Air source heat pump system and operation control method of air source heat pump system

Abstract

The present application relates to the technical field of heat pump system, and particularly provides an air source heat pump system and an operation control method of the air source heat pump system, aiming to solve the problem that the air source heat pump in the existing severe cold region has poor performance in the climate below-30 DEG C, the unit mainly relies on the electric heating system and the energy storage water tank for heating, resulting in the increase of the use cost of the user. For this purpose, the air source heat pump system of the present application comprises a primary air source heat pump system, a secondary air source heat pump system and a water storage tank, the primary air source heat pump system and the secondary air source heat pump system are arranged to heat the circulating water in the water storage tank in a single heating mode or a two-link heating mode. The present application can start the primary air source heat pump system and the secondary air source heat pump system in the linkage heating mode in the severe super-low temperature environment, which is helpful to improve the energy efficiency and achieve the purpose of providing stable heat for the user.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump systems, and particularly provides an air source heat pump system and an operation control method of the air source heat pump system. BACKGROUND

[0002] With the increasing improvement of people's living standards, providing domestic hot water throughout the year has become an important part of people's comfortable life. The traditional gas and electric water heaters have safety hazards such as emission of harmful combustion products and easy leakage, and consume high-quality energy such as coal gas and electricity, which is not consistent with the new energy system based on renewable energy for sustainable development. Due to insufficient sunlight caused by climate and seasonal changes, solar water heaters have the disadvantages of poor heating capacity balance and low annual utilization rate of the device.

[0003] In recent years, air source heat pumps have widely replaced coal-fired heating in rural areas in severe cold regions, but the existing air source heat pumps in severe cold regions have poor performance in terms of unit capacity and energy efficiency when the climate is below -30℃, and cannot produce high capacity. The unit mainly relies on an electric heating system and an energy storage water tank for heating, resulting in increased user costs. The unit has a basic capacity of 50% of the nominal operating capacity under conditions below -37℃.

[0004] Therefore, the present application needs to provide a new air source heat pump system and an operation control method of the air source heat pump system to solve the above technical problems. SUMMARY

[0005] The present application aims to solve the above technical problems, i.e., to solve the problem that the existing air source heat pump widely replaces coal-fired heating in rural areas in severe cold regions, but the existing air source heat pump in severe cold regions has poor performance in terms of unit capacity and energy efficiency when the climate is below -30℃ (severe subzero temperature environment), and the unit mainly relies on an electric heating system and an energy storage water tank for heating, resulting in increased user costs.

[0006] To this end, in a first aspect, the present application provides an air source heat pump system, which comprises a primary air source heat pump system, a secondary air source heat pump system and a water storage tank, the primary air source heat pump system and the secondary air source heat pump system are arranged to heat circulating water in the water storage tank in a single heating mode or a combined heating mode, and in the combined heating mode, the circulating water in the water storage tank heated by the primary air source heat pump system is heated again by the secondary air source heat pump system and then delivered to a user.

[0007] In the case of the above technical solution, in the case of low capacity requirement, heating is only carried out by the first air source heat pump system to avoid waste of overheating; in the case of above zero set temperature, heating can be carried out only by starting the second air source heat pump system; in the case of severe ultra-low temperature environment, the first air source heat pump system and the second air source heat pump system are started in linkage heating mode, the circulating water in the water storage tank is heated by the first air source heat pump system, and then the heated circulating water passes through the second air source heat pump system to provide water inlet temperature rising condition for the second air source heat pump system to generate high hot water, thereby achieving the purpose of providing stable heat for users.

[0008] In the specific embodiment of the above air source heat pump system, the air source heat pump system further comprises a first refrigerant pipeline and a second refrigerant pipeline, in the heating mode, part of the refrigerant discharged from the exhaust port of the first air source heat pump system can be transported to the air inlet of the second air source heat pump system through the first refrigerant pipeline, and part of the refrigerant in the second air source heat pump system after heat exchange with the circulating water in the water storage tank is transported to the first air source heat pump system through the second refrigerant pipeline, a first valve is installed on the first refrigerant pipeline, and a second valve is installed on the second refrigerant pipeline.

[0009] In the case of the above technical solution, in the heating mode, part of the high-temperature gaseous refrigerant discharged from the exhaust port of the first air source heat pump system enters the air inlet of the second air source heat pump system through the first refrigerant pipeline, which improves the refrigerant temperature of the air inlet in the compression process of the second air source heat pump system, provides medium-high gaseous refrigerant for rapid start of the second air source heat pump system, rapidly realizes pressure balance of the unit, reduces the start time of the second compression, and has the effect of supplementing refrigerant for the second air source heat pump system.

