Double-source heat pump direct expansion drying system based on photovoltaic photo-thermal and operation method

Abstract

The invention relates to a double-source heat pump direct expansion drying system based on photovoltaic and photo-thermal and an operation method. The system comprises a photovoltaic and photo-thermal module, a PV / T heat source side plate type heat exchanger, a liquid reservoir, a four-way reversing valve, an evaporator, a condenser, a compressor, a first electromagnetic valve and a second electromagnetic valve. The photovoltaic photo-thermal module is connected with the PV / T heat source side plate heat exchanger and used for providing a heat source for the PV / T heat source side plate heat exchanger, a liquid outlet of the liquid reservoir is connected with a liquid inlet of the PV / T heat source side plate heat exchanger through a first electromagnetic valve and connected with a liquid inlet of the evaporator through a second electromagnetic valve, and the first electromagnetic valve and the second electromagnetic valve are connected in parallel; a liquid outlet of the PV / T heat source side plate heat exchanger is connected with a liquid outlet of the evaporator in parallel through the four-way reversing valve and connected with a liquid inlet of the compressor in series, a liquid outlet of the compressor is connected with the condenser, and the condenser is connected with the liquid reservoir through the four-way reversing valve. Compared with the prior art, the system has the advantages of good operation stability, good energy-saving effect and the like.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a photovoltaic-thermal-based dual-source heat pump direct expansion drying system and an operation method thereof. Background Art

[0002] At present, buildings require a lot of energy for heating, air conditioning, lighting and electricity use, among which cooling and heating consume the most energy. With the global emphasis on environmental protection and sustainable development, the application of renewable energy in the construction field will become more and more extensive. Global environmental issues have made reducing the demand for energy in buildings an important issue.

[0003] By adopting energy-saving technologies, promoting sustainable building materials and developing renewable energy, we can reduce the energy consumption and environmental impact of buildings and promote sustainable energy development.

[0004] However, the current photovoltaic thermal units are unstable due to climate change and the alternation of day and night, which affects the use in daily life. When the temperature of the photovoltaic thermal unit is too high, the photoelectric conversion efficiency will decrease. On the other hand, the air source heat pump also has the problem of performance degradation due to the decrease of ambient temperature.

[0005] The 40-50℃ aging room needs to heat the fresh air for direct expansion drying. At present, the air entering the room is mostly heated by electric heating, but the traditional electric heating has low efficiency in the use of electric energy, which is not conducive to the sustainable development of energy. Therefore, it is necessary to provide a direct expansion drying system that has strong environmental adaptability, stable operation and sustainable development. Summary of the invention

[0006] The purpose of the present invention is to provide a dual-source heat pump direct expansion drying system and operation method based on photovoltaic thermal energy in order to overcome the defects of the above-mentioned prior art in that the fresh air is heated electrically, which has low energy utilization efficiency and is not conducive to the sustainable development of energy.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] This solution provides a photovoltaic-thermal dual-source heat pump direct expansion drying system, including a photovoltaic-thermal module, a PV / T heat source side plate heat exchanger, a liquid storage tank, a four-way reversing valve, an evaporator, a condenser, a compressor, a first solenoid valve, and a second solenoid valve;

[0009] The photovoltaic thermal module is connected to the PV / T heat source side plate heat exchanger to provide heat source to the PV / T heat source side plate heat exchanger, the liquid outlet of the liquid reservoir is connected to the liquid inlet of the PV / T heat source side plate heat exchanger through a first solenoid valve, and is connected to the liquid inlet of the evaporator through a second solenoid valve, and the first solenoid valve and the second solenoid valve are connected in parallel;

[0010] The liquid outlet of the PV / T heat source side plate heat exchanger is connected in parallel with the liquid outlet of the evaporator through a four-way reversing valve and in series with the liquid inlet of the compressor. The liquid outlet of the compressor is connected to the condenser, and the condenser is connected to the liquid receiver through the four-way reversing valve.

[0011] Furthermore, the system also includes a bypass defrost module, which includes a gas-liquid separator, a third solenoid valve and a fourth solenoid valve; the liquid outlet of the compressor is connected to the liquid inlet of the PV / T heat source side plate heat exchanger through the fourth solenoid valve, the liquid outlet of the compressor is connected to the liquid inlet of the evaporator through the third solenoid valve, and the gas-liquid separator is connected in series with the liquid inlet of the compressor.

[0012] Furthermore, the system also includes a temperature sensor, a thermal expansion valve and a one-way valve, wherein the temperature sensor is connected to the thermal expansion valve, and the temperature sensor is used to monitor the temperature of the refrigerant medium in the PV / T heat source side plate heat exchanger, and the thermal expansion valve is located between the first solenoid valve and the liquid inlet of the PV / T heat source side plate heat exchanger; the liquid inlet of the PV / T heat source side plate heat exchanger is connected to the inlet of the one-way valve, and the outlet of the one-way valve is connected to the liquid outlet of the liquid reservoir.

[0013] Furthermore, the condenser is arranged in the room air inlet channel for heating the room air inlet. The room air inlet channel is also provided with an electric heater and a drying air supply temperature sensor. The drying air supply temperature sensor is used to monitor the temperature of the room air inlet, and the electric heater is used to assist in heating the room air inlet.

