JP7622541B2 - Cooling System - Google Patents

Description

This disclosure relates to a cooling system.

Patent document 1 discloses an invention of a cooling system that uses cold water to cool an object to be cooled. This cooling system includes individual temperature regulators that are provided in each of a plurality of mechanical equipment. Each individual temperature regulator includes a storage tank, a cooling water circulation pump, a temperature detector, and a heat exchanger. Cold water whose temperature has increased by cooling the object to be cooled is supplied to the heat exchanger. Hereinafter, cold water whose temperature has increased by cooling the object to be cooled may be referred to as hot water. A cooling fluid is supplied to the heat exchanger from a cooling device. In the heat exchanger, the hot water is cooled by heat exchange between the hot water and the cooling fluid. The hot water is cooled in the heat exchanger and returns to cold water. The cooling device includes a cooling tower and a chiller unit. When the outside air temperature is low, the cooling device cools the cooling fluid whose temperature has increased by heat exchange in the heat exchanger only by the cooling tower. When the outside air temperature is high, the cooling device cools the cooling fluid using the cooling tower and the chiller unit. The flow rate of the cooling fluid flowing into the heat exchanger is controlled by an inverter-controllable cooling fluid circulation pump.

JP 2009-192088 A

For example, when the object to be cooled is a mold of a molding machine, the temperature of the hot water after cooling the mold varies from about 40 to 60 degrees Celsius depending on the part of the mold that is being cooled. Conventionally, it was common to merge multiple hot waters of different temperature ranges and then cool them by heat exchange with the cooling fluid. However, the flow rate of hot water in the high-temperature system is often smaller than the flow rate of hot water in the low-temperature system. If the flow rate of hot water in the high-temperature system is smaller than the flow rate of hot water in the low-temperature system, the temperature of the hot water after merging will be lower than that of the hot water in the high-temperature system. If the same amount of heat is to be dissipated from the hot water in the heat exchanger under the condition that the temperature difference between the hot water and the cooling fluid is small, it is necessary to increase the flow rate of the cooling fluid supplied to the heat exchanger. Increasing the flow rate of the cooling fluid supplied to the heat exchanger increases the power consumption of the cooling fluid circulation pump. In addition, when the cooling tower alone cannot cool the cooling fluid to a sufficient temperature, a chiller unit is used in combination. When a chiller unit is used in combination, the power consumption of the cooling system increases further.

This disclosure has been made in consideration of the above circumstances, and aims to provide a cooling system that consumes less power than conventional systems.

A cooling system according to one aspect of the present disclosure includes an ejector refrigerator. The ejector refrigerator includes an ejector driven by a driving flow generated using heat of a first heat source fluid supplied from an object to be cooled. The ejector refrigerator cools a fluid to be cooled by utilizing suction of the ejector. The cooling system further includes a first heat exchanger for cooling a second heat source fluid supplied from the object to be cooled separately from the first heat source fluid by heat exchange with the first cooling fluid, a first pipe, and a second pipe. The first pipe connects the object to be cooled and a first inlet of the ejector refrigerator. The first heat source fluid flows through the first pipe. The second pipe connects the object to be cooled and a second inlet of the first heat exchanger. The second heat source fluid flows through the second pipe.

1 is a configuration diagram of a cooling system 1A according to a first embodiment. FIG. 11 is a configuration diagram of a cooling system 1B according to a second embodiment. FIG. 11 is a configuration diagram of a cooling system 1C according to a third embodiment. FIG. 11 is a configuration diagram of a cooling system 1D according to a modified example.

A: First embodiment FIG. 1 is a configuration diagram of a cooling system 1A according to a first embodiment of the cooling system of the present disclosure. The cooling system 1A cools an object 6 to be cooled using cold water C1. The object 6 to be cooled in this embodiment is, for example, a mold of a molding machine. In this embodiment, water is used as a cooling fluid for cooling the object 6 to be cooled, but the cooling fluid for cooling the object 6 to be cooled may be oil or air. The temperature of the cold water C1 in this embodiment is about 20 to 40°C. By cooling the object 6 to be cooled using the cold water C1, the temperature of the object 6 to be cooled decreases. On the other hand, by cooling the object 6 to be cooled, the temperature of the cold water C1 increases.

The temperature of the object 6 before cooling by the cold water C1 differs for each part of the object 6. For example, the cold water C1 used to cool the part 6a becomes the hot water Q1, and the cold water C1 used to cool the part 6b becomes the hot water Q2. That is, in this embodiment, the temperature of the hot water Q1 is different from the temperature of the hot water Q2. More specifically, the temperature of the hot water Q2 is lower than the temperature of the hot water Q1. For example, the temperature of the hot water Q2 is 40 to 50°C, and the temperature of the hot water Q1 is 60 to 70°C. That is, in this embodiment, the hot water Q2 is hot water of the low temperature system, and the hot water Q1 is hot water of the high temperature system. Note that the object 6 to be cooled may be a collection of multiple objects to be cooled, and hot water of different temperatures may be discharged from each of the multiple objects to be cooled. Also, the hot water discharged from the multiple objects to be cooled may be merged to generate each of the hot water Q1 and the hot water Q2.

