A dual-source dual-effect heat exchanger energy storage type high-efficiency heat pump hot water system and heating method thereof

Abstract

The present invention discloses a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system and a heating method thereof, and belongs to the field of heating technology. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system includes a first heating cycle for heating when the ambient temperature is not less than 0°C, a second heating cycle for heating when the ambient temperature is less than 0°C but not less than -10°C, and a third heating cycle for heating when the ambient temperature is less than -10°C. The present invention is applied to cross-load heating of buildings in a wide temperature range, and solves the technical problem that the existing air source heat pump or cascade heat pump has too large equipment selection, which makes the unit have low heating efficiency under partial load conditions and low heating seasonal performance coefficient, thereby weakening the economy of both. The heating mode of the equipment can be flexibly switched under different load conditions to adapt to the characteristics of cross-load heating needs of buildings in a wide temperature range.

Description

Technical Field

[0001] The present invention belongs to the technical field of heating, and in particular relates to a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system and a heating method thereof. Background Art

[0002] An air source heat pump is an energy-saving device that uses high-level energy to make heat flow from a low-level heat source to a high-level heat source. It is a type of heat pump technology. However, as the outside temperature drops, the ability of the air source heat pump to extract heat from the low-temperature air decreases, resulting in a significant decrease in heating performance. As a result, the air source heat pump has a low performance coefficient during the heating season.

[0003] Cascade heat pump units are usually used in situations where the load is large. They achieve higher energy efficiency and heating or cooling needs by combining two or more heat pump systems. However, the structure and design of cascade heat pump units are more complex, the equipment capacity is larger, and more sophisticated control logic is required to optimize their working performance under different loads. Moreover, their optimization is mainly for stable loads rather than changing loads. Therefore, their application in variable load conditions is limited.

[0004] In addition, in actual applications, the above two heat pump technologies both have the problem of over-sized equipment, which makes the heating efficiency of the heat pump unit low under partial load conditions, thereby reducing the heating seasonal performance coefficient of the air source heat pump or cascade heat pump and weakening the economy of both. Summary of the invention

[0005] The details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent.

[0006] The present invention proposes a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system, which solves the technical problem that the existing air source heat pump or cascade heat pump has the problem of excessive equipment selection, resulting in low heating efficiency of the unit under partial load conditions and low heating seasonal performance coefficient, thereby weakening the economy of both. The system has the characteristic of flexibly switching the heating mode of the equipment based on different load conditions to adapt to the cross-load heating needs of buildings in a wide temperature range.

[0007] On one hand, the present invention provides a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system for cross-load heating of buildings in a wide temperature range, comprising: a first heating cycle for heating when the ambient temperature is not less than 0°C, a second heating cycle for heating when the ambient temperature is less than 0°C but not less than -10°C, and a third heating cycle for heating when the ambient temperature is less than -10°C;

[0008] The first heating cycle includes a first compressor, a hot water storage tank, an indoor heat exchanger, a first solenoid valve, a second solenoid valve, a first throttle valve, and an outdoor heat exchanger; a refrigerant outlet of the first compressor is connected to a refrigerant inlet of the hot water storage tank; another refrigerant outlet of the first compressor is connected to a refrigerant inlet of the indoor heat exchanger through the first solenoid valve; the refrigerant outlet of the indoor heat exchanger is connected to a refrigerant outlet of the hot water storage tank through the second solenoid valve, and is connected to a refrigerant inlet of the outdoor heat exchanger through the first throttle valve; the refrigerant outlet of the outdoor heat exchanger is connected to a refrigerant inlet of the first compressor;

[0009] The second heating cycle includes the first compressor, the third solenoid valve, the fourth solenoid valve, the hot water storage tank, the first throttle valve, and an outdoor heat exchanger; a refrigerant outlet of the first compressor is connected to a refrigerant inlet of the hot water storage tank; the refrigerant outlet of the hot water storage tank is connected to a refrigerant inlet of the outdoor heat exchanger through the first throttle valve; the refrigerant outlet of the outdoor heat exchanger is connected to a refrigerant inlet of the first compressor;

[0010] The third heating cycle includes a second compressor, the indoor heat exchanger, a second throttle valve, and the hot water storage tank; the refrigerant outlet of the second compressor is connected to the refrigerant inlet of the indoor heat exchanger, and the refrigerant outlet of the indoor heat exchanger is connected to the refrigerant outlet of the hot water storage tank through the second throttle valve; the refrigerant inlet of the hot water storage tank is connected to the refrigerant inlet of the second compressor.

