JP2618057B2 - Two-stage compression cooling / heating hot water supply system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling / heating hot water supply stem using a two-stage compression refrigeration cycle.

2. Description of the Related Art Conventionally, a two-stage compression refrigeration cycle in which two compressors are connected in series to compress a refrigerant in two stages has been adopted for the purpose of improving compression efficiency under operating conditions where the compression ratio increases.

2 and 3 show a conventional two-stage compression refrigeration cycle, respectively, wherein 1 is a low-stage compressor, 2 is a high-stage compressor, 3 is a condenser, 4 is an evaporator, and 5 is Intercooler,
Reference numeral 6 denotes a first aperture device, and 7 denotes a second aperture device.

In the conventional example shown in FIG. 2, the refrigerant discharged from the low-stage compressor 1 and the refrigerant that has exited the first expansion device 6 through the condenser 3 perform heat exchange by direct contact in the intercooler 5. The liquid side is guided to the evaporator 4 via the second expansion device 7 and to the gas side to the suction side of the high-stage compressor 2. In the conventional example shown in FIG. 3, the refrigerant discharged from the low-stage compressor 1 and the refrigerant branched through the condenser 3 and passed through the first expansion device 6 are directly contacted by the intercooler 5. While performing heat exchange, the other refrigerant branched through the condenser 3 passes through the intercooler 5 and exchanges heat, and is guided to the evaporator 4 via the second expansion device 7. The refrigerant gasified by heat exchange in the intercooler 5 is guided to the suction side of the high-stage compressor 2.

When heating and cooling water is supplied using such a two-stage compression refrigeration cycle, the heat of the condenser 3 is used for heating or hot water supply, and the heat of the evaporator 4 is used for cooling.

As described above, by performing the intermediate cooling by employing the two-stage compression refrigeration cycle, it is possible to prevent an abnormal rise in the refrigerant gas temperature discharged from the high-stage compressor under the operating condition in which the compression ratio during the hot and cold water supply operation is increased. In addition, the power required for compressing the refrigerant can be saved.

Problems to be Solved by the Invention However, in a cycle like the above-mentioned conventional example, there is a problem that two compressors are constantly operated even in a cooling operation with a relatively small compression ratio. Since hot water supply and heating will be operated at the same time, a compressor with a large capacity to cover both heating and hot water supply loads is required, and it is not easy to use because the condensation temperature can not be changed between hot water supply and heating. there were.

Means for Solving the Problems The cooling / heating hot water supply system of the present invention comprises a cooling / heating circuit configured by connecting a low-stage compressor, a four-way valve, a use-side heat exchanger, a main throttle device, and a heat-source-side heat exchanger. A side compressor, a hot water supply heat exchanger, an intercooler, and an intermediate expansion device are connected to form a hot water supply circuit, which is connected to the cooling and heating circuit, and a discharge section of the low stage compressor of the cooling and heating circuit. A check valve is provided between the four-way valve and a control valve provided in a pipe branched from between the low-stage compressor and the check valve, and the high-stage compressor is provided through an intercooler in the hot water supply circuit. A check valve is provided in a pipe branched from between the suction pipe of the low-stage compressor and the four-way valve, and is connected to a pipe between the control valve and the intercooler. Branching from between the respective main throttle devices provided between the use side heat exchanger and the heat source side heat exchanger. Connected to the intermediate heat exchanger via a throttle device, a control valve is provided between the high-stage compressor and the hot-water supply heat exchanger on the hot water supply circuit side, and the control valve and the high-stage compressor are provided. A control valve is provided in a pipe branching from the lower stage and connected between a check valve provided on the discharge side of the low-stage compressor and a four-way valve, and hot water supply heat exchange is performed on the discharge side of the high-stage compressor. And an intercooler connected between the main throttle devices of the cooling and heating circuit.

