The change unit 111a further decreases the second opening D2 by the change amount ΔD6 from the current opening amount.

[0095] Therefore, in steps S122 and S123, if the difference between the secondary temperature T2o and the dew-point temperature DP based on the device temperature Td and the relative humidity Hd (i.e., the temperature difference Δ2) is equal to or greater than the reference value V3, the change unit 111a determines the change amount ΔD between the first opening D1 and the second opening D2 to be a change amount ΔD5, and then increases the first opening D1 according to the change amount ΔD5 and decreases the second opening D2 by the change amount ΔD5 so that the temperature of the secondary refrigerant C2 approaches the target temperature Tt. On the other hand, if the difference between the secondary temperature T2o and the dew-point temperature DP based on the device temperature Td and the relative humidity Hd (i.e., the temperature difference Δ2) is less than the reference value V3, the change unit 111a determines the change amount ΔD between the first opening D1 and the second opening D2 to be a change amount ΔD6 smaller than the change amount ΔD5, and changes the first opening D1 and the second opening D2 by the change amount ΔD6. This allows the temperature of the secondary refrigerant C2 to approach the target temperature Tt in a short time and makes it difficult for the temperature to drop below the dew point.

[0096] The reference value V3 is an example of a "reference value" in the present disclosure. The change range ΔD5 is an example of a "first change range" in the present disclosure. The change range ΔD6 is an example of a "second change range" in the present disclosure.

[0097] Specifically, the secondary temperature T2o decreases regardless of whether step S122 or S123 is performed. However, the change amount ΔD6 is smaller than the change amount ΔD5. Therefore, when step S122 is performed, the secondary temperature T2o approaches the target temperature Tt relatively quickly. When step S123 is performed, the secondary temperature T2o is maintained near the target temperature Tt. Furthermore, it becomes difficult for the secondary temperature T2o to become equal to or less than the dew-point temperature DP.

[0098] After step S122 or step S123, the process proceeds to step S114 (see FIG. 3).

[0099] In step S124, the change unit 111a calculates the temperature difference ΔT2 described in step S120.

[0100] Next, in step S125, the change unit 111a determines whether the temperature difference ΔT2 is equal to or greater than a reference value V4.

[0101] If it is determined that the secondary temperature T2o is equal to or greater than the reference value V4 (Yes in step S125), it is determined that the secondary temperature T2o is significantly lower than the target temperature Tt, and the process proceeds to step S126. Step S126 is executed when conditions (f2) and (h1) are met in addition to the above-mentioned condition (c2), as shown in a dotted-line box W7 in FIG. 6. The condition (f2) is that the secondary temperature T2o is less than the target temperature Tt (see step S119). The condition (h1) is that the temperature difference ΔT2 is equal to or greater than the reference value V4 (see step S125).

[0102] On the other hand, if it is determined that the temperature difference ΔT2 is not equal to or greater than the reference value V4 (No in step S125), it is determined that the secondary temperature T2o is slightly lower than the target temperature Tt, and the process proceeds to step S127. Step S127 is executed when condition (h2) is met in addition to the above-mentioned conditions (c2) and (f2), as shown in a dashed-line box W8 in FIG. 6. Condition (h2) is that the temperature difference ΔT2 is less than the reference value V4 (see step S125).

[0103] In step S126, the change unit 111a determines the change amount ΔD to be a change amount ΔD7. In the same step, the change unit 111a further reduces the first opening D1 by the change amount ΔD7 from the current opening amount. The change unit 111a further increases the second opening D2 by the change amount ΔD7 from the current opening amount.

[0104] In step S127, the change unit 111a determines the change amount ΔD to be a change amount ΔD8. In the same step, the change unit 111a further reduces the first opening D1 by the change amount ΔD8 compared to the current opening. The change unit 111a further increases the second opening D2 by the change amount ΔD8 compared to the current opening.

