Ejector-type cooling system

Abstract

The ejector-type cooling system 10A comprises a condenser 18, a refrigerant pump 12, a steam generator 14, an evaporator 20, an ejector 16, and an intermediate heat exchanger 24, and includes a drive pressure sensor 41 for detecting the drive pressure of the drive flow, a drive temperature sensor 42 for detecting the drive temperature of the drive flow, and a control unit 50A that calculates the drive saturation temperature based on the drive pressure and performs feedback control to reduce or stop the rotation speed of the refrigerant pump 12 when the drive superheat, which is the difference between the drive temperature and the drive saturation temperature, falls below a preset reference value.

Description

Technical Field

[0001] The present invention relates to an ejector type cooling device.

Background Art

[0002] Conventionally, as an ejector type cooling device, the one proposed in Patent Document 1 is known. In this ejector type cooling device, an ejector is provided between a steam generator as a refrigerant heating means and a condenser in a circulation path through which a refrigerant circulates, and the refrigerant discharged from the steam generator is supplied to the ejector as a driving fluid, while the refrigerant discharged from the ejector is supplied to the condenser. A branch path is provided in a portion of the circulation path located between the condenser and the refrigerant pump. The branch path includes an expansion valve and an evaporator, and supplies the refrigerant after passing through the evaporator to the ejector as a suction fluid. In this ejector type cooling device, if a heat source such as warm water is supplied to the steam generator and heat dissipation water is supplied to the evaporator, it becomes possible to obtain chilled water cooled in the evaporator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the steam generator evaporates a high-pressure refrigerant using warm water from a steam utilization device or a production line in a factory as a heat source to generate a driving flow for the ejector. It is necessary to ensure a sufficient degree of superheat for this driving flow. When this degree of superheat cannot be ensured and the driving flow to the ejector becomes a gas-liquid two-phase flow, there is a problem that the suction performance of the ejector is significantly reduced and the cooling capacity by the evaporator cannot be ensured.

[0005] In view of the above circumstances, the present invention aims to provide an ejector-type cooling device that can stably ensure the degree of superheating of the drive flow. [Means for solving the problem]

[0006] To achieve the above objective, the ejector-type cooling device according to the present invention comprises: a condenser that condenses a gaseous refrigerant by heat exchange with radiating water; a refrigerant pump that pressurizes and circulates the refrigerant condensed in the condenser; a steam generator to which the refrigerant discharged from the refrigerant pump is supplied and evaporates by heat exchange with hot water; an evaporator to which hot water flows in series downstream of the steam generator, and to which refrigerant is supplied from a branch between the condenser and the refrigerant pump via an expansion valve and evaporates by heat exchange with hot water; and a refrigerant evaporated in the steam generator is supplied to a drive outlet as a drive flow, thereby drawing in the refrigerant supplied from the evaporator as a suction flow. An ejector-type cooling system comprising an ejector connected to draw in refrigerant from an opening and supply the refrigerant to the condenser from a discharge port, and an intermediate heat exchanger that cools hot water by exchanging heat with the heat-dissipating water between the steam generator and the evaporator connected in series, characterized in that it comprises a drive pressure sensor for detecting the drive pressure of the drive flow, a drive temperature sensor for detecting the drive temperature of the drive flow, and a control unit that calculates the drive saturation temperature based on the drive pressure and performs feedback control to reduce or stop the rotation speed of the refrigerant pump when the drive superheating degree, which is the difference between the drive temperature and the drive saturation temperature, falls below a preset reference value.

[0007] Furthermore, the present invention provides an ejector-type cooling device equipped with a hot water input temperature sensor for detecting the hot water input temperature of the hot water supplied to the steam generator, wherein the control unit calculates an estimated hot water input temperature based on the time change of the hot water input temperature detected by the hot water input temperature sensor, and if the subtracted value obtained by subtracting the drive saturation temperature from the estimated hot water input temperature is less than a preset value, the control unit reduces or stops the rotation speed of the refrigerant pump, while if the subtracted value is equal to or greater than the preset value, it performs feedforward control to maintain the rotation speed of the refrigerant pump.