[0014] Further, the photovoltaic thermal module includes a water source side circulating water pump, a PV / T hot water storage tank, a PV / T circulating water pump and a PV / T photovoltaic thermal panel;

[0015] The PV / T hot water storage tank is connected to the PV / T photovoltaic thermal panel via a PV / T circulating water pump, and is used to store the heat energy generated by the PV / T photovoltaic thermal panel in the PV / T hot water storage tank. The PV / T heat source side plate heat exchanger is connected to the PV / T hot water storage tank via a water source side circulating water pump, and is used to thermally exchange the heat in the PV / T hot water storage tank with the medium flowing through the PV / T heat source side plate heat exchanger.

[0016] This solution also provides a dual-source heat pump direct expansion drying operation method based on photovoltaic thermal energy, using the dual-source heat pump direct expansion drying system based on photovoltaic thermal energy, the photovoltaic thermal module includes a PV / T hot water storage tank and a water source temperature sensor, and the operation method includes the following steps:

[0017] The temperature of the medium inside the PV / T hot water storage tank is obtained through the water source temperature sensor;

[0018] When the detected temperature is greater than the threshold, the refrigerant medium is heated by the PV / T heat source side plate heat exchanger and then transported to the compressor. The medium heated and pressurized by the compressor is then transported to the condenser to heat the incoming air in the room.

[0019] When the detected temperature is lower than the threshold, the refrigerant medium is heated by the evaporator and then transported to the compressor. The medium heated and pressurized by the compressor is then transported to the condenser to heat the incoming air in the room.

[0020] Furthermore, the specific steps of heating the refrigerant medium by the PV / T heat source side plate heat exchanger include:

[0021] When the temperature of hot water in the PV / T hot water storage tank is greater than a threshold value, the first solenoid valve is opened and the second solenoid valve is closed;

[0022] Make the PV / T heat source side plate heat exchanger interact with the photovoltaic thermal module to obtain heat from the photovoltaic thermal module;

[0023] The refrigerant in the liquid storage tank is transported to the plate heat exchanger on the PV / T heat source side, and the refrigerant is heated by the plate heat exchanger on the PV / T heat source side;

[0024] The refrigerant heated by the PV / T heat source side plate heat exchanger enters the compressor through a four-way reversing valve for heating and pressurization, and then is transported to the condenser to heat the room air intake;

[0025] The refrigerant cooled in the condenser enters the liquid receiver through the four-way reversing valve.

[0026] Furthermore, the condenser is arranged in the room air inlet channel, and the room air inlet channel is also provided with an electric heater and a drying air supply temperature sensor; the specific steps of the evaporator heating the refrigerant medium include:

[0027] When the temperature of hot water in the PV / T hot water storage tank is less than a threshold value, the first solenoid valve is closed and the second solenoid valve is opened;

[0028] The refrigerant in the liquid storage tank is transported to the evaporator, and the evaporator takes heat from the external environment to heat the refrigerant;

[0029] The heated refrigerant is transported to the compressor for heating and pressurization, and then transported to the condenser to heat the room air intake. The cooled refrigerant in the condenser enters the liquid receiver through the four-way reversing valve;

[0030] The drying air supply temperature sensor detects the room inlet air temperature after heating. When the inlet air temperature is lower than the inlet air threshold, the electric heater is turned on to assist in heating the room inlet air.

[0031] Furthermore, the system also includes a bypass defrost module, a gas-liquid separator, a third solenoid valve and a fourth solenoid valve in the bypass defrost module; the liquid outlet of the compressor is connected to the liquid inlet of the PV / T heat source side plate heat exchanger through the fourth solenoid valve, the liquid outlet of the compressor is connected to the liquid inlet of the evaporator through the third solenoid valve, and the gas-liquid separator is connected in series with the liquid inlet of the compressor;

[0032] The specific steps of the bypass defrosting module for defrosting the PV / T heat source side plate heat exchanger and the evaporator include:

[0033] Close the first solenoid valve and the second solenoid valve, and open the third solenoid valve and the fourth solenoid valve;

[0034] The heated and pressurized refrigerant at the liquid outlet of the compressor flows through the PV / T heat source side plate heat exchanger to release heat, defrost the surface of the PV / T heat source side plate heat exchanger, and the cooled refrigerant enters the gas-liquid separator through the four-way reversing valve;

[0035] The heated and pressurized refrigerant at the liquid outlet of the compressor flows through the evaporator to generate heat, defrosting the surface of the evaporator, and the cooled refrigerant directly enters the gas-liquid separator.

[0036] Furthermore, the system further comprises a temperature sensor, a thermal expansion valve and a one-way valve, wherein the temperature sensor is connected to the thermal expansion valve, and the thermal expansion valve is located between the first solenoid valve and the liquid inlet of the plate heat exchanger on the PV / T heat source side; the liquid inlet of the plate heat exchanger on the PV / T heat source side is connected to the inlet of the one-way valve, and the outlet of the one-way valve is connected to the liquid outlet of the liquid reservoir;

[0037] The temperature of the refrigerant flowing into the liquid inlet of the plate heat exchanger on the PV / T heat source side is detected by a temperature sensor, and the detected temperature is compared with a threshold range;

[0038] If the detected temperature is greater than the threshold range, the flow rate of the thermal expansion valve increases;

[0039] If the detected temperature is lower than the threshold range, the flow rate of the thermal expansion valve is reduced, and part of the refrigerant medium outputted from the liquid receiver flows back to the liquid receiver through the one-way valve.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) This solution detects the temperature of the working fluid of the photovoltaic thermal module and uses the PV / T heat source side plate heat exchanger to transfer the heat of the working fluid of the photovoltaic thermal module. The working fluid heat of the photovoltaic thermal module is used to heat the refrigerant medium in the liquid storage tank first, and the heated and pressurized medium is used to heat the fresh air in the aging room. Secondly, the air heat source is used to heat the fresh air in the aging room. Compared with heating the fresh air in the aging room only by air heat source heat pump, this solution avoids the problem of performance degradation of the air source heat pump due to the instability of climate change and day and night alternation, which leads to the decrease in ambient temperature. The heating of the fresh air in the room is more stable and the energy utilization efficiency is higher.