[0010] In the specific embodiment of the above air source heat pump system, the first air source heat pump system comprises a first compressor, a Venturi ejector and a first heat exchange assembly, the exhaust port of the first compressor is in communication with the air inlet of the Venturi ejector, the air outlet of the Venturi ejector is connected with the air inlet of the first compressor through the first heat exchange assembly, and the Venturi ejector introduces part of the outlet end refrigerant of the second air source heat pump system in the heating mode as an evaporator into the Venturi ejector through the second refrigerant pipeline to reduce the negative pressure of the evaporator.

[0011] In the technical scheme, the Venturi flowmeter sprays high-temperature gaseous refrigerant, and the gaseous refrigerant realizes high-speed flow after the variable-diameter nozzle, and the pressure after the nozzle is reduced, which is beneficial to the injection of low-temperature gaseous refrigerant at the outlet end of the evaporator in the two-stage air source heat pump system in the heating mode, creates lower negative pressure in the evaporator in the two-stage air source heat pump system, makes the two-phase refrigerant in the evaporator in the compression process of the two-stage air source heat pump system absorb more heat in the ambient temperature, makes more low-pressure liquid refrigerant flash into low-pressure gaseous refrigerant, ensures the dryness of the gaseous refrigerant, and is beneficial to the generation of high capacity of the unit.

[0012] In the specific embodiment of the air source heat pump system, the first heat exchange assembly includes a heat exchange coil, a first heat exchanger and a first four-way valve, the heat exchange coil is arranged on the water storage tank, the gas outlet of the Venturi ejector is communicated with the first end of the first heat exchanger through the first four-way valve and the heat exchange coil, the second end of the first heat exchanger is communicated with the suction port of the primary compressor through the first four-way valve, and a third valve is arranged between the first heat exchanger and the first four-way valve.

[0013] In the specific embodiment of the air source heat pump system, the two-stage air source heat pump system includes a two-stage compressor, a second heat exchange assembly and a waste heat recovery assembly, the second heat exchange assembly is arranged between the exhaust port and the suction port of the two-stage compressor, the second heat exchange assembly can exchange heat with the circulating water in the water storage tank, and the waste heat recovery assembly is used for recovering the waste heat of the refrigerant after the second heat exchange assembly exchanges heat with the circulating water in the water storage tank in the heating mode and exchanging heat with the refrigerant entering the suction port of the two-stage compressor.

[0014] In the technical scheme, the waste heat recovery assembly recovers the waste heat of the refrigerant after exchanging heat with the circulating water in the water storage tank, and exchanges heat with the refrigerant entering the suction port, so that the temperature of the refrigerant in the suction port is increased, and basic conditions for high capacity of the two-stage compressor are created.

[0015] In the specific embodiment of the air source heat pump system, the second heat exchange assembly includes a second heat exchanger, a third heat exchanger and a second four-way valve, the exhaust port of the two-stage compressor is communicated with the first end of the third heat exchanger through the second four-way valve and the second heat exchanger, the second end of the third heat exchanger is communicated with the suction port of the two-stage compressor through the second four-way valve, the other end of the second refrigerant pipeline is connected with the second end of the third heat exchanger, and the third heat exchanger is an evaporator in the heating mode.

[0016] In the specific embodiment of the air source heat pump system, the waste heat recovery assembly comprises a temperature-sensitive control valve, a fourth heat exchanger and a first pipeline, the temperature-sensitive control valve, the fourth heat exchanger and a sixth valve are sequentially arranged on the first pipeline in the flow direction of the refrigerant, one end of the first pipeline is in communication with the refrigerant outlet end of the second heat exchanger, and the other end of the first pipeline is in communication with the first end of the third heat exchanger; the refrigerant after passing through the second four-way valve exchanges heat with the fourth heat exchanger and then enters the suction port of the two-stage compressor.

[0017] In the case of adopting the technical scheme, the waste heat of the refrigerant after passing through the second heat exchanger is recovered by using the cooperation of the temperature-sensitive control valve and the fourth heat exchanger, the energy utilization rate is improved, and the temperature of the refrigerant at the suction port of the two-stage compressor is increased, which helps the two-stage compressor to generate high capacity.

[0018] In the specific embodiment of the air source heat pump system, the air source heat pump system further comprises a second pipeline and a third pipeline, the second end of the first heat exchanger is in communication with the exhaust port of the two-stage compressor through the second pipeline, the first end of the first heat exchanger is in communication with the first end of the third heat exchanger through the third pipeline, a fourth valve is arranged on the second pipeline, and a fifth valve is arranged on the third pipeline; the first heat exchanger, the second pipeline, the third pipeline, the two-stage compressor and the second heat exchanger assembly jointly form a refrigeration system for refrigerating circulating water in the water storage tank.