The cooling system 1A cools the hot water Q1 and hot water Q2 supplied from the object to be cooled 6 using cooling water W1. In this embodiment, the temperature of the cooling water W1 is lower than 10 to 30°C. The temperature of the hot water Q1 and hot water Q2 is reduced by cooling using the cooling water W1. Therefore, the hot water Q1 and hot water Q2 return to the cold water C1. As shown in FIG. 1, the cooling system 1A has a cooling tower 2, a heat exchanger 3, a control device 5, a pump 10, a pump 11, a pump 12, an ejector refrigerator 13A, a temperature sensor 14, a temperature sensor 15, and a temperature sensor 16.

The cooling system 1A supplies cold water C1 to the object to be cooled 6 from the supply port 8. Warm water Q1 supplied from the object to be cooled 6 flows into the first inlet 7a of the cooling system 1A. Warm water Q2 supplied from the object to be cooled 6 flows into the second inlet 7b of the cooling system 1A. As shown in FIG. 1, the cooling system 1A has a first pipe L1 and a second pipe L2. The first pipe L1 extends from the first inlet 7a to the inlet 13a of the ejector refrigerator 13A. The second pipe L2 extends from the second inlet 7b to the inlet 3a of the heat exchanger 3. In other words, the warm water Q1 is supplied to the ejector refrigerator 13A. The warm water Q2 is supplied to the heat exchanger 3. In the cooling system 1A, the cooling water W1 is branched into the cooling water W2 and the cooling water W3 at the branch point N1. The cooling water W2 is supplied to the ejector refrigerator 13A. Cooling water W3 is supplied to heat exchanger 3.

In the cooling system 1A, the heat exchanger 3, the cooling tower 2, and the pump 10 are connected in a ring shape to form a circulation path for the cooling water W3. The pump 10 draws up the cooling water W3 and supplies it to the heat exchanger 3. The heat exchanger 3 cools the hot water Q2 flowing in from the inlet 3a by heat exchange with the cooling water W3. The temperature of the hot water Q2 drops as a result of being cooled by the heat exchanger 3. As a result, the hot water Q2 becomes cold water C3. The heat exchanger 3 discharges the cold water C3. The temperature sensor 14 measures the temperature of the cold water C3 discharged from the heat exchanger 3.

In addition, in the cooling system 1A, the ejector refrigerator 13A, the cooling tower 2, and the pump 11 are connected in a ring shape to form a circulation path for the cooling water W2. The pump 11 draws up the cooling water W2 and supplies it to the ejector refrigerator 13A. The ejector refrigerator 13A cools the hot water Q1 flowing in from the inlet 13a by heat exchange with the refrigerant Z2 flowing through the steam generator 24, and further cools it by heat exchange with the refrigerant Z3 flowing through the evaporator 26. The temperature of the hot water Q1 decreases as a result of being cooled by the ejector refrigerator 13A. Therefore, the hot water Q1 becomes cold water C2. The ejector refrigerator 13A discharges cold water C2. The temperature sensor 15 measures the temperature of the cold water C2 discharged from the ejector refrigerator 13A.

The cold water C2 discharged from the ejector refrigerator 13A and the cold water C3 discharged from the heat exchanger 3 join at the joining point N3 to become cold water C1. A tank for storing the cold water C2 discharged from the ejector refrigerator 13A and the cold water C3 discharged from the heat exchanger 3 may be provided at the joining point N3. The pump 12 supplies the cold water C1 from the supply port 8 to the object to be cooled 6. The temperature sensor 16 measures the temperature of the cold water C1 supplied to the object to be cooled 6.

The ejector refrigerator 13A discharges cooling water W2 whose temperature has increased in the process of cooling the hot water Q1. Similarly, the heat exchanger 3 discharges cooling water W3 whose temperature has increased by cooling the hot water Q2. The cooling water W2 discharged from the ejector refrigerator 13A and the cooling water W3 discharged from the heat exchanger 3 merge at the junction N4. The cooling water W2 and the cooling water W3 that merge at the junction N4 become cooling water W1 whose temperature has increased by being used to cool the hot water Q1 and the hot water Q2. The cooling water W1 whose temperature has increased flows into the cooling tower 2. The cooling tower 2 cools and discharges the cooling water W1 whose temperature has increased.

