A solar-driven two-stage jet enthalpy-enhancing heat pump system and its control method

Abstract

This invention proposes a two-stage vapor injection enthalpy-enhancing heat pump based on solar energy and its control method. The first stage is conventional vapor injection enthalpy enhancement, which increases subcooling to absorb more air energy. The second stage is active vapor injection enthalpy enhancement, which converts heat from the external heat source into heat generation through the injection enthalpy difference. Moreover, the first-stage vapor injection enthalpy enhancement can reduce the refrigerant temperature in the main liquid pipe, increase the temperature difference between the injected refrigerant and the external heat source in the active vapor injection enthalpy-enhancing economizer, and improve the utilization rate of the external heat source. The invention also provides a vapor injection enthalpy-enhancing control method, in which the first-stage vapor injection enthalpy enhancement controls the opening of its subcooling electronic expansion valve based on the subcooling of the liquid pipe, and the second-stage active vapor injection enthalpy enhancement controls the opening of its subcooling electronic expansion valve based on the superheat of the temperature difference between the inlet and outlet temperatures of the injected refrigerant. Through the two-stage vapor injection enthalpy enhancement, multi-energy complementarity of solar, electrical, thermal, and air energy can be achieved, and heat storage can be supplied quantitatively and on demand, solving the technical bottleneck that heat pumps cannot be used in extremely low temperature environments.

Description

Technical Field

[0001] This invention relates to solar-driven jet enthalpy enhancement control technology, and more specifically, to a solar-driven two-stage jet enthalpy enhancement heat pump system and control method. Background Technology

[0002] With the continuous development of the economy and daily life, the use of heating equipment has become increasingly widespread, leading to a significant increase in building energy consumption and carbon emissions. Globally, in developed countries, building energy consumption accounts for 37-40% of total social energy consumption, with air conditioning and heating equipment accounting for over 65% of building energy consumption. From 1990 to 2018, CO2 emissions increased by 37%. In China, building energy consumption accounts for over 33% of total social energy consumption, and in 2020, total building carbon emissions reached 5.08 billion tons of CO2, accounting for approximately 50.9% of the country's total carbon emissions. Therefore, replacing traditional coal-fired and natural gas heating equipment with heat pumps has become an inevitable trend.

[0003] Air source heat pumps are heating devices that convert electrical energy and air energy into heat through the work of a compressor, achieving complementarity between electrical energy and air energy to generate heating. However, heating capacity and energy efficiency are severely reduced in low-temperature environments, and they cannot be used in extremely low-temperature environments. The main solutions include solar heat pumps and jet enthalpy enhancement technology.

[0004] Solar heat pumps include two types: solar thermal and photovoltaic. Solar thermal heat pumps mainly include heat pump-assisted solar water heaters and solar-assisted heat pumps. The former involves an independent heat pump system and solar collector system, with the heat pump system serving as an auxiliary heat source when the solar collector system cannot meet the heating demand. The latter uses solar absorbers as evaporators to absorb solar energy, increasing the evaporation temperature and thus improving heating capacity and energy efficiency. In terms of application types, they include direct expansion, indirect expansion, and combined types, offering significant energy savings, but cannot be used for cooling, only for heating. To achieve cooling, the system needs to be designed with two evaporators, one of which is a finned evaporator for cooling. Photovoltaic heat pumps use photovoltaic power generation to drive the heat pump; however, photovoltaic power generation efficiency is low, and without sunlight, the unit becomes a conventional heat pump system. Furthermore, the inherent dispersion and instability of solar energy lead to low utilization rates and difficulty in matching with heat pump systems.

[0005] Currently, vapor injection enthalpy enhancement technology is mainly used to improve heat pump performance. Due to its simple structure and low added cost, it has been commercially applied. However, conventional vapor injection enthalpy enhancement has significant drawbacks, namely: the heat from the injected refrigerant comes from the heat pump itself, which is a passive vapor injection enthalpy enhancement; the enthalpy difference generated during the vapor injection enthalpy enhancement process cannot be converted into heat generation, thus failing to achieve more energy complementarity; the improvement in heat pump performance is limited; and it cannot be used in extremely low temperature environments below -20°C. Summary of the Invention

[0006] In view of this, to overcome the aforementioned technical deficiencies, this invention proposes a two-stage vapor injection enthalpy-enhancing heat pump driven by solar energy. The first stage is conventional vapor injection enthalpy enhancement, which utilizes the heat pump's own heat to inject refrigerant, increasing subcooling to absorb more air energy. The second stage is active vapor injection enthalpy enhancement, which converts heat from an external heat source into heating capacity through injection enthalpy difference. Simultaneously, the first-stage vapor injection enthalpy enhancement can lower the temperature of the refrigerant in the main liquid pipe, bringing it to a subcooled state. This facilitates throttling in the subcooled electronic expansion valve, increases the temperature difference between the injected refrigerant and the external heat source in the active vapor injection enthalpy-enhancing economizer, and thus better absorbs heat from the external heat source and improves its utilization rate.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] A solar-driven two-stage vapor injection enthalpy-enhancing heat pump system includes an outdoor unit module, an indoor unit module, and a solar thermal storage module. The outdoor unit module includes a variable frequency compressor, an oil separator, a four-way valve, an outdoor heat exchanger, a first-stage vapor injection enthalpy-enhancing economizer and a first subcooled electronic expansion valve, and a second-stage active vapor injection enthalpy-enhancing economizer and a second subcooled electronic expansion valve. The solar thermal storage module includes solar collector tubes and a hot water storage tank.

[0009] The discharge pipe of the variable frequency compressor is connected to the d pipe of the four-way valve via an oil separator. The e pipe of the four-way valve is connected to one end of the outdoor heat exchanger. The c pipe of the four-way valve is connected to the gas pipe of the indoor unit module. The s pipe of the four-way valve is connected to the inlet pipe of the gas-liquid separator. The outlet pipe of the gas-liquid separator is connected to the return gas pipe of the variable frequency compressor. The other end of the outdoor heat exchanger is connected to the main liquid pipe.

[0010] The first-stage jet enthalpy-increasing economizer is connected to the main liquid pipe, the liquid storage tank outlet pipe, the first-stage jet branch pipe inlet pipe, and the first-stage jet branch pipe outlet pipe. The main liquid pipe and the first-stage jet branch pipe inlet pipe are connected to the outlet end of the liquid storage tank. The inlet end of the liquid storage tank is connected to the liquid pipe of the indoor unit module. The first-stage jet branch pipe outlet pipe is connected to the variable frequency compressor.

[0011] The secondary active jet enthalpy enhancer is connected to an active jet branch inlet pipe, an active jet branch outlet pipe, an active jet water inlet pipe, and an active jet water outlet pipe. The active jet branch inlet pipe is connected to the main liquid pipe, and the active jet branch outlet pipe is connected to the variable frequency compressor. The active jet water inlet pipe and the active jet water outlet pipe are respectively connected to the outlet and return water inlet of the hot water storage tank. The hot water storage tank is connected to the solar collector tube by a hot water storage inlet pipe and a hot water storage return pipe.