[0019] In the case of adopting the technical scheme, when the two-stage air source heat pump system performs refrigeration, part of the refrigerant enters the first heat exchanger, so that the first heat exchanger and the third heat exchanger jointly perform heat exchange, the heat exchange area is increased, and the refrigeration capacity is ensured.

[0020] In a second aspect, the application further provides a running control method of an air source heat pump system, the air source heat pump system being the air source heat pump system according to any one of the technical schemes, and the running control method comprising:

[0021] In the heating mode, the ambient temperature and the outlet water temperature of the water storage tank are acquired;

[0022] If the ambient temperature is greater than or equal to a first preset ambient temperature value, and the outlet water temperature is less than or equal to a first preset value, the one-stage air source heat pump system is controlled to perform the heating mode, and the two-stage air source heat pump system is in a standby state; and / or

[0023] if the outlet water temperature is greater than a first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to a first preset ambient temperature value or the ambient temperature is greater than or equal to a second preset ambient temperature value and less than a first preset ambient temperature value, the secondary air source heat pump system is controlled to execute a heating mode, and the primary air source heat pump system is in a standby state; and / or

[0024] if the outlet water temperature is greater than a first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to a third preset ambient temperature value and less than a second preset ambient temperature value, the primary air source heat pump system and the secondary air source heat pump system are controlled to execute a linkage heating mode.

[0025] In the above technical solution, in the heating mode, the primary air source heat pump system and the secondary air source heat pump system can be automatically controlled according to different working conditions, and the intelligent degree is high, so that the purpose of providing stable heat for users is achieved.

[0026] In the specific embodiment of the operation control method of the air source heat pump system, a plurality of preset refrigerant temperature difference values corresponding to different ambient temperatures are stored in the air source heat pump system in advance, and the operation control method further comprises:

[0027] According to the size of the ambient temperature, the opening degree of the temperature sensing control valve is controlled to regulate the refrigerant temperature difference value at the inlet end and the outlet end of the fourth heat exchanger.

[0028] In the above technical solution, by controlling the opening degree of the temperature sensing control valve to adjust the suction gas superheat degree, the suction gas superheat degree is ensured, the compressor liquid return can be effectively prevented in the low-temperature heating working condition, and the exhaust gas superheat degree is ensured, thereby providing a basic condition for the unit to provide high capacity. BRIEF DESCRIPTION OF DRAWINGS

[0029] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0030] Fig. 1 is the overall schematic diagram of the air source heat pump system provided by the present application;

[0031] Fig. 2 is the principle diagram of the linkage heating of the primary air source heat pump system and the secondary air source heat pump system;

[0032] Fig. 3 is the principle diagram of the air source heat pump system corresponding to the cooling mode.

[0033] LIST OF REFERENCE NUMERALS:

[0034] 1, primary compressor; 2, venturi ejector; 3, first four-way valve; 4, first heat exchanger; 5, third valve; 6, fourth valve; 7, water storage tank; 8, circulating water outlet; 9, circulating water inlet; 10, second refrigerant pipeline; 11, second valve; 12, third pipeline; 13, first refrigerant pipeline; 14, first valve; 15, second heat exchanger; 16, secondary compressor; 17, second four-way valve; 18, third heat exchanger; 19, first pipeline; 20, temperature control valve; 21, fourth heat exchanger; 22, sixth valve; 23, fifth valve; 24, second pipeline; 25, water supply pipeline; 26, water supplement pipeline. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art will understand that these embodiments are only used to explain the technical principles of the present application, and are not used to limit the protection scope of the present application. Those skilled in the art can make adjustments as needed to adapt to specific application occasions.

[0036] It should be noted that in the description of the present application, the terms indicating the direction or positional relationship such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the related devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the ordinal numbers "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0038] The existing air source heat pump widely replaces coal-fired heating in rural areas in severe cold regions for heating, but the existing air source heat pump in severe cold regions has poor performance in unit capacity and energy efficiency when the climate is lower than -30℃, and the unit mainly relies on electric heating system and energy storage water tank for heating, resulting in increased use cost of users.

[0039] To solve the above technical problems, refer to Figs. 1-3The application provides an air source heat pump system, which comprises a primary air source heat pump system, a secondary air source heat pump system and a water storage tank 7, the primary air source heat pump system and the secondary air source heat pump system are arranged to heat circulating water in the water storage tank 7 in a single heating mode or a combined heating mode, and in the combined heating mode, the circulating water heated by the primary air source heat pump system is heated again by the secondary air source heat pump system and then delivered to users. The water storage tank 7 is an energy storage water tank.

[0040] In the above embodiment, after the circulating water in the water storage tank 7 is heated by the primary air source heat pump system, the heated circulating water is heated again by the secondary air source heat pump system, which provides a water temperature rising condition for the secondary air source heat pump system to generate high-temperature water and helps the secondary air source heat pump system to generate high-temperature water.

