WO2018158827A1

WO2018158827A1 - Heat medium system

Info

Publication number: WO2018158827A1
Application number: PCT/JP2017/007821
Authority: WO
Inventors: 大樹広崎
Original assignee: 三菱電機株式会社
Priority date: 2017-02-28
Filing date: 2017-02-28
Publication date: 2018-09-07
Also published as: JP6645616B2; JPWO2018158827A1

Abstract

A heat medium system (1) is provided with: a first heat exchanger (5) for exchanging heat between a heat medium and a refrigerant compressed by a compressor (4); a second heat exchanger (6) for exchanging heat between the heat medium and the refrigerant prior to compression by the compressor (4); a first passage (7) through which passes the heat medium flowing from the second heat exchanger (6) to the first heat exchanger (5); a second passage (9) through which passes the heat medium flowing from a lower part (2c) of a heat storage tank (2) to a first inlet (8a) of a flow path switching valve (8); a third passage (10) through which passes the heat medium flowing from a middle part (2b) of the heat storage tank (2) to a second inlet (8b) of the flow path switching valve (8); a fourth passage (11) through which passes the heat medium flowing from an outlet (8c) of the flow path switching valve (8) to the second heat exchanger (6); and a control device (50) for controlling the operation of the flow path switching valve (8) during execution of a heat storing operation which causes the heat medium that has passed through the first heat exchanger (5) to flow into an upper part (2a) of the heat storage tank (2).

Description

Heat transfer system

The present invention relates to a heat medium system.

The system disclosed in FIG. 1 of Patent Document 1 below includes a heat exchanger (2) that applies heat from the refrigerant in the refrigerant circuit to the water in the water circuit, and a heat exchange that applies heat from the water in the water circuit to the refrigerant in the refrigerant circuit. And a vessel (5). In this system, when intermediate temperature water exists in the lower part of the hot water storage tank (7), the coefficient of performance (COP) can be improved by giving the heat of the intermediate temperature water to the refrigerant in the heat exchanger (5).

Japanese Unexamined Patent Publication No. 2007-155275

In the conventional system described above, heat cannot be effectively applied from the water to the refrigerant in the heat exchanger that applies heat from the water to the refrigerant unless intermediate temperature water exists in the lower part of the hot water storage tank. That is, unless medium temperature water is present in the lower part of the hot water storage tank, the COP improvement effect by the heat exchanger that gives heat from the water to the refrigerant cannot be obtained.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat medium system that can increase opportunities for improving the coefficient of performance (COP).

The heat medium system of the present invention includes a heat storage tank that stores the heat medium, a compressor that compresses the refrigerant, a refrigerant that is compressed by the compressor, and a first heat exchanger that exchanges heat with the heat medium. A second heat exchanger that exchanges heat between the refrigerant before being compressed by the compressor and the heat medium, and a first passage through which the heat medium flowing from the second heat exchanger to the first heat exchanger passes. , A flow path switching means having a first inlet, a second inlet, and an outlet, a second passage through which a heat medium flowing from the lower part of the heat storage tank to the first inlet of the flow path switching means, and a lower part of the heat storage tank From the third passage through which the heat medium flowing from the middle part to the second inlet of the flow path switching means passes, the fourth path through which the heat medium flowing from the outlet of the flow path switching means to the second heat exchanger passes, and from the first heat exchanger The fifth passage through which the heat medium that flows from the middle to the upper part of the heat storage tank passes, and the heat medium that has passed through the first heat exchanger above the heat storage tank. And control means for controlling the operation of the flow path switching unit during the execution of the thermal storage operation for flowing into those with a.

According to the present invention, since the heat medium can flow from the middle part of the heat storage tank to the second heat exchanger via the third passage, it is possible to increase the opportunities for improving the COP.

1 is a diagram illustrating a heat medium system according to Embodiment 1. FIG. 3 is a time chart illustrating an example of a heat storage operation according to the first embodiment. 3 is a flowchart showing a process during a heat storage operation according to the first embodiment. 6 is a flowchart showing a process during a heat storage operation according to the second embodiment. 10 is a flowchart showing a process during a heat storage operation according to the third embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings, common or corresponding elements are denoted by the same reference numerals, and redundant description is simplified or omitted. The present disclosure may include all combinations of configurations that can be combined among the configurations described in the following embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a heat medium system 1 according to the first embodiment. As shown in FIG. 1, the heat medium system 1 includes a heat storage tank 2 that stores a liquid heat medium. The heat medium in the present invention may be water. The heat medium in the present invention may be a liquid heat medium other than water, such as a calcium chloride aqueous solution, an ethylene glycol aqueous solution, or alcohol. In the heat storage tank 2, it is possible to form a temperature stratification in which the upper side is a high temperature and the lower side is a low temperature due to the difference in the density of the heat medium due to the temperature difference.