[0012] Furthermore: the first subcooled electronic expansion valve is installed on the inlet pipe of the first-stage jet enthalpy enhancer, the second subcooled electronic expansion valve is installed on the inlet pipe of the active jet enthalpy enhancer, the main electronic expansion valve is installed on the main liquid pipe between the first-stage jet enthalpy enhancer and the outdoor heat exchanger, the outdoor heat exchanger is connected to the evaporator inlet pipe, and the main electronic expansion valve connects the main liquid pipe and the evaporator inlet pipe.

[0013] Furthermore, it also includes a temperature detection module, which comprises an outdoor ambient temperature sensor, an exhaust temperature sensor, an intake temperature sensor, a coil temperature sensor on the outdoor heat exchanger, a secondary active vapor injection enthalpy enhancement temperature detection component, a main liquid pipe temperature sensor, and a water tank temperature sensor. The secondary active vapor injection enthalpy enhancement temperature detection component includes a vapor injection enthalpy enhancement inlet water temperature sensor, a vapor injection enthalpy enhancement outlet water temperature sensor, a refrigerant injection inlet pipe temperature sensor, and a refrigerant injection outlet pipe temperature sensor.

[0014] The outdoor ambient temperature sensor is used to detect the outdoor ambient temperature T. ao The exhaust temperature sensor is used to detect the exhaust temperature T. d The inhalation temperature sensor is used to detect the inhalation temperature T. s The main liquid pipe temperature sensor is used to detect the main liquid pipe temperature T. liq The water tank temperature sensor is used to detect the temperature T of the hot water storage tank. tank ,

[0015] The refrigerant injection inlet temperature sensor is used to detect the inlet temperature T of the secondary vapor injection enthalpy-enhancing refrigerant. inj,in The refrigerant injection outlet temperature sensor is used to detect the outlet temperature T of the secondary vapor injection enthalpy-enhancing refrigerant. inj,out The jet enthalpy inlet water temperature sensor is used to detect the inlet temperature T on the side of the secondary jet enthalpy heat source. w-inj,in The jet enthalpy-enhancing water temperature sensor is used to detect the outlet temperature T on the side of the secondary jet enthalpy-enhancing heat source. w-inj,out .

[0016] To achieve the second objective of this invention, a control method for a solar-driven two-stage jet enthalpy-enhancing heat pump is provided, configured in the aforementioned solar-driven two-stage jet enthalpy-enhancing heat pump system, characterized in that:

[0017] Step S1: A preset first-stage jet enthalpy enhancement opening condition is configured. When the first-stage jet enthalpy enhancement opening condition is met, the control of the first-stage jet enthalpy enhancement is activated, and the opening degree of the first subcooled electronic expansion valve is adjusted.

[0018] Step S2: Configure the preset secondary jet enthalpy enhancement opening conditions. When the secondary jet enthalpy enhancement opening conditions are met, activate the control of the secondary active jet enthalpy enhancement and adjust the opening degree of the second subcooled electronic expansion valve.

[0019] Step S3: Configure a first-stage jet enthalpy enhancement shutdown condition and a second-stage jet enthalpy enhancement shutdown condition. When the first-stage jet enthalpy enhancement shutdown condition is met, the first subcooled electronic expansion valve is closed. When the second-stage jet enthalpy enhancement shutdown condition is met, the second subcooled electronic expansion valve is closed.

[0020] Furthermore: the first-stage jet enthalpy enhancement activation condition is configured with a first exhaust superheat threshold. When the compressor exhaust superheat is greater than the preset first exhaust superheat threshold, it is considered that the first-stage jet enthalpy enhancement activation condition is met.

[0021] The secondary jet enthalpy enhancement activation condition is configured with a first subcooled electronic expansion valve opening time threshold and an opening temperature difference threshold. When the opening time of the first subcooled electronic expansion valve exceeds the preset first subcooled electronic expansion valve opening time threshold and the difference between the water tank temperature and the main liquid pipe temperature is greater than the preset opening temperature difference threshold, it is considered that the secondary jet enthalpy enhancement activation condition is met.

[0022] Furthermore: the first-stage jet enthalpy reduction shut-off condition is configured with a second exhaust superheat threshold. When the actual exhaust superheat is less than the preset second exhaust superheat threshold, it is considered that the first-stage jet enthalpy reduction shut-off condition is met.

[0023] The secondary jet enthalpy enhancement shutdown condition is configured with a second exhaust superheat threshold. When the actual exhaust superheat is less than the preset second exhaust superheat threshold, it is considered that the secondary jet enthalpy enhancement shutdown condition is met.

[0024] The secondary jet enthalpy enhancement shutdown condition is further configured with a first temperature difference threshold and a second temperature difference threshold. When the inlet temperature T of the secondary jet enthalpy enhancement heat source is... w-inj,in With the second-stage jet enthalpy-enhancing refrigerant outlet temperature T inj,out The difference is less than the preset first temperature difference threshold, or when the outlet temperature T of the secondary jet enthalpy-enhancing heat source .... w-inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in If the difference is less than the preset second temperature difference threshold, it is considered to meet the second-stage jet enthalpy shut-off condition.

[0025] Furthermore: the subcooling ΔT suc Defined as the saturation temperature P corresponding to high pressure. d_t With the temperature T of the main liquid tube liqIn step S1, a first-stage jet enthalpy enhancement control strategy is configured to adjust the opening degree of the first subcooling electronic expansion valve within a preset opening degree adjustment range so that the current actual subcooling degree reaches the preset target subcooling degree value.

[0026] The first-stage jet enthalpy enhancement control strategy is configured with a target subcooling value and a subcooling hysteresis value.

[0027] If the current actual subcooling value is less than the difference between the target subcooling value and the subcooling hysteresis value, then increase the opening of the first subcooling electronic expansion valve;

[0028] If the current actual subcooling value is greater than the sum of the target subcooling value and the subcooling hysteresis value, then reduce the opening of the first subcooling electronic expansion valve;

[0029] When the current actual subcooling value is between the difference between the target subcooling value and the subcooling hysteresis value and the sum of the target subcooling value and the subcooling hysteresis value, the opening of the first subcooling electronic expansion valve remains unchanged.

[0030] Furthermore: the refrigerant injection temperature difference superheat ΔT inj Defined as the outlet temperature T of the second-stage vapor injection enthalpy-enhancing refrigerant. inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in The difference, in step S2, also includes a secondary jet enthalpy enhancement control condition and an activation control strategy. When the preset secondary jet enthalpy enhancement control condition is met, the corresponding secondary jet enthalpy enhancement activation control strategy is executed:

[0031] The secondary jet enthalpy enhancement control strategy targets a certain jet temperature difference superheat value. This strategy is configured with a target jet temperature difference superheat value and a superheat hysteresis value.

[0032] When the current injection temperature difference is superheated by ΔT inj,cur When the sum of the target injection temperature difference superheat value and the superheat hysteresis value is greater than the preset value, the opening of the second subcooling electronic expansion valve is reduced.