[0042] (2) The system operation method of this scheme monitors the temperature in the PV / T heat storage tank in the photovoltaic thermal module. When the temperature in the PV / T heat storage tank exceeds the threshold, the excess energy in the photovoltaic thermal module is used to heat the fresh air in the aging room through the PV / T heat source side plate heat exchanger. The operation of the entire unit is more stable and the energy-saving effect is significant. It can also ensure that the temperature of the photovoltaic thermal module is within a suitable range, avoiding the problem of photovoltaic thermal module performance degradation due to temperature increase. The PV / T photovoltaic thermal panel is collected and transmitted by the PV / T heat storage tank, and is used in conjunction with a dual-source heat pump to heat the fresh air in the aging room, thereby improving the utilization rate of light energy.

[0043] (3) In this solution, the unit combines multiple energy-saving technologies, integrating photovoltaic thermal heat recovery and direct expansion drying functions into an integrated device, which improves the utilization rate of the equipment. This equipment has intelligent centralized control and can be controlled according to needs. It has a high degree of intelligence and is easy to operate.

[0044] (4) In this scheme, the condenser of the dual-source heat pump unit is arranged at the fresh air inlet of the aging room at 40-50℃. Compared with the traditional method of heating fresh air only by electric heating, the medium is used to obtain solar heat and air heat, and the fresh air in the room is heated, which improves the energy utilization efficiency. In addition, a temperature sensor and an electric heater are set at the fresh air inlet of the room to monitor the room inlet temperature and assist in heating, so as to ensure that the room inlet temperature meets the requirements and ensure the direct expansion drying effect of the room.

[0045] (5) This scheme takes into account that low-temperature and low-pressure refrigerant circulates in the plate heat exchanger on the PV / T heat source side and the evaporator. In extreme weather, frost will form on the surface of the plate heat exchanger on the PV / T heat source side and the evaporator, affecting the heat exchange of the heat exchanger. By connecting the output end of the compressor to the liquid inlet of the plate heat exchanger on the PV / T heat source side and the evaporator, high-temperature and high-pressure gas is introduced into them to remove the frost on the surface and ensure the heat exchange effect, that is, the heating effect of the refrigerant medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of the structure of a dual-source heat pump direct expansion drying system provided by the present invention;

[0047] In the figure: 1. evaporator, 2. condenser, 3. liquid storage tank, 4. four-way reversing valve, 5. electric heater, 6. compressor, 7. gas-liquid separator, 8. PV / T heat source side plate heat exchanger, 9. temperature sensor, 10. thermal expansion valve, 11. filter, 12. first solenoid valve, 13. check valve, 14. variable frequency fan, 15. electronic expansion valve, 16. circulating water pump on water source side, 17. PV / T heat storage tank, 18. PV / T circulating water pump, 19. PV / T photovoltaic thermal panel, 20. drying air supply temperature sensor, 21. second solenoid valve, 22. third solenoid valve, 23. fourth solenoid valve. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0051] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0052] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0053] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0054] Example 1

[0055] like Figure 1 As shown, this embodiment provides a dual-source heat pump direct expansion drying system based on photovoltaic thermal energy, including a photovoltaic thermal energy module, a PV / T heat source side plate heat exchanger 8, a liquid storage tank 3, a four-way reversing valve 4, an evaporator 1, a condenser 2, a compressor 6, a first solenoid valve 12 and a second solenoid valve 21;

[0056] The photovoltaic thermal module is connected to the PV / T heat source side plate heat exchanger 8, and is used to provide heat source to the PV / T heat source side plate heat exchanger 8. The liquid outlet of the liquid reservoir 3 is connected to the liquid inlet of the PV / T heat source side plate heat exchanger 8 through the first solenoid valve 12, and is connected to the liquid inlet of the evaporator 1 through the second solenoid valve 21. The first solenoid valve 12 and the second solenoid valve 21 are connected in parallel;

[0057] The liquid outlet of the PV / T heat source side plate heat exchanger 8 is connected in parallel with the liquid outlet of the evaporator 1 through the four-way reversing valve 4, and is connected in series with the liquid inlet of the compressor 6. The liquid outlet of the compressor 6 is connected to the condenser 2, and the condenser 2 is connected to the liquid receiver 3 through the four-way reversing valve 4.

[0058] The heat of the working fluid of the photovoltaic thermal module is transmitted by the PV / T heat source side plate heat exchanger, and the working fluid heat of the photovoltaic thermal module is used to heat the refrigerant medium in the liquid storage tank, and the heated and pressurized medium is used to heat the fresh air in the aging room, and then the air heat source is used to heat the fresh air in the aging room. Compared with heating the fresh air in the aging room only by the air heat source heat pump, this solution avoids the problem of performance degradation of the air source heat pump due to the instability of climate change and day and night alternation, which leads to the decrease in ambient temperature. The heating of the fresh air in the room is more stable and the energy utilization efficiency is higher.