[0008] Furthermore, the present invention provides an ejector-type cooling device comprising on-off control valves provided on the refrigerant inlet side and the refrigerant outlet side of the steam generator, wherein the control unit stops the refrigerant pump and closes the on-off control valves when the drive superheat level falls below a preset first threshold, and drives the refrigerant pump and opens the on-off control valves when the drive superheat level is equal to or greater than a second threshold (which is equal to or greater than the first threshold).

[0009] Furthermore, the present invention provides an ejector-type cooling device comprising a flow control valve provided on the heat dissipation water inlet side of the intermediate heat exchanger for adjusting the flow rate of heat dissipation water, and a hot water outlet temperature sensor provided on the hot water outlet side of the evaporator for detecting the hot water outlet temperature of the hot water, wherein the control unit controls the opening and closing of the flow control valve so that the added temperature obtained by adding a predetermined value to the hot water outlet temperature detected by the hot water outlet temperature sensor approaches the target intermediate hot water temperature, which is a target value on the hot water outlet side of the intermediate heat exchanger, and controls the opening degree of the expansion valve so that the hot water outlet temperature detected by the hot water outlet temperature sensor approaches the target hot water outlet temperature, which is a target value on the hot water outlet side of the evaporator. [Effects of the Invention]

[0010] According to the present invention, the control unit calculates the drive saturation temperature based on the drive pressure, and performs feedback control to reduce or stop the rotation speed of the refrigerant pump when the drive superheat level, which is the difference between the drive temperature and the drive saturation temperature, falls below a preset reference value. This has the effect of stably ensuring the superheat level of the drive flow. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a block diagram showing the configuration of a production system to which an ejector-type cooling device, an embodiment of the present invention, is applied. [Figure 2] Figure 2 is a circuit diagram showing the configuration of an ejector-type cooling device according to Embodiment 1 of the present invention. [Figure 3]Figure 3 is a flowchart showing the superheating degree control process procedure by the control unit shown in Figure 2. [Figure 4] Figure 4 is a circuit diagram showing the configuration of an ejector-type cooling device according to Embodiment 2 of the present invention. [Figure 5] Figure 5 is a flowchart showing the control processing procedure by the control unit shown in Figure 4. [Figure 6] Figure 6 is a circuit diagram showing the configuration of an ejector-type cooling device according to Embodiment 3 of the present invention. [Figure 7] Figure 7 is a flowchart showing the control processing procedure by the flow control valve opening / closing processing unit of the control unit shown in Figure 6. [Figure 8] Figure 8 is a flowchart showing the control processing procedure by the expansion valve opening adjustment processing unit of the control unit shown in Figure 6. [Modes for carrying out the invention]

[0012] A preferred embodiment of the ejector-type cooling device according to the present invention will be described in detail below with reference to the attached drawings.

[0013] <Embodiment 1> Figure 1 is a block diagram showing the configuration of a production system to which an ejector-type cooling device, an embodiment of the present invention, is applied.

[0014] The production system illustrated here involves connecting an ejector-type cooling device 10, which utilizes an ejector, to a production device 11 such as an aluminum die-casting machine. The ejector-type cooling device 10 cools the hot water W1 discharged from the production device 11, which has reached a high temperature of, for example, about 60°C, to a temperature of, for example, about 25°C, and returns it to the production device 11. The production device 11 then uses the cooled hot water W2 for its cooling process during production. In other words, this production system creates a circulation system for hot water W1, where the ejector-type cooling device 10 cools the cooled hot water used by the production device 11 for its cooling process and returns it to the production device 11 as cooling water once again.

[0015] The object connected to the ejector type cooling device 10 is not limited to the production device 11. The source that supplies the hot water W1 and the destination that supplies the hot water W2 to the ejector type cooling device 10 may be different.

[0016] FIG. 2 is a circuit diagram showing the configuration of an ejector type cooling device according to Embodiment 1 of the present invention. The ejector type cooling device 10A illustrated here includes a refrigerant pump 12, a steam generator 14, an ejector 16, a condenser 18, an evaporator 20, an expansion valve 22, a drive pressure sensor 41, a drive temperature sensor 42, a hot water input temperature sensor 43, and a control unit 50A.