[0041] In one embodiment, the air source heat pump system further comprises a first refrigerant pipeline 13 and a second refrigerant pipeline 10, in the heating mode, part of the refrigerant discharged from the exhaust port of the primary air source heat pump system can be delivered to the suction port of the secondary air source heat pump system through the first refrigerant pipeline 13, and part of the refrigerant in the secondary air source heat pump system after heat exchange with the circulating water in the water storage tank 7 is delivered to the primary air source heat pump system through the second refrigerant pipeline 10, the first valve 14 is installed on the first refrigerant pipeline 13, and the second valve 11 is installed on the second refrigerant pipeline 10.

[0042] In the above embodiment, in the heating mode, part of the high-temperature gaseous refrigerant discharged from the exhaust port of the primary air source heat pump system enters the suction port of the secondary air source heat pump system through the first refrigerant pipeline 13, which improves the refrigerant temperature of the suction port in the compression process of the secondary air source heat pump system, provides medium-high temperature gaseous refrigerant for rapid start of the secondary air source heat pump system, rapidly realizes pressure balance of the unit, reduces the start time of the secondary compression, and has the effect of supplementing refrigerant for the secondary air source heat pump system.

[0043] In one embodiment, the primary air source heat pump system comprises a primary compressor 1, a Venturi ejector 2 and a first heat exchange assembly, the exhaust port of the primary compressor 1 is communicated with the air inlet of the Venturi ejector 2, the air outlet of the Venturi ejector 2 is connected with the air inlet of the primary compressor 1 through the first heat exchange assembly, and the Venturi ejector 2 introduces part of the outlet end refrigerant of the secondary air source heat pump system in the heating mode as an evaporator into the Venturi ejector 2 through the second refrigerant pipeline 10 to reduce the negative pressure of the evaporator.

[0044] Specifically, the exhaust port of the primary compressor 1 is connected to a three-way valve, and the first refrigerant pipeline 13 and the Venturi ejector 2 are connected through the three-way valve. A confluence port is opened on the Venturi ejector 2, one end of the second refrigerant pipeline 10 is communicated with the confluence port, and the high-temperature gaseous refrigerant is injected by the Venturi flowmeter. After passing through the variable-diameter nozzle, the gaseous refrigerant realizes high-speed flow, and the pressure decreases after the nozzle. The pressure in the evaporator of the secondary air source heat pump system in the heating mode is relatively high, so the low-temperature gaseous refrigerant at the outlet end of the evaporator in the secondary air source heat pump system in the heating mode is injected into the Venturi ejector 2, thereby creating lower negative pressure in the evaporator inside the secondary air source heat pump system, enabling the two-phase refrigerant in the evaporator in the compression process of the secondary air source heat pump system to absorb more heat in the ambient temperature, and enabling more low-pressure liquid refrigerant to flash into low-pressure gaseous refrigerant, thereby ensuring the dryness of the gaseous refrigerant and being conducive to generating high capacity of the secondary air source heat pump system.

[0045] In one embodiment, the first heat exchange assembly includes a heat exchange coil, the first heat exchanger 4, and the first four-way valve 3. The heat exchange coil is arranged on the water storage tank 7. The gas outlet of the Venturi ejector 2 is communicated with the first end of the first heat exchanger 4 through the first four-way valve 3 and the heat exchange coil. The second end of the first heat exchanger 4 is communicated with the suction port of the primary compressor 1 through the first four-way valve 3. The third valve 5 is arranged between the first heat exchanger 4 and the first four-way valve 3. The first heat exchanger 4 can be a plate heat exchanger.

[0046] Specifically, the Venturi ejector 2, the first four-way valve 3, the heat exchange coil, and the first heat exchanger 4 are connected through pipelines. An electronic expansion valve is installed on the pipeline between the heat exchange coil and the first heat exchanger 4. The third valve 5 is installed on the pipeline between the first heat exchanger 4 and the first four-way valve 3.

[0047] In one embodiment, the secondary air source heat pump system includes a secondary compressor 16, a second heat exchange assembly, and a waste heat recovery assembly. The second heat exchange assembly is arranged between the exhaust port and the suction port of the secondary compressor 16, and can exchange heat with the circulating water in the water storage tank 7. The waste heat recovery assembly is used to recover the refrigerant waste heat after the second heat exchange assembly exchanges heat with the circulating water in the water storage tank 7 in the heating mode, and exchanges heat with the refrigerant entering the suction port of the secondary compressor 16. The other end of the first refrigerant pipeline 13 is communicated with the suction port of the secondary compressor 16.