[0105] Whether step S126 or S127 is performed, the secondary temperature T2o increases. However, the change amount ΔD8 is smaller than the change amount ΔD7. Therefore, when step S126 is performed, the secondary temperature T2o approaches the target temperature Tt relatively quickly. When step S127 is performed, the secondary temperature T2o is maintained near the target temperature Tt.

[0106] After step S126 or step S127, the process proceeds to step S114 (see FIG. 3).

[0107] [First Modification] 7, in the CDU 1, the sensor unit 19 further detects a primary temperature T1i, which is the temperature of the primary refrigerant C1, upstream of the heat exchanger 18. In particular, the sensor unit 19 further includes a temperature sensor 19d.

[0108] Specifically, the temperature sensor 19d detects the primary temperature T1i between the primary inlet 11 and the inlet 18a, which is upstream of the heat exchanger 18 in the primary flow path 16, and outputs information indicating the primary temperature T1i (hereinafter also simply referred to as the "primary temperature T1i") to the control unit 111.

[0109] The change unit 111a determines a cycle for changing the first opening degree D1 and the second opening degree D2 based on the primary temperature T1i, the device temperature Td, and the relative humidity Hd, and then changes the first opening degree D1 and the second opening degree D2 periodically, thereby making it difficult for condensation to occur inside the CDU 1.

[0110] In detail, as shown in FIG. 8, the processing of CDU1 according to the first modified example further includes steps S201 to S204 after executing any one of steps S112, S113, S117, S118, S122, S123, S126, and S127 and before executing step S114.

[0111] In step S201, the change unit 111a acquires the primary temperature T1i from the sensor unit 19.

[0112] In step S202, the change unit 111a determines whether the primary temperature T1i acquired in step S201 is equal to or lower than the dew-point temperature DP calculated in step S107. If it is determined to be equal to or lower than the dew-point temperature DP (Yes in step S202), the process proceeds to step S203. On the other hand, if it is determined not to be equal to or lower than the dew-point temperature DP (No in step S202), the process proceeds to step S204.

[0113] In step S203, the change unit 111a updates the specific time tp used in step S106 to the specific time tp1.

[0114] In step S204, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0115] According to the first modification, when the primary temperature T1i is equal to or lower than the dew-point temperature DP, the specific time tp is set relatively short, thereby shortening the cycle in which the first opening D1 and the second opening D2 are changed. That is, the first opening D1 and the second opening D2 are changed frequently. In particular, when the primary temperature T1i is equal to or lower than the dew-point temperature DP, steps S112 and S113 may be executed frequently. This makes it difficult for condensation to occur inside the CDU 1.

[0116] [Second Modification] The configuration of the CDU 1 according to the second modification may be the same as that of the CDU 1 according to the embodiment (see FIG. 2), and therefore FIG. 2 is used in the second modification.

[0117] As shown in FIG. 2, the sensor unit 19 detects the secondary temperature T2o downstream of the heat exchanger 18 in the secondary flow path 17 (that is, an example of the "third flow path").

[0118] The change unit 111a determines a cycle for changing the first opening degree D1 and the second opening degree D2 based on at least one of the combination of the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, and the target temperature Tt, and then changes the first opening degree D1 and the second opening degree D2 periodically, thereby making it difficult for condensation to occur inside the CDU 1 or allowing the secondary refrigerant C2 to reach the target temperature Tt in a short time.

[0119] In detail, as shown in FIG. 9, the processing of the CDU 1 according to the second modification further includes steps S301 and S302 instead of steps S112 and S113 (see FIG. 3).

[0120] In step S301, the change unit 111a updates the specific time tp used in step S106 to a specific time tp1 in addition to the process described in step S112.

[0121] In step S302, in addition to the process described in step S113, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0122] As shown in FIG. 10, the processing of the CDU 1 according to the second modification further includes steps S303 and S304 instead of steps S117 and S118 (see FIG. 4).

[0123] In step S303, the change unit 111a performs the process described in step S117, and also updates the specific time tp used in step S106 to the specific time tp1.