By this operation, normal cooling and heating are performed in a single-stage compression operation by the low-stage compressor of the air-conditioning circuit, and when high-temperature air is required for heating, two-stage compression is performed by operation of the high-stage compressor. The discharged high-temperature and high-pressure refrigerant gas flows through the four-way valve to the use-side heat exchanger, thereby increasing the blow-out temperature. For a large heating load, the low-stage and high-stage compressors are operated in parallel (one-stage compression), and the discharged refrigerant gas is joined before the four-way valve and flows together to the use-side heat exchanger, and the refrigerant circulation amount is increased. High capacity operation due to increase in As for the refrigerant, for a large load as in the case of heating, the low-stage and high-stage compressors are operated in parallel (one-stage compression) to combine the discharged refrigerant gas before the four-way valve to increase the refrigerant circulation amount. High capacity operation is achieved by condensing in the heat source side heat exchanger and evaporating in the use side heat exchanger.

During the hot water supply / room heating operation, heating is performed in a cooling / heating circuit by one-stage compression using a low-stage compressor, and the hot-water supply operation is also performed by the high-stage compressor in one-stage compression. Therefore, unlike the conventional case, there is no need for a compression function to cover both loads of heating and hot water supply, and the loads can be independently handled. Furthermore, when high-temperature hot water supply requires high-temperature air heating, high-temperature, high-pressure gas discharged from the high-stage compressor is supplied to the heat exchanger for hot water supply by the control valve and to the use-side heat exchanger through the four-way valve of the cooling and heating circuit. High temperature can be realized by hot water supply and heating by flowing.

During the cooling hot water supply operation, the waste heat of the use side heat exchanger is used, but the liquid refrigerant that has been heated and condensed by the hot water supply heat exchanger using the high-stage compressor is evaporated by the use side heat exchanger. One-stage compression operation in which the four-way valve passes through the check valve and passes through the intercooler to the high-stage compressor, and the low-stage compressor also operates simultaneously (the high-stage compressor and the low-stage compressor The refrigerant gas discharged from each compressor is joined in front of the heat exchanger for hot water supply, the hot water is heated by the heat exchanger for hot water supply, and the condensed liquid refrigerant is evaporated by the heat exchanger on the utilization side to evaporate in all directions. Part of the refrigerant that has passed through the valve passes through the check valve and is sent to the intercooler, and the rest is sucked into the low-stage compressor. Two-stage parallel single-stage compression operation, and when high-temperature hot water supply is required, the low-stage compressor And two-stage compression operation by series operation of the high-stage compressor. When there is no cooling load, the hot water supply alone operation can be performed by switching the use side heat exchanger and the heat source side heat exchanger by switching the four-way valve.

As a result, a low-compression-ratio operation, a high-capacity operation, a high-compression-ratio operation corresponding to a high temperature, and an operation mode according to the load can be selected, and an energy-saving and easy-to-use two-stage compression cooling and heating water supply system can be provided.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a two-stage compression hot / cold hot water supply system according to one embodiment of the present invention, in which 10 is a low-stage compressor, 11 is a check valve, 12 is a four-way valve, 13 is a use side heat exchanger, Reference numerals 14 and 15 denote main expansion devices, and reference numeral 16 denotes a heat source side heat exchanger, and these are sequentially connected to form a cooling / heating circuit 17. Reference numeral 18 denotes a high-stage compressor, 19 denotes a control valve, 20 denotes a heat exchanger for hot water supply, 21 denotes a sub-throttle device, and 22 denotes an intermediate cooler.
A control valve 25 is provided in a pipe branched from the discharge side of the low-stage compressor 10, and is connected to the intercooler 22. Reference numeral 26 denotes a control valve provided in a pipe branched from the discharge side of the high-stage compressor 18, and is connected between the check valve 11 and the four-way valve 12. 27 is a check valve provided in a pipe branched from between the four-way valve 12 and the low-stage compressor 10, and 28 is provided in a pipe branched from between the main throttle devices 14 and 15. Control valve 25 and intercooler 22
To form a two-stage compression cooling / heating hot water supply system.

The operation in such a two-stage compression cooling / heating hot water supply system will be described.

