Photovoltaic power generation cold and heat energy recovery and utilization device and method

Abstract

The present invention relates to the field of new energy application technology, and specifically to a photovoltaic power generation cold and heat energy recovery and utilization device and method. Photovoltaic modules are used and installed in groups and tilted to form a controllable closed structure, and a layer of movable transparent insulation film is installed on the photovoltaic modules to cover and seal the photovoltaic modules for insulation during the heating season; then the light and heat energy absorbed by the photovoltaic modules is collected by a heat pump, and the heat energy is stored by a heat accumulator, and combined with the control of intelligent trough energy storage at night, it is used for heating; in the non-heating season, the photovoltaic closed space is opened, and the transparent insulation film on the module is rolled up to reduce the temperature of the module and the room to improve the efficiency of photovoltaic power generation, and the heat accumulator is used to store cold for indoor use. The present invention can increase the utilization rate of solar energy by 200% compared with simple photovoltaic power generation, and increase the efficiency by more than 40% compared with ordinary heat pumps. It can solve the problems of clean heating and long-term income increase in rural areas at a low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy application, and in particular to a device and method for recycling cold and heat energy from photovoltaic power generation. Background Art

[0002] Solar photovoltaic power generation is a renewable clean energy that uses solar energy to generate electricity that has been developed in recent years. It is now fully mature and is becoming popular.

[0003] Due to the scarcity of natural gas resources in my country and the dispersion and inconvenience of rural areas in the north, it is more appropriate to use clean energy to solve the problem of winter heating in rural areas by replacing coal with electricity. However, for ordinary electric heating, whether or not using off-peak electricity, the heating cost of direct electric heating or replacing coal with natural gas is about three times that of traditional coal. Even for ordinary air-to-air heat pumps with higher efficiency, the heating cost is nearly twice that of coal, which greatly restricts the development of clean energy heating. As a new energy source, photovoltaic power generation has greatly reduced its cost and its technology is fully mature. However, at present, photovoltaic power generation components only convert up to 20% of light into electricity, and more than 70% is converted into heat energy, but this part of heat energy is wasted. If this part of heat energy can be effectively used for winter heating at a low cost, the cost of electric heating can be greatly reduced and the efficiency of solar energy utilization can be improved. However, because photovoltaic modules are exposed to the air, this heat energy will quickly dissipate into the atmosphere in winter due to its low energy temperature and cannot be effectively utilized. The heat pump can be used to transport low-temperature heat source energy to high-end heat source, so there are many explorations in the development of solar energy for winter heating technology. For example, the hot water production solution using a heat pump combined with a solar vacuum tube has high heating efficiency, but the heating capacity is the least in the season that needs heat energy the most, and the utilization rate in other seasons is very low. Therefore, people are exploring more technical applications that combine photovoltaics and solar thermal energy.

[0004] Using photovoltaic power generation as energy storage to directly drive heat pumps for cooling and heating applications is another technical approach to combining solar energy with heat pumps. For example, the invention patent with patent number 201810834187.3 discloses a phase change energy storage floor radiant cooling and heating system driven by a photovoltaic heat pump. It mainly uses photovoltaic power generation as energy and uses air energy heat pumps to produce hot water directly for heating and cooling. These technologies only use the energy of photovoltaic power generation and the energy saving of the heat pump itself, and do not realize the utilization of thermal energy generated in the photovoltaic power generation process, which is equivalent to 3-4 times the energy of photovoltaic power generation itself.

[0005] The utility model patent with the patent number of 201621284826 discloses a photovoltaic heat pump combined system, which is one of the technologies that utilize the thermal energy of the photovoltaic power generation process. It also uses a heat pump to utilize this low-density thermal energy. Its main feature is that the heat pump evaporator is embedded on the back of the photovoltaic module to realize the utilization of thermal energy. The main problem is that a corresponding evaporator needs to be installed on the back of each photovoltaic module, which will greatly increase the complexity and cost of the system. In addition, because the photovoltaic module has double-sided heat dissipation, when heat energy is needed in winter, most of the main heat will be lost from the upper surface, greatly reducing the value. In summer, heat energy is not needed, and the heat pump system needs to be operated for the heat dissipation of the photovoltaic module, thereby reducing the power generation efficiency.

[0006] The invention patent with patent number 201510383263.X discloses a combined heat and power energy supply system and its working method, which is another technology that is beneficial to photovoltaic power generation. In order to improve the utilization rate of thermal energy in winter, it adopts heat pipe type heat collection and insulation photovoltaic components, and cooperates with hot water and heat pump parallel circulation system to efficiently utilize thermal energy. However, due to the high cost of components and complex system configuration, in addition, in the non-heating season, due to the existence of heat pipe insulation, the efficiency of power generation and transmission is greatly reduced, and the overall cost performance is too low to be promoted and utilized. Summary of the invention

[0007] The present invention aims to solve the above problems, thereby providing a photovoltaic power generation heat and cold energy recovery device and method which can efficiently and low-cost utilize the heat energy in the power generation process of ordinary photovoltaic modules without affecting power generation and heat pump use in other seasons.