[0011] In some embodiments, a three-tube heat exchanger is provided in the heat storage tank, and heat exchange and heat storage are performed through the three-tube heat exchanger.

[0012] In some of the embodiments, the three-tube heat exchanger includes a refrigerant pipeline for refrigerant to pass through, a heating and cooling pipeline for supplying heat or cold to users, and a heat storage pipeline for storing excess heat or cold in the refrigerant passing through the refrigerant pipeline in the hot water storage tank.

[0013] In some of the embodiments, the refrigerant passes through the refrigerant pipeline and transfers heat or cold to the medium in the cooling and heating pipeline to provide heating or cooling to the user, and the refrigerant passes through the refrigerant pipeline and transfers heat or cold to the water in the heat storage pipeline to store heat or cold.

[0014] In some of the embodiments, the heat storage pipeline is also provided with a circulation pump for circulating water.

[0015] Another aspect of the present invention provides a heating method for a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system as described in any of the above technical solutions.

[0016] In some embodiments, including: when the ambient temperature is not less than 0°C, the first heating cycle is used for heating and heat storage; when the ambient temperature is less than 0°C but not less than -10°C, the second heating cycle is used for heating; when the ambient temperature is less than -10°C, the third heating cycle is used for heating.

[0017] In some embodiments, when the ambient temperature is not less than 0°C, high-temperature and high-pressure refrigerant is discharged from the first compressor, one path enters the hot water storage tank for heat storage, and the other path enters the indoor heat exchanger through the first solenoid valve to heat the cooling water to the required temperature for heating to achieve heating. After passing through the second solenoid valve, it is mixed with the refrigerant from the hot water storage tank and enters the first throttle valve. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger and is converted into refrigerant vapor, and returns to the first compressor to complete compression, thus forming a cycle.

[0018] In some embodiments, when the ambient temperature is less than 0°C but not less than -10°C, high-temperature and high-pressure refrigerant is discharged from the first compressor and enters the water storage tank to heat the cooling water to the required temperature for heating to achieve heating. The condensed refrigerant enters the first throttle valve. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger and is converted into refrigerant vapor, and returns to the first compressor to complete compression, forming a cycle.

[0019] In some of the embodiments, when the ambient temperature is lower than -10°C, high-temperature and high-pressure refrigerant vapor is discharged from the second compressor, enters the indoor heat exchanger to heat the cooling water to the required temperature for heating, enters the second throttle valve, and the throttled refrigerant absorbs the heat of the water in the heat storage tank and is converted into refrigerant vapor, and returns to the second compressor to complete compression, thus forming a cycle.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention provides a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water unit. Based on different load conditions, the heating mode of the equipment can be flexibly switched to meet the cross-load heating needs of buildings in a wide temperature range. By setting a hot water storage tank with a three-tube heat exchanger and decoupling the cascade heat pump cycle, the air source heat pump can be used for heating and heat storage under low load conditions, and the water ring heat pump can be used for heating under high load conditions to meet the heating needs, so that the unit can achieve efficient operation under different load conditions. Among them, the air source heat pump heating cycle can use the three-tube heat exchanger in the hot water storage tank as a condenser to achieve the heating purpose, and can also use the indoor heat exchanger as a condenser to achieve the heating purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 A schematic diagram of the structure of a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the structure of a three-tube heat exchanger provided in an embodiment of the present invention;

[0025] Figure 3 Another structural schematic diagram of a three-tube heat exchanger provided in an embodiment of the present invention;

[0026] Description of the drawings: 1. First compressor; 2. Three-tube heat exchanger; 201. Refrigerant pipeline; 202. Cooling and heating pipeline; 203. Heat storage pipeline; 204. Circulation pump; 3. Hot water storage tank; 4. First throttle valve; 5. Outdoor heat exchanger; 6. Second compressor; 7. Indoor heat exchanger; 8. Second throttle valve; 9. First solenoid valve; 10. Second solenoid valve; 11. Third solenoid valve; 12. Fourth solenoid valve. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0028] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0029] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present invention may be combined with other embodiments without conflict.