[0033] When the current injection temperature difference is superheated by ΔT inj,cur When the difference between the target injection temperature difference superheat value and the superheat hysteresis value is less than the difference between the target injection temperature difference superheat value and the superheat hysteresis value, the opening of the second subcooling electronic expansion valve is increased.

[0034] When the current injection temperature difference is superheated by ΔT inj,cur When the difference between the target injection temperature difference superheat value and the superheat hysteresis value is equal to the sum of the target injection temperature difference superheat value and the superheat hysteresis value, the opening of the second subcooling electronic expansion valve remains unchanged.

[0035] Furthermore, the two-stage jet enthalpy-enhancing heat pump control method is equipped with a main electronic expansion valve adjustment strategy. During the heating process, the opening of the main electronic expansion valve is adjusted by the suction superheat, and the suction superheat is defined as the suction temperature T. s Temperature T of the coil on the outdoor heat exchanger def The temperature difference between them, the main electronic expansion valve regulation strategy is configured with a target value for suction superheat.

[0036] When the detected current actual intake superheat is greater than the sum of the preset intake superheat target value and the preset intake superheat hysteresis value, the main electronic expansion valve increases its opening.

[0037] When the detected current actual intake superheat is less than the difference between the preset intake superheat target value and the preset intake superheat hysteresis value, the main electronic expansion valve reduces its opening.

[0038] When the current actual intake superheat is detected to be between the difference between the preset intake superheat target value and the preset intake superheat hysteresis value and the sum of the preset intake superheat target value and the preset intake superheat hysteresis value, the main electronic expansion valve increases its opening.

[0039] The main technical effects of this invention are reflected in the following aspects: Through two-stage jet enthalpy enhancement, multi-energy complementarity of light, electricity, heat, and air energy can be achieved, and the stored heat can be supplied quantitatively and on demand, converting it into heating capacity. This significantly improves unit performance, achieves ultra-high energy efficiency, and solves the technical bottleneck that heat pumps cannot be used in extremely low temperature environments. The first stage is conventional jet enthalpy enhancement, which increases subcooling through refrigerant injection to absorb more air energy. The second stage is active jet enthalpy enhancement, which converts external heat source heat into heating capacity through jet enthalpy difference. Moreover, through the first-stage jet enthalpy enhancement, the refrigerant temperature in the main liquid pipe of the system can be reduced, making the main liquid pipe... When the refrigerant reaches a subcooled state, it is beneficial to throttle in the subcooled electronic expansion valve, increase the temperature difference between the injected refrigerant and the external heat source in the active vapor injection enthalpy enhancer, and facilitate the absorption of heat from the external heat source, thereby improving the utilization rate of the external heat source. This invention provides two heat pump system compositions, including a direct expansion capillary radiation heat pump and a heat pump using water as the heat exchange medium, and provides a vapor injection enthalpy enhancement control method. The first-stage vapor injection enthalpy enhancement controls the opening of its subcooled electronic expansion valve with the liquid pipe subcooling degree as the target, while the second-stage active vapor injection enthalpy enhancement controls the opening of its subcooled electronic expansion valve with the refrigerant injection temperature difference superheat degree as the target. Attached Figure Description

[0040] Figure 1 System schematic diagram of a direct expansion two-stage jet enthalpy-increasing heat pump based on solar thermal energy;

[0041] Figure 2 System circulation flow diagram when conventional jet enthalpy enhancement is on and active jet enthalpy enhancement is off;

[0042] Figure 3 System circulation flow diagram when conventional jet enthalpy enhancement is on and active jet enthalpy enhancement is also on;

[0043] Figure 4 System circulation flow diagram when conventional jet enthalpy enhancement is on and active jet enthalpy enhancement is off;

[0044] Figure 5 : Control flow diagram of a solar-driven two-stage jet enthalpy-enhancing heat pump system;

[0045] Figure 6 : Control flow diagram of the main electronic expansion valve in a solar-driven two-stage jet enthalpy-enhancing heat pump system;

[0046] Figure 7 System schematic diagram of a two-stage jet enthalpy-enhancing heat pump based on solar thermal energy.

[0047] Figure label:

[0048] 1. Variable frequency compressor; 2. High pressure sensor; 3. Oil separator; 4. Four-way valve; 5. Outdoor heat exchanger; 6. Main electronic expansion valve; 7. Liquid receiver; 8. Liquid pipe shut-off valve; 9. Gas pipe shut-off valve; 10. Gas-liquid separator; 11. Oil return capillary tube; 21. First-stage jet enthalpy booster economizer; 22. First subcooled electronic expansion valve; 23. Main liquid pipe; 24. First-stage jet branch inlet pipe; 25. First-stage jet branch outlet pipe; 31. Second-stage active jet. 32. Enthalpy-increasing economizer; 33. Second subcooling electronic expansion valve; 34. Active jet branch inlet pipe; 35. Active jet branch outlet pipe; 36. Active jet inlet pipe; 47. Active jet outlet pipe; 48. Solar collector tube; 49. Hot water storage tank; 40. Hot water storage pump; 41. Jet enthalpy-increasing hot water pump; 52. Terminal indoor unit electronic expansion valve; 53. Capillary tube assembly; 64. Fan coil unit; 65. Condenser; 66. Buffer tank; 67. Heating water pump. Detailed Implementation

[0049] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so that the technical solution of the present invention can be more easily understood and mastered.

[0050] Example 1:

[0051] Reference Figure 1As shown, a two-stage vapor injection enthalpy-enhancing heat pump system based on solar energy is characterized by comprising an outdoor unit module, an indoor unit module, and a solar energy storage module. The outdoor unit module includes a variable frequency compressor 1, an oil separator 3, a four-way valve 4, an outdoor heat exchanger 5, a first-stage vapor injection enthalpy-enhancing economizer 21, a second-stage active vapor injection enthalpy-enhancing economizer 31, a main electronic expansion valve 6, a liquid storage tank 7, a first subcooled electronic expansion valve 22, and a second subcooled electronic expansion valve 32. The solar energy and heat storage module includes a hot water storage tank 43 and solar collector tubes 41.

[0052] The exhaust pipe of the variable frequency compressor 1 is connected to the d pipe of the four-way valve 4 via the oil separator 3. The e pipe of the four-way valve 4 is connected to one end of the outdoor heat exchanger 5. The c pipe of the four-way valve 4 is connected to the gas pipe of the indoor unit module. The s pipe of the four-way valve 4 is connected to one end of the gas-liquid separator 10. The other end of the gas-liquid separator 10 is connected to the return gas pipe of the variable frequency compressor 1. The other end of the outdoor heat exchanger is connected to the main liquid pipe.

[0053] The first-stage jet enthalpy-increasing economizer 21 is connected to the main liquid pipe 23, the outlet pipe of the liquid storage tank 7, the inlet pipe 24 of the first-stage jet branch pipe, and the outlet pipe 25 of the first-stage jet branch pipe. The main liquid pipe 23 and the inlet pipe 24 of the first-stage jet branch pipe are connected to the outlet end of the liquid storage tank 7 (viewed from the heating direction). The inlet end of the liquid storage tank 7 (viewed from the heating direction) is connected to the liquid pipe of the indoor unit module. The outlet pipe 25 of the first-stage jet branch pipe is connected to the variable frequency compressor 1.

