JP2022096545A - Cooling system - Google Patents

Abstract

To suppress deterioration of cooling capacity in a high-temperature environment.SOLUTION: A first circulation flow passage 11 in which a first refrigerant circulates includes a first steam generator 13, a first ejector 14, a first heat exchanger 30 and a first pump 16, and a first branch flow passage 12 branched from the first circulation flow passage 11 includes a first expander 17 and an evaporator 18. A second circulation flow passage 21 in which a second refrigerant circulates includes a second steam generator 23, a second ejector 24, a second heat exchanger 25 and a second pump 26, and a second branch flow passage 22 branched from the second circulation flow passage 21 includes a second expander 27 and the first heat exchanger 30. The first heat exchanger 30 condenses the first refrigerant and evaporates the second refrigerant by exchanging heat between the first refrigerant discharged from the first ejector 14 and the second refrigerant decompressed by the first expander 17.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cooling system.

Conventionally, a cooling system using an ejector that mixes a suction flow generated by a drive flow with the drive flow and discharges the suction flow has been proposed. For example, Patent Document 1 discloses a refrigeration cycle including a low-stage ejector and a high-stage ejector. The discharge flow from the low-stage ejector is sucked by the drive flow of the high-stage ejector. The refrigerant discharged from the high-stage ejector is condensed by the condenser.

Japanese Unexamined Patent Publication No. 2011-94814

In the condenser that condenses the refrigerant, a cooling fluid such as cooling water or air is used. For example, in a high temperature environment such as in summer, the temperature of the cooling fluid rises, so that the temperature of the refrigerant in the condenser rises, and as a result, the pressure of the discharge flow of the ejector (hereinafter referred to as "back pressure") rises. There is. When the back pressure increases, the flow rate of the suction flow sucked by the ejector decreases, and there is a problem that the cooling capacity decreases. In consideration of the above circumstances, one aspect of the present invention is to suppress a decrease in cooling capacity in a high temperature environment.

In the cooling system according to one aspect of the present invention, the first steam generator that evaporates the first refrigerant by heat exchange with the heat source fluid and the first refrigerant evaporated by the first steam generator are used as the first drive flow. The first ejector introduced from the first inlet, mixed with the first suction flow introduced from the first suction port, and discharged from the first discharge port, and the first refrigerant discharged from the first ejector are referred to as the second refrigerant. A first heat exchanger that condenses by heat exchange between the two, and a first pump that sends the first refrigerant condensed by the first heat exchanger to the first steam generator are connected in a ring shape. A flow path that branches from the first branch point between the first circulation flow path and the first heat exchanger and the first pump in the first circulation flow path, and is from the first heat exchanger. The first refrigerant is passed through a first expander that decompresses the supplied first refrigerant and an evaporator that evaporates the first refrigerant decompressed by the first expander by heat exchange between the first expander and the medium to be cooled. A second steam generator that evaporates the second refrigerant by heat exchange between the first branch flow path that supplies the first suction port and the heat source fluid, and a second refrigerant that has been evaporated by the second steam generator. A second ejector introduced from the second inlet as a drive flow, mixed with the second suction flow introduced from the second suction port, and discharged from the second discharge port, and a second refrigerant discharged from the second ejector. A second heat exchanger that condenses by heat exchange with the cooling fluid and a second pump that sends the second refrigerant condensed by the second heat exchanger to the second steam generator in an annular shape. A second circulation flow path that is connected and a flow path that branches from the second branch point between the second heat exchanger and the second pump among the second circulation flow paths. The first heat exchanger that evaporates the second refrigerant decompressed by the second expander by heat exchange between the second expander that decompresses the second refrigerant supplied from the heat exchanger and the first refrigerant. It is provided with a second branch flow path for supplying the second refrigerant to the second suction port via the above.

In the above embodiment, the second refrigerant circulates in the above order through the second steam generator, the second ejector, the second heat exchanger, and the second pump, and reaches the second ejector via the second branch flow path. The first refrigerant in the first circulation flow path is cooled by heat exchange with the sucked second refrigerant. Further, the first refrigerant circulates in the above order through the first steam generator, the first ejector, the first heat exchanger, and the first pump, and is sucked into the first ejector through the first branch flow path. 1 The medium to be cooled is cooled by heat exchange with the refrigerant. There are two stages of cooling: an operation of cooling the first refrigerant using the second refrigerant and the second ejector, and an operation of cooling the cooled medium using the first refrigerant and the first ejector after cooling. It will be realized. Therefore, even in an environment where the cooling fluid has a high temperature, a sufficient flow rate of the first suction flow of the first ejector can be sufficiently secured, and as a result, a sufficient cooling capacity can be maintained.