[0059] In a preferred embodiment, the system also includes a bypass defrost module, a bypass defrost module gas-liquid separator 7, a third solenoid valve 22 and a fourth solenoid valve 23; the liquid outlet of the compressor 6 is connected to the liquid inlet of the PV / T heat source side plate heat exchanger 8 through the fourth solenoid valve 23, the liquid outlet of the compressor 6 is connected to the liquid inlet of the evaporator 1 through the third solenoid valve 22, and the gas-liquid separator 7 is connected in series with the liquid inlet of the compressor 6.

[0060] Considering that low-temperature and low-pressure refrigerant circulates in the plate heat exchanger on the PV / T heat source side and the evaporator, in extreme weather, frost will form on the surface of the plate heat exchanger on the PV / T heat source side and the evaporator, affecting the heat exchange of the heat exchanger; by connecting the output end of the compressor to the liquid inlet of the plate heat exchanger on the PV / T heat source side and the evaporator, and passing high-temperature and high-pressure gas into them, the frost on the surface can be removed to ensure the heat exchange effect, that is, the heating effect of the refrigerant medium.

[0061] In a preferred embodiment, the system also includes a temperature sensor 9, a thermal expansion valve 10 and a one-way valve 13. The temperature sensor 9 is connected to the thermal expansion valve 10. The temperature sensor 9 is used to monitor the temperature of the refrigerant medium in the plate heat exchanger 8 on the PV / T heat source side. The thermal expansion valve 10 is located between the first solenoid valve and the liquid inlet of the plate heat exchanger 8 on the PV / T heat source side; the liquid inlet of the plate heat exchanger 8 on the PV / T heat source side is connected to the inlet of the one-way valve 13, and the outlet of the one-way valve 13 is connected to the liquid outlet of the liquid reservoir 3.

[0062] A refrigerant return pipeline is set between the thermal expansion valve 10 and the plate heat exchanger 8 on the PV / T heat source side. When the low-temperature and low-pressure wet steam after throttling does not reach the operating state, part of the liquid refrigerant returns to the liquid storage tank 3 through the one-way valve 13; according to the feedback from the temperature sensor 9, if the temperature of the refrigerant on the plate heat exchanger on the PV / T heat source side is too low, the thermal expansion valve 10 is closed in time to protect the plate heat exchanger on the PV / T heat source side, thereby improving the operating reliability and safety of the system.

[0063] Among them, the condenser 2 is arranged in the room air inlet channel for heating the room air inlet. The room air inlet channel is also provided with an electric heater 5 and a drying air supply temperature sensor 20. The drying air supply temperature sensor 20 is used to monitor the temperature of the room air inlet, and the electric heater 5 is used to assist in heating the room air inlet.

[0064] The dual-source heat pump unit condenser is arranged at the fresh air inlet of the aging room at 40-50℃. Compared with the traditional method of heating fresh air only by electric heating, the medium is used to obtain solar heat and air heat, and the fresh air in the room is heated, which improves the energy utilization efficiency. In addition, a temperature sensor and an electric heater are set at the fresh air inlet of the room to monitor the room's inlet air temperature and assist in heating, ensuring that the room's inlet air temperature meets the requirements and the room's direct expansion drying effect is guaranteed.

[0065] Specifically, the photovoltaic thermal module includes a water source side circulating water pump 16, a PV / T hot water storage tank 17, a PV / T circulating water pump 18 and a PV / T photovoltaic thermal panel 19;

[0066] The PV / T hot water storage tank 17 is connected to the PV / T photovoltaic thermal panel 19 via a PV / T circulating water pump 18, and is used to store the heat energy generated by the PV / T photovoltaic thermal panel 19 in the PV / T hot water storage tank 17. The PV / T heat source side plate heat exchanger 8 is connected to the PV / T hot water storage tank 17 via a water source side circulating water pump 16, and is used to thermally exchange the heat in the PV / T hot water storage tank 17 with the medium flowing through the PV / T heat source side plate heat exchanger 8.

[0067] This embodiment also provides a dual-source heat pump direct expansion drying operation method based on photovoltaic thermal energy. Using the dual-source heat pump direct expansion drying system based on photovoltaic thermal energy, the photovoltaic thermal module includes a PV / T hot water storage tank 17 and a water source temperature sensor. The operation method includes the following steps:

[0068] The temperature of the water inside the PV / T hot water storage tank 17 is obtained through a water source temperature sensor;

[0069] When the detected temperature is greater than the threshold, the refrigerant medium in the liquid storage tank 3 is heated by the PV / T heat source side plate heat exchanger 8 and then transported to the compressor 6. The medium heated and pressurized by the compressor 6 is then transported to the condenser 2 to heat the incoming air of the room;

[0070] When the detected temperature is lower than the threshold, the refrigerant medium in the liquid storage tank 3 is heated by the evaporator 1 and then transported to the compressor 6. The medium heated and pressurized by the compressor 6 is then transported to the condenser 2 to heat the incoming air of the room.

[0071] The temperature in the PV / T heat storage tank in the photovoltaic thermal module is monitored. When the temperature in the PV / T heat storage tank exceeds the threshold, the excess energy in the photovoltaic thermal module is used to heat the fresh air in the aging room through the PV / T heat source side plate heat exchanger. The entire unit operates more stably and has significant energy-saving effects. It can also ensure that the temperature of the photovoltaic thermal module is within a suitable range, avoiding the problem of performance degradation of the photovoltaic thermal module due to temperature increase. The heat collection and transmission of the PV / T photovoltaic thermal panel through the PV / T heat storage tank is used to heat the fresh air in the aging room with a dual-source heat pump, which improves the utilization rate of light energy.

