Gas engine heat pump hot water system with high efficiency in low temperature environment

Abstract

The present invention patent discloses a gas engine heat pump hot water system that operates efficiently in a low-temperature environment, including an air source heat pump system, an engine power system, an engine waste heat recovery system, a transmission system and a hot water system; the hot water system is connected in series with the condenser in the air source heat pump system, the flue gas heat exchanger and the plate heat exchanger in the engine waste heat recovery system, and absorbs the heat released by the condensation of the refrigerant in the condenser and the waste heat of the engine. The air source heat pump system includes a low-pressure compressor, a high-pressure compressor, and five solenoid valves are provided to realize the operation and bypass switching of the low-pressure compressor, so that the unit can operate efficiently under low-temperature environmental conditions. The present invention patent can flexibly switch the operating mode of the compressor, so that the system can operate efficiently in both low-temperature and normal environmental conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas engine heat pumps, and more specifically, relates to a gas engine heat pump hot water system that operates efficiently in a low-temperature environment. Background Art

[0002] As a clean energy, natural gas has gradually become one of the main energy sources in the modern clean energy system. At present, the proportion of natural gas in primary energy consumption is increasing year by year. Natural gas will continue to maintain a rapid development momentum and has a huge market capacity.

[0003] In recent years, companies including Hong Kong and China Gas and China Resources Gas have begun to intensify their exploration and development of efficient natural gas utilization technologies and equipment. Providing users with competitive energy supply solutions and gradually expanding natural gas applications and sales will undoubtedly become the preferred choice for major city gas operators.

[0004] The operating principle of a gas-powered heat pump (GHP) is essentially the same as that of an electricity-driven heat pump (EHP). The difference is that a natural gas engine replaces an electric motor to drive the compressor. In heating mode, the engine's cylinder cooling heat and flue gas waste heat are recovered to supplement heating or provide domestic hot water. It can also be used for dehumidification. Compared to EHPs, GHPs offer advantages such as high primary energy efficiency, high heating temperatures, fast heating rates, and good partial-load operation. However, in cold regions, the heating capacity of a GHP system varies with outdoor temperature; the lower the outdoor temperature, the worse the heating performance. Once the temperature falls below the air-source heat pump's set operating temperature, the entire system will malfunction or even cease operation. Summary of the Invention

[0005] In response to the defects of existing gas engine heat pump technology that often operates abnormally or stops working in low-temperature environments, the present invention provides a gas engine heat pump system that can be used in low-temperature environments in cold areas. It has the advantages of high flexibility, high efficiency, low energy consumption and low system pollutant emissions.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] The present invention provides a gas engine heat pump hot water system that operates efficiently in a low-temperature environment, which includes an air source heat pump system, an engine waste heat recovery system, an engine power transmission system, and a hot water system;

[0008] The air source heat pump system includes a low-pressure compressor, a high-pressure compressor, an oil-gas separator, a four-way reversing valve, a condenser, a first throttle valve, an intermediate heat exchanger, a second throttle valve, an evaporator, a first valve, a second valve, a third valve, a fourth valve, and a fifth valve;

[0009] wherein the four-way reversing valve is provided with a first inlet, a second inlet, a first outlet, and a second outlet; the intermediate heat exchanger is provided with a first passage and a second passage; the low-pressure compressor, the fifth valve, the high-pressure compressor, and the oil-gas separator are connected to the first inlet of the four-way reversing valve, and the first outlet of the four-way reversing valve is divided into two paths after passing through the condenser, one of which passes through the first passage of the intermediate heat exchanger, the second throttle valve, and the evaporator to be connected to the second inlet of the four-way reversing valve, and the other passes through the first valve, the first throttle valve, the second passage of the intermediate heat exchanger, and the second valve to be connected to the high-pressure compressor; the second outlet of the four-way reversing valve is connected to the high-pressure compressor through the third valve, and the second outlet of the four-way reversing valve is connected to the low-pressure compressor through the fourth valve;

[0010] The low-pressure compressor and the high-pressure compressor are both connected to the engine waste heat recovery system through the engine power transmission system; the condenser is connected to the hot water system and the engine power transmission system; and the evaporator is connected to the engine power transmission system.