[0030] Unless otherwise defined, the technical terms or scientific terms involved in the present invention shall have the usual meanings understood by persons with ordinary skills in the technical field to which the present invention belongs. The words "one", "a", "a", "the" and the like involved in the present invention do not indicate a quantity limitation and may indicate the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in the present invention are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in the present invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in the present invention refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" may indicate: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects in the front and back relation are in an "or" relationship. The terms "first", "second", "third" and the like involved in the present invention are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0031] The embodiment of the present invention provides a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system. Figure 1 The schematic diagram of the structure of the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to an embodiment of the present invention is shown in FIG. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system is used for cross-load heating of buildings in a wide temperature range. Figure 1 As shown, it includes: a first heating cycle for heating when the ambient temperature is not less than 0°C, a second heating cycle for heating when the ambient temperature is less than 0°C but not less than -10°C, and a third heating cycle for heating when the ambient temperature is less than -10°C;

[0032] The first heating cycle includes a first compressor 1, a hot water storage tank 3, an indoor heat exchanger 7, a first solenoid valve 9, a second solenoid valve 10, a first throttle valve 4, and an outdoor heat exchanger 5; a refrigerant outlet of the first compressor 1 is connected to a refrigerant inlet of the hot water storage tank 3; another refrigerant outlet of the first compressor 1 is connected to a refrigerant inlet of the indoor heat exchanger 7 through the first solenoid valve 9; a refrigerant outlet of the indoor heat exchanger 7 is connected to a refrigerant outlet of the hot water storage tank 3 through the second solenoid valve 10, and is connected to a refrigerant inlet of the outdoor heat exchanger 5 through the first throttle valve 4; a refrigerant outlet of the outdoor heat exchanger 5 is connected to a refrigerant inlet of the first compressor 1;

[0033] The second heating cycle includes the first compressor 1, the third solenoid valve 11, the fourth solenoid valve 12, the hot water storage tank 3, the first throttle valve 4, and the outdoor heat exchanger 5; a refrigerant outlet of the first compressor 1 is connected to the refrigerant inlet of the hot water storage tank 3; the refrigerant outlet of the hot water storage tank 3 is connected to the refrigerant inlet of the outdoor heat exchanger 5 through the first throttle valve 4; the refrigerant outlet of the outdoor heat exchanger 5 is connected to the refrigerant inlet of the first compressor 1;

[0034] The third heating cycle includes a second compressor 6, the indoor heat exchanger 7, a second throttle valve 8, and the hot water storage tank 3; the refrigerant outlet of the second compressor 6 is connected to the refrigerant inlet of the indoor heat exchanger 7, and the refrigerant outlet of the indoor heat exchanger 7 is connected to the refrigerant outlet of the hot water storage tank 3 through the second throttle valve 8; the refrigerant inlet of the hot water storage tank 3 is connected to the refrigerant inlet of the second compressor 6.