[0072] Specifically, the specific steps of the PV / T heat source side plate heat exchanger 8 heating the refrigerant medium include:

[0073] When the temperature of the hot water in the PV / T hot water storage tank 17 is greater than a threshold value, the first solenoid valve 12 is opened and the second solenoid valve 21 is closed;

[0074] Make the PV / T heat source side plate heat exchanger 8 interact with the photovoltaic thermal module to obtain heat in the photovoltaic thermal module;

[0075] The refrigerant in the liquid storage tank 3 is transported to the PV / T heat source side plate heat exchanger 8, and the PV / T heat source side plate heat exchanger 8 heats the refrigerant;

[0076] The refrigerant heated by the PV / T heat source side plate heat exchanger 8 enters the compressor 6 through the four-way reversing valve 4 for heating and pressurization, and then is transported to the condenser 2 to heat the room air;

[0077] The refrigerant cooled in the condenser 2 enters the liquid receiver 3 through the four-way reversing valve 4 .

[0078] The condenser 2 is arranged in the air inlet passage of the room, and an electric heater 5 and a drying air supply temperature sensor 20 are also arranged in the air inlet passage of the room; the specific steps of heating the refrigerant medium by the evaporator 1 include:

[0079] When the temperature of hot water in the PV / T hot water storage tank 17 is less than a threshold value, the first solenoid valve 12 is closed and the second solenoid valve 21 is opened;

[0080] The refrigerant in the liquid storage tank 3 is transported to the evaporator 1, and the evaporator 1 takes heat from the external environment to heat the refrigerant;

[0081] The heated refrigerant is transported to the compressor 6 for heating and pressurization, and then transported to the condenser 2 to heat the room air intake. The cooled refrigerant in the condenser 2 enters the liquid receiver 3 through the four-way reversing valve 4;

[0082] The drying air supply temperature sensor 20 detects the room inlet air temperature after heating. When the inlet air temperature is lower than the inlet air threshold, the electric heater 5 is turned on to assist in heating the room inlet air.

[0083] In a preferred embodiment, the system further includes a bypass defrost module, a bypass defrost module gas-liquid separator 7, a third solenoid valve 22 and a fourth solenoid valve 23; the liquid outlet of the compressor 6 is connected to the liquid inlet of the PV / T heat source side plate heat exchanger 8 through the fourth solenoid valve 23, the liquid outlet of the compressor 6 is connected to the liquid inlet of the evaporator 1 through the third solenoid valve 22, and the gas-liquid separator 7 is connected in series with the liquid inlet of the compressor 6;

[0084] The specific steps of the bypass defrosting module for defrosting the PV / T heat source side plate heat exchanger 8 and the evaporator 1 include:

[0085] Close the first solenoid valve 12 and the second solenoid valve 21, and open the third solenoid valve 22 and the fourth solenoid valve 23;

[0086] The heated and pressurized refrigerant at the liquid outlet of the compressor 6 flows through the PV / T heat source side plate heat exchanger 8 to release heat, defrost the surface of the PV / T heat source side plate heat exchanger 8, and the cooled refrigerant passes through the four-way reversing valve 4 and enters the gas-liquid separator 7;

[0087] The heated and pressurized refrigerant at the liquid outlet of the compressor 6 flows through the evaporator 1 to generate heat, defrosting the surface of the evaporator 1, and the cooled refrigerant directly enters the gas-liquid separator 7.

[0088] Furthermore, the system also includes a temperature sensor 9, a thermal expansion valve 10 and a one-way valve 13. The temperature sensor 9 is connected to the thermal expansion valve 10. The thermal expansion valve 10 is located between the first solenoid valve and the liquid inlet of the plate heat exchanger 8 on the PV / T heat source side; the liquid inlet of the plate heat exchanger 8 on the PV / T heat source side is connected to the inlet of the one-way valve 13, and the outlet of the one-way valve 13 is connected to the liquid outlet of the liquid reservoir 3;

[0089] The temperature of the refrigerant flowing into the liquid inlet of the plate heat exchanger 8 on the PV / T heat source side is detected by the temperature sensor 9, and the detected temperature is compared with the threshold range;

[0090] If the detected temperature is greater than the threshold range, the flow rate of the thermal expansion valve 10 increases;

[0091] If the detected temperature is lower than the threshold range, the flow rate of the thermal expansion valve 10 is reduced, and part of the refrigerant medium outputted from the liquid reservoir 3 flows back into the liquid reservoir 3 through the one-way valve 13 .

[0092] The unit combines a variety of energy-saving technologies, integrating photovoltaic thermal heat recovery and direct expansion drying functions into an integrated device, which improves the utilization rate of the equipment. This equipment has intelligent centralized control and can be controlled according to needs. It has a high degree of intelligence and is easy to operate.

[0093] In combination with the above preferred implementation modes, Figure 1 As shown, this embodiment also provides a more specific implementation method:

[0094] The photovoltaic thermal dual-source heat pump direct expansion drying system includes; evaporator 1, condenser 2, liquid storage tank 3, four-way reversing valve 4, electric heater 5, compressor 6, gas-liquid separator 7, PV / T heat source side plate heat exchanger 8, temperature sensor 9, thermal expansion valve 10, filter 11, first solenoid valve 12, one-way valve 13, variable frequency fan 14, electronic expansion valve 15, water source side circulating water pump 16, PV / T heat storage tank 17, PV / T circulating water pump 18, PV / T photovoltaic thermal panel 19, drying air supply temperature sensor 20 and second solenoid valve 21, etc.