[0017] The refrigerant pump 12 boosts the pressure of the liquid-phase refrigerant and circulates it in the circuit. The steam generator 14 is supplied with the refrigerant discharged from the refrigerant pump 12, exchanges heat with the hot water W1, and evaporates it.

[0018] The ejector 16 is supplied with the refrigerant evaporated in the steam generator 14 to the drive port 16a and supplied to the condenser 18. The condenser 18 exchanges heat between the gaseous-phase refrigerant supplied from the ejector 16 and the heat dissipation water and condenses it. This heat dissipation water is supplied through the branch portion B2 of the flow path L3 in the cooling water circuit. The heat dissipation water supplied from the flow path L3 is mainly industrial water or supply water from a circulating cooling tower. The heat dissipation water that has exchanged heat with the refrigerant in the condenser 18 is discharged from the flow path L4. The refrigerant condensed in the condenser 18 is introduced into the refrigerant pump 12 through the branch portion B1 of the refrigerant circuit and circulates in the circuit. A reservoir tank may be provided in the flow path from the condenser 18 to the refrigerant pump 12.

[0019] The expansion valve 22 is provided between the branch portion B1 of the refrigerant circuit and the evaporator 20, and controls the liquid-phase refrigerant supplied from the condenser 18 to a predetermined low pressure.

[0020] The evaporator 20 evaporates the refrigerant supplied via the branch section B1 and the expansion valve 22 by exchanging heat with hot water. The evaporator 20 is connected to the steam generator 14 so that the hot water flows in series downstream. The hot water W2 cooled by heat exchange with the refrigerant in the evaporator 20 is output from the flow path L2. In the evaporator 20, the refrigerant is a low-pressure refrigerant produced by the depressurization and expansion action of the expansion valve 22, and its latent heat is used to cool the hot water.

[0021] The evaporator 20 is connected so that the evaporated refrigerant is drawn in through the suction port 16c of the ejector 16. In the ejector 16, the high-pressure refrigerant introduced from the drive port 16a is depressurized by a nozzle (not shown) and ejected. At this time, the refrigerant is drawn into the main body as a suction flow through the suction port 16c, and the drive flow and the suction flow are mixed and pressurized through the merging / mixing section and diffuser, and then discharged from the discharge port 16b.

[0022] The ejector-type cooling device 10A is further equipped with an intermediate heat exchanger 24 and a flow control valve 26. The intermediate heat exchanger 24 cools the hot water by exchanging heat with the radiating water and is installed in series between the steam generator 14 and the evaporator 20. That is, it cools the hot water W31, which is relatively hot upstream, to a relatively low temperature W32 downstream of the hot water W3 between the steam generator 14 and the evaporator 20.

[0023] The radiant water that exchanges heat with the hot water in the intermediate heat exchanger 24 is branched at branching section B2 and further supplied via flow control valve 26. The radiant water that has exchanged heat with the hot water in the intermediate heat exchanger 24 merges with the radiant water discharged from the condenser 18 at confluence section J and is led out of the system. The flow control valve 26 adjusts the amount of radiant water flowing, thereby adjusting the capacity of the intermediate heat exchanger 24 to cool the hot water. Since the radiant water used in the intermediate heat exchanger 24 is supplied by branching from branching section B2, there is no need to prepare a separate dedicated cooling source.

[0024] As can be seen from Figure 2, the hot water W1 is cooled in the order of steam generator 14, intermediate heat exchanger 24, and evaporator 20. The steam generator 14 is located at the upstream end because a sufficient amount of heat is needed in addition to the input high-pressure refrigerant in order to output the refrigerant as a high-temperature, high-pressure gas drive to the ejector 16. The evaporator 20 is located at the downstream end because, in order to effectively utilize its heat exchange capacity and sufficiently cool the hot water before outputting it, it is necessary to exchange heat with the refrigerant, which has become cold in the expansion valve 22. Therefore, it is preferable to install the intermediate heat exchanger 24, which further cools the hot water, in series between the steam generator 14 and the evaporator 20.