[0035] The above-mentioned dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system can achieve reliable heating in a wide temperature range, and based on different load conditions, realize the switching of three heating modes, so that the unit is in the high-efficiency operation area, and improve the heating season performance coefficient of the unit. When the ambient temperature is high, the air source heat pump can not only meet the heating demand, but also store the excess heat in the water storage tank 3, so as to avoid the air source heat pump from operating under partial load conditions, so that the air source heat pump can be efficiently heated and the purpose of heat storage can be achieved, thus avoiding energy waste. The water storage tank 3 with a three-tube heat exchanger 2 decouples the cascade heat pump cycle, and can switch the heating and heat storage modes to keep the unit running in the high-efficiency zone. When the ambient temperature is low, the water ring heat pump is used for heating, which avoids the problem of poor low-temperature heating performance of the air source heat pump, and can enable the equipment to achieve high-efficiency heating under low ambient temperature conditions. It should be noted that the system effectively decouples the cascade heat pump cycle by introducing a water storage tank 3 with a three-tube heat exchanger 2. This decoupling strategy enables the system to optimize operating efficiency by flexibly switching heating modes under different load conditions. Under low load conditions, the air source heat pump can use the hot water storage tank 3 for heating and heat storage, while under high load conditions, it can switch to the water ring heat pump to meet higher heating needs. In addition, the heating cycle of the air source heat pump has a dual function. It can not only use the three-tube heat exchanger 2 in the hot water storage tank 3 as a condenser for heating, but also use the indoor heat exchanger 7 as a condenser when necessary. This flexible configuration improves the adaptability and energy efficiency of the system, especially when the temperature changes greatly or the load fluctuates frequently. The design of the system not only takes into account energy efficiency, but also fully considers the various situations faced by the system in actual operation, providing an efficient and flexible solution for building heating, which not only helps to improve energy utilization efficiency, but also has significant benefits in reducing energy consumption and reducing operating costs.

[0036] In some embodiments, a three-tube heat exchanger 2 is provided in the heat storage tank 3, and heat exchange and heat storage are performed through the three-tube heat exchanger 2. Figure 2 , 3 As shown, the three-tube heat exchanger 2 includes a refrigerant pipeline 201 for refrigerant to pass through, a heating and cooling pipeline 202 for supplying heat or cold to users, and a heat storage pipeline 203 for storing excess heat or cold in the refrigerant passing through the refrigerant pipeline 201 in the hot water storage tank 3. In some embodiments, the refrigerant passes through the refrigerant pipeline 201 and transfers heat or cold to the medium in the heating and cooling pipeline 202 for heating or cooling the user, and the refrigerant passes through the refrigerant pipeline 201 and transfers heat or cold to the water in the heat storage pipeline 203 for heat storage or cold storage. In some embodiments, the heat storage pipeline 203 is also provided with a circulating pump 204 for circulating water.

[0037] The existing energy storage water tank has a single structure and cannot meet the functional requirements of the multi-energy complementary energy supply system. At present, the multi-energy complementary system is often equipped with 2 to 3 energy storage water tanks, one tank is used as a buffer tank, and one tank is used as an energy storage tank, which makes the system pipeline complex and difficult to arrange, and requires a large space in the application site, which weakens the economic efficiency of the multi-energy complementary system.

[0038] The energy storage water tank with the three-tube heat exchanger 2 can be used for energy storage and energy release of a certain heat pump system, and can also be used for energy storage and energy release of a multi-energy complementary energy supply system. It can achieve the purpose of heating / cooling while storing energy. In particular, when the equipment is working at a low load, it often operates under partial load conditions, and the purpose of heating / cooling is achieved through intermittent operation, which reduces the operating efficiency of the equipment. By setting up an energy storage water tank with a three-tube heat exchanger 2, the equipment can be operated at full load. While heating / cooling, the excess heat / cold can be stored in the water tank to improve the energy efficiency of the equipment.