First, normal cooling / heating operation is performed in the cooling / heating circuit 17. In the heating operation, the refrigerant gas discharged from the low-stage compressor 10 passes through the check valve 11 and is condensed and liquefied in the use side heat exchanger 13 from the four-way valve 12. apparatus
The pressure is reduced at 15, the gas is vaporized by the heat source side heat exchanger 16, and is again sucked into the low-stage compressor 10 from the four-way valve 12. In the cooling operation, the refrigerant circulation direction is reversed by switching the four-way valve 12, and the refrigerant is evaporated by the use side heat exchanger 13. In this heating / cooling operation, since the compression ratio is relatively low, one-stage compression operation is performed by the low-stage compressor 10, and at this time, the high-stage compressor 18, the control valves 19, 2
5, 26, the aperture device 28 is closed.

Next, when performing a high-temperature blowing operation that provides a comfortable feeling of heating in the heating operation, a two-stage compression operation corresponding to a high compression ratio is performed. That is, the intermediate-pressure refrigerant gas discharged from the low-stage compressor 10 is further sucked and compressed by the high-stage compressor 18 through the intermediate cooler 22 from the control valve 25, and the high-temperature and high-pressure refrigerant gas is controlled by the control valve. The air flows from the four-way valve 12 to the use-side heat exchanger 13 via 26, and exchanges heat with indoor air to achieve high-temperature blowing. The condensed and liquefied high-pressure refrigerant liquid passes through the main throttle device 14, is decompressed by the main throttle device 15, becomes low pressure, evaporates and gasifies in the heat source side heat exchanger 16, and is sucked into the low-stage compressor 10 again from the four-way valve 12. At this time, in order to prevent an abnormal rise in the discharge temperature of the high-stage compressor 18, the high-pressure liquid refrigerant before the main throttle device 15 is converted into intermediate-pressure refrigerant gas discharged from the low-stage compressor 10 via the throttle device 28. Inject. Thereby, even if the discharge gas at the intermediate pressure of the low-stage compressor 10 is cooled and further compressed by the high-stage compressor 18, an abnormal rise in the discharge temperature can be prevented. Thus, when high-temperature blowing is required in the heating operation, high-temperature blowing can be realized by the two-stage compression operation. At this time, the control valve
19 is closed, and the check valves 11, 27 prevent the intermediate pressure / low pressure and the high pressure / intermediate pressure from being mixed due to the high pressure on the outlet side.

Next, for a large heating load, the refrigerant gas discharged from the low-stage compressor 10 via the check valve 11 and the refrigerant gas discharged from the high-stage compressor 18 via the control valve 26 The refrigerant liquid which is merged in front of the four-way valve 12 and enters the use-side heat exchanger 13 via the four-way valve 12 passes through the main expansion device 14 and is depressurized by the main expansion device 15, and is decompressed by the heat source-side heat exchanger. At 16, it is vaporized and gasified again, passes through the four-way valve 12 again, and a part is sucked into the low-stage compressor 10, and a part is sucked from the intercooler 22 to the high-stage compressor 18 via a check valve 27. The high-stage compressor 18 and the low-stage compressor
The high-capacity heating operation is performed by increasing the amount of circulating refrigerant flowing to the use-side heat exchanger 13 by the parallel operation of the ten. In the case of cooling as well, for a large load like heating, the low-stage compressor 10 and the high-stage compressor 18 are operated in parallel, and high-capacity operation can be realized by increasing the amount of circulating refrigerant. However, the four-way valve 12 is switched and the use-side heat exchanger 13 is used as an evaporator. Note that the control valves 19 and 25 and the expansion device 28 are closed for both heating and cooling.

During the hot water supply / heating operation, heating is performed in the cooling / heating circuit 17 by one-stage compression using the low-stage compressor 10 (same as normal heating), and hot-water supply operation is performed by one-stage compression using the high-stage compressor 18. Is performed. That is, the refrigerant gas discharged from the high-stage compressor 18 passes through the control valve 19, enters the hot-water supply heat exchanger 20, exchanges heat with the hot-water supply, condenses and liquefies, and passes through the intermediate cooler 22 to use-side heat exchange. Liquid refrigerant coming out of the heat exchanger 13, is decompressed by the main throttle device 15, is vaporized and gasified by the heat source side heat exchanger 16, passes through the four-way valve 12, and partially passes through the four-way valve 12 as a heating refrigerant in the cooling / heating circuit 17.
10 and the remaining refrigerant passes through check valve 27 and intercooler
From 22, it is sucked into the high-stage compressor 18. In the operation mode, the control valves 25 and 26, the expansion device 28, the intermediate expansion device 21
Is closed. By doing so, hot water supply and heating at a relatively low compression ratio can be independently operated in a single-stage compression operation, and a condensing temperature according to demand can be obtained. Therefore, unlike the conventional case, there is no need for a compression function to cover both heating and hot water supply loads, and the system can handle the loads independently and is a convenient system.