[0008] The present invention solves the above-mentioned problem by adopting the following technical solution:

[0009] A photovoltaic power generation cold and heat energy recovery and utilization device comprises a photovoltaic module, a heat pump heat collection system, a heat accumulator, and an indoor energy heat exchanger. The photovoltaic modules are arranged in rows and groups and tilted in a closed space of a closed structure. The closed structure comprises a seal arranged around and above the top of the photovoltaic module, and a heat insulation film module arranged above the photovoltaic module and capable of being unfolded or retracted. The heat pump heat collection system comprises a heat pump evaporator arranged in the closed space corresponding to the photovoltaic module, a heat pump compressor and a condenser arranged outside the closed space and connected to the heat pump evaporator. The heat accumulator is connected to the indoor energy heat exchanger through an external circulation pump to form a closed loop. In the heating season, the heat insulation film module is unfolded to cover the photovoltaic module and the surrounding of the closed photovoltaic module for heat insulation, the light and heat energy absorbed by the photovoltaic module is collected by the heat pump heat collection system, and the heat energy is stored in the heat accumulator for indoor heating. In the non-heating season, the heat insulation film module is retracted to open the closed space of the photovoltaic module to reduce the temperature of the photovoltaic module and the indoor temperature to improve the photovoltaic power generation efficiency, and the cold is stored in the indoor cooling period through the heat pump heat collection system and the heat accumulator.

[0010] Preferably, photovoltaic modules for power generation and heat energy conversion elements are arranged in rows with an inclination, and at least two rows above and below are installed in a group.

[0011] Preferably, the sealing members on both sides of the row of photovoltaic modules in the length direction and above the top of the inclined surface are provided with an openable portion.

[0012] Preferably, the openable portion is one of a door, a window, and a movable shutter.

[0013] Preferably, the sealing member is one of a color steel plate, a tile plate, a transparent sunlight plate, a glass plate and an anti-aging plastic film.

[0014] Preferably, the thermal insulation film assembly includes slides symmetrically arranged on the left and right or upper and lower sealing parts of the photovoltaic assembly, a reel placed between the two slides, a transparent film wound on the reel, a driving device connected to both ends of the reel, and the driving device is used to drive the reel to move along the slide, one end of the transparent film is fixed on the reel, and the other end is fixed on the side of the end point of the slide.

[0015] Preferably, the heat pump evaporator comprises a plurality of groups of dispersedly installed evaporation heat exchangers, each group of evaporation heat exchangers contains at least two upper and lower metal tube fin heat exchangers arranged in parallel and a pair of quick-connect connectors, the number of heat pump evaporator groups is the same as the number of vertical rows of inclined photovoltaic modules and they are connected in series with each other, that is, one group of evaporation heat exchangers is installed for one width of the photovoltaic module, installed in the space at the top of the inclined surface of the photovoltaic module, and an axial flow fan group is installed on the upper part of the evaporation heat exchanger.

[0016] Preferably, an insulation layer is provided on the outside of the heat accumulator, and an energy storage liquid containing antifreeze and a small amount of phase change balls are placed inside, so that the heat storage capacity reaches more than ten hours of energy; the condenser is installed inside the heat accumulator, and temperature measuring points and interface tanks are also installed inside the heat accumulator, and an internal circulation pump for heat storage liquid is installed. The inlet and outlet of the built-in condenser are respectively connected to one end of the heat pump compressor and the heat pump evaporator installed on the upper part of the inclined surface of the photovoltaic module, and the heat or cold energy delivered by the heat pump is transferred to the heat accumulator for storage through the condenser; the inlet and outlet of the external circulation pump for supplying indoor hot and cold energy is also connected to the lower outer shell of the heat accumulator, and the inlet and outlet of the external circulation pump are symmetrically arranged; the heat accumulator is also provided with an internal circulation pump of the heat storage medium, which runs together with the operation of the heat pump compressor to force the heat storage medium inside the heat accumulator to flow and improve the heat exchange effect of the built-in condenser.

[0017] A method for recycling cold and heat energy of photovoltaic power generation, using the above-mentioned photovoltaic power generation cold and heat energy recycling device, comprises the following steps:

[0018] (1) In the winter heating season, the ventilation space around the photovoltaic modules is closed, and the installed transparent insulation film is covered on the photovoltaic modules to keep them warm. The heat energy absorbed by the photovoltaic modules is sealed in the closed structure of the photovoltaic modules;

[0019] (2) During the photovoltaic panel power generation period, the heat pump is operated at full speed for immediate indoor heating and energy storage. When the heating circulation pump stops and the accumulator temperature reaches the upper limit, the heat pump is stopped for heating;

[0020] (3) The heat energy generated during the photovoltaic power generation period during the day accounts for more than 60% of the total daily heat consumption, and less than 40% during the trough period. No heat is generated during the peak period outside the power generation period:

[0021] (a) The starting and stopping temperature of the heat pump during the heating season is 2-25 degrees higher than the night trough period;

[0022] (b) Determine the time when photovoltaic power generation starts in the morning. The closer to the power generation time, the lower the start-stop heat pump heating temperature control value will be. Until 60 minutes before sunrise on the same day, the heat pump heating will be stopped even if the temperature in the accumulator does not reach the minimum temperature for stopping the heat pump.