The ejector refrigerator 13A is configured as follows.
As shown in FIG. 1, the ejector refrigerator 13A includes an ejector 21, a condenser 22, a pump 23, a steam generator 24, an expansion valve 25, and an evaporator 26. The pump 23 is connected to an inlet 21a through which a driving flow is introduced into the ejector 21 via a steam generator 24. The expansion valve 25 is connected to a suction port 21b through which a suction flow is introduced into the ejector 21 via an evaporator 26. The ejector refrigerator 13A discharges a fluid in which the driving flow and the suction flow are mixed. The condenser 22 is connected to a discharge port 21c of the ejector 21. The ejector refrigerator 13A is a device that cools hot water Q1 using, for example, a liquid-phase refrigerant Z1. In this embodiment, the temperature at which the refrigerant Z1 changes from the liquid phase to the gas phase is lower than 60° C. Specific examples of the refrigerant Z1 include fluorocarbons such as hydrofluorocarbons and hydrofluoroolefins. In the ejector refrigerator 13A, the cooling water W2 is used to condense the refrigerant Z1 that has become gaseous by absorbing heat from the hot water Q1.

As shown in FIG. 1, refrigerant Z1 is divided into liquid-phase refrigerant Z2 and liquid-phase refrigerant Z3 at branch point N2 on the flow path from condenser 22 to pump 23. Pump 23 pressurizes refrigerant Z2 and sends it to steam generator 24. Steam generator 24 is a heat exchanger that evaporates refrigerant Z2 by heat exchange between hot water Q1 and refrigerant Z2 to generate gas-phase refrigerant A1. The temperature at which refrigerant Z2 changes from liquid to gas under pressure in steam generator 24 is lower than 60°C, and the temperature of hot water Q1 is 60 to 70°C, so that refrigerant Z2 can be evaporated by heat exchange between hot water Q1 and refrigerant Z2. Refrigerant A1 is introduced into inlet 21a of ejector 21. Refrigerant A1 introduced into inlet 21a becomes the driving flow in ejector 21. That is, in the ejector refrigerator 13A in this embodiment, the driving flow of the ejector 21 is generated by using the heat of the hot water Q1 to be cooled. The hot water Q1 that has undergone heat exchange in the steam generator 24 is supplied to the evaporator 26.

The expansion valve 25 is supplied with refrigerant Z3. The expansion valve 25 expands the supplied refrigerant Z3 by reducing its pressure. Any type of pressure reduction 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 expansion valve 25. The refrigerant Z3 is reduced in pressure by the expansion valve 25 and is sent to the evaporator 26 by the suction action caused by the static pressure reduction in the ejector 21 generated by the driving flow.

The evaporator 26 is a heat exchanger that evaporates the refrigerant Z3 by heat exchange between the hot water Q1 that has passed through the steam generator 24 and the refrigerant Z3 whose pressure has been reduced by the expansion valve 25, to generate gas-phase refrigerant A2. In other words, the evaporator 26 uses the latent heat of the refrigerant Z3, the pressure of which has been reduced by the suction action of the ejector 21, to cool the hot water Q1 that has passed through the steam generator 24. The hot water Q1 supplied to the evaporator 26 via the steam generator 24 is cooled in the evaporator 26 to become cold water C2.

The refrigerant A2 is introduced into the ejector 21 through the suction port 21b of the ejector 21. The refrigerant A2 introduced into the ejector 21 through the suction port 21b becomes the suction flow of the ejector 21. In the ejector 21, the suction flow and the driving flow are mixed. The fluid obtained by mixing the suction flow and the driving flow, i.e., the gas phase refrigerant A3, is pressurized by the diffuser and discharged from the discharge port 21c. The refrigerant A3 discharged from the ejector 21 is introduced into the condenser 22. The refrigerant A3 introduced into the condenser 22 is cooled by heat exchange with the cooling water W2. The refrigerant A3 cooled in the condenser 22 is condensed into the liquid phase refrigerant Z1.

The control device 5 is a computer such as a CPU (Central Processing Unit). The control device 5 controls the operation of the pumps 10, 11, and 12 by operating according to a program stored in a storage device (not shown). More specifically, the control device 5 controls the operation of the pumps 10, 11, and 12 so that cold water C1, whose temperature measured by the temperature sensor 16 is within a target temperature range (for example, a temperature range of T0±t), is supplied to the object to be cooled 6 at a constant flow rate. The target temperature range is the temperature range of the cold water C1 for keeping the temperature of the object to be cooled 6 constant. The target temperature range in this embodiment is 20 to 40°C.