[0095] Specifically, the evaporator 1 is located outdoors and utilizes the energy of outdoor air. The compressor 6, condenser 2, four-way reversing valve 4 and liquid reservoir 3 are connected in sequence, one end of the liquid reservoir 3 is connected to the PV / T heat source side plate heat exchanger 8, and the other end is connected to the evaporator 1; the PV / T heat source side plate heat exchanger is connected to the compressor 6 through the four-way reversing valve 4 and the evaporator 1, forming a refrigerant pipeline circulation. A gas-liquid separator 7 is provided between the PV / T heat source side plate heat exchanger 8 and the evaporator 1 and the compressor 6.

[0096] The condenser 2 is installed at the fresh air inlet of the 40-50℃ aging room to heat the fresh air for direct expansion drying; a PV / T hot water storage tank 17 is arranged between the PV / T photovoltaic thermal panel 19 and the PV / T heat source side plate heat exchanger 8, and a PV / T circulating water pump 18 is arranged between the PV / T photovoltaic thermal panel 19 and the PV / T hot water storage tank 17 to collect and store the heat of the PV / T photovoltaic thermal panel 19; a water source side circulating water pump 16 is arranged between the PV / T hot water storage tank 17 and the PV / T heat source side plate heat exchanger 8 to transfer the heat stored in the PV / T hot water storage tank 17.

[0097] An electric heater 5 and a supply air temperature sensor 20 are also arranged in sequence at the fresh air inlet of the 40-50°C aging room to assist heating and temperature detection when the heat exchange of the condenser 2 is insufficient.

[0098] A first solenoid valve 12 and a thermal expansion valve 10 are provided between the liquid reservoir 3 and the plate heat exchanger 8 on the PV / T heat source side, and a second solenoid valve 21 and an electronic expansion valve 15 are provided between the liquid reservoir 3 and the evaporator 1. According to the feedback from the temperature sensor 9, if the temperature of the refrigerant on the plate heat exchanger on the PV / T heat source side is too low, the thermal expansion valve 10 is closed in time to protect the plate heat exchanger on the PV / T heat source side. A refrigerant return pipeline is provided between the thermal expansion valve 10 and the plate heat exchanger 8 on the PV / T heat source side. When the low-temperature and low-pressure wet steam after throttling does not reach the operating state, part of the liquid refrigerant flows back to the liquid reservoir 3 through the one-way valve 13.

[0099] A refrigerant bypass pipeline is arranged at the outlet of the compressor 6, and the outlet of the compressor 6 is respectively connected to the inlet of the plate heat exchanger 8 on the PV / T heat source side and the inlet of the evaporator 1. A fourth solenoid valve 23 is arranged on the bypass pipeline between the compressor 6 and the plate heat exchanger 8 on the PV / T heat source side, and a third solenoid valve 22 is arranged on the bypass pipeline between the compressor 6 and the evaporator 1. The high-temperature and high-pressure refrigerant generated by the compressor 6 is used to defrost the plate heat exchanger 8 on the PV / T heat source side and the evaporator 1.

[0100] Specifically, the unit is also equipped with a temperature sensor for detecting the working fluid of the photovoltaic thermal module, and is connected to the control module to perform strict temperature monitoring on the entire unit. It is also equipped with a patch sensor, an automatic exhaust valve, an electromagnetic flow meter, a pressure sensor, a pressure gauge, a flow switch and a thermometer, which are conventional settings in the prior art to ensure the normal operation of each heat exchange module, and will not be described in detail.

[0101] This embodiment also provides a more specific operation process of the above system:

[0102] The specific process of direct expansion drying in 40-50℃ aging room is as follows:

[0103] Detect the temperature of hot water in the PV / T hot water storage tank 17. When the detected temperature exceeds the threshold, the circulating water pump 16 on the water source side is turned on, the first solenoid valve 12 on the plate heat exchanger 8 on the PV / T heat source side is turned on, and the second solenoid valve 21 on the evaporator 1 side is closed. The system takes heat from the hot water storage tank 17, and the refrigerant flows from the liquid storage tank 3 through the plate heat exchanger 8 on the PV / T heat source side for heating, and then passes through the four-way reversing valve 4E→S direction to return to the compressor 6 inlet. The high-temperature and high-pressure refrigerant processed by the compressor 6 releases heat through the condenser 2 at the fresh air inlet of the 40-50°C aging room. The fresh air is heated and blown into the aging room by the fan for direct expansion drying. After that, the refrigerant passes through the four-way reversing valve 4D→C direction to return to the liquid storage 3;

[0104] Detect the temperature of hot water in the PV / T hot water storage tank 17. When the detected temperature does not exceed the threshold, the first solenoid valve 12 on the plate heat exchanger 8 side of the PV / T heat source is closed and the second solenoid valve 21 on the evaporator 1 side is opened. The system takes heat from the outdoor air, and the refrigerant flows from the liquid receiver 3 through the evaporator 1 and is heated back to the compressor 6. The high-temperature and high-pressure refrigerant treated by the compressor 6 releases heat through the condenser 2 at the fresh air inlet of the 40-50°C aging room. The fresh air is heated and blown into the aging room by the fan for direct expansion drying. After that, the refrigerant passes through the four-way reversing valve 4D→C and returns to the liquid receiver 3;

[0105] The drying air supply temperature sensor 20 detects the air supply temperature. When the detected temperature does not exceed the threshold, the electric heater 5 is turned on to assist in heating the fresh air for the drying task.