In a preferred embodiment of the present invention, the first refrigerant and the second refrigerant are different types of refrigerants. For example, the saturation temperature of the first refrigerant is lower than the saturation temperature of the second refrigerant. In the above embodiment, since the first refrigerant and the second refrigerant are different types of refrigerant, the discharge efficiency of the first ejector and the second ejector is maintained at a high level in both high temperature and low temperature environments. Therefore, sufficient cooling capacity can be realized in both high temperature and low temperature environments.

In a preferred embodiment of the present invention, the heat source fluid obtained by evaporating the second refrigerant in the second steam generator is introduced into the first steam generator. According to the above aspect, since the heat source fluid is shared by the first steam generator and the second steam generator, a separate heat source fluid is supplied to the first steam generator and the second steam generator. Compared with, the increase in the scale of the cooling system can be suppressed.

It is a block diagram of the cooling system in an embodiment. It is a Ph diagram in a cooling system. It is a block diagram of the cooling system in inverse proportion. It is explanatory drawing of the 1st refrigerant and the 2nd refrigerant.

FIG. 1 is a block diagram of a cooling system 100 according to an embodiment of the present invention. The cooling system 100 is a system for cooling the medium to be cooled Q3. The cooling medium Q3 is a medium to be cooled by the cooling system 100, and is, for example, a fluid such as water, oil, or air. As illustrated in FIG. 1, the cooling system 100 of the present embodiment includes a first system 10, a second system 20, and a first heat exchanger 30.

The first system 10 includes a first circulation flow path 11, a first branch flow path 12, a first steam generator 13, a first ejector 14, a first pump 16, a first expander 17, and an evaporator 18. .. The first refrigerant circulates in the first circulation flow path 11 and the first branch flow path 12. The first steam generator 13, the first ejector 14, the first heat exchanger 30, and the first pump 16 are installed in the first circulation flow path 11 in the above order. That is, the first circulation flow path 11 is formed by connecting the first steam generator 13, the first ejector 14, the first heat exchanger 30, and the first pump 16 in a ring shape.

The second system 20 includes a second circulation flow path 21, a second branch flow path 22, a second steam generator 23, a second ejector 24, a second heat exchanger 25, a second pump 26, and a second expander 27. Equipped with. The second refrigerant circulates in the second circulation flow path 21 and the second branch flow path 22. The second steam generator 23, the second ejector 24, the second heat exchanger 25, and the second pump 26 are installed in the second circulation flow path 21 in the above order. That is, the second circulation flow path 21 is formed by connecting the second steam generator 23, the second ejector 24, the second heat exchanger 25, and the second pump 26 in an annular shape.

The first heat exchanger 30 is a first circulation flow path by heat exchange between the first refrigerant of the gas phase in the first circulation flow path 11 and the second refrigerant of the liquid phase in the second branch flow path 22. The first refrigerant in 11 is condensed and the second refrigerant in the second branch flow path 22 is evaporated. As can be understood from the above description, in the cooling system 100 of the present embodiment, the first system 10 and the second system 20 are connected to each other via the first heat exchanger 30. In other words, the first system 10 and the second system 20 share the first heat exchanger 30. The first heat exchanger 30 may be grasped as one element of the first system 10 and the second system 20.

The flow path of the first system 10 (first circulation flow path 11 and first branch flow path 12) and the flow path of the second system 20 (second circulation flow path 21 and second branch flow path 22) are mutually connected. It is a separate flow path that does not communicate. That is, the first refrigerant and the second refrigerant are not mixed. Therefore, the type of the first refrigerant and the type of the second refrigerant are individually selected. In the present embodiment, the first refrigerant used in the first system 10 and the second refrigerant used in the second system 20 are different types of refrigerants. That is, for example, the composition or characteristics of the first refrigerant and the second refrigerant are different. Specifically, the saturation temperature (condensation temperature or evaporation temperature) of the second refrigerant exceeds the saturation temperature (condensation temperature or evaporation temperature) of the first refrigerant. That is, the saturation pressure of the second refrigerant exceeds the saturation pressure of the first refrigerant.