The basic concept of the operation control of pumps 10, 11, and 12 using the control device 5 is as follows. In order to keep the flow rate of cold water C1 supplied to the cooling object 6 constant, the control device 5 controls pump 12 so that the rotation speed is constant. On the other hand, for pumps 10 and 11, the control device 5 controls the rotation speed of each according to the temperature measured by temperature sensor 14, the temperature measured by temperature sensor 15, and the temperature measured by temperature sensor 16. By controlling the rotation speed of pump 10, the flow rate of cooling water W3 flowing into heat exchanger 3 is controlled. Similarly, by controlling the rotation speed of pump 11, the flow rate of cooling water W2 flowing into ejector refrigerator 13A is controlled. The control device 5 controls the flow rate of cooling water W2 and the flow rate of cooling water W3 according to the temperature measured by temperature sensor 15 and the temperature measured by temperature sensor 14 so that the temperature measured by temperature sensor 16 is within the target temperature range. In this embodiment, controlling the flow rate of cooling water W2 and the flow rate of cooling water W3 means controlling the distribution when cooling water W1 is divided into cooling water W2 and cooling water W3.

The reason why the control device 5 controls the flow rates of the cooling water W2 and the cooling water W3 according to the temperatures measured by the temperature sensors 15 and 14 so that the temperature measured by the temperature sensor 16 falls within the target temperature range is as follows. If heat loss during mixing of the cold water C3 and the cold water C2 is ignored, the temperature T3 of the cold water C1 obtained by mixing the cold water C3 and the cold water C2 is expressed by the following formula (1). T1 in formula (1) is the temperature of the cold water C2 measured by the temperature sensor 15. T2 in formula (1) is the temperature of the cold water C3 measured by the temperature sensor 14. G1 in formula (1) is the flow rate of the cold water C2 discharged from the ejector refrigerator 13A. G2 in formula (1) is the flow rate of the cold water C3 discharged from the heat exchanger 3. In this embodiment, G1 and G2 are constants.
T3=(G1×T1+G2×T2)/(G1+G2)…(1)

Since G1 and G2 are constants, the temperature T3 of the cold water C1 is determined according to the temperature T1 of the cold water C2 and the temperature T2 of the cold water C3. The higher the cooling capacity of the heat exchanger 3, the lower the temperature T2 of the cold water C3. In other words, the temperature measured by the temperature sensor 14 represents the cooling capacity of the heat exchanger 3. The cooling capacity of the heat exchanger 3 is determined according to the flow rate of the cooling water W3 supplied to the heat exchanger 3. This is because the greater the flow rate of the cooling water W3 supplied to the heat exchanger 3, the greater the amount of heat that can be absorbed from the hot water Q2 through heat exchange with the cooling water W3. Similarly, the temperature measured by the temperature sensor 15 represents the cooling capacity of the ejector refrigerator 13A, and the cooling capacity of the ejector refrigerator 13A is determined according to the flow rate of the cooling water W2 supplied to the ejector refrigerator 13A. The greater the flow rate of the cooling water W2 supplied to the ejector refrigerator 13A, the lower the temperature of the refrigerant Z1 that condenses through heat exchange with the cooling water W2, and the greater the amount of heat that can be absorbed from the hot water Q1.

When the temperature measured by the temperature sensor 16 is higher than the target temperature range, the control device 5 increases the flow rate of the cooling water W2 and decreases the flow rate of the cooling water W3. This is because increasing the flow rate of the cooling water W2 can lower the temperature of the cold water C2, and lowering the temperature of the cold water C2 can lower the temperature of the cold water C1. In this embodiment, the control device 5 controls the flow rate of the cooling water W2 and the flow rate of the cooling water W3 so that the flow rate of the cooling water W3 supplied to the heat exchanger 3 is minimized. This minimizes the contribution of the heat exchanger 3 to the cooling of the cold water C1 whose temperature has increased by cooling the object to be cooled 6, and the cooling of the cold water C1 whose temperature has increased by cooling the object to be cooled 6 is performed by making maximum use of the cooling capacity of the ejector refrigerator 13A.

In the cooling system 1A of this embodiment, the driving flow of the ejector 21 is generated using the heat of the hot water Q1, so a compressor is not required to generate the driving flow. The ejector refrigerator 13A of this embodiment can cool the hot water Q1 with less power consumption than an ejector refrigerator that uses a compressor to generate the driving flow, since it does not use a compressor. In addition, in a cooling system that cools the hot water Q1 and the hot water Q2 using only a heat exchanger, all of the heat of the hot water Q1 and the hot water Q2 is wasted. In contrast, in the cooling system 1A of this embodiment, the heat of the hot water Q1 is used to cool the hot water Q1. Therefore, according to this embodiment, the power consumption required to cool the hot water Q1 and the hot water Q2 can be kept low compared to a mode in which the hot water Q1 and the hot water Q2 are cooled only by a heat exchanger. In addition, according to this embodiment, the power consumption required to cool the hot water Q1 can be kept low even compared to a mode in which an ejector refrigerator that generates a driving flow using a compressor and a heat exchanger are used in combination.