[0054] The secondary active jet enthalpy enhancer 31 is connected to an active jet branch inlet pipe 33, an active jet branch outlet pipe 34, an active jet water inlet pipe 35, and an active jet water outlet pipe 36. The active jet branch inlet pipe 33 is connected to the main liquid pipe 23, the active jet branch outlet pipe 34 is connected to the variable frequency compressor 1, the active jet water inlet pipe 35 and the active jet water outlet pipe 36 are respectively connected to the outlet and return water inlet of the hot water storage tank 42, and the hot water storage tank 42 is connected to the solar collector tube 41 by a hot water storage inlet pipe and a hot water storage return pipe.

[0055] A first subcooled electronic expansion valve 22 is installed on the first-stage jet enthalpy enhancer 21, the first-stage jet branch inlet pipe 24 is installed on the second-stage active jet enthalpy enhancer 31, the second subcooled electronic expansion valve 32 is installed on the active jet branch inlet pipe 33, a main electronic expansion valve 6 is installed on the main liquid pipe between the first-stage jet enthalpy enhancer 21 and the outdoor heat exchanger 5, the outdoor heat exchanger 5 is connected to the evaporator inlet pipe (viewed from the heating direction), and the main electronic expansion valve 6 connects the main liquid pipe 23 and the evaporator inlet pipe.

[0056] A first subcooled electronic expansion valve is installed on the inlet pipe of the first-stage jet enthalpy enhancer, and a second subcooled electronic expansion valve is installed on the inlet pipe of the active jet enthalpy enhancer. A main electronic expansion valve is installed between the first-stage jet enthalpy enhancer and the outdoor heat exchanger. An evaporator inlet pipe is connected to the outdoor heat exchanger, and the main electronic expansion valve is connected to the main liquid pipe and the evaporator inlet pipe.

[0057] This application describes four operating states for the primary vapor injection enthalpy enhancer and the secondary active vapor injection enthalpy enhancer: primary vapor injection enthalpy enhancer on and secondary active vapor injection enthalpy enhancer off; both primary and secondary active vapor injection enthalpy enhancers on; and both primary and secondary active vapor injection enthalpy enhancers off. The following description, based on the operating states of the primary and secondary active vapor injection enthalpy enhancers, illustrates the circulation path of the heat pump system:

[0058] When the first-stage vapor injection enthalpy booster is activated, the injected refrigerant passes through the first subcooled electronic expansion valve 22 and enters the first-stage vapor injection enthalpy booster economizer 21. The injected refrigerant and the refrigerant in the main liquid line exchange heat in the first-stage vapor injection enthalpy booster economizer 21. The injected refrigerant is then injected into the intermediate pressure chamber of the variable frequency compressor 1. The main liquid line temperature T... liq The temperature decreases, the subcooling increases, and thus more air energy is absorbed. At the same time, because the refrigerant is injected into the intermediate pressure chamber of the inverter compressor 1, the compression work increases, thereby increasing the heating capacity.

[0059] The system loop flow diagram is as follows Figure 2 As shown, the high-temperature gaseous refrigerant discharged from the variable frequency compressor 1 enters the indoor unit module for heat exchange after passing through the oil separator 3, the d-pipe of the four-way valve 4, the c-pipe of the four-way valve 4, and the gas pipe shut-off valve 9. After releasing heat, the refrigerant passes through the liquid pipe shut-off valve 8 and the liquid receiver 7. Part of the refrigerant flows through the main liquid pipe: through the first-stage vapor injection enthalpy booster economizer 21, the main electronic expansion valve 6, the outdoor heat exchanger 5, the e-pipe of the four-way valve 4, the s-pipe of the four-way valve 4, and the gas-liquid separator 10 before returning to the variable frequency compressor 1. The other part of the refrigerant is throttled by the first subcooled electronic expansion valve 22 and enters the first-stage vapor injection enthalpy booster economizer 21 to exchange heat with the refrigerant in the main liquid pipe, and then returns to the variable frequency compressor 1 through the first-stage injection branch pipe outlet 25.

[0060] When both the primary vapor injection enthalpy enhancer and the secondary active vapor injection enthalpy enhancer are activated, during heat pump heating operation, the hot water in the storage tank 42 is pumped to the secondary active vapor injection enthalpy enhancer economizer 31 by the vapor injection enthalpy enhancer hot water pump 44. The injected refrigerant passes through the second subcooled electronic expansion valve 32 and enters the secondary active vapor injection enthalpy enhancer economizer 31, where it exchanges heat with the hot water. The refrigerant that has absorbed heat is then injected into the intermediate pressure chamber of the variable frequency compressor 1, converting the heat from the external hot water into heating capacity, significantly improving the performance of the heat pump unit. The flow rate of the vapor injection enthalpy enhancer hot water can be adjusted, thereby achieving on-demand quantitative supply of stored heat, which is then converted into heating capacity.

[0061] The system loop flow diagram is as follows Figure 3 As shown, the high-temperature gaseous refrigerant discharged from the variable frequency compressor 1 passes through the oil separator 3, the d-pipe of the four-way valve 4, the c-pipe of the four-way valve 4, and the gas pipe shut-off valve 9 before reaching the indoor unit module for heat exchange. After releasing heat, the refrigerant passes through the liquid pipe shut-off valve 8 and the liquid receiver 7. A portion of the refrigerant then flows through the main liquid pipe: through the first-stage vapor injection enthalpy enhancer 21, the main electronic expansion valve 6, the outdoor heat exchanger 5, the e-pipe of the four-way valve 4, the s-pipe of the four-way valve 4, and the gas-liquid separator 10 before returning to the variable frequency compressor 1; a portion... After being throttled by the first subcooled electronic expansion valve 22, the refrigerant enters the first-stage vapor injection enthalpy enhancer economizer 21 to exchange heat with the refrigerant in the main liquid pipe, and then returns to the variable frequency compressor 1 through the first-stage injection branch pipe outlet. Another portion of the refrigerant is throttled by the second subcooled electronic expansion valve 32 and enters the second-stage active vapor injection enthalpy enhancer economizer 31 to exchange heat with an external heat source. After evaporating and absorbing heat, it flows out through the active vapor injection pipe outlet and merges with the refrigerant flowing out of the first-stage injection branch pipe outlet, entering the intermediate pressure chamber of the variable frequency compressor 1. In this embodiment, the external heat source is specifically supplied by the hot water storage tank 42. The hot water in the hot water storage tank 42 is pumped by the vapor injection enthalpy enhancer hot water pump 44 and flows through the second-stage active vapor injection enthalpy enhancer economizer 31 to exchange heat with the refrigerant flowing through the second-stage active vapor injection enthalpy enhancer economizer 31.