[0124] In step S304, in addition to the process described in step S118, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0125] According to the second modification, when the secondary temperature T2o is significantly different from the dew-point temperature DP, the specific time tp is set relatively short, so that the first opening D1 and the second opening D2 are changed frequently, thereby making it difficult for condensation to occur inside the CDU 1.

[0126] As shown in FIG. 11, the processing of the CDU 1 according to the second modification further includes steps S305, S306, S307, and S308 instead of steps S122, S123, S126, and S127 (see FIG. 5).

[0127] In step S305, the change unit 111a performs the process described in step S122, and also updates the specific time tp used in step S106 to the specific time tp1.

[0128] In step S306, in addition to the process described in step S123, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0129] In step S307, the change unit 111a performs the process described in step S126, and also updates the specific time tp used in step S106 to the specific time tp1.

[0130] In step S308, in addition to the process described in step S127, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0131] According to the second modification, when there is a large difference between the secondary temperature T2o and the target temperature Tt, the specific time tp is set relatively short, so that the first opening D1 and the second opening D2 are changed frequently, and thus the secondary temperature T2o quickly approaches the target temperature Tt.

[0132] [Third Modification] 12, the CDU 1 according to the third modification includes a proportional control type motor-operated three-way valve 112 instead of the joint 16a, the valves 16c and 16d, and the pipes 16f and 16h. The motor-operated three-way valve 112 also allows the change unit 111a to change the position of the valve element 112a in the motor-operated three-way valve 112 to change the first opening degree D1 and the second opening degree D2, as in the embodiment.

[0133] Furthermore, the drawings mainly show each component in a schematic manner to facilitate understanding of the present disclosure, and the thickness, length, number, spacing, etc. of each component shown in the drawings may differ from the actual configuration due to the convenience of creating the drawings. Furthermore, the configuration of each component shown in the above embodiment is an example and is not particularly limited, and it goes without saying that various modifications are possible within a scope that does not substantially deviate from the effects of the present disclosure.

[0134] The valve 16c adjusts the first flow rate F1. The first flow rate F1 is the flow rate of the primary refrigerant C1 in the flow path extending from the joint 16a to the joint 16b via the valve 16c (i.e., the “first flow path” of the present disclosure). The valve 16d adjusts the second flow rate F2. The second flow rate F2 is the flow rate of the primary refrigerant C1 in the flow path extending from the joint 16a to the joint 16b via the valve 16d (i.e., the “second flow path” of the present disclosure). The change unit 111a may change the first opening degree D1 of the valve 16c and the second opening degree D2 of the valve 16d based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd so that the sum of the first flow rate F1 and the second flow rate F2 becomes a predetermined value Vp2. This also suppresses a pressure increase of the primary refrigerant C1 in the joint 16a, the pipes 16e and 16f, and the valve 16c. In this case, the first flow rate F1 and the second flow rate F2 may be measured by flow rate sensors provided in the pipes 16g and 16j, respectively. The change unit 111a may further change the first opening degree D1 and the second opening degree D2 so that the sum of the first flow rate F1 and the second flow rate F2 becomes a predetermined value Vp2.

[0135] In the embodiment, the control unit 111 is provided in the CDU 1. However, this is not limiting, and the control unit 111 may be provided in an external device other than the CDU 1, such as the cooling device 6. Alternatively, the control unit 111 may be provided in an electronic device, which is an example of the heat source 5. In this case, the control unit 111 controls each component of the CDU 1 via communication.

[0136] In the embodiment, the first flow path and the second flow path join at the joint 16b inside the housing 15. However, this is not limiting, and the first flow path and the second flow path may join outside the housing 15.

[0137] 3 to 5, the predetermined value Pv is a fixed value. However, this is not limiting, and in step S107, the change unit 111a may determine the predetermined value Pv based on the dew-point temperature DP calculated in the same step. Specifically, the lower the dew-point temperature DP, the smaller the predetermined value Pv is determined to be. This suppresses condensation within the CDU 1 and also suppresses a pressure increase in the primary flow path 16 of the primary refrigerant C1.