The heat storage tank 2 has an upper part 2a, a middle part 2b, and a lower part 2c. The upper part 2a is higher than the middle part 2b. The middle part 2b is higher than the lower part 2c. The portions corresponding to 1/3 of the capacity of the heat storage tank 2 may be regarded as the upper portion 2a, the middle portion 2b, and the lower portion 2c, respectively, and the upper portion 2a, the middle portion 2b, and the lower portion 2c are determined at different positions. Also good. In the present invention, when the heat storage tank includes a plurality of tanks connected in series, in the entire hierarchy from the highest tank to the lowest tank, the upper, middle, and lower parts of the heat storage tank You just have to decide.

In the present embodiment, a water supply pipe 3 is connected to the lower part 2c of the heat storage tank 2. The water supplied from the water source, that is, the low-temperature heat medium flows into the heat storage tank 2 through the water supply pipe 3, so that the heat storage tank 2 is maintained full.

The heat medium system 1 includes a compressor 4, a first heat exchanger 5, a second heat exchanger 6, a first passage 7, a flow path switching valve 8, a second passage 9, and a third passage 10. And a fourth passage 11, a fifth passage 12, and a control device 50.

Compressor 4 compresses the refrigerant. The refrigerant may be, for example, carbon dioxide, ammonia, propane, isobutane, chlorofluorocarbon such as HFC, HFO-1123, or HFO-1234yf. The first heat exchanger 5 exchanges heat between the refrigerant compressed by the compressor 4 and the heat medium. In the first heat exchanger 5, the heat of the high-temperature and high-pressure refrigerant is given to the heat medium.

The second heat exchanger 6 exchanges heat between the refrigerant before being compressed by the compressor 4 and the heat medium. In the second heat exchanger 6, the heat of the heat medium is given to the low-pressure refrigerant. The heat medium that has passed through the second heat exchanger 6 can flow to the first heat exchanger 5 through the first passage 7.

The flow path switching valve 8 has a first inlet 8a, a second inlet 8b, and an outlet 8c. The flow path switching valve 8 is an example of a flow path switching means. The second passage 9 connects between the lower part 2 c of the heat storage tank 2 and the first inlet 8 a of the flow path switching valve 8. The heat medium in the lower part 2 c of the heat storage tank 2 can flow to the first inlet 8 a of the flow path switching valve 8 through the second passage 9. The third passage 10 connects between the middle part 2 b of the heat storage tank 2 and the second inlet 8 b of the flow path switching valve 8. The heat medium in the middle part 2 b of the heat storage tank 2 can flow to the second inlet 8 b of the flow path switching valve 8 through the third passage 10.

The fourth passage 11 connects the outlet 8c of the flow path switching valve 8 and the second heat exchanger 6. The heat medium can flow from the outlet 8 c of the flow path switching valve 8 to the second heat exchanger 6 through the fourth passage 11. The fifth passage 12 connects between the first heat exchanger 5 and the upper part 2 a of the heat storage tank 2. The heat medium that has passed through the first heat exchanger 5 can flow to the upper portion 2 a of the heat storage tank 2 through the fifth passage 12.

The heat medium system 1 can execute a heat storage operation for storing heat in the heat storage tank 2. In the heat storage operation, the heat medium heated by the first heat exchanger 5 flows into the upper portion 2 a of the heat storage tank 2 through the fifth passage 12. The control device 50 controls the operation of the flow path switching valve 8 during execution of the heat storage operation.

In the present embodiment, the heat medium system 1 further includes a circulation pump 13, a decompression device 14, an evaporator 15, and a third heat exchanger 16. The circulation pump 13 circulates the heat medium. The circulation pump 13 is connected in the middle of the fourth passage 11. The decompression device 14 expands and decompresses the high-pressure refrigerant that has passed through the first heat exchanger 5. The decompression device 14 may be, for example, an expansion valve whose opening degree can be adjusted, or a capillary tube.