[0023] (c) Automatically increase the heat storage temperature as the heat pump heating efficiency reaches a high efficiency period, increasing the temperature gradient by (1-3) degrees per hour;

[0024] (4) In the non-heating season, open the ventilation around the photovoltaic modules and roll up the transparent insulation film on the top of the photovoltaic modules to the side scroll of the modules to increase the heat dissipation of the photovoltaic modules and improve the power generation efficiency:

[0025] (a) Utilize low temperatures at night and low electricity prices to cool the room, store the cold energy in the accumulator, and then pump it to the room for cooling. This will fully improve the cooling efficiency of the heat pump and reduce the cooling cost;

[0026] (b) During the peak period of photovoltaic power generation at noon, the heat pump cooling is also started to fully reduce the impact of photovoltaic power generation on the power grid. When the heat pump is started, the axial flow fan installed on the top of the photovoltaic module group will be turned on to reduce the temperature of the photovoltaic module, thereby increasing the power generation.

[0027] Compared with the prior art, the present invention adopting the above technical solution has the following outstanding features:

[0028] The photovoltaic power generation and heat pump heating and cooling can be achieved in an efficient, low-consumption and low-cost manner. The solar energy utilization rate can be increased by 200% compared with photovoltaic power generation alone, and the efficiency can be increased by more than 40% compared with ordinary heat pumps. It can solve the problems of clean heating and long-term income increase in rural areas at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of an embodiment of the present invention;

[0030] In the figure: photovoltaic module 1; closed structure 2; scroll 3; slide 4; transparent film 5; heat pump evaporator 6; axial flow fan 7; heat storage device 8; condenser 9; heat pump compressor 10; internal circulation pump 11; external circulation pump 12; indoor energy heat exchanger 13. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0032] See also Figure 1 A photovoltaic power generation cold and heat energy recovery and utilization device comprises a photovoltaic module 1, a heat pump heat collection system, a heat storage device 8, and an indoor energy heat exchanger 13. The photovoltaic modules 1 are arranged in rows and groups and tilted in a closed space of a closed structure 2. The closed structure 2 comprises a sealing member arranged around and above the top of the photovoltaic module 1, and a heat preservation film component arranged above the photovoltaic module 1 and capable of being unfolded or retracted. The heat pump heat collection system comprises a heat pump evaporator 6 arranged in the closed space corresponding to the photovoltaic module 1, a heat pump compressor 10 arranged outside the closed space and connected to the heat pump evaporator 6, and a condenser 9. The heat accumulator 8 is connected to the indoor energy heat exchanger 13 through the external circulation pump 12 to form a closed loop; in the heating season, the thermal insulation film component is unfolded to cover the photovoltaic component 1 and the surrounding of the closed photovoltaic component 1 for insulation, and the light and heat energy absorbed by the photovoltaic component 1 is collected by the heat pump heating system, and then the heat energy is stored in the heat accumulator 8 for indoor heating; in the non-heating season, the thermal insulation film component is folded up and the enclosed space of the photovoltaic component 1 is opened to reduce the temperature of the photovoltaic component 1 and the indoor temperature to improve the efficiency of photovoltaic power generation, and the cold energy is stored in the indoor cooling period through the heat pump heating system and the heat accumulator 8.

[0033] The photovoltaic modules 1 are used for power generation and heat energy conversion elements, which are arranged in rows and tilted, and at least two rows are installed in a group; openable parts are arranged on the seals on both sides of the length direction of the photovoltaic modules 1 in the row and above the top of the inclined surface; the openable part is one of a door, a window, and a movable shutter; the seal is one of a color steel plate, a tile plate, a transparent sun plate, a glass plate and an anti-aging plastic film.

[0034] The thermal insulation film assembly includes slideways 4 symmetrically arranged on the left and right or upper and lower sealing parts of the photovoltaic assembly 1, a reel 3 placed between the two slideways 4, a transparent film 5 wound on the reel 3, and a driving device connected to both ends of the reel 3. The driving device is used to drive the reel 3 to move along the slideway 4. One end of the transparent film 5 is fixed on the reel 3, and the other end is fixed on the side of the end of the slideway 4.

[0035] The heat pump evaporator 6 includes multiple groups of dispersedly installed evaporation heat exchangers, each group of evaporation heat exchangers contains at least two metal tube fin heat exchangers arranged in parallel above and below and a pair of quick-connect joints. The number of heat pump evaporators 6 is the same as the number of vertical rows of inclined photovoltaic modules 1 and they are connected in series with each other, that is, one group of evaporation heat exchangers is installed for one width of the photovoltaic module 1, which is installed in the space at the top of the inclined surface of the photovoltaic module 1, and an axial flow fan 7 is installed on the upper part of the evaporation heat exchanger.