The hot water flow path 91 in FIG. 1 is a flow path extending between the first system 10 and the second system 20. Hot water Q1 is supplied to the hot water flow path 91 as a heat source fluid. The hot water Q1 is, for example, waste water such as factory wastewater or used cooling water. The first system 10 is located on the downstream side of the second system 20 in the hot water flow path 91. The hot water flow path 91 may be individually installed for each of the first system 10 and the second system 20. Each of the first system 10 and the second system 20 will be described in detail below.

[First system 10]
First, a specific configuration of the first system 10 will be described. The first steam generator 13 of the first system 10 evaporates the first refrigerant by heat exchange between the hot water Q1 supplied to the hot water flow path 91 and the first refrigerant in the first circulation flow path 11. It is a vessel (collector).

The first ejector 14 includes a first inflow port 14a, a first suction port 14b, and a first discharge port 14c. The first refrigerant of the gas phase sent out from the first steam generator 13 is supplied to the first inflow port 14a as the first drive flow X1. The first ejector 14 sucks the first refrigerant in the first branch flow path 12 as the first suction flow Y1 from the first suction port 14b due to the decrease in static pressure generated by the first drive flow X1. The first drive flow X1 supplied to the first inflow port 14a and the first suction flow Y1 supplied to the first suction port 14b are mixed, and the first refrigerant in the gas phase after mixing is boosted by the diffuser. Is discharged from the first discharge port 14c. As described above, in the first ejector 14, the first refrigerant evaporated in the first steam generator 13 is introduced as the first drive flow X1 from the first inflow port 14a, and is introduced from the first suction port 14b. 1 Mix with suction flow Y1 and discharge from the first discharge port 14c.

The first heat exchanger 30 condenses the first refrigerant of the gas phase supplied from the first ejector 14. The first pump 16 is a liquid phase pump that sends out the first refrigerant of the liquid phase condensed by the first heat exchanger 30 to the first steam generator 13. The first refrigerant in the first circulation flow path 11 is boosted to the driving pressure of the first ejector 14 by the first pump 16.

The first branch flow path 12 is a flow path that branches from the first circulation flow path 11. That is, a part of the first refrigerant flowing through the first circulation flow path 11 is supplied to the first branch flow path 12. Specifically, the first branch flow path 12 is the first branch point N1 between the first heat exchanger 30 and the first pump 16 in the first circulation flow path 11, and the first of the first ejector 14. Connect to the suction port 14b. That is, the first branch flow path 12 is a flow path that supplies the first refrigerant that becomes the first suction flow Y1 to the first ejector 14. A first inflator 17 and an evaporator 18 are installed in the first branch flow path 12. The evaporator 18 is located between the first inflator 17 and the first suction port 14b of the first ejector 14.

A part of the first refrigerant condensed by the first heat exchanger 30 is supplied to the first expander 17. The first expander 17 expands by depressurizing the first refrigerant in the first branch flow path 12. Any type of decompression mechanism, such as an electronic expansion valve, a manual expansion valve, a constant pressure expansion valve, an orifice or a capillary, is used as the first inflator 17.

The evaporator 18 is a heat exchanger that evaporates the first refrigerant by heat exchange between the cooled medium Q3 supplied to the cooled flow path 93 and the liquid phase refrigerant decompressed by the first expander 17. Is. The first refrigerant in the gas phase generated by the evaporator 18 is sucked into the first suction port 14b of the first ejector 14 as the first suction flow Y1. The cooled medium Q3 is cooled by utilizing the latent heat of the first refrigerant whose pressure has dropped due to suction from the first ejector 14.

In the above configuration, the first refrigerant of the first system 10 is first in the order of the first steam generator 13 → the first ejector 14 → the first heat exchanger 30 → the first pump 16 → the first steam generator 13. It circulates in the circulation flow path 11. Then, the first refrigerant branched from the first circulation flow path 11 to the first branch flow path 12 is sucked into the first suction port 14b of the first ejector 14 via the first expander 17 and the evaporator 18. To. The cooled medium Q3 in the cooled flow path 93 is cooled by heat exchange with the first refrigerant in the evaporator 18. As can be understood from the above description, the first branch flow path 12 branches from the first branch point N1 between the first heat exchanger 30 and the first pump 16 in the first circulation flow path 11, and is the first. 1 This is a flow path for supplying the first refrigerant to the first suction port 14b via the expander 17 and the evaporator 18.