[0062] When both the first-stage jet enthalpy enhancement and the second-stage active jet enthalpy enhancement are off, the system circulation flow diagram is as follows: Figure 4 As shown, the high-temperature gaseous refrigerant discharged from the variable frequency compressor 1 passes through the oil separator 3, the d-pipe of the four-way valve 4, the c-pipe of the four-way valve 4, and the gas pipe shut-off valve 9 before reaching the indoor unit module for heat exchange. After releasing heat, the refrigerant passes through the liquid pipe shut-off valve 8 and the liquid receiver 7, then through the first-stage vapor injection enthalpy enhancer 21, the main electronic expansion valve 6, the outdoor heat exchanger 5, the e-pipe of the four-way valve 4, the s-pipe of the four-way valve 4, and the gas-liquid separator 10 before returning to the variable frequency compressor 1.

[0063] The thermodynamic cycle principle and effects of two-stage jet enthalpy enhancement can be found in the description of another patent published by the applicant, CN115235004A, and will not be repeated here. The actual problem solved by this invention is to formulate an optimized control strategy, provide control logic, and achieve optimal unit performance. In addition, it addresses how to reduce the refrigerant temperature in the main liquid pipe through the first jet enthalpy enhancement, thereby making the refrigerant in the liquid pipe subcooled, increasing the subcooling degree of the refrigerant in the liquid pipe, increasing the temperature difference between the external heat source and the injected refrigerant during the second-stage jet enthalpy enhancement, thereby improving the utilization rate of the external heat source and reducing the volume of the heat storage device.

[0064] It also includes a temperature detection module, which includes an outdoor ambient temperature sensor, an exhaust temperature sensor, an intake temperature sensor, a coil temperature sensor on the outdoor heat exchanger, a secondary active vapor injection enthalpy enhancement temperature detection component, a main liquid pipe temperature sensor, and a water tank temperature sensor. The secondary active vapor injection enthalpy enhancement temperature detection component includes a refrigerant injection inlet pipe temperature sensor, a refrigerant injection outlet pipe temperature sensor, a vapor injection enthalpy enhancement water inlet temperature sensor, and a vapor injection enthalpy enhancement water outlet temperature sensor.

[0065] The outdoor ambient temperature sensor is used to detect the outdoor ambient temperature, the exhaust temperature sensor is used to detect the exhaust temperature, and the intake temperature sensor is used to detect the intake temperature T. s The main liquid pipe temperature sensor is used to detect the temperature of the main liquid pipe, and the water tank temperature sensor is used to detect the temperature of the hot water in the hot water storage tank 42.

[0066] The active injection inlet sensor is used to detect the inlet temperature T of the secondary jet enthalpy-enhancing refrigerant. inj,in The active injection outlet sensor is used to detect the outlet temperature T of the second-stage vapor injection enthalpy-enhancing refrigerant. inj,out The jet enthalpy inlet water temperature sensor is used to detect the inlet temperature T on the side of the secondary jet enthalpy heat source. w-inj,in The jet enthalpy-enhancing water temperature sensor is used to detect the outlet temperature T on the side of the secondary jet enthalpy-enhancing heat source. w-inj,out .

[0067] In this embodiment, the indoor unit module includes multiple sets of capillary tube assemblies 52 connected in parallel and one or more fan coil units 53. Figure 1 Only one set of fan coil units is provided in the document, but in practice, multiple sets of fan coil units can be freely matched. Figure 1 The diagram shows two sets of capillary tube assemblies 52 and one set of fan coil unit 53. In reality, multiple sets of capillary tube assemblies 52 and fan coil unit 53 can be freely matched. Each capillary tube assembly 52 or fan coil unit 53 is equipped with an electronic expansion valve 51 at the end of the indoor unit.

[0068] To achieve the second objective of this invention, please refer to Figure 5This paper provides a control method for a solar-driven two-stage jet enthalpy-enhancing heat pump, configured in a solar-driven two-stage jet enthalpy-enhancing heat pump system as described above.

[0069] Step S1: A preset first-stage jet enthalpy enhancement opening condition is configured. When the first-stage jet enthalpy enhancement opening condition is met, the control of the first-stage jet enthalpy enhancement is activated, and the opening degree of the first subcooled electronic expansion valve 22 is adjusted.

[0070] Step S2: Configure the preset secondary jet enthalpy enhancement opening conditions. When the secondary jet enthalpy enhancement opening conditions are met, activate the secondary active jet enthalpy enhancement and adjust the opening degree of the second subcooled electronic expansion valve 22.

[0071] Step S3: Configure a first-stage jet enthalpy enhancement shutdown condition and a second-stage jet enthalpy enhancement shutdown condition. When the first-stage jet enthalpy enhancement shutdown condition is met, the first subcooled electronic expansion valve 22 is closed. When the second-stage jet enthalpy enhancement shutdown condition is met, the second subcooled electronic expansion valve 32 is closed.

[0072] For ease of understanding, the following description will proceed in the following order: opening the first-stage jet enthalpy enhancement, controlling the first-stage jet enthalpy enhancement, closing the first-stage jet enthalpy enhancement, opening the second-stage jet enthalpy enhancement, controlling the second-stage jet enthalpy enhancement, and closing the second-stage jet enthalpy enhancement.

[0073] Activation of the first-stage jet enthalpy enhancement:

[0074] The first-stage jet enthalpy activation condition is configured with a first exhaust superheat threshold ΔT. d,set1 [Setting Value 1] When the current actual compressor exhaust superheat is greater than the preset first exhaust superheat threshold, it is considered that the first-level jet enthalpy enhancement opening condition is met, specifically: the current exhaust superheat ΔT d ≥Preset first exhaust superheat threshold ΔT d,set1 [Setting 1] defines exhaust superheat ΔT d =Exhaust temperature T d - The saturation temperature P corresponding to high pressure d_t Therefore, this system is also equipped with a high-pressure sensor 2 to detect the corresponding high-pressure and calculate the corresponding saturation temperature P. d_t Thus, the corresponding exhaust superheat ΔT can be calculated. d To enable jet enthalpy enhancement, the first stage of jet enthalpy enhancement is activated, and the first subcooled electronic expansion valve 21 opens to its initial opening degree, which is V. open1 [Setting value 2].

[0075] Control of first-stage jet enthalpy enhancement:

[0076] In step S1, a first-stage jet enthalpy boosting control strategy is also configured. The first-stage jet enthalpy boosting control strategy is configured to adjust the opening of the first subcooling electronic expansion valve 22 within a preset opening adjustment range so that the subcooling reaches the preset target subcooling value.

[0077] With subcooling ΔT suc The opening of the first subcooling electronic expansion valve 22 must be adjusted to the target, and the target subcooling is set to ΔT. suc,tar [Set value 3], subcooling ΔT suc Defined as the saturation temperature P corresponding to high pressure. d_t With the temperature T of the main liquid tube liq The difference. The first-stage jet enthalpy boosting control strategy is configured with a target subcooling value ΔT. suc,tar [Setting value 3] and subcooling hysteresis value [Setting value 4].