[0036] The heat accumulator 8 is provided with an insulation layer on the outside, and contains an energy storage liquid with antifreeze and a small amount of phase change balls, and the heat storage capacity reaches more than ten hours of energy; the condenser 9 is installed inside the heat accumulator 8, and the heat accumulator 8 is also equipped with temperature measuring points and various interface tanks, and is equipped with an internal circulation pump 11 for heat storage liquid. The inlet and outlet of the built-in condenser 9 are respectively connected to one end of the heat pump compressor 10 and the heat pump evaporator 6 installed on the upper part of the inclined surface of the photovoltaic module 1, and the heat or cold energy sent by the heat pump is transferred to the heat accumulator 8 for storage through the condenser 9; the inlet and outlet of the external circulation pump 12 for supplying indoor hot and cold energy is also connected to the lower outer shell of the heat accumulator 8, and the inlet and outlet of the external circulation pump 12 are symmetrically arranged; the heat accumulator 8 is also provided with an internal circulation pump 11 of the heat storage medium, which runs together with the heat pump compressor 10 to force the heat storage medium inside the heat accumulator 8 to flow and improve the heat exchange effect of the built-in condenser 9.

[0037] Ordinary photovoltaic modules 1 are used, and the photovoltaic modules 1 are installed obliquely in rows, with at least two rows installed in a group, and in the structure of the photovoltaic modules 1 in the group, except for the bottom of the inclined surface being open, the seals on both sides of the length direction of the photovoltaic modules 1 installed in the row and the three upper sides of the inclined installation can be a closed structure that can be partially opened. The seals can be color steel plates, tile plates, transparent sun panels, glass plates or anti-aging plastic films, etc., and the partially movable opening methods can be doors, windows or movable shutters, etc., and the opening methods are electric or manual; when heating is needed in the heating season, the left and right upper three sides of the photovoltaic installation group are closed, and the lower part is the air inlet. In the non-heating season, all of them are opened to allow natural ventilation to cool the photovoltaic modules.

[0038] A set of slideways 4 is installed symmetrically above and below or left and right of the photovoltaic module 1 installation group. The height of the slideways 4 is higher than the plane of the photovoltaic module 1, so that when the transparent film 5 covers the photovoltaic module 1, there is a gap of at least 20 mm between the transparent film 5 and the photovoltaic module 1, thereby improving the thermal insulation effect. A reel 3 of the transparent film 5 is installed between the two slideways 4, and driving devices are installed at both ends of the reel 3. The driving device can move along the slideway 4. One end of the transparent film 5 is fixed on the reel 3, and the other end is fixed on the end side of the slideway 4. When heating is needed in the heating season, the transparent film 5 is covered on the photovoltaic module 1 to reduce heat loss. In the non-heating season, the transparent film 5 is rolled up without affecting the heat dissipation and power generation of the photovoltaic module 1.

[0039] In order to effectively utilize the heat energy generated by photovoltaic power generation during the heating season, a heat pump, a device that can convert low-temperature heat sources into high-temperature heat sources, is used to extract the low-temperature heat energy enclosed in the space of the photovoltaic module 1 and store it through the heat accumulator 8 to meet the heat needs of the heating season.

[0040] The characteristic of the present invention of utilizing a heat pump to extract heat energy is that a heat pump evaporator 6 is installed in the upper end space of the tilted photovoltaic module 1. It is not directly installed on the back of the photovoltaic module 1 or inside the module for contact heat exchange as in the prior art, but relies on the natural convection of the air in the space heated by the photovoltaic module 1 to bring the heat of the photovoltaic module 1 to the space where the heat pump evaporator 6 is installed by air convection. In addition, an axial flow fan 7 is installed on the upper part of the evaporative heat exchanger, and the heat of the photovoltaic module 1 is easily absorbed by the heat pump evaporator 6. In this utilization method, multiple photovoltaic modules 1 installed up and down tilted can be realized with only a set of standard independent heat pump evaporators 6 and an axial flow fan 7, and they are independently installed outside the photovoltaic module 1, making construction and maintenance extremely simple, especially in the non-heating season, and does not affect the power generation of the original photovoltaic module 1 at all.

[0041] The heat pump evaporator 6 comprises a plurality of groups of dispersedly installed metal tube fin heat exchangers, each group of heat exchangers contains at least two metal tube fin heat exchangers arranged in parallel above and below and a pair of quick-connect joints, so as to increase the hot air heat exchange path and improve the thermal energy utilization rate; and the number of heat pump evaporators 6 groups is the same as the number of inclined photovoltaic modules 1 in a single row and are connected in series with each other, that is, one group of evaporation heat exchangers is installed for one width of each photovoltaic module 1, which is installed in the top space of the inclined surface of the photovoltaic module group, and an axial flow fan group is installed on the upper part of the evaporation heat exchanger, and the axial flow fan is also equipped with shutters that open and close with the exhaust.