[0048] In one embodiment, the second heat exchange assembly comprises a second heat exchanger 15, a third heat exchanger 18 and a second four-way valve 17, the exhaust port of the secondary compressor 16 is communicated with the first end of the third heat exchanger 18 through the second four-way valve 17 and the second heat exchanger 15, the second end of the third heat exchanger 18 is communicated with the suction port of the secondary compressor 16 through the second four-way valve 17, the other end of the second refrigerant pipeline 10 is connected with the second end of the third heat exchanger 18, and the third heat exchanger 18 is an evaporator in the heating mode. The second heat exchanger 15 can be a double-pipe heat exchanger, and the third heat exchanger 18 can be a plate heat exchanger. The circulating water in the water storage tank 7 enters the second heat exchanger 15 to exchange heat and is then transported to the circulating water outlet 8 of the water storage tank 7, and the user obtains hot water or cold water from the circulating water outlet 8.

[0049] Specifically, the exhaust port of the secondary compressor 16 is connected with the second four-way valve 17 through a pipeline, the second four-way valve 17 is connected with the second heat exchanger 15 through a pipeline, the second heat exchanger 15 is connected with the third heat exchanger 18 through a pipeline, the third heat exchanger 18 is connected with the second four-way valve 17 through a pipeline, and the second four-way valve 17 is connected with the suction port of the secondary compressor 16 through a pipeline. An electromagnetic expansion valve is installed on the pipeline between the second heat exchanger 15 and the third heat exchanger 18. The pipeline between the second four-way valve 17 and the secondary compressor 16 passes through the fourth heat exchanger 21, so that heat exchange is performed. A water delivery pipeline 25 is arranged on the water storage tank 7, the water delivery pipeline 25 is connected with the water inlet of the second heat exchanger 15, and the water delivery pipeline 25 is connected with a water supplement pipeline 26 for supplementing water to the water storage tank 7. The circulating water in the water storage tank 7 can enter the second heat exchanger 15 through the water delivery pipeline 25 to exchange heat. The water storage tank 7 is provided with a circulating water outlet 8 and a circulating water inlet 9. The water from the circulating water outlet 8 is directly transported to the user, and the circulating water in the water storage tank 7 returns to the water storage tank 7 from the circulating water outlet 8 to realize the water circulation function. A one-way valve is installed on the pipeline between the second four-way valve 17 and the suction port of the secondary compressor 16.

[0050] In one embodiment, the waste heat recovery assembly comprises a temperature-sensitive control valve 20, a fourth heat exchanger 21 and a first pipeline 19. The temperature-sensitive control valve 20, the fourth heat exchanger 21 and a sixth valve 22 are sequentially installed on the first pipeline 19 according to the flow direction of the refrigerant. One end of the first pipeline 19 is communicated with the refrigerant outlet end of the second heat exchanger 15, and the other end of the first pipeline 19 is communicated with the first end of the third heat exchanger 18. The refrigerant after passing through the second four-way valve 17 exchanges heat with the fourth heat exchanger 21 and then enters the suction port of the secondary compressor 16. A capillary tube is installed on the first pipeline 19 between the fourth heat exchanger 21 and the sixth valve 22, and the fourth heat exchanger 21 can be a shell heat exchanger. In the heating mode, the refrigerant in the first refrigerant pipeline 13 exchanges heat with the fourth heat exchanger 21 and then enters the suction port of the secondary compressor 16. In the heating mode, the temperature of the gaseous refrigerant increases after passing through the fourth heat exchanger 21. A one-way valve is installed on the first pipeline 19 between the temperature-sensitive control valve 20 and the second heat exchanger 15.

[0051] In the above embodiment, the temperature difference of the refrigerant entering the fourth heat exchanger 21 and the refrigerant after leaving the fourth heat exchanger 21 is regulated by adjusting the opening of the temperature sensing control valve 20, so as to regulate the suction superheat degree, which can effectively prevent the compressor from backflowing in the low-temperature heating mode, thereby ensuring the exhaust superheat degree and providing the basic condition for the unit to provide high capacity, and the refrigerant waste heat after passing through the second heat exchanger 15 is recycled, thereby improving the energy utilization rate, and the refrigerant waste heat is exchanged with the refrigerant before entering the suction port of the secondary compressor 16, thereby increasing the refrigerant temperature of the suction port of the secondary compressor 16, creating a high-capacity basic condition for the secondary compressor 16, which is helpful for the secondary compressor 16 to generate high capacity.

[0052] In one embodiment, the air source heat pump system further comprises a second pipeline 24 and a third pipeline 12, the second end of the first heat exchanger 4 is communicated with the exhaust port of the secondary compressor 16 through the second pipeline 24, the first end of the first heat exchanger 4 is communicated with the first end of the third heat exchanger 18 through the third pipeline 12, a fourth valve 6 is installed on the second pipeline 24, and a fifth valve 23 is installed on the third pipeline 12, the first heat exchanger 4, the second pipeline 24, the third pipeline 12, the secondary compressor 16 and the second heat exchange assembly together form a refrigeration system for refrigerating the circulating water in the water storage tank 7.