The evaporator 15 evaporates the low-pressure refrigerant on the downstream side of the decompression device 14. In the present embodiment, the evaporator 15 evaporates the refrigerant by causing the refrigerant to absorb the heat of the outside air. A fan motor 17 and a fan 18 are disposed adjacent to the evaporator 15. When the fan motor 17 rotates the fan 18, outside air is blown to the evaporator 15. Instead of such a configuration, the evaporator 15 may evaporate the refrigerant with the heat of other heat sources such as ground water, drainage, solar hot water, and geothermal heat.

The third heat exchanger 16 exchanges heat between the high-pressure refrigerant that has passed through the first heat exchanger 5 and the low-pressure refrigerant that has passed through the evaporator 15. In the third heat exchanger 16, the heat of the high-pressure refrigerant is given to the low-pressure refrigerant. The high-pressure refrigerant that has passed through the first heat exchanger 5 can flow to the decompression device 14 via the third heat exchanger 16. The low-pressure refrigerant that has passed through the evaporator 15 can flow to the second heat exchanger 6 via the third heat exchanger 16. The low-pressure refrigerant that has passed through the second heat exchanger 6 is sucked into the compressor 4.

In the present embodiment, the flow of the refrigerant and the heat medium in the first heat exchanger 5 is a counter flow. Moreover, the flow of the refrigerant and the heat medium in the second heat exchanger 6 is a counter flow. In the following description, the temperature of the heat medium flowing into the first heat exchanger 5 may be referred to as “inlet temperature”. The heat medium system 1 may include a temperature sensor 19 as a means for detecting the inlet temperature. In the illustrated example, a temperature sensor 19 is attached to the first passage 7.

In the following description, the temperature of the heat medium in the lower part 2c of the heat storage tank 2 may be referred to as “lower temperature”. The heat medium system 1 may include a temperature sensor 20 as means for detecting the lower temperature. In the illustrated example, the temperature sensor 20 is attached to the lower part 2 c of the heat storage tank 2. Instead of this, the temperature sensor 20 may be attached to the second passage 9.

In the following description, the temperature of the heat medium in the middle part 2b of the heat storage tank 2 may be referred to as “middle part temperature”. The heat medium system 1 may include a temperature sensor 21 as a means for detecting the middle temperature. In the illustrated example, a temperature sensor 21 is attached to the middle part 2 b of the heat storage tank 2. Instead of this, the temperature sensor 21 may be attached to the third passage 10.

The heat medium system 1 of the present embodiment can supply a heat medium from the heat storage tank 2 to the heat demand unit 60. The heat demand unit 60 may include at least one heater that warms the room with the heat of the heat medium. The heating appliance may be, for example, at least one of a floor heating panel installed under the floor, a radiator or panel heater installed on an indoor wall surface, and a fan convector. The heat demand unit 60 is not limited to heating, and may include, for example, a heat exchanger for keeping water in a bathtub or a swimming pool. Alternatively, the heat demand unit 60 may be a hot water supply heat exchanger that heats water by exchanging heat between water supplied from a water supply pipe (not shown) and a heat medium.

The sixth passage 61 connects the upper part 2a of the heat storage tank 2 and the heat demand section 60. The seventh passage 62 connects the lower part 2 c of the heat storage tank 2 and the heat demand unit 60. A circulation pump 63 is connected in the middle of the seventh passage 62. When the circulation pump 63 is operated, a high-temperature heat medium is supplied from the heat storage tank 2 to the heat demand unit 60 through the sixth passage 61. The heat medium that has passed through the heat demand section 60 flows into the lower portion 2 c of the heat storage tank 2 through the seventh passage 62.

In the present embodiment, a hot water supply pipe 22 is connected to the upper portion 2a of the heat storage tank 2. A hot-water tap 23 is connected downstream of the hot water supply pipe 22. The hot-water tap 23 may supply hot water to at least one of faucets such as a bathtub, a shower, and a kitchen. When the user opens the hot-water tap 23, hot water, which is a high-temperature heat medium in the heat storage tank 2, is supplied to the hot-water tap 23 through the hot-water pipe 22. At the same time as hot water flows out from the heat storage tank 2 to the hot water supply pipe 22, water, which is a low-temperature heat medium, flows into the heat storage tank 2 from the water supply pipe 3, whereby the heat storage tank 2 maintains a full state. A mixing valve (not shown) for adjusting the hot water supply temperature by mixing low temperature water supplied from a water source may be provided in the middle of the hot water supply pipe 22.