[0106] The specific process of refrigerant bypass defrosting is as follows:

[0107] Since low-temperature and low-pressure refrigerant flows through the PV / T heat source side plate heat exchanger 8 and the evaporator 1, in extreme weather, frost will form on the surface of the PV / T heat source side plate heat exchanger 8 and the evaporator 1, affecting the heat exchange of the heat exchanger.

[0108] ① Defrosting process of the plate heat exchanger 8 on the PV / T heat source side: the first solenoid valve 12 on the plate heat exchanger 8 on the PV / T heat source side and the second solenoid valve 21 on the evaporator 1 side are closed, and the fourth solenoid valve 23 is opened. The high-temperature and high-pressure refrigerant treated by the compressor 6 flows through the bypass pipe through the plate heat exchanger 8 on the PV / T heat source side to release heat, and defrosts the surface of the plate heat exchanger 8 on the PV / T heat source side. Then the refrigerant returns to the gas-liquid separator 7 before the inlet of the compressor 6 through the four-way reversing valve 4E→S.

[0109] ② Defrosting process of evaporator 1: the first solenoid valve 12 on the plate heat exchanger 8 side of the PV / T heat source is closed and the second solenoid valve 21 on the evaporator 1 side is closed, and the third solenoid valve 22 is opened. The high-temperature and high-pressure refrigerant treated by the compressor 6 flows through the evaporator 1 through the bypass pipe to release heat and defrost the surface of the evaporator 1. Then the refrigerant returns to the gas-liquid separator 7 before the inlet of the compressor 6.

[0110] System protection specific process:

[0111] The temperature sensor 9 feedbacks that the superheat of the plate heat exchanger 8 on the PV / T heat source side is greater than 10°C, and the flow of the thermal expansion valve 10 increases; the superheat of the plate heat exchanger 8 on the PV / T heat source side is less than 5°C, and the flow of the thermal expansion valve 10 decreases.

[0112] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A dual-source heat pump direct expansion drying system based on photovoltaic thermal energy, characterized in that: It comprises a photovoltaic thermal module, a PV / T heat source side plate heat exchanger (8), a liquid storage tank (3), a four-way reversing valve (4), an evaporator (1), a condenser (2), a compressor (6), a first solenoid valve (12) and a second solenoid valve (21); The photovoltaic thermal module is connected to the PV / T heat source side plate heat exchanger (8) for providing heat source to the PV / T heat source side plate heat exchanger (8); the liquid outlet of the liquid reservoir (3) is connected to the liquid inlet of the PV / T heat source side plate heat exchanger (8) via a first solenoid valve (12), and is connected to the liquid inlet of the evaporator (1) via a second solenoid valve (21); the first solenoid valve (12) and the second solenoid valve (21) are connected in parallel; The liquid outlet of the PV / T heat source side plate heat exchanger (8) is connected in parallel with the liquid outlet of the evaporator (1) through a four-way reversing valve (4), and is connected in series with the liquid inlet of the compressor (6); the liquid outlet of the compressor (6) is connected to the condenser (2), and the condenser (2) is connected to the liquid storage tank (3) through the four-way reversing valve (4).

2. A photovoltaic-thermal dual-source heat pump direct expansion drying system according to claim 1, characterized in that: The system also includes a bypass defrost module, the bypass defrost module includes a gas-liquid separator (7), a third solenoid valve (22) and a fourth solenoid valve (23); the liquid outlet of the compressor (6) is connected to the liquid inlet of the PV / T heat source side plate heat exchanger (8) through the fourth solenoid valve (23), the liquid outlet of the compressor (6) is connected to the liquid inlet of the evaporator (1) through the third solenoid valve (22), and the gas-liquid separator (7) is connected in series with the liquid inlet of the compressor (6).

3. The photovoltaic-thermal dual-source heat pump direct expansion drying system according to claim 1 is characterized in that: The system further comprises a temperature sensor (9), a thermal expansion valve (10) and a one-way valve (13); the temperature sensor (9) is connected to the thermal expansion valve (10); the temperature sensor (9) is used to monitor the temperature of the cold medium in the plate heat exchanger (8) on the PV / T heat source side; the thermal expansion valve (10) is located between the first solenoid valve and the liquid inlet of the plate heat exchanger (8) on the PV / T heat source side; the liquid inlet of the plate heat exchanger (8) on the PV / T heat source side is connected to the inlet of the one-way valve (13); and the outlet of the one-way valve (13) is connected to the liquid outlet of the liquid reservoir (3).

4. The photovoltaic-thermal dual-source heat pump direct expansion drying system according to claim 1 is characterized in that: The condenser (2) is arranged in the room air inlet channel and is used to heat the room air inlet. The room air inlet channel is also provided with an electric heater (5) and a drying air supply temperature sensor (20). The drying air supply temperature sensor (20) is used to monitor the temperature of the room air inlet, and the electric heater (5) is used to assist in heating the room air inlet.

5. The photovoltaic-thermal dual-source heat pump direct expansion drying system according to claim 1 is characterized in that: The photovoltaic thermal module comprises a water source side circulating water pump (16), a PV / T hot water storage tank (17), a PV / T circulating water pump (18) and a PV / T photovoltaic thermal panel (19); The PV / T hot water storage tank (17) is connected to the PV / T photovoltaic thermal panel (19) via a PV / T circulating water pump (18) and is used to store the heat energy generated by the PV / T photovoltaic thermal panel (19) in the PV / T hot water storage tank (17); the PV / T heat source side plate heat exchanger (8) is connected to the PV / T hot water storage tank (17) via a water source side circulating water pump (16) and is used to perform thermal interaction between the heat in the PV / T hot water storage tank (17) and the medium flowing through the PV / T heat source side plate heat exchanger (8).