[Second system 20]
Next, a specific configuration of the second system 20 will be described. The second steam generator 23 of the second system 20 evaporates the second refrigerant by heat exchange between the hot water Q1 supplied to the hot water flow path 91 and the second refrigerant in the second circulation flow path 21. It is a vessel (collector). Hot water Q1 whose temperature has dropped due to heat exchange in the second steam generator 23 (that is, hot water Q1 obtained by evaporating the second refrigerant) is supplied to the first steam generator 13 of the first system 10. That is, the temperature of the hot water Q1 in the first steam generator 13 is lower than the temperature of the hot water Q1 in the second steam generator 23.

The second ejector 24 includes a second inflow port 24a, a second suction port 24b, and a second discharge port 24c. The second refrigerant of the gas phase sent out from the second steam generator 23 is supplied to the second inflow port 24a as the second drive flow X2. The second ejector 24 sucks the second refrigerant in the second branch flow path 22 as the second suction flow Y2 from the second suction port 24b due to the decrease in static pressure generated by the second drive flow X2. The second drive flow X2 supplied to the second inflow port 24a and the second suction flow Y2 supplied to the second suction port 24b are mixed, and the second refrigerant in the gas phase after mixing is boosted by the diffuser. Is discharged from the second discharge port 24c. As described above, the second ejector 24 introduces the second refrigerant evaporated in the second steam generator 23 as the second drive flow X2 from the second inflow port 24a, and is introduced from the second suction port 24b. 2 Mix with suction flow Y2 and discharge from the second discharge port 24c.

The second heat exchanger 25 condenses the second refrigerant of the gas phase discharged from the second ejector 24. Specifically, the second heat exchanger 25 exchanges heat between the second refrigerant supplied from the second ejector 24 and the cooling fluid Q2 supplied to the heat dissipation flow path 92 to exchange the second refrigerant. Condensate. The cooling fluid Q2 is, for example, low-temperature industrial water or cooling water supplied from a circulating cooling tower. The second refrigerant in the second circulation flow path 21 condenses by radiating heat to the cooling fluid Q2.

The second pump 26 is a liquid phase pump that sends out the second refrigerant of the liquid phase condensed by the second heat exchanger 25 to the second steam generator 23. The second refrigerant in the second circulation flow path 21 is boosted to the driving pressure of the second ejector 24 by the second pump 26.

The second branch flow path 22 is a flow path that branches from the second circulation flow path 21. That is, a part of the second refrigerant flowing in the second circulation flow path 21 is supplied to the second branch flow path 22. Specifically, the second branch flow path 22 is the second branch point N2 between the second heat exchanger 25 and the second pump 26 in the second circulation flow path 21, and the second of the second ejector 24. Connect to the suction port 24b. That is, the second branch flow path 22 is a flow path that supplies the second refrigerant that becomes the second suction flow Y2 to the second ejector 24. A second expander 27 and a first heat exchanger 30 are installed in the second branch flow path 22. The first heat exchanger 30 is located between the second expander 27 and the second suction port 24b of the second ejector 24.

A part of the second refrigerant condensed by the second heat exchanger 25 is supplied to the second expander 27. The second expander 27 expands by depressurizing the second refrigerant in the second branch flow path 22. Any type of decompression mechanism, such as an electronic expansion valve, a manual expansion valve, a constant pressure expansion valve, an orifice or a capillary, is used as the second expander 27.

The first refrigerant discharged from the first ejector 14 is supplied to the first heat exchanger 30 via the first circulation flow path 11, and the second refrigerant decompressed by the second expander 27 is second. It is supplied via the branch flow path 22. The first heat exchanger 30 exchanges heat between the first refrigerant of the gas phase discharged from the first ejector 14 and the second refrigerant of the liquid phase supplied from the second expander 27 to exchange the first refrigerant. Condensate and evaporate the second refrigerant. That is, the first heat exchanger 30 functions as a condenser that condenses the first refrigerant and an evaporator that evaporates the second refrigerant. The second refrigerant of the gas phase generated in the second branch flow path 22 by the first heat exchanger 30 is sucked into the second suction port 24b of the second ejector 24 as the second suction flow Y2. The first refrigerant in the first circulation flow path 11 is cooled by utilizing the latent heat of the second refrigerant whose pressure has dropped due to suction from the second ejector 24.