[0025] Furthermore, in the ejector-type cooling system 10A, in order to further lower the temperature of the output hot water W2, it is conceivable to increase the rotational speed of the refrigerant pump 12 and increase the amount of refrigerant supplied to the steam generator 14. However, since the steam generator 14 has the function of supplying a drive flow to the ejector 16 in addition to cooling the supplied hot water W1, there is a limit to the amount of refrigerant that can be sufficiently gasified as a drive flow. For this reason, even if there is surplus capacity in the condenser 18 to dissipate the heat from the refrigerant, the amount of refrigerant supplied to the steam generator 14 cannot be increased beyond a predetermined level, and it is desirable to provide an intermediate heat exchanger 24 as an alternative cooling means.

[0026] The drive pressure sensor 41 is located between the steam generator 14 and the ejector 16. This drive pressure sensor 41 detects the drive pressure P1, which is the pressure of the drive flow. The drive temperature sensor 42 is located between the steam generator 14 and the ejector 16, similar to the drive pressure sensor 41. This drive temperature sensor 42 detects the drive temperature T1, which is the temperature of the drive flow. The hot water input temperature sensor 43 is located in the flow path L1 connected to the hot water inlet side of the steam generator 14. This hot water input temperature sensor 43 detects the temperature T2 of the hot water W1 supplied to the steam generator 14 (hot water input temperature).

[0027] The control unit 50A acquires detection values ​​from the drive pressure sensor 41, drive temperature sensor 42, and hot water input temperature sensor 43, and controls the refrigerant pump 12 and other components based on these detection values. In particular, the control unit 50A has a feedback control processing unit 51 and a feedforward control processing unit 52, and controls the drive of the refrigerant pump 12 based on the drive pressure P1, drive temperature T1, and hot water input temperature T2 to control the superheating degree of the drive flow.

[0028] In other words, the control unit 50A performs feedback control through the feedback control processing unit 51 and feedforward control through the feedforward control processing unit 52. The degree of superheating is the degree of temperature rise when the gas temperature is higher than the saturation temperature of the gas under a certain pressure.

[0029] Furthermore, the control unit 50A may be implemented by, for example, causing a processing unit such as a CPU (Central Processing Unit) to execute a program, i.e., by software; by, by, hardware such as an IC (Integrated Circuit); or by, by, a combination of software and hardware.

[0030] Figure 3 is a flowchart showing the superheating control process procedure by the control unit 50A shown in Figure 2. As shown in Figure 3, the control unit 50A first measures the drive pressure P1 (step S101). Then, the control unit 50A calculates the drive saturation temperature Ts based on the drive pressure P1 (step S102). After that, the control unit 50A performs parallel processing of feedback control by the feedback control processing unit 51 and feedforward control by the feedforward control processing unit 52.

[0031] In feedback control, the drive temperature T1 is measured (step S103), and the drive superheat degree Ta is calculated by subtracting the drive temperature T1 from the drive saturation temperature Ts (step S104). Subsequently, the feedback control processing unit 51 determines whether the drive superheat degree Ta is less than a preset reference value TA (step S105). The reference value TA used in step S105 is a value used to determine whether the drive flow is in a gas phase state, and is set in advance.

[0032] If the drive superheat level Ta is less than the reference value TA (step S105: Yes), the feedback drive processing unit performs feedback control to reduce the rotational speed of the refrigerant pump 12 (step S106) and terminates this process. On the other hand, if the drive superheat level Ta is equal to or greater than the reference value TA (step S105: No), the rotational speed of the refrigerant pump 12 is maintained and this process terminates as is.

[0033] In feedforward control, first, the hot water input temperature T2 is measured (step S107). Then, the feedforward control processing unit 52 calculates the estimated hot water input temperature Tb based on the time change of the hot water input temperature T2 measured in step S107 (step S108).

[0034] The feedforward control processing unit 52, having calculated the estimated hot water input temperature Tb in this manner, determines whether the subtracted value (Tb-Ts), obtained by subtracting the drive saturation temperature Ts from the estimated hot water input temperature Tb, is less than a preset value TB (step S109). The preset value TB used in step S109 is a value used to determine whether the drive flow is in a gas phase state, and is set in advance.