[0053] In the above embodiment, when the secondary air source heat pump system is refrigerating, part of the refrigerant enters the first heat exchanger 4, so that the first heat exchanger 4 and the third heat exchanger 18 jointly perform heat exchange, thereby increasing the heat exchange area and ensuring the refrigeration capacity.

[0054] It should be noted that the value of the starting and rising to the highest frequency of the primary compressor 1 is less than the value of the starting and rising to the highest frequency of the secondary compressor 16.

[0055] The working principle of the present application is as follows: in the heating mode, the fourth valve 6 and the fifth valve 23 are in the closed state, the secondary air source heat pump system does not work when the primary air source heat pump system is in the single heating mode, at this time, the first valve 14, the second valve, the sixth valve 22 and the temperature sensing control valve 20 are in the closed state, and the third valve 5 is in the open state, specifically, the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the primary compressor 1 enters the heat exchange coil through the first four-way valve 3 after passing through the Venturi ejector 2, exchanges heat with the circulating water in the water storage tank 7, so as to increase the temperature of the circulating water, and the refrigerant in the heat exchange coil becomes low-pressure liquid, which becomes low-pressure liquid refrigerant after passing through the electronic expansion valve, and then becomes low-pressure gaseous refrigerant after passing through the first heat exchanger 4, and then flows back to the suction port of the primary compressor 1 through the first four-way valve 3 to complete the single heating mode.

[0056] When the secondary air source heat pump system is in the single heating mode, the primary air source heat pump system is not working, at this time, the first valve 14, the second valve and the third valve 5 are in the closed state, the sixth valve 22 and the temperature sensing control valve 20 are opened, the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the secondary compressor 16 is transported to the second heat exchanger 15 through the second four-way valve 17 to exchange heat with the circulating water, part of the refrigerant after heat exchange is transported to the third heat exchanger 18 through the first pipeline 19, and the other part is transported to the third heat exchanger 18 through the electronic expansion valve, the refrigerant passing through the third heat exchanger 18 is low-pressure gaseous refrigerant, and then enters the suction port of the secondary compressor 16 through the second four-way valve 17, and exchanges heat with the fourth heat exchanger 21 before entering the suction port, thereby improving the temperature of the refrigerant in the suction port, and the single heating mode is completed.

[0057] When the primary air source heat pump system and the secondary air source heat pump system are in the linkage heating mode, as shown in Fig. 2 , the temperature sensing control valve 20, the sixth valve 22 and the third valve 5 are opened, the primary compressor 1 and the secondary compressor 16 are started, after the start is completed, the first valve 14 is started first, and after a preset time, the second valve is started, which helps to guide the refrigerant in the third heat exchanger 18 to the venturi ejector 2, part of the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the primary compressor 1 enters the suction port of the secondary compressor 16 through the first refrigerant pipeline 13, which helps to improve the temperature of the refrigerant in the suction port and plays a role in liquid supplement, part of the refrigerant in the third heat exchanger 18 is guided to the venturi ejector 2, which creates lower negative pressure in the third heat exchanger 18, so that more liquid refrigerant is flashed into gaseous refrigerant, which ensures the dryness of the gaseous refrigerant and is beneficial to the generation of high capacity of the secondary compressor 16, the circulating water in the water storage tank 7 is heated once after heat exchange through the heat exchange coil, and then is heated again in the second heat exchanger 15, thereby realizing secondary heating, and the circulating water after secondary heating is directly transported to the circulating water outlet 8 of the water storage tank 7 for user use, thereby improving the temperature of the hot water. The preset time is flexibly designed according to actual use, and exemplarily, the preset time is 1 min.

[0058] The refrigeration mode, as shown in Fig. 3As shown, only the secondary air source heat pump system works, at this time the fourth valve 6 and the fifth valve 23 are opened, the first valve 14, the second valve, the third valve 5, the temperature control valve 20 and the sixth valve 22 are in the closed state, when working, the second four-way valve 17 is switched to the refrigeration mode, the high-temperature and high-pressure gaseous refrigerant discharged by the secondary compressor 16, part of which enters the third heat exchanger 18 through the second four-way valve 17, and the other part enters the first heat exchanger 4 through the first pipeline 19, and the refrigerant after heat exchange in the first heat exchanger 4 and the second heat exchanger 15 enters the second heat exchanger 15 to exchange heat with the circulating water, so that the temperature of the circulating water is lowered to achieve the purpose of refrigeration, and the refrigerant after the second heat exchanger 15 flows back to the suction port of the secondary compressor 16 through the second four-way valve 17, completing the refrigeration process.