The control device 50 may control not only the flow path switching valve 8 but also at least one of the operation of the compressor 4, the circulation pump 13, the decompression device 14, the fan motor 17, and the circulation pump 63. Each function of the control device 50 may be realized by a processing circuit. The processing circuit of the control device 50 may include at least one processor and at least one memory. The at least one processor may realize each function of the control device 50 by reading and executing a program stored in at least one memory. The processing circuit of the control device 50 may include at least one dedicated hardware. The configuration is not limited to the configuration in which the operation is controlled by the single control device 50, and the configuration may be such that the operation is controlled by cooperation of a plurality of control devices.

The heat medium system 1 may include a temperature sensor 24 as means for detecting the temperature of the heat medium flowing out from the first heat exchanger 5. At the time of the heat storage operation, the control device 50 has at least one of the circulation pump 13, the compressor 4, the decompression device 14, and the fan motor 17 so that the temperature detected by the temperature sensor 24 is equal to the target temperature. One operation may be controlled.

When the circulation pump 63 is operated, an intermediate temperature heat medium that has been deprived of heat while passing through the heat demand section 60 flows into the heat storage tank 2 from the seventh passage 62. For this reason, when the circulation pump 63 is operated, an intermediate temperature heat medium layer may be formed in the middle part 2b and the lower part 2c of the heat storage tank 2. Further, when the hot-water tap 23 is opened and a low-temperature heat medium flows into the lower portion 2 c of the heat storage tank 2 from the water supply pipe 3, the medium-temperature heat medium layer can move up in the heat storage tank 2. For this reason, a medium-temperature heat medium may accumulate in the middle part 2b of the heat storage tank 2.

In the present embodiment, in the heat storage operation, the second heat exchanger 6 passes the medium temperature heat medium in the middle part 2b of the heat storage tank 2 through the third passage 10, the flow path switching valve 8, and the fourth passage 11. Can be allowed to flow into. In the second heat exchanger 6, the medium temperature heat medium heats the refrigerant, whereby the enthalpy of the refrigerant sucked into the compressor 4 can be increased. Thereby, a coefficient of performance (COP) can be improved. Further, the COP tends to increase as the inlet temperature to the first heat exchanger 5 decreases. If it is this Embodiment, since the entrance temperature to the 1st heat exchanger 5 will fall because a heat carrier is cooled with the 2nd heat exchanger 6, COP can be improved.

As described above, according to the present embodiment, not only when the medium temperature heat medium is present in the lower part 2c of the heat storage tank 2, but also when the medium temperature heat medium is present in the middle part 2b of the heat storage tank 2, The effect of COP improvement by the second heat exchanger 6 is obtained. For this reason, it becomes possible to increase the opportunity to improve COP.

In addition, according to the present embodiment, it is possible to reliably prevent the liquid refrigerant from flowing into the compressor 4 by the heat medium heating the refrigerant in the second heat exchanger 6. Therefore, liquid compression by the compressor 4 can be reliably prevented, so that the reliability of the compressor 4 in the heat medium system 1 can be improved.

In the heat storage operation of the present embodiment, the operation is as follows. When the central temperature detected by the temperature sensor 21 is equal to or lower than the reference temperature, the control device 50 switches the flow path switching valve 8 so that the first inlet 8a is closed and the second inlet 8b is opened. Thereby, the heat medium flowing out from the middle part 2 b of the heat storage tank 2 flows into the second heat exchanger 6 through the third passage 10, the flow path switching valve 8, and the fourth passage 11. In the following description, the reference temperature is set to 30 ° C. as an example. When the central temperature detected by the temperature sensor 21 is higher than the reference temperature of 30 ° C., the control device 50 switches the flow path switching valve 8 so that the first inlet 8a is opened and the second inlet 8b is closed. Thereby, the heat medium flowing out from the lower part 2 c of the heat storage tank 2 flows into the second heat exchanger 6 through the second passage 9, the flow path switching valve 8, and the fourth passage 11. According to said control, since it can prevent more reliably that the entrance temperature to the 1st heat exchanger 5 becomes high too much, the fall of COP can be prevented more reliably.