[0011] In one embodiment, preferably, when the first valve, the second valve, the fourth valve, and the fifth valve are opened and the third valve is closed, the air source heat pump system is in a two-stage compression operation state. After being compressed by the low-pressure compressor, the refrigerant is mixed with the refrigerant after heat exchange in the intermediate heat exchanger and enters the high-pressure compressor. After being compressed, it enters the condenser to heat the return water of the hot water system. The high-temperature and high-pressure refrigerant is condensed into a liquid refrigerant with a certain degree of supercooling. The liquid refrigerant is divided into two streams. One stream is throttled and cooled by the first throttle valve, and then mixed with the refrigerant at the outlet of the low-pressure compressor after passing through the second passage of the intermediate heat exchanger. The other stream is cooled by the first passage of the intermediate heat exchanger, and then cooled and cooled by the second throttle valve. Finally, it enters the evaporator to exchange heat with the air and the flue gas after heat recovery in the engine waste heat recovery system, and is converted into a low-temperature and low-pressure gaseous refrigerant. Finally, it enters the low-pressure compressor to complete the refrigerant cycle in the heat pump system.

[0012] In one embodiment, preferably, the low-pressure compressor is put into operation and shut down by controlling the first valve, the second valve, the third valve, the fourth valve, the fifth valve and the engine power transmission system.

[0013] In one embodiment, preferably, the engine power transmission system includes a gas engine and an electromagnetic clutch, and the power of the gas engine can be transmitted to the low-pressure compressor and the high-pressure compressor through the electromagnetic clutch; the low-pressure compressor and the high-pressure compressor are put into operation and disconnected by controlling the electromagnetic clutch.

[0014] In one embodiment, preferably, the transmission method used in the engine power transmission system is belt drive, and the low-pressure compressor and the high-pressure compressor are connected to the pulley through the electromagnetic clutch.

[0015] In one embodiment, preferably, the engine waste heat recovery system includes a gas engine, a three-way catalytic converter, a first flue gas heat exchanger, a coolant heat exchanger, an internal circulation water pump and a second flue gas heat exchanger;

[0016] The gas engine, the three-way catalytic converter, the first flue gas heat exchanger, the internal circulation water pump, and the coolant heat exchanger form a first waste heat recovery path;

[0017] In the first waste heat recovery path, the internal circulating coolant enters the cylinder liner of the gas engine, absorbs the heat generated during the operation of the gas engine, passes through the three-way catalytic converter and the first flue gas heat exchanger in sequence to absorb heat in the flue gas, and finally enters the coolant heat exchanger to heat the cold water of the hot water system to produce hot water. The cooled coolant returns to the cylinder liner of the gas engine to complete the coolant circulation.

[0018] In one embodiment, preferably, the gas engine, the three-way catalytic converter, the first flue gas heat exchanger, the second flue gas heat exchanger, and the evaporator form a second waste heat recovery path;

[0019] In the second waste heat recovery path, the flue gas generated by the gas engine recovers heat after passing through the three-way catalytic converter, the first flue gas heat exchanger and the second flue gas heat exchanger, and finally enters the evaporator to be mixed with air and then discharged.

[0020] In one embodiment, preferably, the hot water system includes a water pump, a condenser, a second flue gas heat exchanger, a coolant heat exchanger and a hot water storage tank; cold water is pressurized by the water pump and enters the condenser to absorb heat released by condensation of the refrigerant, then enters the second flue gas heat exchanger to further absorb heat in the flue gas, and then is connected to the coolant heat exchanger to absorb heat in the coolant, and the generated hot water enters the hot water storage tank.

[0021] In one embodiment, preferably, the heat storage tank is further provided with a hot water supply pipeline; the temperature of the hot water supplied by the heat storage tank is 45°C~80°C.

[0022] In one embodiment, preferably, the low-pressure compressor and the high-pressure compressor are open scroll compressors or open reciprocating compressors.