In the above configuration, the second refrigerant of the second system 20 is the second in the order of the second steam generator 23 → the second ejector 24 → the second heat exchanger 25 → the second pump 26 → the second steam generator 23. It circulates in the circulation flow path 21. Then, the second refrigerant branched from the second circulation flow path 21 to the second branch flow path 22 passes through the second expander 27 and the first heat exchanger 30, and is the second suction port 24b of the second ejector 24. Is sucked into. The first refrigerant in the first circulation flow path 11 is cooled by heat exchange with the second refrigerant in the first heat exchanger 30. As can be understood from the above description, the second branch flow path 22 branches from the second branch point N2 between the second heat exchanger 25 and the second pump 26 in the second circulation flow path 21, and is the second. 2 This is a flow path for supplying the second refrigerant to the second suction port 24b via the expander 27 and the first heat exchanger 30.

FIG. 2 is a Ph diagram with respect to the cooling system 100. The state of the first refrigerant in the first system 10 is shown by a solid line, and the state of the second refrigerant in the second system 20 is shown by a broken line.

Due to the heat exchange in the first steam generator 13, the state of the first refrigerant in the first circulation flow path 11 changes from the state a1 to the state b1. The state of the first refrigerant changes from the state b1 to the state c1 by the process in which the first ejector 14 mixes and discharges the first drive flow X1 and the first suction flow Y1. The pressure P in the state c1 corresponds to the back pressure of the first ejector 14. Due to heat exchange (condensation) in the first heat exchanger 30, the state of the first refrigerant in the first circulation flow path 11 changes from the state c1 to the state d1. Then, the portion of the first refrigerant in the first circulation flow path 11 supplied to the first pump 16 is boosted by the first pump 16, so that the state of the first refrigerant changes from the state d1 to the above-mentioned state. Transition to a1. On the other hand, the state of the first refrigerant supplied from the first circulation flow path 11 to the first branch flow path 12 changes from the state d1 to the state e1 due to the depressurization in the first expander 17. The state of the first refrigerant after depressurization changes from the state e1 to the state f1 by heat exchange in the evaporator 18. The first refrigerant of the gas phase sent out from the evaporator 18 is sucked into the first ejector 14 as the first suction flow Y1, so that the state of the first refrigerant changes from the state f1 to the above-mentioned state c1. The state c1 corresponds to the mixing of the first drive flow X1 and the first suction flow Y1 in the first ejector 14.

Due to the heat exchange in the second steam generator 23, the state of the second refrigerant in the second circulation flow path 21 changes from the state a2 to the state b2. The state of the second refrigerant changes from the state b2 to the state c2 by the process in which the second ejector 24 mixes and discharges the second drive flow X2 and the second suction flow Y2. The pressure P in the state c2 corresponds to the back pressure of the second ejector 24. Due to the condensation in the second heat exchanger 25, the state of the second refrigerant in the second circulation flow path 21 changes from the state c2 to the state d2. Then, the portion of the second refrigerant supplied to the second pump 26 in the second circulation flow path 21 is boosted by the second pump 26, so that the state of the second refrigerant changes from the state d2 to the above-mentioned state. Transition to a2. On the other hand, the state of the second refrigerant supplied from the second circulation flow path 21 to the second branch flow path 22 changes from the state d2 to the state e2 due to the depressurization in the second expander 27. The state of the second refrigerant after depressurization changes from the state e2 to the state f2 by heat exchange in the first heat exchanger 30. The second refrigerant of the gas phase sent out from the first heat exchanger 30 is sucked into the second ejector 24 as the second suction flow Y2, so that the state of the second refrigerant changes from the state f2 to the above-mentioned state c2. do. The state c2 corresponds to the mixing of the second drive flow X2 and the second suction flow Y2 in the second ejector 24.