The second reference temperature is lower than the reference temperature described above. In the following description, the second reference temperature is set to 20 ° C. as an example. At the time of the heat storage operation of the present embodiment, the operation is as follows. When the central temperature detected by the temperature sensor 21 is equal to or higher than the second reference temperature of 20 ° C., the control device 50 controls the flow path switching valve 8 so that the first inlet 8a is closed and the second inlet 8b is opened. Switch. In this case, the heat medium flowing out from the middle part 2 b of the heat storage tank 2 flows into the second heat exchanger 6 through the third passage 10, the passage switching valve 8, and the fourth passage 11. When the central temperature detected by the temperature sensor 21 is lower than the second reference temperature of 20 ° C., the controller 50 controls the flow path switching valve 8 so that the first inlet 8a is opened and the second inlet 8b is closed. Switch. In this case, the heat medium flowing out from the lower portion 2 c of the heat storage tank 2 flows into the second heat exchanger 6 through the second passage 9, the flow path switching valve 8, and the fourth passage 11. According to said control, it can prevent more reliably that the heat medium of the lower part 2c of the thermal storage tank 2 retains over a long time.

FIG. 2 is a time chart showing an example of the heat storage operation according to the first embodiment. This time chart shows changes in the middle temperature, the lower temperature, and the state of the flow path switching valve 8. The heat storage operation starts at time t0 in FIG. At time t0, the medium temperature heat medium of 20 ° C. or more in the heat storage tank 2 exists above the position of the temperature sensor 21, and the middle temperature and the lower temperature are less than 20 ° C. For this reason, when the heat storage operation starts, the control device 50 opens the first inlet 8 a communicating with the second passage 9 and closes the second inlet 8 b communicating with the third passage 10. As a result, the heat medium flowing out from the lower part 2 c of the heat storage tank 2 is operated so as to pass through the second heat exchanger 6 and the first heat exchanger 5 and flow into the upper part 2 a of the heat storage tank 2. When the operation continues in this manner, the medium temperature heat medium of 20 ° C. or more in the heat storage tank 2 gradually moves downward. At time t1 in FIG. 2, the central temperature detected by the temperature sensor 21 reaches 20 ° C. Thereby, the control device 50 opens the second inlet 8 b communicating with the third passage 10 and closes the first inlet 8 a communicating with the second passage 9. As a result, from time t1, the heat medium flowing out from the middle part 2b of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and flows into the upper part 2a of the heat storage tank 2. Driven. Thereafter, at time t2 in FIG. 2, the central temperature detected by the temperature sensor 21 reaches 30 ° C. Thereby, the control device 50 opens the first inlet 8 a communicating with the second passage 9 and closes the second inlet 8 b communicating with the third passage 10. As a result, from time t2, the heat medium flowing out from the lower part 2c of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and flows into the upper part 2a of the heat storage tank 2. Driven.

FIG. 3 is a flowchart showing processing during the heat storage operation according to the first embodiment. The controller 50 periodically repeats the process of this flowchart in the heat storage operation. In step S 1 of FIG. 3, the control device 50 detects the middle temperature Ta by the temperature sensor 21. The process proceeds to step S2. If the middle temperature Ta is 30 ° C. or less of the reference temperature and the middle temperature Ta is 20 ° C. or more of the second reference temperature, the process proceeds from step S2 to step S3. In step S3, the control device 50 closes the first inlet 8a to block the second passage 9, and opens the second inlet 8b so that the third passage 10 is opened. Switch. On the other hand, if the intermediate temperature Ta is higher than the reference temperature 30 ° C. or the intermediate temperature Ta is lower than the second reference temperature 20 ° C. in step S2, the process proceeds from step S2 to step S4. In step S4, the control device 50 closes the second inlet 8b so as to block the third passage 10 and opens the first inlet 8a so that the second passage 9 is opened. Switch.

The control device 50 may control the operation of the flow path switching valve 8 so that the flow path switching valve 8 is gradually switched. By doing so, sudden changes in the temperature of the heat medium flowing into the fourth passage 11 from the flow path switching valve 8 can be reliably prevented, so that sudden changes in the temperature of the heat medium flowing out from the first heat exchanger 5 are ensured. Can be prevented.

In the first embodiment, the heat medium system 1 only needs to include at least a means for detecting the middle temperature, and may not include other temperature detection means.

Embodiment 2. FIG.
Next, the second embodiment will be described with reference to FIG. 4. The description will focus on the differences from the first embodiment described above, and the description of the same or corresponding parts will be simplified or omitted. The hardware configuration of the heat medium system 1 of the second embodiment is the same as or similar to that of the first embodiment shown in FIG. FIG. 4 is a flowchart showing the processing during the heat storage operation according to the second embodiment. In the second embodiment, the control device 50 periodically repeats the process of the flowchart of FIG. 4 during the heat storage operation.