[0042] The present technology is characterized in that the condenser 9 is directly placed in the heat accumulator 8, the heat accumulator 8 contains an insulation layer on the outside, contains antifreeze heat storage liquid and a small amount of phase change balls, and the heat storage capacity must reach more than 10 hours of energy; the accumulator 8 is provided with a condenser 9, a temperature measuring point and each interface tank and an energy storage liquid internal circulation pump 11; the internal condenser 9 inlet and outlet are respectively connected to one end of the heat pump compressor 10 and the heat pump evaporator 6 installed on the upper part of the inclined surface of the photovoltaic module 1, and the heat or cold energy sent by the heat pump is exchanged to the heat storage medium of the heat accumulator 8 for storage through the condenser 9, and its storage capacity can meet the indoor heat and cold needs for at least 10 hours; the lower shell of the heat accumulator 8 is also connected to the inlet and outlet of the indoor heat and cold energy circulation pump, and the inlet and outlet are arranged in opposite directions of 180 degrees; the heat accumulator 8 is also provided with a heat storage medium internal circulation pump 11, which runs together with the heat pump compressor 10 to force the heat storage medium inside the heat accumulator 8 to flow to improve the heat exchange effect of the built-in condenser 9.

[0043] A photovoltaic power generation cold and heat energy recovery and utilization method is performed using the photovoltaic power generation cold and heat energy recovery and utilization device as described above. The heat energy produced during the photovoltaic power generation period during the day accounts for more than 60% of the total daily heat consumption, and the trough period is less than about 40%. No heat is produced during the peak period other than the power generation period, so as to achieve the effect of efficient use of heat energy that is difficult to achieve with the prior art, and reduce the heating or cooling cost:

[0044] (1) During the heating season, the starting and stopping temperature of the heat pump during the power generation period is 2-25 degrees higher than the night trough period, so that more heat can be stored in the daytime when the heat pump is operating efficiently.

[0045] (2) Determine when the time for photovoltaic power generation to start in the morning is approaching. The closer it is to the power generation time, the lower the start-stop heat pump heating temperature control value will be. Until 60 minutes before sunrise on the same day, the heat pump heating will be stopped even if the temperature in the accumulator does not reach the minimum temperature for stopping the heat pump.

[0046] (3) When the photovoltaic power generation period arrives, the temperature value for starting the heat pump is automatically corrected according to the time and the temperature in the heat storage device 8. That is, the closer it is to noon, the higher the start and stop temperature of the heat pump is adjusted. The temperature correction gradient value is (1-4 degrees) / hour. That is, based on the temperature at 7 o'clock in the morning, the start and stop temperature of the heat pump is automatically increased by (1-4 degrees) every hour, so that the heat pump can generate more heat when the evaporator temperature is high, thereby further improving the heating efficiency of the heat pump.

[0047] (4) In the non-heating season, the ventilation around the photovoltaic module 1 is opened, and the transparent film 5 on the top of the photovoltaic module 1 is rolled up onto the side reel of the module to increase the heat dissipation of the photovoltaic module and improve the power generation efficiency.

[0048] (5) Utilize the high efficiency of low-temperature refrigeration at night and the off-peak electricity price period for refrigeration, store the cold energy in the accumulator, and then use water pump to deliver it to the indoor cooling. This can fully improve the efficiency of the heat pump and reduce the refrigeration cost.

[0049] (6) During the peak period of photovoltaic power generation at noon, the heat pump cooling is also started to fully reduce the impact of photovoltaic power generation on the power grid. When the heat pump is started, the axial flow fan installed on the top of the photovoltaic module group will be turned on to reduce the temperature of the photovoltaic module, thereby increasing the power generation.

[0050] Through the above control method, it is possible to achieve the effect of using photovoltaic power generation and heat pump heating and cooling in a high-efficiency, low-consumption and low-cost manner, which is different from the existing technical methods. Its main principle is to use the characteristics of the heat pump reverse Carnot cycle to "transport" heat.

[0051] The theoretical efficiency of a heat pump is Th / (Th-Tc), where Th is the hot end temperature and Tc is the cold end temperature, in K. A simple calculation based on heat pump heating is performed. Assuming that the temperature Th of the heat storage device at the hot end of the heat pump is 60°C, that is, 333K (this is the refrigerant temperature in the condenser, and the medium temperature of the heat storage device can provide an external heating temperature of about 50 degrees), when ordinary air-energy heat pumps are used for heating, in order to use the valley electricity price, it is often necessary to heat and store energy when the ambient temperature is the lowest in the second half of the night. At this time, the ambient temperature of the evaporator is very low. According to the average Tc1=-7 degrees, that is, 266K, the conventional heat pump n1= Th / (Th-Tc1)=333 / (333-266)=5 times, which is actually about 50% of the theoretical value, that is, the average thermal efficiency is about 2.5 times. The evaporator temperature Tc2=20 degrees, that is, 293K, which can be achieved mainly by sunlight during the day and through the photothermal conversion of the photovoltaic module and under the condition of insulation, is calculated. The theoretical efficiency of heat pump heating is: The theoretical maximum efficiency of the heat pump after heat extraction by the photovoltaic module = n2= Th / (Th-Tc2)=333 / (333-293)=8.32 times, the actual efficiency is 50% of the theoretical efficiency, 1kwh of electrical energy can get 4.16kwh of thermal energy. It is 66% higher than the operating efficiency of conventional heat pumps (4.15-2.5) / 2.5, which shows that its efficiency will greatly exceed that of conventional heat pumps, and it is incomparable to ordinary electric heating.