FIG. 3 is a block diagram of a cooling system related to inverse proportion. The inverse proportion is a configuration in which the second system 20 in the first embodiment is omitted and the first heat exchanger 30 is replaced with the second heat exchanger 25. In inverse proportion, the first refrigerant in the first circulation flow path 11 is generated by heat exchange between the first refrigerant discharged from the first ejector 14 and the cooling fluid Q2 supplied to the heat dissipation flow path 92. It is condensed. In inverse proportion, only the first refrigerant is used.

For example, in a high temperature environment such as in summer, the temperature of the cooling fluid Q2 rises. When the temperature of the cooling fluid Q2 rises in inverse proportion, the condensation temperature of the first refrigerant rises, which may raise the pressure (that is, back pressure) of the discharge flow of the first ejector 14. When the back pressure of the first ejector 14 increases, the difference between the pressure of the first suction flow Y1 and the back pressure increases, so that the flow rate of the first suction flow Y1 sucked by the first ejector 14 (that is, the first branch flow). The flow rate of the first refrigerant flowing through the road 12) is reduced. Therefore, in inverse proportion, there is a problem that the ability to cool the medium to be cooled Q3 (hereinafter referred to as “cooling ability”) decreases in a high temperature environment.

If the pressure of the first drive flow X1 is increased, the flow rate of the first suction flow Y1 increases. However, since the pressure of the first drive flow X1 depends on the temperature difference between the hot water Q1 in the first steam generator 13 and the first refrigerant in the first circulation flow path 11, the pressure of the first drive flow X1 is sufficient. It is practically difficult to increase the pressure. Further, a method of suppressing a decrease in the temperature of the hot water Q1 by increasing the flow rate of the hot water Q1 and increasing the pressure of the first drive flow X1 by increasing the evaporation temperature of the first refrigerant is also envisioned. However, since the power required for the pump that supplies the hot water Q1 to the hot water flow path 91 increases, there is a problem that the scale of the entire device or the cost required for cooling increases.

In contrast to inverse proportion, in the first embodiment, the cooling system 100 is composed of a first system 10 and a second system 20. In the above configuration, the second refrigerant branched from the second circulation flow path 21 to the second branch flow path 22 passes through the second expander 27 and the first heat exchanger 30 and is the second of the second ejector 24. It is sucked into the suction port 24b. The first refrigerant in the first circulation flow path 11 is cooled by heat exchange by the first heat exchanger 30. Then, the first refrigerant cooled by the second system 20 branches from the first circulation flow path 11 to the first branch flow path 12, and passes through the first expander 17 and the evaporator 18 to the first ejector 14. It is sucked into the first suction port 14b of. The cooled medium Q3 in the cooled flow path 93 is cooled by heat exchange by the evaporator 18.

As described above, in the present embodiment, the cooled medium Q3 is cooled by heat exchange with the first refrigerant after cooling by the second system 20. That is, the operation of the second system 20 using the second refrigerant and using the first refrigerant, and the operation of the first system 10 using the first refrigerant cooled by the second system 20 to cool the cooled medium Q3. Two-stage cooling with operation is realized. By cooling the first refrigerant in the first circulation flow path 11, the back pressure of the first ejector 14 is maintained at a low pressure even in an environment where the cooling fluid Q2 becomes high temperature. That is, the difference between the pressure of the first suction flow Y1 and the back pressure in the first ejector 14 is reduced. Therefore, even in a high temperature environment, the flow rate of the first suction flow Y1 by the first ejector 14 is sufficiently secured, and as a result, a sufficient cooling capacity can be maintained.

FIG. 4 is a graph showing the relationship between the temperature T and the discharge efficiency E of the ejector for each of the first refrigerant and the second refrigerant. In the relative proportion in which only the first refrigerant is used, the discharge efficiency E of the first ejector 14 is maintained at a high numerical value E1 in an environment where the cooling fluid Q2 is a low temperature TL. However, in the relative proportion in which only the first refrigerant is used, the discharge efficiency E of the first ejector 14 drops to the numerical value E2 in an environment where the cooling fluid Q2 has a high temperature TH. Therefore, under inverse proportion, sufficient cooling capacity cannot be achieved in an environment where the cooling fluid Q2 has a high temperature TH.