In the second embodiment, the control device 50 controls the operation of the flow path switching valve 8 based on the lower temperature and the inlet temperature. In the second embodiment, at the beginning of the heat storage operation, the flow path switching valve 8 switches so as to open the second inlet 8 b communicating with the third passage 10 and close the first inlet 8 a communicating with the second passage 9. It has been. That is, at the beginning of the heat storage operation, the heat medium flowing out from the middle part 2 b of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and flows into the upper part 2 a of the heat storage tank 2. Drive to.

4, the control device 50 detects the lower temperature Tb by the temperature sensor 20. The process proceeds to step S 12, and the control device 50 detects the inlet temperature Tc by the temperature sensor 19. The process proceeds to step S13.

The “first temperature” is a temperature obtained by adding a predetermined positive value to the lower temperature Tb. In the following description, this “predetermined value” is set to 5 ° C. as an example. In step S13, the control device 50 compares the inlet temperature Tc with the first temperature (Tb + 5 ° C.). If the inlet temperature Tc is equal to or lower than the first temperature (Tb + 5 ° C.), the process proceeds from step S13 to step S14. In step S 14, the control device 50 operates the flow path switching valve 8 in a direction that increases the flow rate of the heat medium passing through the third passage 10. That is, the control device 50 switches the flow path so that the opening degree of the second inlet 8b communicating with the third passage 10 is slightly increased and the opening degree of the first inlet 8a communicating with the second passage 9 is slightly reduced. Actuate valve 8. Here, when the opening degree of the second inlet 8b is already fully opened and the opening degree of the first inlet 8a is already fully closed, the state is maintained.

On the other hand, if the inlet temperature Tc is higher than the first temperature (Tb + 5 ° C.) in step S13, the process proceeds to step S15. In step S 15, the control device 50 operates the flow path switching valve 8 in a direction to increase the flow rate of the heat medium passing through the second passage 9. That is, the control device 50 switches the flow path so that the opening degree of the first inlet 8a communicating with the second passage 9 is slightly increased and the opening degree of the second inlet 8b communicating with the third passage 10 is slightly reduced. Actuate valve 8. Here, when the opening degree of the first inlet 8a is already fully opened and the opening degree of the second inlet 8b is already fully closed, the state is maintained.

In the second embodiment, the heat storage operation is as follows. As described above, at the beginning of the heat storage operation, the heat medium flowing out from the middle part 2b of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and enters the upper part 2a of the heat storage tank 2. It is operated to flow in. Thereafter, since the temperature of the heat medium flowing out from the middle portion 2b of the heat storage tank 2 to the third passage 10 gradually increases, the inlet temperature Tc gradually increases. When the inlet temperature Tc becomes higher than the first temperature (Tb + 5 ° C.), the first inlet 8a of the flow path switching valve 8 starts to open by the process of step S15. Thereby, the heat medium flowing out from the middle part 2b of the heat storage tank 2 to the third passage 10 and the heat medium flowing out from the lower part 2c of the heat storage tank 2 to the second passage 9 are mixed and flow into the fourth passage 11. Drive to. When the inlet temperature Tc continues to be higher than the first temperature (Tb + 5 ° C.), the flow rate of the heat medium passing through the second passage 9 further increases and the flow rate of the heat medium passing through the third passage 10 decreases.

In the second embodiment, in addition to the effects similar to those of the first embodiment, the following effects can be obtained. Since the switching operation of the flow path switching valve 8 becomes gradual, a sudden change in the temperature of the heat medium flowing into the fourth passage 11 from the flow path switching valve 8 can be prevented more reliably. As a result, a sudden change in the temperature of the heat medium flowing out from the first heat exchanger 5 can be prevented more reliably.

Embodiment 3 FIG.
Next, the third embodiment will be described with reference to FIG. 5. The description will focus on the differences from the first embodiment described above, and the description of the same or corresponding parts will be simplified or omitted. The hardware configuration of the heat medium system 1 of the third embodiment is the same as or similar to that of the first embodiment shown in FIG. FIG. 5 is a flowchart showing the processing during the heat storage operation according to the third embodiment. In Embodiment 3, control device 50 periodically repeats the process of the flowchart of FIG. 5 during the heat storage operation.