[0023] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0024] First, the ability to flexibly switch between the single-unit compression mode and the two-stage compression mode of the heat pump system according to the operating environment conditions can greatly improve the environmental adaptability of the gas engine heat pump system, solve the problem of low efficiency or even unusable gas engine heat pump units in low-temperature environments, improve the operating efficiency and reliability of the system, and reduce the consumption of fossil fuels by traditional gas engine systems in low-temperature environments;

[0025] Secondly, the cascaded heat recovery system can maximize the recovery of heat generated by the gas engine and waste heat in the flue gas. Finally, the flue gas is passed into the evaporator for heat exchange, which improves the system's operating thermal efficiency and effectively reduces hot water energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Reference numerals:

[0028] 1- low-pressure compressor, 2- high-pressure compressor, 3- oil-gas separator, 4- four-way reversing valve, 5- condenser, 6- first throttle valve, 7- intermediate heat exchanger, 8- second throttle valve, 9- evaporator, 10- first valve, 11- second valve, 12- third valve, 13- fourth valve, 14- fifth valve, 15- second flue gas heat exchanger, 16- coolant heat exchanger, 17- engine, 18- three-way catalytic converter, 19- first flue gas heat exchanger, 20- internal circulation water pump, 21- heat storage tank, 22- water pump, 23- electromagnetic clutch. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0030] like Figure 1As shown, the present invention provides a gas engine heat pump hot water system that operates efficiently in low-temperature environments. The system comprises an air-source heat pump system, an engine waste heat recovery system, an engine power transmission system, and a hot water system. The system can be used in cold regions to achieve efficient operation in low-temperature environments. The air-source heat pump system is primarily used to absorb heat energy from the air through the circulation of a refrigerant; the engine waste heat recovery system is used to recover heat generated during engine operation and waste heat from flue gas; the engine power transmission system provides a power source for the compressor in the air-source heat pump system; and the hot water system is used to absorb heat generated by the air-source heat pump system and the engine waste heat system to provide hot water for users.

[0031] The air source heat pump system includes a low-pressure compressor 1, a high-pressure compressor 2, an oil-gas separator 3, a four-way reversing valve 4, a condenser 5, a first throttle valve 6, an intermediate heat exchanger 7, a second throttle valve 8, an evaporator 9, a first valve 10, a second valve 11, a third valve 12, a fourth valve 13, and a fifth valve 14.

[0032] Among them, the four-way reversing valve 4 is provided with a first inlet, a second inlet, a first outlet, and a second outlet; the intermediate heat exchanger 7 is provided with a first passage and a second passage; the low-pressure compressor 1, the fifth valve 14, the high-pressure compressor 2, and the oil-gas separator 3 are connected to the first inlet of the four-way reversing valve 4, and the first outlet of the four-way reversing valve 4 is divided into two paths after passing through the condenser 5, one of which passes through the first passage of the intermediate heat exchanger 7, the second throttle valve 8, and the evaporator 9 to be connected to the second inlet of the four-way reversing valve 4, and the other passes through the first valve 10, the first throttle valve 6, the second passage of the intermediate heat exchanger 7, and the second valve 11 to be connected to the high-pressure compressor 2; the second outlet of the four-way reversing valve 4 is connected to the high-pressure compressor 2 through the third valve 12, and the second outlet of the four-way reversing valve 4 is connected to the low-pressure compressor 1 through the fourth valve 13.

[0033] The low-pressure compressor 1 and the high-pressure compressor 2 are both connected to the engine waste heat recovery system through the engine power transmission system; the condenser 5 is connected to the hot water system and the engine power transmission system; and the evaporator 9 is connected to the engine power transmission system.

[0034] In this embodiment, when the first valve 10, the second valve 11, the fourth valve 13, and the fifth valve 14 are open and the third valve 12 is closed, the air source heat pump system is in a two-stage compression operation state. After being compressed by the low-pressure compressor 1, the refrigerant is mixed with the refrigerant after heat exchange through the intermediate heat exchanger 7 and enters the high-pressure compressor 2. After being compressed, it enters the condenser 5 to heat the return water of the hot water system. The high-temperature and high-pressure refrigerant is condensed into a liquid refrigerant with a certain degree of subcooling. The liquid refrigerant is divided into two streams. One stream is throttled and cooled by the first throttle valve 6, and then passes through the second passage of the intermediate heat exchanger 7 and mixes with the refrigerant at the outlet of the low-pressure compressor 1. The other stream is cooled by the first passage of the intermediate heat exchanger 7, and then cooled and cooled by the second throttle valve 8. Finally, it enters the evaporator 9 to exchange heat with the air and the flue gas after heat recovery in the engine waste heat recovery system, and is converted into a low-temperature and low-pressure gaseous refrigerant. Finally, it enters the low-pressure compressor 1, completing the refrigerant cycle in the heat pump system.