[0035] If the subtraction value is less than the set value TB (step S109: Yes), feedforward control is performed to reduce the rotation speed of the refrigerant pump 12 (step S110), and this process is terminated. On the other hand, if the subtraction value is equal to or greater than the set value TB (step S109: No), the rotation speed of the refrigerant pump 12 is maintained, and this process is terminated as is. The above process is repeated at predetermined intervals.

[0036] As described above, according to the ejector-type cooling device 10A, which is Embodiment 1 of the present invention, the control unit 50A calculates the drive saturation temperature Ts based on the drive pressure P1, and when the drive superheat degree Ta, which is the difference between the drive temperature T1 and the drive saturation temperature Ts, falls below a preset reference value TA, it performs feedback control to reduce the rotation speed of the refrigerant pump 12, thereby ensuring a stable superheat degree of the drive flow.

[0037] According to the ejector-type cooling device 10A described above, in parallel with the feedback control, the control unit 50A calculates an estimated hot water input temperature Tb based on the time change of the hot water input temperature T2 detected by the hot water input temperature sensor 43. If the subtracted value obtained by subtracting the drive saturation temperature Ts from the estimated hot water input temperature Tb is less than a preset value TB, the rotation speed of the refrigerant pump 12 is reduced. On the other hand, if the subtracted value is equal to or greater than the set value TB, feedforward control is performed to maintain the rotation speed of the refrigerant pump 12. As a result, the rotation speed of the refrigerant pump 12 can be reduced in accordance with the decrease in the hot water input temperature T2, and the degree of superheating of the drive flow can be stably ensured.

[0038] <Embodiment 2> Figure 4 is a circuit diagram showing the configuration of an ejector-type cooling device according to Embodiment 2 of the present invention. Note that components identical to those in the ejector-type cooling device 10A of Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

[0039] The ejector-type cooling system 10B illustrated here comprises a refrigerant pump 12, a steam generator 14, an ejector 16, a condenser 18, an evaporator 20, an expansion valve 22, a drive pressure sensor 41, a drive temperature sensor 42, on / off control valves 44 and 45, and a control unit 50B.

[0040] There are two on / off control valves 44 and 45, one on the refrigerant inlet side of the steam generator 14 and the other on the refrigerant outlet side of the steam generator 14. Specifically, on / off control valve 44 is, for example, a solenoid valve and is installed between the discharge port of the refrigerant pump 12 and the refrigerant inlet of the steam generator 14. On / off control valve 45 is, for example, a solenoid valve and is installed between the drive pressure sensor 41 and the ejector 16.

[0041] The control unit 50B acquires detection values ​​from the drive pressure sensor 41 and the drive temperature sensor 42, and controls the refrigerant pump 12 and the on / off control valves 44 and 45 based on these detection values, and has a feedback control processing unit 51 and a drive processing unit 53. The feedback control processing unit 51 performs the feedback control described above. The drive processing unit 53 controls the opening and closing of the on / off control valves 44 and 45 and the driving of the refrigerant pump 12 based on the drive superheat Ta.

[0042] Furthermore, the control unit 50B may be implemented, for example, by causing a processing unit such as a CPU (Central Processing Unit) to execute a program, i.e., by software; by hardware such as an IC (Integrated Circuit); or by using a combination of software and hardware.

[0043] Figure 5 is a flowchart showing the control processing procedure by the control unit 50B shown in Figure 4. This control processing is performed in parallel with the feedback control performed by the feedback control processing unit 51. Since the feedback control is the process described in steps S101 to S106 above, its explanation is omitted here.

[0044] As shown in Figure 5, the drive processing unit 53 of the control unit 50B calculates the drive superheat degree Ta (step S202) when the drive pressure P1 and drive temperature T1 are measured by feedback control while the refrigerant pump 12 is in operation (step S201: Yes).

[0045] Subsequently, the drive processing unit 53 of the control unit 50B determines whether the drive superheat Ta is less than a preset first threshold TC (step S203). The first threshold TC used in step S203 is a value used to determine whether the drive flow is in a gas phase state, and is set in advance.