In the third embodiment, the control device 50 controls the operation of the flow path switching valve 8 based on the lower temperature, the middle temperature, and the inlet temperature. In the third embodiment, at the beginning of the heat storage operation, the flow path switching valve 8 switches so as to open the second inlet 8 b communicating with the third passage 10 and close the first inlet 8 a communicating with the second passage 9. It has been. That is, at the beginning of the heat storage operation, the heat medium flowing out from the middle part 2 b of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and flows into the upper part 2 a of the heat storage tank 2. Drive to.

5, the control device 50 detects the middle temperature Ta by the temperature sensor 21. The process proceeds to step S22, and the control device 50 detects the lower temperature Tb by the temperature sensor 20. The process proceeds to step S23, and the control device 50 detects the inlet temperature Tc by the temperature sensor 19. The process proceeds to step S24.

The “first temperature” is a temperature obtained by adding a predetermined positive value to the lower temperature Tb. In the following description, this “predetermined value” is set to 5 ° C. as an example. The “first condition” is a condition that the inlet temperature Tc is equal to or lower than the first temperature (Tb + 5 ° C.). The “second condition” is a condition that the middle temperature Ta is equal to or lower than the reference temperature. In the following description, this reference temperature is set to 30 ° C. as an example.

In step S24, the control device 50 determines whether or not the “first condition” and the “second condition” are satisfied. When both the “first condition” and the “second condition” are satisfied, that is, when the inlet temperature Tc is not more than the first temperature (Tb + 5 ° C.) and the middle temperature Ta is not more than the reference temperature 30 ° C. The process proceeds from step S24 to step S25. In step S 25, the control device 50 operates the flow path switching valve 8 in a direction to increase the flow rate of the heat medium passing through the third passage 10. That is, the control device 50 switches the flow path so that the opening degree of the second inlet 8b communicating with the third passage 10 is slightly increased and the opening degree of the first inlet 8a communicating with the second passage 9 is slightly reduced. Actuate valve 8. Here, when the opening degree of the second inlet 8b is already fully opened and the opening degree of the first inlet 8a is already fully closed, the state is maintained.

On the other hand, if at least one of the “first condition” and “second condition” is not satisfied in step S24, that is, the inlet temperature Tc is higher than the first temperature (Tb + 5 ° C.), or the middle temperature Ta is the reference. If the temperature is higher than 30 ° C, the process proceeds to step S26. In step S 26, the control device 50 operates the flow path switching valve 8 in a direction to increase the flow rate of the heat medium passing through the second passage 9. That is, the control device 50 switches the flow path so that the opening degree of the first inlet 8a communicating with the second passage 9 is slightly increased and the opening degree of the second inlet 8b communicating with the third passage 10 is slightly reduced. Actuate valve 8. Here, when the opening degree of the first inlet 8a is already fully opened and the opening degree of the second inlet 8b is already fully closed, the state is maintained.

In the third embodiment, the heat storage operation is as follows. As described above, at the beginning of the heat storage operation, the heat medium flowing out from the middle part 2b of the heat storage tank 2 passes through the second heat exchanger 6 and the first heat exchanger 5 and enters the upper part 2a of the heat storage tank 2. It is operated to flow in. Thereafter, since the temperature of the heat medium flowing out from the middle portion 2b of the heat storage tank 2 to the third passage 10 gradually increases, the inlet temperature Tc gradually increases. When the inlet temperature Tc becomes higher than the first temperature (Tb + 5 ° C.), the first inlet 8a of the flow path switching valve 8 starts to open by the process of step S26. Thereby, the heat medium flowing out from the middle part 2b of the heat storage tank 2 to the third passage 10 and the heat medium flowing out from the lower part 2c of the heat storage tank 2 to the second passage 9 are mixed and flow into the fourth passage 11. Drive to. When the inlet temperature Tc continues to be higher than the first temperature (Tb + 5 ° C.), the flow rate of the heat medium passing through the second passage 9 further increases and the flow rate of the heat medium passing through the third passage 10 decreases. Further, when the middle temperature Ta becomes higher than the reference temperature of 30 ° C., the process of step S26 is repeatedly performed, so that the flow rate of the heat medium passing through the third passage 10 is reduced to zero.