In contrast to inverse proportion, different types of first and second refrigerants are used in this embodiment. Specifically, the saturation temperature of the second refrigerant exceeds the saturation temperature of the first refrigerant. For example, in a low temperature environment such as winter, since the first refrigerant is maintained at the low temperature TL in FIG. 4, the discharge efficiency E of the first ejector 14 is maintained at a high numerical value E1 as in the case of direct proportion. On the other hand, as can be understood from FIG. 4, the discharge efficiency E of the second ejector 24 is maintained at a high numerical value E3 even in an environment where the cooling fluid Q2 has a high temperature TH. That is, in a high temperature environment such as summer, the second ejector 24 operates with a high discharge efficiency E, so that the first refrigerant of the first system 10 is effectively cooled. As described above, in the present embodiment, since different types of the first refrigerant and the second refrigerant are used, the effect of suppressing the decrease in the cooling capacity in a high temperature environment is particularly remarkable. However, the first refrigerant and the second refrigerant may be the same type of refrigerant.

Note that FIG. 8 of Patent Document 1 discloses a cooling system including a low-stage ejector and a high-stage ejector. The discharge flow from the low-stage ejector is sucked into the high-stage ejector. In contrast to the configuration of Patent Document 1, in the first embodiment, the first system 10 including the first ejector 14 and the second system 20 including the second ejector 24 are via the first heat exchanger 30. Therefore, it is remarkably different from the configuration disclosed in Patent Document 1.

100 ... Cooling system, 10 ... 1st system, 11 ... 1st circulation flow path, 12 ... 1st branch flow path, 13 ... 1st steam generator, 14 ... 1st ejector, 14a ... 1st inlet, 14b ... 1st suction port, 14c ... 1st discharge port, 16 ... 1st pump, 17 ... 1st inflator, 18 ... evaporator, 20 ... 2nd system, 21 ... 2nd circulation flow path, 22 ... 2nd branch flow Road, 23 ... 2nd steam generator, 24 ... 2nd ejector, 24a ... 2nd inlet, 24b ... 2nd suction port, 24c ... 2nd discharge port, 25 ... 2nd heat exchanger, 26 ... 2nd pump , 27 ... second expander, 30 ... first heat exchanger, 91 ... hot water flow path, 92 ... heat dissipation flow path, 93 ... cooled flow path.

Claims (4)

The first steam generator that evaporates the first refrigerant by heat exchange with the heat source fluid, and the first refrigerant evaporated by the first steam generator are introduced as the first drive flow from the first inlet and from the first suction port. A first heat exchange that mixes with the introduced first suction flow and discharges from the first discharge port, and a first heat exchange that condenses the first refrigerant discharged from the first ejector by heat exchange with the second refrigerant. A first circulation flow path formed by connecting a device and a first pump that sends out a first refrigerant condensed by the first heat exchanger to the first steam generator in an annular shape.
A flow path that branches from the first branch point between the first heat exchanger and the first pump in the first circulation flow path, and the first refrigerant supplied from the first heat exchanger is used. The first refrigerant is sent to the first suction port via a first expander that reduces the pressure and an evaporator that evaporates the first refrigerant decompressed by the first expander by heat exchange between the first expander and the medium to be cooled. The first branch flow path to be supplied and
A second steam generator that evaporates the second refrigerant by heat exchange with the heat source fluid, and a second refrigerant evaporated by the second steam generator are introduced as a second drive flow from the second inlet and from the second suction port. A second heat exchange that mixes with the introduced second suction flow and discharges from the second discharge port, and a second heat exchange that condenses the second refrigerant discharged from the second ejector by heat exchange with the cooling fluid. A second circulation flow path formed by connecting the device and the second pump that sends the second fluid condensed by the second heat exchanger to the second steam generator in an annular shape.
Of the second circulation flow path, the flow path that branches from the second branch point between the second heat exchanger and the second pump, and the second refrigerant supplied from the second heat exchanger is used. The second refrigerant is passed through the second expander for depressurizing and the first heat exchanger for evaporating the second refrigerant decompressed by the second expander by heat exchange between the first refrigerant and the first refrigerant. 2 A cooling system including a second branch flow path for supplying to the suction port. The cooling system according to claim 1, wherein the first refrigerant and the second refrigerant are different types of refrigerants. The cooling system according to claim 2, wherein the saturation temperature of the first refrigerant is lower than the saturation temperature of the second refrigerant. The cooling system according to any one of claims 1 to 3, wherein the heat source fluid obtained by evaporating the second refrigerant in the second steam generator is introduced into the first steam generator.

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