[0046] If the drive superheat level Ta is less than the first threshold TC (step S204: Yes), the drive processing unit 53 stops the refrigerant pump 12 and closes the on / off control valves 44 and 45 (step S204), and terminates this process. This restricts the flow of refrigerant to the ejector 16.

[0047] On the other hand, if the drive superheat Ta is equal to or greater than the first threshold TC (step S204: No), the drive processing unit 53 terminates this process while maintaining the drive of the refrigerant pump 12 and keeping the on / off control valves 44 and 45 open.

[0048] By the way, when the refrigerant pump 12 is stopped (step S201: No), the drive processing unit 53 of the control unit 50B calculates the drive superheat degree Ta (step S205) when the drive pressure P1 and drive temperature T1 are measured by feedback control.

[0049] Subsequently, the drive processing unit 53 of the control unit 50B determines whether the drive superheat Ta is equal to or greater than a preset second threshold TD (step S206). The second threshold TD used in step S206 is a value equal to or greater than the first threshold TC, and is a value used to determine whether or not the drive flow is in a gas phase state, and is set in advance.

[0050] If the drive superheat level Ta is greater than or equal to the second threshold TD (step S206: Yes), the drive processing unit 53 drives the refrigerant pump 12 and opens the on / off control valves 44 and 45 (step S207), and terminates this process. On the other hand, if the drive superheat level Ta is less than the second threshold TD (step S206: No), the drive processing unit 53 terminates this process while keeping the refrigerant pump 12 stopped and the on / off control valves 44 and 45 closed.

[0051] As described above, according to the ejector-type cooling device 10B, which is Embodiment 2 of the present invention, the control unit 50B calculates the drive saturation temperature Ts based on the drive pressure P1, and when the drive superheat degree Ta, which is the difference between the drive temperature T1 and the drive saturation temperature Ts, falls below a preset reference value TA, it performs feedback control to reduce the rotation speed of the refrigerant pump 12, thereby ensuring a stable superheat degree of the drive flow.

[0052] According to the ejector-type cooling device 10B described above, in parallel with the feedback control, the control unit 50B stops the refrigerant pump 12 and closes the on / off control valves 44 and 45 when the drive superheat Ta falls below a preset first threshold TC, while driving the refrigerant pump 12 and opening the on / off control valves 44 and 45 when the drive superheat Ta is equal to or greater than a second threshold TD. This prevents the supply of gas-liquid two-phase refrigerant as the drive flow to the ejector 16, and ensures a stable superheat of the drive flow.

[0053] <Embodiment 3> Figure 6 is a circuit diagram showing the configuration of an ejector-type cooling device according to Embodiment 3 of the present invention. Note that components identical to those in the ejector-type cooling device 10A of Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

[0054] The ejector-type cooling system 10C illustrated here comprises a refrigerant pump 12, a steam generator 14, an ejector 16, a condenser 18, an evaporator 20, an expansion valve 22, a drive pressure sensor 41, a drive temperature sensor 42, a hot water outlet temperature sensor 46, and a control unit 50C.

[0055] The hot water outlet temperature sensor 46 is installed on the hot water outlet side of the evaporator 20 and detects the temperature (hot water outlet temperature) T3 of the hot water W2 output from the evaporator 20.

[0056] The control unit 50C acquires detection values ​​from the drive pressure sensor 41, drive temperature sensor 42, and hot water outlet temperature sensor 46, and controls the refrigerant pump 12, flow control valve 26, and expansion valve 22 based on these detection values. It includes a feedback control processing unit 51, a flow control valve opening / closing processing unit 54, and an expansion valve opening degree adjustment processing unit 55. The feedback control processing unit 51 performs the feedback control described above. The flow control valve opening / closing processing unit 54 controls the opening and closing of the flow control valve 26, and the expansion valve opening degree adjustment processing unit 55 adjusts the opening degree of the expansion valve 22.

[0057] Furthermore, the control unit 50C may be implemented by, for example, causing a processing unit such as a CPU (Central Processing Unit) to execute a program, i.e., by software; by, by, hardware such as an IC (Integrated Circuit); or by, by, a combination of software and hardware.