[0052] This device uses the installation method:

[0053] Taking a 90-square-meter bungalow structure as an example, 80 square meters (36 pieces) of double-glass photovoltaic modules 1 are installed on the roof of the bungalow. There are 12 modules in each row, and a total of three rows are installed on the roof at an angle. Except for a 20 cm gap from the bottom, the left and right sides of the modules are sealed with a rollable high-strength anti-aging transparent plastic film (module sealing structure 2). Because it only needs to be closed once in the heating season and opened once in the non-heating season, manual opening and closing is selected to reduce costs.

[0054] In this embodiment, a slideway 4 is installed at the bottom of the inclined surface of the photovoltaic module 1 installation group at a distance of 100mm from the module, and a slideway 4 is installed on the upper part of the heat pump evaporator 6 connected to the upper end of the module. A reel 3 is installed on the slideway 4, and a transparent film 5 is fixed on the reel 3. The transparent film 5 is fixed at the left end and the other end is fixed on the reel. The reel 3 slides along the slideway 4, driving the transparent film to unfold or roll up. When covering the photovoltaic module, the transparent film and the photovoltaic module have a gap of about 50-70mm. In this way, a large amount of heat energy generated by the photovoltaic module when exposed to light will be enclosed below the transparent film. In addition, the periphery of the module is also enclosed. In the heating season, most of the heat energy can be used by the heat pump evaporator. Rolling up the transparent film in the non-heating season does not affect the heat dissipation and power generation of the module.

[0055] In this embodiment, the heat pump evaporator 6 is a heat pump component that extracts heat energy. A total of 12 groups of dispersedly installed metal tube fin heat exchangers are used. One group of evaporative heat exchangers is installed for each width of the tilted photovoltaic module. Each group of heat exchangers contains three metal tube fin heat exchangers arranged in parallel up and down and a pair of quick-connect connectors connected in series with each other. The photovoltaic module is heated by light to the air in the space near the module. The natural convection of the air brings the heat to the space of the heat pump evaporator 6. In addition, due to the action of the axial flow fan 7 on the upper part of the heat pump evaporator 6, the heat of the photovoltaic module 1 is easily absorbed by the heat pump evaporator 6. Because multiple photovoltaic modules are installed up and down tilted, only one group of standard independent evaporators and one axial flow fan can be used. In addition, they are independently installed outside the photovoltaic module, making construction and maintenance extremely simple, especially in the non-heating season, and it does not affect the power generation of the original photovoltaic module at all.

[0056] The effective volume of the heat accumulator 8 is about 2 cubic meters, and the heat storage capacity can meet the heat demand in winter for about 12 hours; the outside contains a 60mm insulation layer, and the inside contains ethylene glycol aqueous solution for the heat accumulator to prevent the equipment from freezing in case of accidents. At the same time, about 15% of the volume capacity of the phase change heat storage ball is placed inside to increase the heat storage effect. The heat accumulator is equipped with a heat pump condenser 9, temperature measurement points and various interface tanks and an internal circulation pump for energy storage liquid. The internal condenser inlet and outlet are connected to one end of the heat pump compressor 10 and the heat pump evaporator 6 installed on the upper part of the inclined surface of the photovoltaic module 1. The heat or cold energy sent by the heat pump is exchanged to the heat storage medium of the heat accumulator through the condenser 9. The inlet and outlet of the indoor cold and heat energy circulation pump are also connected to the lower shell of the heat accumulator, and the inlet and outlet are arranged in the opposite direction of 180 degrees. When the heat pump is heating or cooling, if the external heat supply circulation pump is running, the internal circulation pump 11 can not be run. When the external circulation pump is not running, the internal circulation pump 11 is running.

[0057] In this embodiment, during the heating season, the heat energy produced during the daytime photovoltaic power generation period accounts for 70% of the total daily heat consumption, and the trough period accounts for about 30%. No heating is performed during the peak period outside the power generation period, so as to achieve the effect of efficient use of heat energy that is difficult to achieve with the existing technology and reduce the heating or cooling cost:

[0058] (1) During the daytime power generation period of the heating season, the starting and stopping temperature of the heat pump is 8 degrees higher than that of the night trough period. That is, it is easier to start the heat pump during the day and more difficult to stop it. At night, the heat pump is started only when the temperature is 8 degrees lower than the highest temperature during the day, so that the heat pump can operate efficiently during the day and store more heat.

[0059] (2) The closer the heating season is to the start of photovoltaic power generation in the morning and the more efficient the power generation is, the lower the start-stop temperature control value of the heat pump heating is. The heat pump heating is stopped 60 minutes before sunrise (for example, if the sunrise is 7:30 on the same day, the heat pump stops running at 6:30 on the same day) to make full use of the efficient zone during the high temperature period during the day.