In the cooling system 1A, the driving flow of the ejector 21 is generated by utilizing the heat of the hot water Q1, so if the temperature of the hot water Q1 is too low, the driving pressure of the ejector 21 decreases. If the driving pressure of the ejector 21 decreases, the suction capacity of the ejector 21 decreases, and the cooling capacity of the ejector refrigerator 13A decreases. Suppose that hot water obtained by mixing hot water from the high-temperature system and hot water from the low-temperature system is provided to the cooling system 1A, and the provided hot water is diverted into hot water Q1 and hot water Q2 inside the cooling system 1A. In this case, if the flow rate of the hot water from the high-temperature system is less than the flow rate of the hot water from the low-temperature system, the temperature of the hot water obtained by mixing the hot water from the high-temperature system and the hot water from the low-temperature system will be significantly lower than the temperature of the hot water from the high-temperature system, and there is a risk that a sufficient cooling effect will not be obtained. In this embodiment, when the hot water of the high-temperature system and the hot water of the low-temperature system are discharged separately from the object to be cooled 6, only the hot water of the high-temperature system is used to drive the ejector refrigerator 13A, thereby preventing a decrease in cooling performance.

B: Second embodiment When it is necessary to cool warm water Q3 supplied from a heat source other than the object to be cooled 6 and discharge it into a river or the like, the present disclosure may be applied to a cooling system that cools warm water Q3 in addition to warm water Q1 and warm water Q2.

The cooling system 1B shown in FIG. 2 has an ejector refrigerator 13B instead of the ejector refrigerator 13A, and further has a temperature sensor 17. The ejector refrigerator 13B differs from the ejector refrigerator 13A in that hot water Q3 is supplied to the evaporator 26. In the cooling system 1B shown in FIG. 2, the hot water Q3 is cooled by heat exchange with the refrigerant Z3 in the evaporator 26. Therefore, in the ejector refrigerator 13B, the hot water Q3 becomes cold water C4. The ejector refrigerator 13B discharges cold water C4. The temperature sensor 17 is a sensor that measures the temperature of the cold water C4 discharged from the ejector refrigerator 13B. In the cooling system 1B, the hot water Q1 is also supplied to the steam generator 24 of the ejector refrigerator 13B, so that the hot water Q1 is cooled in the steam generator 24 and becomes cold water C2.

As in the first embodiment, the control device 5 in the cooling system 1B controls the pump 12 so that the rotation speed is constant. As in the first embodiment, the control device 5 in the cooling system 1B controls the rotation speed of the pump 10 and the rotation speed of the pump 11 in accordance with the temperature measured by the temperature sensor 15 and the temperature measured by the temperature sensor 14 so that the temperature measured by the temperature sensor 16 is within a target temperature range. The control device 5 may also control the flow rate of the hot water Q3 flowing into the ejector refrigerator 13B so that the temperature measured by the temperature sensor 17 is equal to or lower than a reference value set by a local government or the like.

In this embodiment, as in the first embodiment, a compressor is not used to generate the driving flow of the ejector 21. Therefore, according to this embodiment, the power consumption required to cool the hot water Q1, hot water Q2, and hot water Q3 can be kept low compared to an embodiment in which the hot water Q1, hot water Q2, and hot water Q3 are cooled only by a heat exchanger, and an embodiment in which an ejector refrigerator that generates a driving flow using a compressor and a heat exchanger are used in combination.

C: Third embodiment FIG. 3 is a diagram showing a configuration example of a cooling system 1C according to a third embodiment of the present disclosure. The cooling system 1C shown in FIG. 3 is the same as the cooling system 1B in that it has an ejector refrigerator 13B. The cooling system 1C of this embodiment is different from the cooling system 1B in that it does not receive a supply of hot water Q3, does not have a temperature sensor 17, hot water Q1 is supplied to a steam generator 24 of the ejector refrigerator 13B, and hot water Q2 cooled by a heat exchanger 3 is supplied to an evaporator 26 of the ejector refrigerator 13B. In the cooling system 1C, the hot water Q1 is cooled by generating a driving flow of the ejector 21 using the heat of the hot water Q1. Therefore, the hot water Q1 becomes cold water C2 in the ejector refrigerator 13B. In the cooling system 1C, the hot water Q2 is cooled by heat exchange with the cooling water W3 in the heat exchanger 3 and heat exchange with the refrigerant Z3 in the evaporator 26. As a result, the hot water Q2 becomes cold water C3 in the ejector refrigerator 13B.