[0059] On the other hand, the application also provides a running control method of an air source heat pump system, the air source heat pump system being the air source heat pump system described in any of the above technical solutions, and the running control method comprising:

[0060] receiving an instruction to start the air source heat pump system and selecting a heating mode or a refrigeration mode according to the instruction;

[0061] in the refrigeration mode, controlling a refrigeration system in the air source heat pump system to perform refrigeration;

[0062] in the heating mode, obtaining an ambient temperature and a water outlet temperature of the water storage tank 7;

[0063] if the ambient temperature is greater than or equal to a first preset ambient temperature value and the water outlet temperature is less than or equal to a first preset value, controlling the primary air source heat pump system to perform the heating mode and the secondary air source heat pump system to be in a standby state;

[0064] if the water outlet temperature is greater than the first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to the first preset ambient temperature value or the ambient temperature is greater than or equal to a second preset ambient temperature value and less than the first preset ambient temperature value, controlling the secondary air source heat pump system to perform the heating mode and the primary air source heat pump system to be in the standby state;

[0065] if the water outlet temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to a third preset ambient temperature value and less than the second preset ambient temperature value, controlling the primary air source heat pump system and the secondary air source heat pump system to perform a linked heating mode.

[0066] In the above embodiment, in the heating mode, the application can automatically control the working state of the primary air source heat pump system and the secondary air source heat pump system according to different working conditions, has high intelligent degree, and achieves the purpose of providing stable heat for users.

[0067] It should be noted that the water temperature of the water storage tank 7 refers to the water temperature of the circulating water outlet 8 for conveying the water temperature to the user. The specific values of the first preset ring temperature, the second preset ring temperature, the third preset ring temperature, the first preset value and the second preset value are not limited in the present application, and are flexibly set according to the actual use condition. Exemplarily, the first preset ring temperature is 0℃, the second preset ring temperature is -25℃, the third preset ring temperature is -45℃, the first preset value is 35℃, and the second preset value is 60℃.

[0068] In one embodiment, a plurality of preset refrigerant temperature difference values corresponding to different ambient temperatures are pre-stored in the air source heat pump system, and the operation control method further comprises:

[0069] According to the size of the ambient temperature, the opening degree of the temperature-sensitive control valve 20 is controlled to regulate the refrigerant temperature difference value between the inlet end and the outlet end of the fourth heat exchanger 21.

[0070] In the above embodiment, the suction superheat degree is adjusted by controlling the opening degree of the temperature-sensitive control valve 20 to ensure the suction superheat degree, which can effectively prevent the compressor from returning liquid in the low-temperature heating condition, thereby ensuring the discharge superheat degree and providing the unit with high-capacity basic conditions.

[0071] The preset refrigerant temperature difference values corresponding to different ambient temperatures are not limited in the present application, and are flexibly set according to the actual use condition. Exemplarily, when the ambient temperature is -25℃ to 0℃, the refrigerant temperature difference value is 5℃; when the ambient temperature is -35℃ to -25℃, the refrigerant temperature difference value is 15℃; and when the ambient temperature is -45℃ to -35℃, the refrigerant temperature difference value is 25℃.

[0072] In the above various embodiments and various extended embodiments, only the primary air source heat pump system is used for heating in the condition of low-capacity requirement, to avoid waste of overheating; only the secondary air source heat pump system is started to heat when the ambient temperature is above -20℃; and the primary air source heat pump system and the secondary air source heat pump system are started in the linkage heating mode in the severe super-low-temperature environment, to provide stable power for the heat pump unit by using the double-compressor technology, so as to provide stable heat for the user and reduce the use cost of the user.

[0073] So far, the technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical scheme after the changes or replacements will fall within the protection scope of the present application.

Claims

1. An air source heat pump system, characterized by, The air source heat pump system comprises a primary air source heat pump system, a secondary air source heat pump system and a water storage tank, the primary air source heat pump system and the secondary air source heat pump system are arranged to heat circulating water in the water storage tank in a single heating mode or a combined heating mode, and in the combined heating mode, the circulating water heated by the primary air source heat pump system in the water storage tank is heated again by the secondary air source heat pump system and then delivered to a user; The air source heat pump system further comprises a second refrigerant pipeline, in the heating mode, part of the refrigerant in the secondary air source heat pump system after heat exchange with the circulating water in the water storage tank is delivered to the primary air source heat pump system through the second refrigerant pipeline; The primary air source heat pump system comprises a primary compressor, a Venturi ejector and a first heat exchange assembly, the exhaust port of the primary compressor is communicated with the air inlet of the Venturi ejector, the air outlet of the Venturi ejector is connected with the air inlet of the primary compressor through the first heat exchange assembly, the Venturi ejector is connected with the air outlet of the secondary air source heat pump system in the heating mode through the second refrigerant pipeline to reduce the negative pressure of the evaporator. The secondary air source heat pump system comprises a secondary compressor, a second heat exchange assembly and a waste heat recovery assembly, the second heat exchange assembly is arranged between the exhaust port and the air inlet of the secondary compressor, the second heat exchange assembly can exchange heat with the circulating water in the water storage tank, and the waste heat recovery assembly is used for recovering the waste heat of the refrigerant after the second heat exchange assembly exchanges heat with the circulating water in the water storage tank in the heating mode and exchanging heat with the refrigerant entering the air inlet of the secondary compressor.