[0058] Figure 7 is a flowchart showing the control processing procedure by the flow control valve opening / closing processing unit 54 of the control unit 50C shown in Figure 6, and Figure 8 is a flowchart showing the control processing procedure by the expansion valve opening degree adjustment processing unit 55 of the control unit 50C shown in Figure 6.

[0059] These control processes are performed in parallel with the feedback control carried out by the feedback control processing unit 51. Since the feedback control is the process described in steps S101 to S106 above, its explanation is omitted here.

[0060] As shown in Figure 7, the flow control valve opening / closing processing unit 54 of the control unit 50C measures the hot water outlet temperature T3 (step S301). Then, the flow control valve opening / closing processing unit 54 adds a predetermined value to the hot water outlet temperature T3 measured in step S301 to calculate the added temperature (step S302). The predetermined value used in step S302 is set in advance.

[0061] Having calculated the added temperature in this manner, the flow control valve opening / closing processing unit 54 controls the opening and closing of the flow control valve 26 so that the added temperature approaches the target intermediate hot water temperature, which is the target value on the hot water outlet side of the intermediate heat exchanger 24 (step S303), and then terminates this process.

[0062] As shown in Figure 8, the expansion valve opening adjustment processing unit 55 of the control unit 50C measures the hot water outlet temperature T3 (step S401). Then, the expansion valve opening adjustment processing unit 55 controls the opening of the expansion valve 22 so that the hot water outlet temperature T3 measured in step S401 approaches the target hot water outlet temperature, which is the target value on the hot water outlet side of the evaporator 20 (step S402), and terminates this process.

[0063] As described above, according to the ejector-type cooling device 10C, which is Embodiment 3 of the present invention, the control unit 50C calculates the drive saturation temperature Ts based on the drive pressure P1, and performs feedback control to reduce the rotation speed of the refrigerant pump 12 when the drive superheat degree Ta, which is the difference between the drive temperature T1 and the drive saturation temperature Ts, falls below a preset reference value TA, thereby ensuring a stable superheat degree of the drive flow.

[0064] According to the ejector-type cooling device 10C described above, in parallel with the feedback control, the control unit 50C controls the opening and closing of the flow rate adjustment valve 26 so that the added temperature, obtained by adding a predetermined value to the hot water outlet temperature T3 detected by the hot water outlet temperature sensor 46, approaches the target intermediate hot water temperature. At the same time, the opening degree of the expansion valve 22 is controlled so that the hot water outlet temperature T3 detected by the hot water outlet temperature sensor 46 approaches the target hot water outlet temperature. Therefore, even if the hot water input temperature changes rapidly, the hot water outlet temperature T3 can be stabilized.

[0065] Although preferred embodiments 1 to 3 of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made.

[0066] In the above-described embodiment 1, the control unit 50A included a feedback control processing unit 51 and a feedforward control processing unit 52. However, in the present invention, the control unit may perform only feedback control.

[0067] In embodiments 1 to 3 described above, the rotation of the refrigerant pump 12 was reduced in the feedback control, but in the present invention, the refrigerant pump may be stopped from driving.

[0068] In the first embodiment described above, the rotation of the refrigerant pump 12 was reduced in the feedforward control, but in the present invention, the refrigerant pump may be stopped from driving.

[0069] In this invention, the ejector-type cooling device is not limited to consumer or industrial applications. The present invention is not limited to embodiments 1 to 3 described above, and can be freely modified without departing from the spirit of the invention. [Explanation of Symbols]

[0070] 10A, 10B, 10C... Ejector-type cooling system, 12... Refrigerant pump, 14... Steam generator, 16... Ejector, 18... Condenser, 20... Evaporator, 22... Expansion valve, 24... Intermediate heat exchanger, 26... Flow control valve, 41... Drive pressure sensor, 42... Drive temperature sensor, 43... Hot water input temperature sensor, 44, 45... On / off control valve, 46... Hot water outlet temperature sensor, 50A, 50B, 50C... Control unit, 51... Feedback control unit, 52... Feedforward control unit, 53... Drive unit, 54... Flow control valve on / off unit, 55... Expansion valve opening degree adjustment unit.