[0039] Specifically, when heating, the refrigerant enters the three-tube heat exchanger 2 from one port of the refrigerant pipeline 201, heats the medium in the cooling and heating pipeline 202 of the three-tube heat exchanger 2, and the hot water flowing into the cooling and heating pipeline 202 from one port is heated to the heating temperature, and then flows out from the other port of the cooling and heating pipeline 202 of the three-tube heat exchanger 2 to provide heating to the user side. At the same time, the refrigerant enters the three-tube heat exchanger 2 from one port of the refrigerant pipeline 201, heats the circulating water in the heat storage pipeline 203 in the hot water storage tank 3 on the other side, stores the excess heat in the hot water storage tank 3, and the cooled refrigerant flows out from the other port of the refrigerant pipeline 201 of the three-tube heat exchanger 2. Among them, the circulating water in the three-tube heat exchanger 2 is realized by the circulating pump 204, which is an open cycle. When cooling, the refrigerant enters the three-tube heat exchanger 2 from one port of the refrigerant pipeline 201, cools the medium in the cooling and heating pipeline 202 of the three-tube heat exchanger 2, and the cold water flowing into the cooling and heating pipeline 202 from one port is cooled to the cooling temperature, and then flows out from the other port of the cooling and heating pipeline 202 of the three-tube heat exchanger 21 to the user side for cooling. At the same time, the refrigerant enters the three-tube heat exchanger 2 from one port of the refrigerant pipeline 201 and cools the circulating water in the cold storage water tank on the other side, and stores the excess cold in the cold storage water tank. The heated refrigerant flows out from the other port of the refrigerant pipeline 201 of the three-tube heat exchanger 2. Among them, the circulating water in the three-tube heat exchanger 2 is realized by the circulating pump 204, which is an open cycle. The above-mentioned hot water storage tank 3 equipped with a three-tube heat exchanger 2 can achieve the purpose of heating / cooling while storing energy, simplifying the number of water tanks in the energy storage system and improving the economy of the system. It can ensure the full operation of the energy supply equipment, reduce the operation time of partial load conditions, and improve the energy efficiency of the equipment.

[0040] Another aspect of the present invention provides a heating method for a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system as described in any of the above technical solutions. When the ambient temperature is not less than 0°C, the first heating cycle is used for heating and heat storage; when the ambient temperature is less than 0°C but not less than -10°C, the second heating cycle is used for heating; when the ambient temperature is less than -10°C, the third heating cycle is used for heating. Specifically:

[0041] When the ambient temperature is not less than 0°C, high-temperature and high-pressure refrigerant is discharged from the first compressor 1, one path enters the hot water storage tank 3 for heat storage, and the other path enters the indoor heat exchanger 7 through the first solenoid valve 9 to heat the cooling water to the required temperature for heating to achieve heating. After passing through the second solenoid valve 10, it is mixed with the refrigerant from the hot water storage tank 3 and enters the first throttle valve 4. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger 5 and is converted into refrigerant vapor, and returns to the first compressor 1 to complete compression, thus forming a cycle.

[0042] When the ambient temperature is less than 0°C but not less than -10°C, high-temperature and high-pressure refrigerant is discharged from the first compressor 1 and enters the hot water storage tank 3 to heat the cooling water to the required temperature for heating to achieve heating. The condensed refrigerant enters the first throttle valve 4. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger 5 and is converted into refrigerant vapor, and returns to the first compressor 1 to complete compression, forming a cycle.

[0043] When the ambient temperature is lower than -10°C, high-temperature and high-pressure refrigerant vapor is discharged from the second compressor 6, enters the indoor heat exchanger 7 to heat the cooling water to the required temperature for heating, and enters the second throttle valve 8. The throttled refrigerant absorbs the heat of the water in the hot water tank 3 and is converted into refrigerant vapor, and returns to the second compressor 6 to complete compression, forming a cycle.