[0138] 3, if it is determined that the secondary temperature T2o is equal to or lower than the dew-point temperature DP (Yes in step S109), the predetermined value Pv may be reduced, thereby suppressing condensation in the CDU 1 and suppressing a pressure increase in the primary flow path 16 of the primary refrigerant C1.

[0139] The present technology can also employ the following configuration.

[0140] (1) a common flow path through which the primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; a sensor unit for detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; a change unit that changes a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value; A refrigerant circulation device comprising:

[0141] (2) The refrigerant circulation device described in (1), wherein the change unit periodically determines a change range between the first opening and the second opening based on the secondary temperature, the device temperature, and the relative humidity, and then changes the first opening and the second opening by the change range.

[0142] (3) A setting unit that sets a target temperature of the secondary temperature is further provided, The refrigerant circulation device according to (1) or (2), wherein the change unit changes the first degree of opening and the second degree of opening so that the secondary temperature approaches the target temperature.

[0143] (4) The refrigerant circulation device described in (3), wherein the change unit changes the first opening degree and the second opening degree so that the secondary temperature does not become lower than the dew point based on the device temperature and the relative humidity while the target temperature is lower than the dew point based on the device temperature and the relative humidity.

[0144] (5) The sensor unit further detects a primary temperature, which is the temperature of the primary refrigerant, upstream of the heat exchanger; The refrigerant circulation device described in any one of (1) to (4), wherein the change unit determines a period for changing the first opening degree and the second opening degree based on the primary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree at the period.

[0145] (6) The sensor unit detects the secondary temperature downstream of the heat exchanger in the third flow path, The refrigerant circulation device described in (3), wherein the change unit determines a period for changing the first opening degree and the second opening degree based on at least one of the combination of the secondary temperature, the device temperature, and the relative humidity and the target temperature, and then changes the first opening degree and the second opening degree at the period.

[0146] (7) The first valve is a two-way valve disposed in the first flow path, the second valve is a two-way valve disposed in the second flow path, The refrigerant circulation device according to any one of (1) to (6), wherein the flow rates of the first flow path and the second flow path are the same.

[0147] (8) A refrigerant circulation device described in any one of (1) to (7), wherein the change unit includes an electronic circuit and is located above the common flow path, the first flow path, the second flow path, and the third flow path in the vertical direction of the device.

[0148] (9) The change unit When a difference between the secondary temperature and a dew point based on the device temperature and the relative humidity is equal to or greater than a reference value, a change range between the first degree of opening and the second degree of opening is determined as a first change range, and then the first degree of opening is increased according to the first change range and the second degree of opening is decreased by the first change range so that the temperature of the secondary refrigerant approaches the target temperature; When the difference between the secondary temperature and the dew point is less than a reference value, the change range of the first opening and the second opening is determined to be a second change range that is smaller than the first change range, and the first opening and the second opening are changed by the second change range.

[0149] (10) The refrigerant circulation device according to any one of (1) to (9), wherein the change unit changes the predetermined value based on the secondary temperature, the device temperature, and the relative humidity.

[0150] (11) The refrigerant circulation device according to any one of (1) to (10), wherein the change unit decreases the predetermined value when the secondary temperature is equal to or lower than a dew point.

[0151] (10) a common flow path through which the primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts a first flow rate that is a flow rate of the primary refrigerant in the first flow path; a second valve that adjusts a second flow rate that is a flow rate of the primary refrigerant in the second flow path; a sensor unit for detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; a change unit that changes a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first flow rate and the second flow rate becomes a predetermined value; A refrigerant circulation device comprising:

[0152] (11) a common flow path through which the primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; A control method for a refrigerant circulation device comprising: Detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; A control method in which a first opening degree, which is the opening degree of the first valve, and a second opening degree, which is the opening degree of the second valve, are changed based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value. [Industrial Applicability]

[0153] The refrigerant circulation device and control method according to the present disclosure have industrial applicability. [Explanation of symbols]