[0078] When the current actual subcooling value ΔT suc <Preset target subcooling value ΔT suc,tar - If the subcooling hysteresis value is increased, the opening of the first subcooling electronic expansion valve 22 will be increased;

[0079] When the current actual subcooling value ΔT suc >Preset target subcooling value ΔT suc,tar If [Setting value 3] + subcooling hysteresis value [Setting value 4], then reduce the opening of the first subcooling electronic expansion valve 22;

[0080] When the preset target supercooling value ΔT suc,tar [Settings 3] - Subcooling Hysteresis [Settings 4] ≤ Current Actual Subcooling Value ΔT suc ≤Preset target subcooling value ΔT suc,tar [Set value 3] + subcooling hysteresis value [Set value 4], the opening of the first subcooling electronic expansion valve 22 remains unchanged.

[0081] Considering that an excessively large subcooling valve opening increases the compressor's operating load, leading to high compressor power and reduced energy efficiency, the subcooling valve opening range is set to V. open1,min ~V open1,max V open1,min Press [Setting value 5], V open1,max Press [Setting value 6].

[0082] Shutdown of the first-stage jet enthalpy enhancement:

[0083] In step S3, the first-stage jet enthalpy reduction shut-off condition is configured with a second exhaust superheat threshold. When the exhaust superheat is less than the second exhaust superheat threshold, the first-stage jet enthalpy reduction shut-off condition is considered to be met; that is, when the current actual exhaust superheat ΔT is detected... d ≤Second exhaust superheat ΔTd,set2 When [Set Value 7] is reached, the first subcooled electronic expansion valve 22 is closed.

[0084] The activation of the second-stage jet enthalpy enhancement:

[0085] In step S2, the secondary jet enthalpy enhancement opening conditions are configured with a first subcooled electronic expansion valve opening time threshold and an opening temperature difference threshold. When the opening time of the first subcooled electronic expansion valve 22 exceeds the first subcooled electronic expansion valve opening time threshold and the current water tank temperature T tank With the current main liquid pipe temperature T liq The difference is greater than the preset opening temperature difference threshold ΔT tank,liq When this occurs, it is considered that the conditions for opening the secondary jet enthalpy enhancement valve are met. That is: after the first-stage jet enthalpy enhancement valve has been running for time t [set value 8], if the current water tank temperature T is detected... tank Current main liquid pipe temperature T liq The second stage of jet enthalpy enhancement is activated, and the corresponding second subcooled electronic expansion valve 32 is opened with an initial opening degree V. open2 [Set value 9], using the hot water from the external hot water storage tank 43 as the heat source for jet enthalpy enhancement, the water pump is turned on, and the water flow rate is kept constant at Y m 3 / h[Set value 10].

[0086] With the primary jet enthalpy enhancement on, after the secondary jet enthalpy enhancement shutdown time reaches the preset waiting time [set value 11], a determination is made as to whether the conditions for the secondary jet enthalpy enhancement to be on are met. If the conditions are met, the secondary active jet enthalpy enhancement is performed again.

[0087] Control of secondary jet enthalpy enhancement:

[0088] In step S2, a secondary jet enthalpy enhancement start-up control strategy is also configured. When the preset secondary jet enthalpy enhancement start-up conditions are met, the corresponding secondary jet enthalpy enhancement start-up control strategy is executed:

[0089] The secondary jet enthalpy enhancement control strategy takes a certain jet temperature difference superheat value as the control target, and the secondary jet enthalpy enhancement control strategy is configured with a target jet temperature difference superheat value [set value 12] and a superheat hysteresis value [set value 13].

[0090] When the current injection temperature difference is superheated by ΔT inj,cur When the actual injection temperature difference superheat value ΔT is greater than the preset sum of the target injection temperature difference superheat value and the superheat hysteresis value, the opening of the second subcooling electronic expansion valve 32 is reduced; that is: when the current actual injection temperature difference superheat value ΔT is greater than the preset sum of the target injection temperature difference superheat value and the superheat hysteresis value, the opening of the second subcooling electronic expansion valve 32 is reduced; that is: when the actual injection temperature difference superheat value ΔT inj_cur >ΔT inj_set [Set value 12] + Superheat Hysteresis Value δT inj [Set value 13], the opening of the second subcooled electronic expansion valve 32 is reduced;

[0091] When the current injection temperature difference is superheated by ΔT inj,cur When the difference between the target injection temperature difference superheat value and the superheat hysteresis value is less than the target injection temperature difference superheat value, the opening of the second subcooling electronic expansion valve 32 is increased; that is: when the actual injection superheat ΔT inj_cur <ΔT inj_set [Set value 12] - Superheat hysteresis value δT inj [Set value 13], the opening of the second subcooled electronic expansion valve 32 is increased;

[0092] When the current injection temperature difference is superheated by ΔT inj,cur When the difference between the target injection temperature difference superheat value and the superheat hysteresis value is equal to the sum of the target injection temperature difference superheat value and the superheat hysteresis value, the opening of the second subcooling electronic expansion valve 32 remains unchanged. That is: when the set value ΔT... inj_set [Set value 12] - Superheat hysteresis value δT inj [Set value 13] ≤ Actual injection superheat ΔT inj_cur ≤ΔT inj_set [Set value 12] + Superheat Hysteresis Value δT inj [Set value 13], the second subcooled electronic expansion valve 32 maintains its current opening.

[0093] Shutdown of the second-stage jet enthalpy enhancement:

[0094] The secondary jet enthalpy enhancement shutdown condition is configured with a second exhaust superheat threshold. When the exhaust superheat is less than the preset second exhaust superheat threshold, the secondary jet enthalpy enhancement shutdown condition is considered met; that is, when the actual exhaust superheat ΔT is detected... d ≤Second exhaust superheat threshold ΔT d,set2 When [set value 14] is reached, the second subcooled electronic expansion valve closes 32, and the second-stage jet enthalpy enhancement stops operating.

[0095] The secondary jet enthalpy shut-off condition is also configured with a first temperature difference threshold T. w-in,inj-out,set1 Second temperature difference threshold T w-in,inj-out,set2 When the inlet temperature T of the secondary jet enthalpy-enhancing heat source side w-inj,in With the second-stage jet enthalpy-enhancing refrigerant outlet temperature T inj,out The difference is less than the preset first temperature difference threshold, or when the outlet temperature T of the secondary jet enthalpy-enhancing heat source .... w-inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in If the difference is less than the preset second temperature difference threshold, it is considered to meet the second-stage jet enthalpy shut-off condition; that is: when T is detected... w-inj,in <T inj,out +T w-in,inj-out,set1 or T w-inj,out <T inj,in +T w-out,inj-in,set2At that time, that is, the inlet temperature T on the side of the secondary jet enthalpy enhancement heat source. w-inj,in With the second-stage jet enthalpy-enhancing refrigerant outlet temperature T inj,out The difference is less than T w-in,inj-out,set1 Or the outlet temperature T of the secondary jet enthalpy source. w-inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in The difference is less than T w-out,inj-in,set2 When it is determined that the unit can no longer effectively utilize external heat sources to increase heat production, the jet enthalpy-enhancing hot water pump 44 is immediately shut down, the active jet flow regulating valve is adjusted to the closed state, and the opening of the second subcooling electronic expansion valve 32 is adjusted to 0. (T) w-in,inj-out,set1 and T w-out,inj-in,set2 The values ​​can be set to the same value.