6. A photovoltaic-thermal dual-source heat pump direct expansion drying operation method, using a photovoltaic-thermal dual-source heat pump direct expansion drying system according to any one of claims 1 to 5, characterized in that: The photovoltaic thermal module comprises a PV / T hot water storage tank (17) and a water source temperature sensor, and the operation method comprises the following steps: Obtaining the temperature of water inside the PV / T hot water storage tank (17) through a water source temperature sensor; When the detected temperature is greater than the threshold, the refrigerant medium is heated by the PV / T heat source side plate heat exchanger (8) and then transported to the compressor (6). The medium heated and pressurized by the compressor (6) is then transported to the condenser (2) to heat the incoming air of the room. When the detected temperature is lower than the threshold value, the refrigerant medium is heated by the evaporator (1) and then transported to the compressor (6). The medium heated and pressurized by the compressor (6) is then transported to the condenser (2) to heat the incoming air of the room.

7. The operating method according to claim 6, characterized in that: The specific steps of heating the refrigerant medium by the PV / T heat source side plate heat exchanger (8) include: When the temperature of hot water in the PV / T hot water storage tank (17) is greater than a threshold value, the first solenoid valve (12) is opened and the second solenoid valve (21) is closed; The PV / T heat source side plate heat exchanger (8) interacts with the photovoltaic thermal module to obtain heat from the photovoltaic thermal module; The refrigerant in the liquid storage tank (3) is transported to the PV / T heat source side plate heat exchanger (8), and the PV / T heat source side plate heat exchanger (8) heats the refrigerant; The refrigerant heated by the PV / T heat source side plate heat exchanger (8) passes through the four-way reversing valve (4) into the compressor (6) for heating and pressurization, and then is transported to the condenser (2) to heat the room air; The refrigerant cooled in the condenser (2) is transported to the liquid storage tank (3) through the four-way reversing valve (4).

8. The operating method according to claim 6, characterized in that: The condenser (2) is arranged in the room air inlet passage, and the room air inlet passage is also provided with an electric heater (5) and a drying air supply temperature sensor (20); the specific steps of the evaporator (1) heating the refrigerant medium include: When the temperature of hot water in the PV / T hot water storage tank (17) is lower than a threshold value, the first solenoid valve (12) is closed and the second solenoid valve (21) is opened; The refrigerant in the liquid storage device (3) is transported to the evaporator (1), and the evaporator (1) takes heat from the external environment to heat the refrigerant; The heated refrigerant is transported to the compressor (6) for heating and pressurization, and then transported to the condenser (2) to heat the room air intake. The refrigerant cooled in the condenser (2) enters the liquid storage tank (3) through the four-way reversing valve (4); The drying air supply temperature sensor (20) detects the room inlet air temperature after heating, and when the inlet air temperature is lower than the inlet air threshold, the electric heater (5) is turned on to assist in heating the room inlet air.

9. The operating method according to claim 6, characterized in that: The system further comprises a bypass defrost module, the bypass defrost module comprises a gas-liquid separator (7), a third solenoid valve (22) and a fourth solenoid valve (23); the liquid outlet of the compressor (6) is connected to the liquid inlet of the PV / T heat source side plate heat exchanger (8) through the fourth solenoid valve (23), the liquid outlet of the compressor (6) is connected to the liquid inlet of the evaporator (1) through the third solenoid valve (22), and the gas-liquid separator (7) is connected in series with the liquid inlet of the compressor (6); The specific steps of the bypass defrosting module defrosting the PV / T heat source side plate heat exchanger (8) and the evaporator (1) include: The first solenoid valve (12) and the second solenoid valve (21) are closed, and the third solenoid valve (22) and the fourth solenoid valve (23) are opened; The heated and pressurized refrigerant at the liquid outlet of the compressor (6) flows through the PV / T heat source side plate heat exchanger (8) to release heat, defrosting the surface of the PV / T heat source side plate heat exchanger (8), and the cooled refrigerant passes through the four-way reversing valve (4) and enters the gas-liquid separator (7); The heated and pressurized refrigerant at the liquid outlet of the compressor (6) flows through the evaporator (1) to generate heat, thereby defrosting the surface of the evaporator (1), and the cooled refrigerant directly enters the gas-liquid separator (7).

10. The operating method according to claim 6, characterized in that: The system further comprises a temperature sensor (9), a thermal expansion valve (10) and a one-way valve (13); the temperature sensor (9) is connected to the thermal expansion valve (10); the thermal expansion valve (10) is located between the first solenoid valve and the liquid inlet of the plate heat exchanger (8) on the PV / T heat source side; the liquid inlet of the plate heat exchanger (8) on the PV / T heat source side is connected to the inlet of the one-way valve (13); and the outlet of the one-way valve (13) is connected to the liquid outlet of the liquid reservoir (3); The temperature of the refrigerant flowing into the liquid inlet of the plate heat exchanger (8) on the PV / T heat source side is detected by a temperature sensor (9), and the detected temperature is compared with a threshold range; If the detected temperature is greater than the threshold range, the flow rate of the thermal expansion valve (10) increases; If the detected temperature is lower than the threshold value range, the flow rate of the thermal expansion valve (10) is reduced, and part of the refrigerant medium output from the liquid storage device (3) flows back into the liquid storage device (3) through the one-way valve (13).

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