2. The air source heat pump system of claim 1, wherein, The air source heat pump system further comprises a first refrigerant pipeline, in the heating mode, part of the refrigerant discharged from the exhaust port of the primary air source heat pump system can be delivered to the air inlet of the secondary air source heat pump system through the first refrigerant pipeline, a first valve is arranged on the first refrigerant pipeline, and a second valve is arranged on the second refrigerant pipeline.

3. The air source heat pump system of claim 2, wherein, The first heat exchange assembly comprises a heat exchange coil, a first heat exchanger and a first four-way valve, the heat exchange coil is arranged on the water storage tank, the air outlet of the Venturi ejector is communicated with the first end of the first heat exchanger through the first four-way valve and the heat exchange coil, the second end of the first heat exchanger is communicated with the air inlet of the primary compressor through the first four-way valve, and a third valve is arranged between the first heat exchanger and the first four-way valve.

4. The air source heat pump system of claim 2, wherein, The second heat exchange assembly comprises a second heat exchanger, a third heat exchanger and a second four-way valve, the exhaust port of the secondary compressor is communicated with the first end of the third heat exchanger through the second four-way valve and the second heat exchanger, the second end of the third heat exchanger is communicated with the air inlet of the secondary compressor through the second four-way valve, the other end of the second refrigerant pipeline is connected with the second end of the third heat exchanger, and in the heating mode, the third heat exchanger is an evaporator.

5. The air source heat pump system of claim 4, wherein, The waste heat recovery assembly comprises a temperature-sensitive control valve, a fourth heat exchanger and a first pipeline, the temperature-sensitive control valve, the fourth heat exchanger and a sixth valve are sequentially arranged on the first pipeline in the flow direction of the refrigerant, one end of the first pipeline is communicated with the refrigerant outlet end of the second heat exchanger, and the other end of the first pipeline is communicated with the first end of the third heat exchanger; the refrigerant after the second four-way valve is exchanged with the fourth heat exchanger and then enters the suction port of the secondary compressor.

6. The air source heat pump system of claim 4, wherein, The air source heat pump system further comprises a second pipeline and a third pipeline, the second end of the first heat exchanger is communicated with the exhaust port of the secondary compressor through the second pipeline, the first end of the first heat exchanger is communicated with the first end of the third heat exchanger through the third pipeline, a fourth valve is arranged on the second pipeline, and a fifth valve is arranged on the third pipeline; the first heat exchanger, the second pipeline, the third pipeline, the secondary compressor and the second heat exchanger assembly jointly form a refrigeration system for refrigerating the circulating water in the water storage tank.

7. A method for operating control of an air source heat pump system, characterized by, The air source heat pump system is the air source heat pump system according to any one of claims 1-6, and the operation control method comprises: In the heating mode, the ambient temperature and the outlet water temperature of the water storage tank are obtained; If the ambient temperature is greater than or equal to a first preset ambient temperature value, and the outlet water temperature is less than or equal to a first preset value, the primary air source heat pump system is controlled to execute the heating mode, and the secondary air source heat pump system is in a standby state; and / or If the outlet water temperature is greater than the first preset value and less than or equal to a second preset value, and the ambient temperature is greater than or equal to the first preset ambient temperature value or the ambient temperature is greater than or equal to a second preset ambient temperature value and less than the first preset ambient temperature value, the secondary air source heat pump system is controlled to execute the heating mode, and the primary air source heat pump system is in a standby state; and / or If the outlet water temperature is greater than the first preset value and less than or equal to the second preset value, and the ambient temperature is greater than or equal to a third preset ambient temperature value and less than the second preset ambient temperature value, the primary air source heat pump system and the secondary air source heat pump system are controlled to execute the linked heating mode.

8. The operation control method of an air-source heat pump system according to claim 7 as dependent on claim 5, characterized in that, The air source heat pump system pre-stores a plurality of preset refrigerant temperature difference values corresponding to different ambient temperatures, and the operation control method further comprises: According to the size of the ambient temperature, the opening degree of the temperature-sensitive control valve is controlled to regulate the refrigerant temperature difference value between the inlet end and the outlet end of the fourth heat exchanger.

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