[0096] like Figure 6 As shown, the two-stage jet enthalpy-enhancing heat pump control method is equipped with a main electronic expansion valve adjustment strategy. Upon receiving a heating start-up command, the machine starts, and the main electronic expansion valve 6 opens to a preset initial degree. During the heating process, the opening degree of the main electronic expansion valve 6 is adjusted by the suction superheat, and the suction superheat is defined as the suction temperature T. s The coil temperature T on outdoor heat exchanger 5 def The temperature difference between them, the main electronic expansion valve regulation strategy is configured with a target value for suction superheat.

[0097] When the detected current actual intake superheat is greater than the preset intake superheat target value + the preset intake superheat hysteresis value, the main electronic expansion valve 6 increases its opening.

[0098] When the detected current actual intake superheat is less than the preset intake superheat target value - the preset intake superheat hysteresis value, the main electronic expansion valve 6 reduces its opening.

[0099] When the preset intake superheat target value - preset intake superheat hysteresis value ≤ current actual intake superheat ≤ preset intake superheat target value + preset intake superheat hysteresis value, the main electronic expansion valve 6 increases its opening.

[0100] After each adjustment of the opening degree, the main electronic expansion valve 6 re-detects the current actual intake superheat after a certain preset time interval.

[0101] If any of the following conditions are met, exit the current control and follow the control procedure below:

[0102] 1) When the unit enters defrosting mode, the main electronic expansion valve remains at the preset defrosting opening;

[0103] 2) The unit is shut down. After the preset time has elapsed since the shutdown, the main electronic expansion valve 6 is closed.

[0104] Example 2:

[0105] like Figure 7 As shown, Example 2 provides a system schematic diagram of a two-stage jet enthalpy-increasing heat pump using water as the heat exchange medium. Unlike Example 1, the indoor unit module in Example 2 is specifically a heat pump unit using water as the heat exchange medium. The indoor unit is a hydraulic module, which consists of a condenser 61, a heating water pump 63, and a buffer tank 62. It can be used to heat other home facilities, such as underfloor heating. The control method is the same as in Example 1.

[0106] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A control method for a solar-driven two-stage jet enthalpy-enhancing heat pump, characterized in that: Configured in a solar-driven two-stage vapor injection enthalpy-enhancing heat pump system, the system includes an outdoor unit module, an indoor unit module, and a solar thermal storage module. The outdoor unit module includes a variable frequency compressor (1), an oil separator (3), a four-way valve (4), an outdoor heat exchanger (5), a first-stage vapor injection enthalpy-enhancing economizer (21) and a first subcooled electronic expansion valve (22), a second-stage active vapor injection enthalpy-enhancing economizer (31) and a second subcooled electronic expansion valve (32). The solar thermal storage module includes a solar collector tube (41) and a hot water storage tank (42). The exhaust pipe of the variable frequency compressor (1) is connected to the d pipe of the four-way valve (4) through the oil separator (3). The e pipe of the four-way valve (4) is connected to one end of the outdoor heat exchanger (5). The c pipe of the four-way valve (4) is connected to the gas pipe of the indoor unit module. The s pipe of the four-way valve (4) is connected to the inlet pipe of the gas-liquid separator (10). The outlet pipe of the gas-liquid separator (10) is connected to the return gas pipe of the variable frequency compressor (1). The other end of the outdoor heat exchanger (5) is connected to the main liquid pipe (23). The first-stage jet enthalpy booster (21) is connected to the main liquid pipe (23), the outlet pipe of the liquid storage tank (7), the inlet pipe (24) of the first-stage jet branch pipe, and the outlet pipe (25) of the first-stage jet branch pipe. The main liquid pipe (23) and the inlet pipe (24) of the first-stage jet branch pipe are connected to the outlet end of the liquid storage tank (7). The inlet end of the liquid storage tank (7) is connected to the liquid pipe of the indoor unit module. The outlet pipe (25) of the first-stage jet branch pipe is connected to the variable frequency compressor (1). The secondary active jet enthalpy enhancer (31) is connected to an active jet branch inlet pipe (33), an active jet branch outlet pipe (34), an active jet water inlet pipe (35), and an active jet water outlet pipe (36). The active jet branch inlet pipe (33) is connected to the main liquid pipe (23), the active jet branch outlet pipe (34) is connected to the variable frequency compressor (1), the active jet water inlet pipe (35) and the active jet water outlet pipe (36) are respectively connected to the outlet and return water inlet of the hot water storage tank (42), and the hot water storage tank (42) and the solar collector pipe (41) are connected by a hot water storage inlet pipe and a hot water storage return pipe. The first subcooled electronic expansion valve (22) is installed on the first-stage jet enthalpy enhancer's first-stage jet branch inlet pipe (24), the second subcooled electronic expansion valve (32) is installed on the second-stage active jet enthalpy enhancer's active jet branch inlet pipe (33), the main liquid pipe between the first-stage jet enthalpy enhancer (21) and the outdoor heat exchanger (5) is installed with a main electronic expansion valve (6), the outdoor heat exchanger (5) is connected to an evaporator inlet pipe, and the main electronic expansion valve (6) is connected to the main liquid pipe (23) and the evaporator inlet pipe; The two-stage jet enthalpy-enhancing heat pump control method includes: Step S1: Configure the preset first-stage jet enthalpy enhancement opening conditions. When the first-stage jet enthalpy enhancement opening conditions are met, activate the control of the first-stage jet enthalpy enhancement and adjust the opening degree of the first subcooled electronic expansion valve (22). Step S2: Configure the preset secondary jet enthalpy enhancement opening conditions. When the secondary jet enthalpy enhancement opening conditions are met, activate the control of the secondary active jet enthalpy enhancement and adjust the opening degree of the second subcooled electronic expansion valve (32). Step S3: Configure a first-stage jet enthalpy enhancement shutdown condition and a second-stage jet enthalpy enhancement shutdown condition. When the first-stage jet enthalpy enhancement shutdown condition is met, the first subcooled electronic expansion valve (22) is closed. When the second-stage jet enthalpy enhancement shutdown condition is met, the second subcooled electronic expansion valve (32) is closed. The first-stage jet enthalpy enhancement activation condition is configured with a first exhaust superheat threshold. When the compressor exhaust superheat is greater than the preset first exhaust superheat threshold, it is considered that the first-stage jet enthalpy enhancement activation condition is met. The secondary jet enthalpy enhancement activation condition is configured with a first subcooled electronic expansion valve opening time threshold and an opening temperature difference threshold. When the opening time of the first subcooled electronic expansion valve exceeds the preset first subcooled electronic expansion valve opening time threshold and the difference between the water tank temperature and the main liquid pipe temperature is greater than the preset opening temperature difference threshold, it is considered that the secondary jet enthalpy enhancement activation condition is met.