Claims

1. A condenser that condenses a gaseous refrigerant by exchanging heat with a heat-dissipating water, A refrigerant pump that pressurizes and circulates the refrigerant condensed in the condenser, A steam generator to which the refrigerant discharged from the aforementioned refrigerant pump is supplied and which exchanges heat with hot water to evaporate it, Hot water is connected to the steam generator so as to flow in series downstream, and a refrigerant is supplied from a branch between the condenser and the refrigerant pump via an expansion valve to evaporate the hot water through heat exchange. An ejector is connected such that the refrigerant evaporated in the steam generator is supplied as a driving flow to the driving flow port, thereby drawing in the refrigerant supplied from the evaporator as a suction flow from the suction port, and supplying these refrigerants to the condenser from the discharge port, An intermediate heat exchanger is used to cool hot water by exchanging heat with the heat-dissipating water between the steam generator and the evaporator, which are connected in series. An ejector-type cooling device equipped with, A drive pressure sensor for detecting the drive pressure of the drive flow, A drive temperature sensor for detecting the drive temperature of the drive flow, A control unit calculates the drive saturation temperature based on the drive pressure, and performs feedback control to reduce or stop the rotation speed of the refrigerant pump when the drive superheating degree, which is the difference between the drive temperature and the drive saturation temperature, falls below a preset reference value. A hot water input temperature sensor for detecting the hot water input temperature of the hot water supplied to the steam generator, Equipped with, The ejector-type cooling system is characterized in that the control unit calculates an estimated hot water input temperature based on the time change of the hot water input temperature detected by the hot water input temperature sensor, and if the subtracted value obtained by subtracting the drive saturation temperature from the estimated hot water input temperature is less than a preset value, it reduces or stops the rotation speed of the refrigerant pump, while if the subtracted value is equal to or greater than the preset value, it performs feedforward control to maintain the rotation speed of the refrigerant pump.

2. A condenser that condenses a gaseous refrigerant by exchanging heat with a heat-dissipating water, A refrigerant pump that pressurizes and circulates the refrigerant condensed in the condenser, A steam generator to which the refrigerant discharged from the aforementioned refrigerant pump is supplied and which exchanges heat with hot water to evaporate it, Hot water is connected to the steam generator so as to flow in series downstream, and a refrigerant is supplied from a branch between the condenser and the refrigerant pump via an expansion valve to evaporate the hot water through heat exchange. An ejector is connected such that the refrigerant evaporated in the steam generator is supplied as a driving flow to the driving flow port, thereby drawing in the refrigerant supplied from the evaporator as a suction flow from the suction port, and supplying these refrigerants to the condenser from the discharge port, An intermediate heat exchanger is used to cool hot water by exchanging heat with the heat-dissipating water between the steam generator and the evaporator, which are connected in series. An ejector-type cooling device equipped with, A drive pressure sensor for detecting the drive pressure of the drive flow, A drive temperature sensor for detecting the drive temperature of the drive flow, A control unit calculates the drive saturation temperature based on the drive pressure, and performs feedback control to reduce or stop the rotation speed of the refrigerant pump when the drive superheating degree, which is the difference between the drive temperature and the drive saturation temperature, falls below a preset reference value. A flow control valve is provided on the heat dissipation water inlet side of the intermediate heat exchanger and adjusts the flow rate of the heat dissipation water, A hot water outlet temperature sensor is provided on the hot water outlet side of the evaporator and detects the hot water outlet temperature of the hot water. Equipped with, The ejector-type cooling system is characterized in that the control unit controls the opening and closing of the flow rate control valve so that the added temperature, obtained by adding a predetermined value to the hot water outlet temperature detected by the hot water outlet temperature sensor, approaches the target hot water intermediate temperature, which is a target value on the hot water outlet side of the intermediate heat exchanger, and controls the opening degree of the expansion valve so that the hot water outlet temperature detected by the hot water outlet temperature sensor approaches the target hot water outlet temperature, which is a target value on the hot water outlet side of the evaporator.

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