[0035] In this embodiment, the low-pressure compressor 1 is put into operation and shut down by controlling the first valve 10, the second valve 11, the third valve 12, the fourth valve 13, the fifth valve 14 and the engine power transmission system.

[0036] In this embodiment, the engine power transmission system includes a gas engine 17 and an electromagnetic clutch 23. The power of the gas engine 17 can be transmitted to the low-pressure compressor 1 and the high-pressure compressor 2 through the electromagnetic clutch 23; the low-pressure compressor 1 and the high-pressure compressor 2 are put into operation and disconnected by controlling the electromagnetic clutch 23.

[0037] In this embodiment, the transmission method used in the engine power transmission system is belt drive, and the low-pressure compressor 1 and the high-pressure compressor 2 are connected to the pulley through the electromagnetic clutch 23.

[0038] In this embodiment, the engine waste heat recovery system includes a gas engine 17 , a three-way catalytic converter 18 , a first flue gas heat exchanger 19 , a coolant heat exchanger 16 , an internal circulation water pump 20 and a second flue gas heat exchanger 15 .

[0039] The gas engine 17 , the three-way catalytic converter 18 , the first flue gas heat exchanger 19 , the internal circulation water pump 20 , and the coolant heat exchanger 16 form a first waste heat recovery path.

[0040] In the first waste heat recovery path, the internal circulating coolant enters the cylinder liner of the gas engine 17, absorbs the heat generated during the operation of the gas engine 17, passes through the three-way catalytic converter 18 and the first flue gas heat exchanger 19 in sequence to absorb heat in the flue gas, and finally enters the coolant heat exchanger 16 to heat the cold water of the hot water system to produce hot water. The cooled coolant returns to the cylinder liner of the gas engine 17 to complete the coolant circulation.

[0041] In this embodiment, the gas engine 17 , the three-way catalytic converter 18 , the first flue gas heat exchanger 19 , the second flue gas heat exchanger 15 , and the evaporator 9 form a second waste heat recovery path.

[0042] In the second waste heat recovery path, the flue gas generated by the gas engine 17 recovers heat after passing through the three-way catalytic converter 18, the first flue gas heat exchanger 19 and the second flue gas heat exchanger 15, and finally enters the evaporator 9 to be mixed with air and then discharged.

[0043] In this embodiment, the hot water system includes a water pump 22, a condenser 5, a second flue gas heat exchanger 15, a coolant heat exchanger 16, and a hot water storage tank 21. After being pressurized by the water pump 22, cold water enters the condenser 5 to absorb heat released by the condensation of the refrigerant, enters the second flue gas heat exchanger 15 to further absorb heat from the flue gas, and then enters the coolant heat exchanger 16 to absorb heat from the coolant. The generated hot water enters the hot water storage tank 21 and is provided to the user.

[0044] In this embodiment, the hot water storage tank 21 is further provided with a hot water supply pipeline; the hot water supplied by the hot water storage tank 21 has a temperature of 45°C to 80°C.

[0045] In this embodiment, the low-pressure compressor 1 and the high-pressure compressor 2 are open scroll compressors or open reciprocating compressors.

[0046] The present invention solves the problem of low heating efficiency of gas engine heat pumps in low-temperature environments through two-stage compressed air source heat pump technology. It can also flexibly switch the operating mode of the compressor in the gas engine heat pump system according to different ambient temperatures through the coordination of valves and transmission systems, thereby achieving continuous and efficient operation of the gas engine heat pump system, reducing system energy consumption, and reducing carbon dioxide emissions.