In the third embodiment, in addition to the effects similar to the first embodiment, the following effects can be obtained. Since the switching operation of the flow path switching valve 8 becomes gradual, a sudden change in the temperature of the heat medium flowing into the fourth passage 11 from the flow path switching valve 8 can be prevented more reliably. As a result, a sudden change in the temperature of the heat medium flowing out from the first heat exchanger 5 can be prevented more reliably.

1 heat medium system, 2 heat storage tank, 4 compressor, 5 first heat exchanger, 6 second heat exchanger, 7 first passage, 8 flow path switching valve, 8a first inlet, 8b second inlet, 8c outlet , 9 2nd passage, 10 3rd passage, 11 4th passage, 12 5th passage, 13 circulation pump, 14 decompression device, 15 evaporator, 19, 20, 21, 24 temperature sensor, 23 hot water tap, 50 control device 60 heat demand department

Claims

A heat storage tank for storing a heat medium;
A compressor for compressing the refrigerant;
A first heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the heat medium;
A second heat exchanger that exchanges heat between the refrigerant before being compressed by the compressor and the heat medium;
A first passage through which the heat medium flowing from the second heat exchanger to the first heat exchanger passes;
Flow path switching means having a first inlet, a second inlet, and an outlet;
A second passage through which the heat medium flowing from the lower part of the heat storage tank to the first inlet of the flow path switching unit passes,
A third passage through which the heat medium flowing from the middle part above the lower part of the heat storage tank to the second inlet of the flow path switching unit passes;
A fourth passage through which the heat medium flowing from the outlet of the flow path switching unit to the second heat exchanger passes,
From the first heat exchanger, a fifth passage through which the heat medium flowing to the upper part above the middle part of the heat storage tank passes,
Control means for controlling the operation of the flow path switching means during execution of a heat storage operation in which the heat medium that has passed through the first heat exchanger flows into the upper portion of the heat storage tank;
A heat medium system comprising:
Means for detecting a middle temperature which is a temperature of the heat medium in the middle of the heat storage tank;
The control means switches the flow path switching means so that the first inlet is closed and the second inlet is opened when the middle temperature is equal to or lower than a reference temperature, and when the middle temperature is higher than the reference temperature. The heat medium system according to claim 1, wherein the flow path switching means is switched so that the first inlet is opened and the second inlet is closed.
The second reference temperature is a temperature lower than the reference temperature,
The control means switches the flow path switching means so that the first inlet is closed and the second inlet is opened when the intermediate temperature is equal to or higher than the second reference temperature, and the intermediate temperature is set to the second reference temperature. The heat medium system according to claim 2, wherein when the temperature is lower than the temperature, the flow path switching unit is switched so that the first inlet is opened and the second inlet is closed.
Means for detecting a lower temperature which is a temperature of the heat medium in the lower part of the heat storage tank;
Means for detecting an inlet temperature which is a temperature of the heat medium flowing into the first heat exchanger;
With
The heat medium system according to claim 1, wherein the control unit controls the operation of the flow path switching unit based on the lower temperature and the inlet temperature.
The first temperature is a temperature obtained by adding a predetermined value to the lower temperature,
When the inlet temperature is equal to or lower than the first temperature, the control means operates the flow path switching means so that the flow rate through the first inlet decreases and the flow rate through the second inlet increases. 5. When the inlet temperature is higher than the first temperature, the flow path switching means is operated so that the flow rate through the first inlet increases and the flow rate through the second inlet decreases. The heat carrier system described.
Means for detecting a lower temperature which is a temperature of the heat medium in the lower part of the heat storage tank;
Means for detecting a middle temperature which is a temperature of the heat medium in the middle of the heat storage tank;
Means for detecting an inlet temperature which is a temperature of the heat medium flowing into the first heat exchanger;
With
The heat medium system according to claim 1, wherein the control unit controls the operation of the flow path switching unit based on the lower temperature, the middle temperature, and the inlet temperature.
When both the first condition and the second condition are satisfied, the control means controls the flow path switching means so that the flow rate through the first inlet decreases and the flow rate through the second inlet increases. The flow path switching means is operated so that when at least one of the first condition and the second condition is not satisfied, the flow rate through the first inlet increases and the flow rate through the second inlet decreases. And
The first temperature is a temperature obtained by adding a predetermined value to the lower temperature,
The first condition is a condition that the inlet temperature is equal to or lower than the first temperature,
The heat medium system according to claim 6, wherein the second condition is a condition that the intermediate temperature is equal to or lower than a reference temperature.