[0154] 1: Refrigerant circulation device 16: Primary flow path 16e: Pipe (common flow path) 16a, 16b: Joints (first flow path, second flow path) 16f, 16g, 16j: Pipe (first flow path) 16c: Valve (first flow path, first valve) 16h, 16i: Pipe (second flow path) 16d: Valve (second flow path, second valve) 17: Secondary flow path (third flow path) 18: Heat exchanger 18e: Flow path (first flow path) 19: Sensor section 111: Control unit 111a: Change section 111b: Setting section

Claims

1. a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; a sensor unit for detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; a change unit that changes a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value; A refrigerant circulation device comprising:

2. 2. The refrigerant circulation device according to claim 1, wherein the change unit periodically determines a change amount between the first opening degree and the second opening degree based on the secondary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree by the change amount.

3. a setting unit that sets a target temperature of the secondary temperature; The refrigerant circulation device according to claim 1 , wherein the change unit changes the first degree of opening and the second degree of opening so that the secondary temperature approaches the target temperature.

4. 4. The refrigerant circulation device according to claim 3, wherein the change unit changes the first opening degree and the second opening degree so that the secondary temperature does not become equal to or lower than the dew point based on the device temperature and the relative humidity while the target temperature is equal to or lower than the dew point based on the device temperature and the relative humidity.

5. The sensor unit further detects a primary temperature, which is the temperature of the primary refrigerant, upstream of the heat exchanger, 3. The refrigerant circulation device according to claim 1, wherein the change unit determines a period for changing the first opening degree and the second opening degree based on the primary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree at the period.

6. the sensor unit detects the secondary temperature downstream of the heat exchanger in the third flow path, 4. The refrigerant circulation device according to claim 3, wherein the change unit determines a period for changing the first opening degree and the second opening degree based on at least one of a combination of the secondary temperature, the device temperature, and the relative humidity and the target temperature, and then changes the first opening degree and the second opening degree at the period.

7. the first valve is a two-way valve disposed in the first flow path, the second valve is a two-way valve disposed in the second flow path, The refrigerant circulation device according to claim 1 or 2, wherein the flow rates of the first flow path and the second flow path are the same.

8. The refrigerant circulation device according to claim 1 , wherein the change unit includes an electronic circuit and is located above the common flow path, the first flow path, the second flow path, and the third flow path in the up-down direction of the device.

9. The change unit When a difference between the secondary temperature and a dew point based on the device temperature and the relative humidity is equal to or greater than a reference value, a change range between the first degree of opening and the second degree of opening is determined as a first change range, and then the first degree of opening is increased according to the first change range and the second degree of opening is decreased by the first change range so that the temperature of the secondary refrigerant approaches the target temperature; 4. The refrigerant circulation device according to claim 3, wherein when the difference between the secondary temperature and the dew point is less than the reference value, the change amount of the first opening and the second opening is determined to be a second change amount that is smaller than the first change amount, and the first opening and the second opening are changed by the second change amount.

10. The refrigerant circulation device according to claim 1 , wherein the change unit changes the predetermined value based on the secondary temperature, the device temperature, and the relative humidity.

11. The refrigerant circulation device according to claim 1 , wherein the change unit decreases the predetermined value when the secondary temperature is equal to or lower than a dew point.

12. a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts a first flow rate that is a flow rate of the primary refrigerant in the first flow path; a second valve that adjusts a second flow rate that is a flow rate of the primary refrigerant in the second flow path; a sensor unit for detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; a changing unit that changes a first opening degree that is an opening degree of the first valve and a second opening degree that is an opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first flow rate and the second flow rate becomes a predetermined value; A refrigerant circulation device comprising:

13. a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which the secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which performs heat exchange between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; A control method for a refrigerant circulation device comprising: Detecting a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; A control method in which a first opening degree, which is the opening degree of the first valve, and a second opening degree, which is the opening degree of the second valve, are changed based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a predetermined value.

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