[0060] (3) When the photovoltaic power generation period arrives, the control temperature of the start-stop heat pump is automatically increased at a rate of 2 degrees per hour at sunrise until it is constant at the highest temperature value at 1 pm. If the control temperature of the accumulator is 40 degrees +- 2 degrees at night, the start-stop heat pump control temperature will be controlled at 7, 8, 9, 10, 11, 12, 13, and 14 in the morning respectively, and the control temperature will be automatically corrected to 40, 42, 44, 46, 48, 50, 52, and 52 degrees +- 3 degrees.

[0061] (4) In the non-heating season, the ventilation around the photovoltaic module is opened, and the transparent insulation film on the top of the photovoltaic module is rolled up onto the side reel 3 of the photovoltaic module 1 to increase the heat dissipation of the photovoltaic module 1 and improve the power generation efficiency.

[0062] (5) Utilize the high efficiency of low-temperature refrigeration at night and the off-peak electricity price period for refrigeration, store the cold energy in the accumulator 8, and then use water pump to deliver the cold energy to the indoor space, so as to fully improve the efficiency of the heat pump and reduce the refrigeration cost.

[0063] (6) During the peak period of photovoltaic power generation at noon, the heat pump cooling is also started to fully reduce the impact of photovoltaic power generation on the power grid. When the heat pump is started, the axial flow fan 7 installed on the top of the photovoltaic module 1 will be turned on to reduce the temperature of the photovoltaic module 1, thereby increasing the power generation.

[0064] Through the above control method, when used for heating in the heating season, the temperature of the enclosed space of the photovoltaic module 1 under the transparent film can reach 10-35 degrees, with an average of 20 degrees, that is, 293K. According to the theoretical efficiency of the heat pump, Th / (Th-Tc), where Th is the hot end temperature and Tc is the cold end temperature, the unit is K. The average heating and heat storage glycol water temperature of the heat accumulator 8 during the daytime is 53, and the refrigerant temperature Th in the heat pump heat accumulator 8 is 61℃, that is, 334k, then the calculated efficiency is 334 / (334-293)=8.15 times, and the actual operating efficiency is about 4.1 times, that is, 1 degree of electrical energy is input, and 4.1KWh of thermal energy can be obtained, which is close to the actual light-heat conversion rate of the photovoltaic module 1.

[0065] At the same time, considering the volume cost of the energy storage device and the actual heating capacity limitation of solar energy, this design is based on 70% of the capacity of the photovoltaic heat pump, and the remaining 30% is powered by the trough period at night. During the trough electric heating period, the ambient temperature of the evaporator is very low (but higher than the ambient temperature of the ordinary heat pump evaporator, because in a closed environment, part of the heat energy dissipated from the roof of the room will be circulated to the heat pump evaporator 6 and reused, resulting in the temperature of the heat pump evaporator 6 being at least 1 degree higher than the ambient temperature). According to the average Tc1=-6 degrees, that is, 267K, the high-end Th temperature of this heat pump operation mode is five degrees lower than the conventional heat pump evaporator 6 temperature, that is, 329 degrees. The night heating efficiency n1= Th / (Th-Tc1)=329 / (329-267)=5.3 times, which is actually about 50% of the theoretical value, that is, the average thermal efficiency is about 2.65 times.

[0066] The average heat pump efficiency that this solution can achieve is 70%x4.1+30x2.65=3.67

[0067] Conventional heat pumps are designed to operate only during the trough period to meet the needs of energy storage throughout the day. The high-end Th must also be relatively high at 333k, and the low-end temperature is the average night temperature of -7 degrees. The heat pump efficiency is calculated to be about 2.5. The pump operation efficiency under this technical solution is about (3.67-2.5) / 2.5=46% higher than the existing ordinary heat pump heating efficiency. It can be seen that its efficiency will greatly exceed that of conventional heat pump heating, and it is incomparable to ordinary electric heating.

[0068] The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made using the contents of the present specification and its drawings are included in the scope of rights of the present invention.