[0047] The hot water system is connected in series with the condenser in the air source heat pump system, the flue gas heat exchanger and the plate heat exchanger in the engine waste heat recovery system, absorbing the heat released by the condensation of the refrigerant in the condenser and the waste heat of the engine. The air source heat pump system includes a low-pressure compressor, a high-pressure compressor, and five solenoid valves to realize the operation and bypass switching of the low-pressure compressor, so that the unit can operate efficiently under low-temperature environmental conditions. The patent of this invention can flexibly switch the operating mode of the compressor, so that the system can operate efficiently under both low-temperature and normal environmental conditions.

[0048] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0049] First, the ability to flexibly switch between the single-unit compression mode and the two-stage compression mode of the heat pump system according to the operating environment conditions can greatly improve the environmental adaptability of the gas engine heat pump system, solve the problem of low efficiency or even unusable gas engine heat pump units in low-temperature environments, improve the operating efficiency and reliability of the system, and reduce the consumption of fossil fuels by traditional gas engine systems in low-temperature environments;

[0050] Secondly, the cascaded heat recovery system can maximize the recovery of heat generated by the gas engine and waste heat in the flue gas. Finally, the flue gas is passed into the evaporator for heat exchange, which improves the system's operating thermal efficiency and effectively reduces hot water energy consumption.

[0051] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A gas engine heat pump hot water system that operates efficiently in a low temperature environment, characterized in that: Including air source heat pump system, engine waste heat recovery system, engine power transmission system and hot water system; The air source heat pump system comprises a low-pressure compressor (1), a high-pressure compressor (2), an oil-gas separator (3), a four-way reversing valve (4), a condenser (5), a first throttle valve (6), an intermediate heat exchanger (7), a second throttle valve (8), an evaporator (9), a first valve (10), a second valve (11), a third valve (12), a fourth valve (13), and a fifth valve (14); wherein the four-way reversing valve (4) is provided with a first inlet, a second inlet, a first outlet, and a second outlet; the intermediate heat exchanger (7) is provided with a first passage and a second passage; the low-pressure compressor (1), the fifth valve (14), the high-pressure compressor (2), and the oil-gas separator (3) are connected to the first inlet of the four-way reversing valve (4); the first outlet of the four-way reversing valve (4) is divided into two paths after passing through the condenser (5), one of which passes through the first passage of the intermediate heat exchanger (7), the second throttle valve (8), and the evaporator (9) and is connected to the second inlet of the four-way reversing valve (4); the other of which passes through the first valve (10), the first throttle valve (6), the second passage of the intermediate heat exchanger (7), and the second valve (11) and is connected to the inlet of the high-pressure compressor (2); the second outlet of the four-way reversing valve (4) is connected to the inlet of the high-pressure compressor (2) through the third valve (12), and the second outlet of the four-way reversing valve (4) is connected to the inlet of the low-pressure compressor (1) through the fourth valve (13); The low-pressure compressor (1) and the high-pressure compressor (2) are both connected to the engine waste heat recovery system through the engine power transmission system; the condenser (5) is connected to the hot water system and the engine power transmission system; and the evaporator (9) is connected to the engine power transmission system.

2. A gas engine heat pump hot water system that operates efficiently in a low temperature environment as claimed in claim 1, characterized in that: When the first valve (10), the second valve (11), the fourth valve (13), and the fifth valve (14) are opened and the third valve (12) is closed, the air source heat pump system is in a two-stage compression operation state. The refrigerant is compressed by the low-pressure compressor (1), mixed with the refrigerant after heat exchange in the intermediate heat exchanger (7), and enters the high-pressure compressor (2). After compression, it enters the condenser (5) to heat the return water of the hot water system. The high-temperature and high-pressure refrigerant is condensed into a liquid refrigerant with a certain degree of subcooling. The liquid refrigerant is The refrigerant is divided into two streams. One stream is throttled and cooled by the first throttle valve (6), and then mixed with the refrigerant at the outlet of the low-pressure compressor (1) after passing through the second passage of the intermediate heat exchanger (7). The other stream is cooled by the first passage of the intermediate heat exchanger (7), and then cooled and cooled by the second throttle valve (8). Finally, the refrigerant enters the evaporator (9) to exchange heat with the air and the flue gas after heat recovery in the engine waste heat recovery system, and is converted into a low-temperature and low-pressure gaseous refrigerant. Finally, the refrigerant enters the low-pressure compressor (1), completing the circulation of the refrigerant in the heat pump system.