In this embodiment, as in the first and second embodiments, a compressor is not used to generate the driving flow of the ejector 21. Therefore, this embodiment can also reduce the power consumption required to cool the hot water Q1 and the hot water Q2, compared to a configuration in which an ejector refrigerator that generates a driving flow using a compressor and a heat exchanger are used in combination. In addition, in the cooling system 1C of this embodiment, the heat of the hot water Q1 is used to cool the hot water Q2. Therefore, according to this embodiment, the power consumption required to cool the hot water Q1 and the hot water Q2 can be reduced, compared to a configuration in which the hot water Q1 and the hot water Q2 are cooled only by the heat exchanger. In this embodiment, the hot water Q2 that has been cooled by the heat exchanger 3 is provided to the evaporator 26, but the first pipe L1 and the evaporator 26 may be connected, and the hot water Q2 that has been cooled by the ejector refrigerator 13B may be provided to the heat exchanger 3.

D: Modifications Each of the embodiments described above may be modified as follows.
(1) Although the cooling system 1A has the heat exchanger 3, when the cooling load of the object to be cooled 6 falls below the cooling capacity of the ejector refrigerator 13A, that is, when the temperature of the object to be cooled 6 can be kept constant by the ejector refrigerator 13A alone, the cooling tower 2, the heat exchanger 3, the temperature sensor 14, and the pump 10 may be omitted. Similarly, in the cooling system 1B, the cooling tower 2, the heat exchanger 3, the temperature sensor 14, and the pump 10 may be omitted.

(2) In the cooling system 1A of the first embodiment, the temperature of the cold water C1 was controlled by controlling the flow rate of the cooling water W2 and the flow rate of the cooling water W3. As is clear from the formula (1), the temperature of the cold water C1 can also be controlled by controlling the flow rate of the cold water C2 and the flow rate of the cold water C3. The flow rate of the cold water C2 is equal to the flow rate of the hot water Q1, and the flow rate of the cold water C3 is equal to the flow rate of the hot water Q2. Therefore, a first valve for controlling the flow rate of the hot water Q1 may be provided in the first pipe L1, and a second valve for controlling the flow rate of the hot water Q2 may be provided in the second pipe L2, and the first valve and the second valve may be controlled by the control device 5. According to this aspect, the control device 5 can control the temperature of the cold water C1 by controlling the flow rate of the hot water Q1 and the flow rate of the hot water Q2 according to the temperatures measured by the temperature sensors 14, 15, and 16, respectively.

(3) It is possible to use an external heat source fluid other than hot water Q1 and hot water Q2, and the temperature of the hot water Q1 is lower than the temperature of the external heat source fluid, and the temperature of the hot water Q1 is not high enough to generate a driving flow. The temperature of the hot water Q1 is not high enough to generate a driving flow means that the temperature of the hot water Q1 is lower than the temperature at which the refrigerant Z2 changes from the liquid phase to the gas phase under pressure in the steam generator 24. An example of an external heat source fluid is hot water Q3. In this case, as in the cooling system 1D shown in FIG. 4, a heat exchanger 27 is provided to raise the temperature of the hot water Q1 by heat exchange with hot water Q3, which is higher in temperature than the hot water Q1, and the hot water Q1 heated by the heat exchanger 27 may be provided to the ejector refrigerator 13A.

(4) The cooling systems 1A to 1D cool the hot water Q1 and hot water Q2 used to cool manufacturing machinery such as the molds of a molding machine, but may also be used to cool hot water used to sterilize beverages such as milk, soft drinks, or alcoholic beverages.

E: Aspects Graspable from Each Embodiment and Modification The present disclosure is not limited to the above-mentioned embodiments and modifications, and can be realized in various aspects without departing from the spirit of the present disclosure. For example, the present disclosure can also be realized in the following aspects. The technical features in the above-mentioned embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined in order to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. In addition, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

A cooling system according to one aspect of the present disclosure has an ejector refrigerator. The ejector refrigerator includes an ejector 21 driven by a driving flow generated using heat from hot water Q1 supplied from an object to be cooled 6. This ejector refrigerator cools the fluid to be cooled by using the suction of the ejector 21. The hot water Q1 is an example of a first heat source fluid in the present disclosure. The cooling system further includes a heat exchanger 3 for cooling hot water Q2 supplied from an object to be cooled 6 separately from the hot water Q1 by heat exchange with cooling water W3, a first pipe L1, and a second pipe L2. The hot water Q2 is an example of a second heat source fluid in the present disclosure. The cooling water W3 is an example of a first cooling fluid in the present disclosure. The heat exchanger 3 is an example of a first heat exchanger in the present disclosure, and is provided outside the ejector refrigerator. The first pipe L1 connects the object to be cooled 6 and the inlet 13a of the ejector refrigerator. The inlet 13a is an example of a first inlet in this disclosure. Warm water Q1 flows through the first pipe L1. The second pipe L2 connects the object to be cooled 6 to the inlet 3a of the heat exchanger 3. The inlet 3a is an example of a second inlet in this disclosure. Warm water Q2 flows through the second pipe L2.