2. The control method for a solar-driven two-stage jet enthalpy-enhancing heat pump as described in claim 1, characterized in that: The two-stage vapor injection enthalpy-enhancing heat pump system also includes a temperature detection module, which comprises an outdoor ambient temperature sensor, an exhaust temperature sensor, an intake temperature sensor, a coil temperature sensor on the outdoor heat exchanger, a main liquid pipe temperature sensor, a water tank temperature sensor, and a secondary active vapor injection enthalpy-enhancing temperature detection component. The secondary active vapor injection enthalpy-enhancing temperature detection component includes a vapor injection enthalpy-enhancing water inlet temperature sensor, a vapor injection enthalpy-enhancing water outlet temperature sensor, a refrigerant injection inlet pipe temperature sensor, and a refrigerant injection outlet pipe temperature sensor. The outdoor ambient temperature sensor is used to detect the outdoor ambient temperature T. ao The exhaust temperature sensor is used to detect the exhaust temperature T. d The inhalation temperature sensor is used to detect the inhalation temperature T. s The main liquid pipe temperature sensor is used to detect the main liquid pipe temperature T. liq The water tank temperature sensor is used to detect the temperature T of the hot water storage tank (42). tank , The refrigerant injection inlet temperature sensor is used to detect the inlet temperature T of the secondary vapor injection enthalpy-enhancing refrigerant. inj,in The refrigerant injection outlet temperature sensor is used to detect the outlet temperature T of the secondary vapor injection enthalpy-enhancing refrigerant. inj,out The jet enthalpy inlet water temperature sensor is used to detect the inlet temperature T on the side of the secondary jet enthalpy heat source. w-inj,in The jet enthalpy-enhancing water temperature sensor is used to detect the outlet temperature T on the side of the secondary jet enthalpy-enhancing heat source. w-inj,out .

3. The two-stage jet enthalpy-enhancing heat pump control method based on solar energy as described in claim 1, wherein the first-stage jet enthalpy-enhancing shut-off condition is configured with a second exhaust superheat threshold. When the actual exhaust superheat is less than the preset second exhaust superheat threshold, it is considered that the first-stage jet enthalpy-enhancing shut-off condition is met. The secondary jet enthalpy enhancement shutdown condition is configured with a second exhaust superheat threshold. When the actual exhaust superheat is less than the preset second exhaust superheat threshold, it is considered that the secondary jet enthalpy enhancement shutdown condition is met. The secondary jet enthalpy enhancement shutdown condition is further configured with a first temperature difference threshold and a second temperature difference threshold. When the inlet temperature T of the secondary jet enthalpy enhancement heat source is... w-inj,in With the second-stage jet enthalpy-enhancing refrigerant outlet temperature T inj,out The difference is less than the preset first temperature difference threshold, or when the outlet temperature T of the secondary jet enthalpy-enhancing heat source .... w-inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in If the difference is less than the preset second temperature difference threshold, it is considered to meet the second-stage jet enthalpy shut-off condition.

4. The method for controlling a solar-driven two-stage jet enthalpy-enhancing heat pump as described in claim 1, wherein the subcooling ΔT suc Defined as the saturation temperature P corresponding to high pressure. d_t With the temperature T of the main liquid tube liq The difference, in step S1, is further configured with a first-stage jet enthalpy boosting control strategy, which is configured to adjust the opening of the first subcooling electronic expansion valve (22) within a preset opening adjustment range so that the current actual subcooling reaches the preset target subcooling value. The first-stage jet enthalpy enhancement control strategy is configured with a target subcooling value and a subcooling hysteresis value. When the current actual subcooling value is less than the difference between the target subcooling value and the subcooling hysteresis value, the opening of the first subcooling electronic expansion valve (22) is increased; If the current actual subcooling value is greater than the sum of the target subcooling value and the subcooling hysteresis value, then reduce the opening of the first subcooling electronic expansion valve (22); When the preset target supercooling value ΔT suc,tar - Subcooling hysteresis value ≤ Current actual subcooling value ΔT suc ≤Preset target subcooling value ΔT suc,tar + Subcooling hysteresis value, the opening of the first subcooling electronic expansion valve (22) remains unchanged.

5. The method for controlling a solar-driven two-stage jet enthalpy-enhancing heat pump as described in claim 1, wherein the refrigerant injection temperature difference superheat ΔT inj Defined as the outlet temperature T of the second-stage vapor injection enthalpy-enhancing refrigerant. inj,out With the inlet temperature T of the second-stage jet enthalpy-enhancing refrigerant inj,in The difference, in step S2, also includes a secondary jet enthalpy enhancement control condition and an activation control strategy. When the preset secondary jet enthalpy enhancement control condition is met, the corresponding secondary jet enthalpy enhancement activation control strategy is executed: The secondary jet enthalpy enhancement control strategy targets a certain jet temperature difference superheat value. This strategy is configured with a target jet temperature difference superheat value and a superheat hysteresis value. When the current injection temperature difference is superheated by ΔT inj,cur When the sum of the target injection temperature difference superheat value and the superheat hysteresis value is greater than the preset target injection temperature difference superheat value, the opening degree of the second subcooling electronic expansion valve (32) is reduced. When the current injection temperature difference is superheated by ΔT inj,cur When the difference between the target injection temperature difference superheat value and the superheat hysteresis value is less than the difference between the target injection temperature difference superheat value and the superheat hysteresis value, the opening degree of the second subcooling electronic expansion valve (32) is increased. When the target spray temperature difference superheat value ΔT inj_set -Superheat Hysteresis Value δT inj ≤Current injection temperature difference superheat ΔT inj_cur ≤Target injection temperature difference superheat value ΔT inj_set +Superheat Hysteresis Value δT inj The opening of the second subcooled electronic expansion valve (32) remains unchanged.

6. A control method for a solar-driven two-stage vapor injection enthalpy-enhancing heat pump as described in claim 1, wherein the two-stage vapor injection enthalpy-enhancing heat pump control method is configured with a main electronic expansion valve adjustment strategy, wherein the opening of the main electronic expansion valve is adjusted by the suction superheat during the heating process, and the suction superheat is defined as the suction temperature T. s The temperature T of the coil on the outdoor heat exchanger (5) def The temperature difference between them, the main electronic expansion valve regulation strategy is configured with a target value for suction superheat. When the detected current actual intake superheat is greater than the sum of the preset intake superheat target value and the preset intake superheat hysteresis value, the main electronic expansion valve (6) increases the opening. When the detected current actual intake superheat is less than the difference between the preset intake superheat target value and the preset intake superheat hysteresis value, the main electronic expansion valve (6) reduces its opening. When the preset target value of intake superheat - the preset hysteresis value of intake superheat ≤ the current actual intake superheat ≤ the preset target value of intake superheat + the preset hysteresis value of intake superheat, the main electronic expansion valve (6) increases its opening.

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