[0044] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0045] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system, characterized in that: Used for cross-load heating of buildings in a wide temperature range, including: a first heating cycle for heating when the ambient temperature is not less than 0°C, a second heating cycle for heating when the ambient temperature is less than 0°C but not less than -10°C, and a third heating cycle for heating when the ambient temperature is less than -10°C; The first heating cycle includes a first compressor, a hot water storage tank, an indoor heat exchanger, a first solenoid valve, a second solenoid valve, a first throttle valve, and an outdoor heat exchanger; a refrigerant outlet of the first compressor is connected to a refrigerant inlet of the hot water storage tank; another refrigerant outlet of the first compressor is connected to a refrigerant inlet of the indoor heat exchanger through the first solenoid valve; the refrigerant outlet of the indoor heat exchanger is connected to a refrigerant outlet of the hot water storage tank through the second solenoid valve, and is connected to a refrigerant inlet of the outdoor heat exchanger through the first throttle valve; the refrigerant outlet of the outdoor heat exchanger is connected to a refrigerant inlet of the first compressor; The second heating cycle includes the first compressor, the third solenoid valve, the fourth solenoid valve, the hot water storage tank, the first throttle valve, and an outdoor heat exchanger; a refrigerant outlet of the first compressor is connected to a refrigerant inlet of the hot water storage tank; the refrigerant outlet of the hot water storage tank is connected to a refrigerant inlet of the outdoor heat exchanger through the first throttle valve; the refrigerant outlet of the outdoor heat exchanger is connected to a refrigerant inlet of the first compressor; The third heating cycle includes a second compressor, the indoor heat exchanger, a second throttle valve, and the hot water storage tank; the refrigerant outlet of the second compressor is connected to the refrigerant inlet of the indoor heat exchanger, and the refrigerant outlet of the indoor heat exchanger is connected to the refrigerant outlet of the hot water storage tank through the second throttle valve; the refrigerant inlet of the hot water storage tank is connected to the refrigerant inlet of the second compressor.

2. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 1 is characterized in that: A three-tube heat exchanger is arranged in the heat storage tank, and heat exchange and heat storage are performed through the three-tube heat exchanger.

3. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 2 is characterized in that: The three-tube heat exchanger includes a refrigerant pipeline for refrigerant to pass through, a heating and cooling pipeline for supplying heat or cold to users, and a heat storage pipeline for storing excess heat or cold in the refrigerant passing through the refrigerant pipeline in the hot water storage tank.

4. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 3 is characterized in that: The refrigerant passes through the refrigerant pipeline and transfers heat or cold to the medium in the cooling and heating pipeline to provide heating or cooling to the user. The refrigerant passes through the refrigerant pipeline and transfers heat or cold to the water in the heat storage pipeline to store heat or cold.

5. The dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 3 is characterized in that: The heat storage pipeline is also provided with a circulation pump for circulating water.

6. A heating method for a dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system, characterized in that: Heating is performed using the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system described in any one of claims 1 to 5.

7. The heating method of the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 6, characterized in that: include: When the ambient temperature is not less than 0°C, the first heating cycle is used for heat supply and heat storage; When the ambient temperature is less than 0°C but not less than -10°C, the second heating cycle is used for heating; When the ambient temperature is lower than -10°C, the third heating cycle is used for heating.

8. The heating method of the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 7, characterized in that: When the ambient temperature is not less than 0°C, high-temperature and high-pressure refrigerant is discharged from the first compressor, one path enters the hot water storage tank for heat storage, and the other path enters the indoor heat exchanger through the first solenoid valve to heat the cooling water to the required temperature for heating to achieve heating. After passing through the second solenoid valve, it is mixed with the refrigerant from the hot water storage tank and enters the first throttle valve. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger and is converted into refrigerant vapor, and returns to the first compressor to complete compression, thus forming a cycle.

9. The heating method of the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 7, characterized in that: When the ambient temperature is less than 0°C but not less than -10°C, high-temperature and high-pressure refrigerant is discharged from the first compressor and enters the water storage tank to heat the cooling water to the required temperature for heating to achieve heating. The condensed refrigerant enters the first throttle valve. The throttled refrigerant absorbs the heat of the low-temperature air in the outdoor heat exchanger and is converted into refrigerant vapor, and returns to the first compressor to complete compression, forming a cycle.

10. The heating method of the dual-source double-effect heat exchanger energy storage type high-efficiency heat pump hot water system according to claim 7, characterized in that: When the ambient temperature is lower than -10°C, high-temperature and high-pressure refrigerant vapor is discharged from the second compressor, enters the indoor heat exchanger to heat the cooling water to the required temperature for heating, and enters the second throttle valve. The throttled refrigerant absorbs the heat of the water in the heat storage tank and turns into refrigerant vapor, and returns to the second compressor to complete compression, forming a cycle.

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