If high temperature is required for hot water supply and heating, use a low-stage compressor.
The intermediate-pressure refrigerant gas discharged from 10 is further suction-compressed by the high-stage compressor 18 through the intermediate cooler 22 from the control valve 25, and the high-temperature and high-pressure refrigerant gas is changed by the opening of the control valves 26 and 19. Separate for heating and hot water. The high-temperature and high-pressure gas for heating separated by the control valve 26 is supplied from the four-way valve 12 to the use side heat exchanger.
13 and exchange heat with indoor air to achieve high-temperature blowing. The condensed and liquefied high-pressure refrigerant liquid passes through the main throttle device 14 and is decompressed by the main throttle device 15 to a low pressure, so that the heat source side heat exchanger
The gas is vaporized in 16 and is again sucked into the low-stage compressor 10 from the four-way valve 12. On the other hand, the high-temperature and high-pressure hot water supply refrigerant gas separated by the control valve 19 heats the hot water in the hot water supply heat exchanger 20,
The condensed high-pressure liquid refrigerant passes through the intercooler 22, is depressurized by the main throttle device 15, is vaporized by the heat source side heat exchanger 16, and is vaporized.
The four-way valve 12 sucks into the low-stage compressor 10. At this time, cooling of the intermediate-pressure discharge gas of the low-stage compressor 10 is performed by the intermediate expansion device 21,
Alternatively, any of the aperture devices 28 may be used.

In addition, by adjusting the opening degrees of the control valves 19 and 26, it is possible to adjust the capacity of hot water supply and heating.

Thereby, in the two-stage compression operation, high-temperature blowing can be performed in the heating operation, and high-temperature hot water can be supplied in the hot water supply. At this time, the non-return valves 11, 27 prevent the intermediate pressure / low pressure and the high pressure / intermediate pressure from being mixed due to the high pressure on the outlet side.

During the cooling hot water supply operation, the cooling use side heat exchanger 13
The refrigerant gas discharged from the high-stage compressor 18 heats the hot water in the hot water supply heat exchanger 20 and condenses the liquid refrigerant through the intercooler 22 to the main expansion device 14. Then, the heat is exchanged with the indoor air in the use side heat exchanger 13 to evaporate and gasified, and is sucked from the four-way valve 12 through the check valve 27 to the high-stage compressor 18 through the intermediate cooler 22. At this time, the control valves 25, 26
Is closed. This operation is a one-stage compression operation and does not require a high hot water supply temperature, and an energy saving operation of heating hot water with waste heat of cooling can be realized. Next, when a large load is applied to both the cooling and hot water supply, the low-stage compressor 10 is simultaneously operated in the above-mentioned operation cycle, and the discharged refrigerant gas passes through the check valve 11 and passes through the control valve 26 before the control valve 19. Then, the refrigerant gas is merged with the refrigerant gas discharged from the high-stage compressor 18, the flow rate of the refrigerant increases, and heat exchange with hot water is performed by the heat exchanger 20 for hot water supply to condense.
At this time, the control valve 25 is closed. As the amount of circulating refrigerant increases, the hot water supply capacity increases. User side heat exchanger at the same time
13 also has an increased evaporation capacity. The evaporated refrigerant gas is
A part of the refrigerant passes through the four-way valve 12 and passes through the check valve 27 and intercooler
It is sucked into the high-stage compressor 18 via 22. The rest is sucked into the low-stage compressor 10. Further, when there is a demand for high-temperature hot water supply, a two-stage compression operation can be realized by a series operation of the low-stage compressor 10 and the high-stage compressor 18. The entire amount of the refrigerant gas discharged from the low-stage compressor 10 passes through the control valve 25, passes through the intercooler 22, is cooled, and is sucked into the high-stage compressor 18. High side compressor
The refrigerant gas discharged from 18 is condensed and liquefied in a hot water supply heat exchanger 20 and partially decompressed to an intermediate pressure by an intermediate expansion device 21 and used in an intermediate cooler 22 to cool the discharge gas of the low-stage compressor 10. The remaining liquid refrigerant passes through the intercooler 22, is supercooled, is decompressed by the main expansion device 14, is vaporized by the use side heat exchanger 13, is vaporized by the use side heat exchanger 13, and is sucked into the low stage compressor 10 via the four-way valve 12. You. At this time, the control valve 26 is closed. When there is no cooling load, use side heat exchanger 13 and heat source side heat exchanger by switching four-way valve 12.
Switching to 16 makes it possible to perform a two-stage compression operation using only hot water.