The ejector refrigerator 13A in the cooling system 1A uses the suction of the driving flow generated using the heat of the hot water Q1 to cool the hot water Q1 used to generate the driving flow, i.e., the hot water Q1 after heat exchange with the driving flow. In other words, the cooled fluid in the cooling system 1A is the hot water Q1 after heat exchange with the driving flow. The ejector refrigerator 13B in the cooling system 1B uses the suction of the driving flow generated using the heat of the hot water Q1 to cool the hot water Q3, which is an external fluid. In other words, the cooled fluid in the cooling system 1B is an external fluid. The ejector refrigerator 13B in the cooling system 1C uses the suction of the driving flow generated using the heat of the hot water Q1 to cool the hot water Q2 that has been cooled by the heat exchanger 3, i.e., the hot water Q2 after heat exchange with the cooling water W3. In other words, the cooled fluid in the cooling system 1C is the hot water Q2 after heat exchange with the cooling water W3. The cooling system 1C may be modified to cool the hot water Q2 using the ejector refrigerator 13B, and cool the hot water Q2 after cooling by the ejector refrigerator 13B using the heat exchanger 3. In other words, the fluid to be cooled may be the hot water Q2.

According to the cooling system 1A or 1C, the power consumption required to cool the hot water Q1 and the hot water Q2 can be kept low compared to a configuration in which the hot water Q1 and the hot water Q2 are all cooled by a heat exchanger, and a configuration in which the hot water Q1 and the hot water Q2 are cooled by using a heat exchanger in combination with an ejector refrigerator that generates a driving flow using a compressor. Also, according to the cooling system 1B, the power consumption required to cool the hot water Q1, the hot water Q2, and the hot water Q3 can be kept low compared to a configuration in which the hot water Q1, the hot water Q2, and the hot water Q3 are all cooled by a heat exchanger, and a configuration in which the hot water Q1, the hot water Q2, and the hot water Q3 are cooled by using a heat exchanger in combination with an ejector refrigerator that generates a driving flow using a compressor.

In another preferred embodiment of the cooling system, the temperature of the hot water Q2 may be lower than the temperature of the hot water Q1. According to this embodiment, it is possible to cool the hot water Q2 of the hot water Q1 and the hot water Q2 supplied separately from the object to be cooled 6 by the heat exchanger 3, and to cool the hot water Q1 by the ejector refrigerator 13A.

In another preferred embodiment of the cooling system, the ejector refrigerator includes a steam generator 24, an evaporator 26, and a condenser 22 in addition to the ejector 21. The steam generator 24 evaporates the refrigerant Z2 obtained by dividing the refrigerant Z1 into the refrigerant Z2 and the refrigerant Z3 by heat exchange with the hot water Q1. The refrigerant Z1 is an example of the first refrigerant in this disclosure. The refrigerant Z2 is an example of the second refrigerant in this disclosure. The refrigerant Z3 is an example of the third refrigerant in this disclosure. The evaporator 26 evaporates the refrigerant Z3 by heat exchange with the cooled fluid to generate a suction flow. The ejector 21 uses the refrigerant Z2 evaporated in the steam generator 24 as a driving flow, and discharges a fluid obtained by mixing the suction flow and the driving flow introduced from the suction port. The condenser 22 cools the fluid discharged from the ejector 21 by heat exchange with the cooling water W2 to condense it into the refrigerant Z1. The cooling water W2 is an example of the second cooling fluid in this disclosure. According to this embodiment, the heat of the hot water Q1 can be used to generate the driving flow of the ejector 21. In addition, in a more preferred embodiment of the cooling system, the cold water C1 obtained by joining the cold water C2 discharged from the steam generator 24 and the cold water C3 discharged from the heat exchanger 3 may be supplied to the object to be cooled 6. The cold water C2 is an example of a first heat source fluid that is cooled by the steam generator 24 and discharged from the steam generator 24. The cold water C3 is an example of a second heat source fluid that is cooled by the heat exchanger 3 and discharged from the heat exchanger 3.

In a further preferred embodiment of the cooling system, the temperature of the hot water Q1 is lower than the temperature of the hot water Q3, and the cooling system may include a heat exchanger 27 that raises the temperature of the hot water Q1 by heat exchange with the hot water Q3. The heat exchanger 27 is an example of a second heat exchanger in the present disclosure. The cooling system 1D is an example of a cooling system of this embodiment. According to this embodiment, the driving flow of the ejector 21 is generated using the hot water Q1 heated by the heat exchanger 27 as a heat source, so that even if the temperature of the hot water Q1 is not sufficiently high, it is possible to avoid a decrease in cooling performance caused by the temperature of the hot water Q1 not being sufficiently high.