3. A gas engine heat pump water heating system that operates efficiently in a low temperature environment as claimed in claim 1, characterized in that: The low-pressure compressor (1) is put into operation and shut down by controlling the first valve (10), the second valve (11), the third valve (12), the fourth valve (13), the fifth valve (14) and the engine power transmission system.

4. A gas engine heat pump hot water system that operates efficiently in a low temperature environment as claimed in claim 1, characterized in that: The engine power transmission system includes a gas engine (17) and an electromagnetic clutch (23), wherein the power of the gas engine (17) can be transmitted to the low-pressure compressor (1) and the high-pressure compressor (2) through the electromagnetic clutch (23); and the low-pressure compressor (1) and the high-pressure compressor (2) can be put into operation and disconnected by controlling the electromagnetic clutch (23).

5. A gas engine heat pump water heating system that operates efficiently in a low temperature environment as claimed in claim 4, characterized in that: The transmission method used in the engine power transmission system is belt drive, and the low-pressure compressor (1) and the high-pressure compressor (2) are connected to the pulley via the electromagnetic clutch (23).

6. A gas engine heat pump hot water system that operates efficiently in a low temperature environment as claimed in claim 1, characterized in that: The engine waste heat recovery system comprises a gas engine (17), a three-way catalytic converter (18), a first flue gas heat exchanger (19), a coolant heat exchanger (16), an internal circulation water pump (20), and a second flue gas heat exchanger (15); The gas engine (17), the three-way catalytic converter (18), the first flue gas heat exchanger (19), the internal circulation water pump (20), and the coolant heat exchanger (16) form a first waste heat recovery path; In the first waste heat recovery path, the internal circulating coolant enters the cylinder liner of the gas engine (17), absorbs the heat generated during the operation of the gas engine (17), passes through the three-way catalytic converter (18) and the first flue gas heat exchanger (19) in sequence to absorb the heat in the flue gas, and finally enters the coolant heat exchanger (16) to heat the cold water of the hot water system to produce hot water. The cooled coolant returns to the cylinder liner of the gas engine (17) to complete the coolant circulation.

7. A gas engine heat pump water heating system that operates efficiently in a low temperature environment as claimed in claim 6, characterized in that: The gas engine (17), the three-way catalytic converter (18), the first flue gas heat exchanger (19), the second flue gas heat exchanger (15), and the evaporator (9) form a second waste heat recovery path; In the second waste heat recovery path, the flue gas generated by the gas engine (17) recovers heat through the three-way catalytic converter (18), the first flue gas heat exchanger (19), and the second flue gas heat exchanger (15), and finally enters the evaporator (9) to be mixed with air and then discharged.

8. The gas engine heat pump water heating system capable of operating efficiently in a low temperature environment as claimed in claim 1, characterized in that: The hot water system comprises a water pump (22), a condenser (5), a second flue gas heat exchanger (15), a coolant heat exchanger (16) and a hot water storage tank (21); cold water is pressurized by the water pump (22) and enters the condenser (5) to absorb heat released by condensation of the refrigerant, then enters the second flue gas heat exchanger (15) to further absorb heat in the flue gas, and then enters the coolant heat exchanger (16) to absorb heat in the coolant, and the generated hot water enters the hot water storage tank (21).

9. A gas engine heat pump water heating system that operates efficiently in a low temperature environment as claimed in claim 8, characterized in that: The heat storage tank (21) is also provided with a hot water supply pipeline; the temperature of the hot water supplied by the heat storage tank (21) is 45°C to 80°C.

10. The gas engine heat pump water heating system capable of operating efficiently in a low temperature environment as claimed in claim 1, characterized in that: The low-pressure compressor (1) and the high-pressure compressor (2) are open scroll compressors or open reciprocating compressors.

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