As described above, in the ordinary cooling and heating operation, the compression ratio is relatively small, so the low compression ratio operation of only the low-stage compressor 10, that is, the one-stage compression operation, is performed. High-performance operation becomes possible by the parallel operation of the high-pressure side compressor 18 and the high-pressure side compressor 18. Furthermore, a high compression ratio operation corresponding to a high temperature is possible for each of the hot water supply and heating, and the hot water supply operation of the hot water supply circuit 24, the cooling and heating operation of the cooling and heating circuit 17 and the operation at the condensing temperature according to the load can be performed. The machine 18 has a good ability to cover only the hot water supply load, can also perform the hot water supply operation of cooling waste heat, can select an operation mode according to various loads, and can provide a two-stage compression cooling / heating hot water supply system that is energy-saving and easy to use.

Advantageous Effects of the Invention As is clear from the above description, the present invention provides, during hot water supply / heating / cooling operation, single operation with a low-stage compressor and a high-stage compressor, parallel operation with high capacity at high load, Furthermore, high compression ratio operation corresponding to high temperature is possible for each hot water supply and heating,
In the case of heating, high-temperature air can be realized and comfort is improved, cooling and hot water supply operation by the high-stage compressor can be performed, and waste heat of cooling can be used for hot water supply, and condensing temperature can be optimized in cooling and heating and hot water supply operation.
The operation mode can be selected according to various loads, and it is an energy-saving and easy-to-use two-heat compression / heating / hot water supply system which exerts a great effect in practical use.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a two-warming compression / heating / hot water supply system according to one embodiment of the present invention, and FIGS. 2 and 3 are configuration diagrams of a conventional two-stage compression refrigeration cycle. 10 ... Low-stage compressor, 11, 27 ... Check valve, 12 ... Four-way valve, 13 ... Use heat exchanger, 14, 15 ... Main throttle device, 16
... heat source side heat exchanger, 17 ... air conditioning circuit, 18 ... high stage compressor, 19, 25, 26 ... control valve, 20 ... hot water supply heat exchanger, 21 ... intermediate throttle device, 22 … Intercooler, 24… hot water supply circuit, 28… throttle device.

Claims (1)

(57) [Claims] 1. A low-stage compressor, a four-way valve, a use-side heat exchanger,
A main throttle device, a heat source side heat exchanger is connected to form a cooling and heating circuit, a high-stage compressor, a hot water supply heat exchanger, an intercooler, and an intermediate throttle device are connected to form a hot water supply circuit. A pipe that is connected and has a check valve provided between the discharge part of the low-stage compressor and the four-way valve of the cooling / heating circuit, and branches from between the low-stage compressor and the check valve. A control valve is provided in the passage, connected to the suction side of the high-stage compressor through the intercooler of the hot water supply circuit, and is connected to a pipeline branched from between the suction pipe of the low-stage compressor and the four-way valve. A stop valve is provided, connected to a pipeline between the control valve and the intercooler, and branched from between the respective main throttle devices provided between the use side heat exchanger and the heat source side heat exchanger. Connected to an intermediate heat exchanger via a squeezing device, and the high-stage compressor and the hot-water supply heat exchange A check valve and a four-way valve are provided between the control valve and the high-stage compressor. A two-stage compression hot / cold hot water supply, which is connected between the main throttle devices of the cooling / heating circuit via a hot water supply heat exchanger and an intercooler on the discharge side of the high stage compressor. system.