Claims

1. A method for recycling cold and heat energy from photovoltaic power generation, using a device for recycling cold and heat energy from photovoltaic power generation, the device comprising a photovoltaic module, a heat pump heating system, a heat accumulator, and an indoor energy heat exchanger, characterized in that: The photovoltaic modules are arranged in rows and groups tilted in a closed space of a closed structure. Specifically, the photovoltaic modules are used for power generation and heat energy conversion elements and are arranged in rows tilted, and at least two rows are installed in a group, and the sealing members on both sides of the length direction of the photovoltaic modules in the row and above the top of the tilted surface are provided with openable parts; The closed structure includes a seal arranged around and above the top of the photovoltaic module, and an insulation film assembly arranged above the photovoltaic module that can be unfolded or retracted; the insulation film assembly includes slideways symmetrically arranged on the left and right or upper and lower seals of the photovoltaic module, a reel placed between the two slideways, a transparent film wound on the reel, and a driving device connected to both ends of the reel. The driving device is used to drive the reel to move along the slideway, one end of the transparent film is fixed on the reel, and the other end is fixed on one side of the end of the slideway. The height of the slideway is higher than the plane of the photovoltaic module. When the transparent film covers the photovoltaic module, there is a gap of at least 20 mm between the transparent film and the photovoltaic module. The heat pump heating system includes a heat pump evaporator arranged in a confined space corresponding to the photovoltaic module, a heat pump compressor and a condenser arranged outside the confined space and connected to the heat pump evaporator; the heat pump evaporator includes multiple groups of dispersedly installed evaporation heat exchangers, each group of evaporation heat exchangers contains at least two metal tube fin heat exchangers arranged in parallel up and down and a pair of quick-connect joints, the number of heat pump evaporator groups is the same as the number of vertical rows of inclined photovoltaic modules and they are connected in series with each other, that is, one group of evaporation heat exchangers is installed for one width of the photovoltaic module, installed in the space at the top of the inclined surface of the photovoltaic module, and an axial flow fan group is installed on the upper part of the evaporation heat exchanger; The heat accumulator is connected to the indoor energy heat exchanger through an external circulation pump to form a closed loop; an insulation layer is arranged on the outside of the heat accumulator, which contains energy storage liquid with antifreeze and a small amount of phase change balls, and the heat storage capacity reaches more than ten hours of energy; the condenser is installed inside the heat accumulator, and the heat accumulator is also equipped with temperature measuring points and various interface tanks, and is equipped with an internal circulation pump for heat storage liquid. The inlet and outlet of the built-in condenser are respectively connected to one end of the heat pump compressor and the heat pump evaporator installed on the upper part of the inclined surface of the photovoltaic module, and the heat or cold energy sent by the heat pump is transferred to the heat accumulator for storage through the condenser; the inlet and outlet of the external circulation pump for supplying indoor hot and cold energy are also connected to the lower shell of the heat accumulator, and the inlet and outlet of the external circulation pump are symmetrically arranged; the heat accumulator is also provided with an internal circulation pump for the heat storage medium, which runs together with the operation of the heat pump compressor to force the heat storage medium inside the heat accumulator to flow and improve the heat exchange effect of the built-in condenser; In the heating season, the thermal insulation film components are deployed to cover the photovoltaic modules and the surrounding of the photovoltaic modules for insulation. The light and heat energy absorbed by the photovoltaic modules is collected through the heat pump heating system, and then the heat energy is stored in the heat storage device for indoor heating. In the non-heating season, the thermal insulation film components are folded up and the enclosed space of the photovoltaic modules is opened to reduce the temperature of the photovoltaic modules and the indoor temperature to improve the efficiency of photovoltaic power generation, and the heat pump heating system and the heat storage device are used to store the cold energy for indoor cooling during the high-efficiency cooling period. The photovoltaic power generation cold and heat energy recovery and utilization method comprises the following steps: (1) In the winter heating season, the ventilation space around the photovoltaic modules is closed, and the installed transparent insulation film is covered on the photovoltaic modules to keep them warm. The heat energy absorbed by the photovoltaic modules is sealed in the closed structure of the photovoltaic modules; (2) During the photovoltaic panel power generation period, the heat pump is operated at full speed for immediate indoor heating and energy storage. When the heating circulation pump stops and the accumulator temperature reaches the upper limit, the heat pump is stopped for heating; (3) The heat energy generated during the photovoltaic power generation period during the day accounts for more than 60% of the total heat consumption throughout the day, and less than 40% during the trough period. No heat is generated during the peak period outside the power generation period: (a) The starting and stopping temperature of the heat pump during the heating season is 2-25 degrees higher than the night trough period; (b) Determine the time when photovoltaic power generation starts in the morning. The closer to the power generation time, the lower the start-stop heat pump heating temperature control value will be. Until 60 minutes before sunrise on the same day, the heat pump heating will be stopped even if the temperature in the accumulator does not reach the minimum temperature for stopping the heat pump. (c) Automatically increase the heat storage temperature as the heat pump heating efficiency reaches a high efficiency period, increasing the temperature gradient by (1-3) degrees per hour; (4) In the non-heating season, open the ventilation around the photovoltaic modules and roll up the transparent insulation film on the top of the photovoltaic modules to the side reel of the modules to increase the heat dissipation of the photovoltaic modules and improve the power generation efficiency: (a) Utilize low temperatures at night and low electricity prices to cool the room, store the cold energy in the accumulator, and then pump it to the indoor room for cooling, so as to fully improve the cooling efficiency of the heat pump and reduce the cooling cost; (b) During the peak period of photovoltaic power generation at noon, the heat pump cooling is also started to fully reduce the impact of photovoltaic power generation on the power grid. When the heat pump is started, the axial flow fan installed on the top of the photovoltaic module group will be turned on to reduce the temperature of the photovoltaic module, thereby increasing the power generation.

2. The photovoltaic power generation cold and heat energy recovery and utilization method according to claim 1 is characterized by: The openable part is one of a door, a window, and a movable shutter.

3. The photovoltaic power generation cold and heat energy recovery and utilization method according to claim 1 is characterized by: The sealing member is one of a color steel plate, a tile plate, a transparent sunlight plate, a glass plate and an anti-aging plastic film.

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