A more preferred embodiment of the cooling system may include a temperature sensor 14, a temperature sensor 15, a temperature sensor 14, and a control device 5. The temperature sensor 15 measures the temperature of the hot water Q1 cooled by the ejector refrigerator, i.e., the cold water C2. The cold water C2 is an example of a third cooling fluid in this disclosure. The temperature sensor 15 is an example of a first temperature sensor in this disclosure. The temperature sensor 14 measures the temperature of the hot water Q2 cooled by the heat exchanger 3, i.e., the cold water C3. The cold water C3 is an example of a fourth cooling fluid in this disclosure. The temperature sensor 14 is an example of a second temperature sensor in this disclosure. The temperature sensor 16 measures the temperature of the cold water C1 obtained by mixing the cold water C2 and the cold water C3. The cold water C1 is an example of a fifth cooling fluid in this disclosure. The temperature sensor 16 is an example of a third temperature sensor in this disclosure.

The control device 5 controls the flow rates of the cooling water W2 and the cooling water W3 according to the temperature measured by the temperature sensor 15 and the temperature measured by the temperature sensor 14 so that the temperature measured by the temperature sensor 16 is within a predetermined temperature range. More specifically, the control device 5 controls the flow rates of the cooling water W2 and the cooling water W3 according to the temperature measured by the temperature sensor 15 and the temperature measured by the temperature sensor 14 so that the temperature measured by the temperature sensor 16 is within a predetermined temperature range and the flow rate of the cooling water W3 supplied to the heat exchanger 3 is minimized. According to this aspect, it is possible to maintain the temperature of the cooling water C1 within a predetermined temperature range while making maximum use of the cooling capacity of the ejector refrigerator.

1A, 1B, 1C, 1D...cooling system, 2...cooling tower, 3...heat exchanger, 5...control device, 10, 11, 12...pump, 13A, 13B...ejector refrigerator, 14, 15, 16, 17...temperature sensor.

Claims (5)

an ejector refrigerator to which a first heat source fluid is supplied from an object to be cooled ;
a pump for delivering a first cooling fluid;
a first heat exchanger that cools a second heat source fluid supplied from the object to be cooled separately from the first heat source fluid by heat exchange between the second heat source fluid and the first cooling fluid delivered from the pump ;
The ejector refrigerator comprises:
an ejector that ejects a fluid obtained by mixing a driving flow and a suction flow;
a condenser that condenses the fluid discharged by the ejector into a first refrigerant;
A pressure increasing unit that increases the pressure of a second refrigerant that is a part of the first refrigerant;
a vapor generator that evaporates the pressurized second refrigerant through heat exchange with the first heat source fluid to generate the driving flow;
a pressure reducing mechanism for expanding a third refrigerant which is another part of the first refrigerant;
an evaporator that generates the suction flow by evaporating the expanded third refrigerant through heat exchange with the second heat source fluid cooled by the first heat exchanger.
Cooling system. an ejector refrigerator that receives a first heat source fluid from an object to be cooled and cools a fluid to be cooled ;
a pump for delivering a first cooling fluid;
a first heat exchanger that cools a second heat source fluid supplied from the object to be cooled separately from the first heat source fluid by heat exchange between the second heat source fluid and the first cooling fluid delivered from the pump ;
The ejector refrigerator comprises:
an ejector that ejects a fluid obtained by mixing a driving flow and a suction flow;
a condenser that cools the fluid discharged by the ejector through heat exchange with a second cooling fluid to condense the first refrigerant;
A pressure increasing unit that increases the pressure of a second refrigerant that is a part of the first refrigerant;
a vapor generator that evaporates the pressurized second refrigerant through heat exchange with the first heat source fluid to generate the driving flow;
a pressure reducing mechanism for expanding a third refrigerant which is another part of the first refrigerant;
an evaporator that evaporates the expanded third refrigerant by heat exchange with the cooled fluid to generate the suction flow.
Cooling system. the first heat source fluid is at a lower temperature than the external heat source fluid;
a second heat exchanger that raises the temperature of the first heat source fluid by heat exchange with the external heat source fluid;
The first heat source fluid is supplied to the steam generator via the second heat exchanger.
The cooling system of claim 2 . a first temperature sensor that measures a temperature of a third cooling fluid that is the first heat source fluid cooled by the ejector refrigerator;
a second temperature sensor that measures a temperature of a fourth cooling fluid that is the second heat source fluid cooled by the first heat exchanger;
a third temperature sensor that measures a temperature of a fifth cooling fluid obtained by mixing the third cooling fluid and the fourth cooling fluid;
a control device that controls a flow rate of the first cooling fluid and a flow rate of the second cooling fluid in response to the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor so that the temperature measured by the third temperature sensor is within a predetermined temperature range;
The cooling system of claim 2 or claim 3 , comprising: The temperature of the second heat source fluid is lower than the temperature of the first heat source fluid .
The cooling system according to any one of claims 1 to 4 .

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