Micro-channel type pvt heat collecting evaporator and heat pump system using solar energy and air energy comprehensively

Abstract

The application discloses a micro-channel type PVT heat collecting evaporator and heat pump system which comprehensively utilizes solar energy and air energy, and relates to the technical field of PVT heat pumps.The PVT heat collecting evaporator comprises, from top to bottom, a photovoltaic panel, heat-conducting silica gel, a ribbed micro-channel heat exchanger, a back cover plate and a fan; the photovoltaic panel and the ribbed micro-channel heat exchanger are bonded by the heat-conducting silica gel; the back cover plate is bonded to the photovoltaic panel by EVA glue; the fan is installed on the back cover plate by bolts; the ribbed micro-channel heat exchanger is internally provided with low-temperature refrigerant, and an oil return pipe is arranged on one side of the bottom of the heat exchanger close to the outlet; the oil return pipe is used for collecting and conveying the lubricating oil deposited due to gravity. The application can solve the technical problems of low energy utilization rate, low building roof space utilization rate, low evaporation temperature and difficult oil return of the existing PVT heat pump, so that the types of resource utilization are rich and comprehensive, the building roof space is reasonably planned, and the heat exchange performance is comprehensively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PVT heat pump, in particular to a micro-channel PVT heat collecting evaporator and heat pump system utilizing solar energy and air energy. BACKGROUND

[0002] As a clean and renewable energy, the establishment of a solar energy utilization-based building energy supply system can effectively promote the development of China's green building energy saving and emission reduction industry. However, the current common solar thermal and solar power generation technologies only utilize solar energy in a single form, which limits the popular application of solar energy in the building field to some extent. In contrast, PVT heat pump (Photovoltaic Thermal Heat Pump) has both heating and power generation functions, showing good development and application potential.

[0003] As the key of PVT heat pump system, the PVT heat collecting evaporator directly affects the heat collecting and power generating performance of the heat pump system. In the existing PVT heat pump system, either a heat collecting evaporator with single PV side heat extraction is used, or a heat collecting evaporator with PV side heat extraction and an evaporator with air side heat extraction are used in parallel, or the PV collector and the evaporator are separated into two components, which cannot realize efficient utilization of the building roof space. Based on this, developing a heat collecting evaporator that comprehensively utilizes solar energy and air energy to realize uninterrupted heating all day long will help to realize the integration of heat pump system structure form and the diversification of operation mode.

[0004] In order to improve the evaporation temperature of the PVT heat collecting evaporator, a heat collecting evaporator that can provide sufficient heat exchange area, heat exchange time and small flow resistance needs to be developed. The commonly used PVT heat collecting evaporator either adopts a honeycomb type, a snake type or other blown complex flow channels from the perspective of increasing the heat exchange area between the refrigerant and the PV side, or adopts a plate-and-tube type parallel flow channel to realize the line contact heat transfer between the refrigerant pipe and the PV side from the perspective of reducing the flow resistance of the refrigerant. The utilization rate of a single photovoltaic panel area is less than 20%, which does not meet the needs of the heat collecting evaporator "large heat exchange area and small flow resistance", so there is generally a low evaporation temperature. As a new type of high-efficiency heat exchanger, the heat exchange performance of the micro-channel heat exchanger will be greatly improved when the flow channel size is less than 3mm, and the convective heat transfer coefficient increases by 50%-100% or even more. Therefore, it is an ideal choice to apply micro-channel to the flow channel of the PVT heat collecting evaporator.

[0005] To ensure that the refrigerant can be completely vaporized in the evaporator, when the evaporator is assembled with the inclined photovoltaic panel, the outlet of the evaporator is usually arranged on the upper side of the inclined surface to facilitate the smooth discharge of the gaseous refrigerant with smaller density. However, at this time, whether the U-shaped circuit layout with the inlet on the upper side is adopted or the inlet-on-the-lower-side down-inlet-up-outlet flow channel is adopted, there is a risk that the lubricating oil will be stranded in the evaporator and cannot return to the compressor. Long-term operation will cause insufficient lubrication of the compressor, seriously damage the service life of the compressor, and affect the heat exchange performance of the PVT heat collecting evaporator. Therefore, it has practical engineering significance to design a flow channel scheme that can balance the complete vaporization of the refrigerant and the effective return of the lubricating oil. SUMMARY

[0006] The purpose of the present application is to provide a micro-channel PVT heat collecting evaporator and heat pump system that comprehensively utilizes solar energy and air energy, aiming to solve or improve at least one of the above technical problems.

[0007] To achieve the above-mentioned purpose, the present application provides the following scheme:

[0008] A micro-channel PVT heat collecting evaporator that comprehensively utilizes solar energy and air energy, comprising:

[0009] A photovoltaic panel, a heat-conducting silicone, a ribbed micro-channel heat exchanger, a back cover plate and a fan are sequentially arranged from top to bottom; wherein the photovoltaic panel and the ribbed micro-channel heat exchanger are bonded by the heat-conducting silicone; the back cover plate is bonded with the photovoltaic panel by EVA glue; the fan is installed on the back cover plate by bolts; the ribbed micro-channel heat exchanger is internally provided with low-temperature refrigerant, and an oil return pipe is arranged on one side of the bottom of the heat exchanger close to the outlet, which is used to collect and transport the lubricating oil deposited due to gravity.

[0010] Optionally, the ribbed micro-channel heat exchanger specifically comprises a gas collecting pipe, a flat tube, a liquid conveying pipe, a partition piece, a liquid distribution pipe, a fin and an oil return pipe.

[0011] The fins are equidistantly welded on the flat tube, dividing the flat tube into two conveying areas, and both of the two conveying areas are symmetrically arranged along the center line, one end of one of the two conveying areas is connected with the liquid distribution pipe, one end of the other conveying area is connected with the gas collecting pipe, and the other ends of the two conveying areas are both connected with the liquid conveying pipe, forming a U-shaped circuit; the oil return pipe is connected with one side of the liquid conveying pipe close to the refrigerant outlet; the partition piece is used to divide the liquid distribution pipe and the gas collecting pipe; the liquid distribution pipe and the gas collecting pipe are arranged on the upper side of the inclined photovoltaic panel, the gaseous refrigerant flows out from the upper gas collecting pipe, and the liquid conveying pipe and the oil return pipe are arranged on the lower side of the inclined photovoltaic panel, the lubricating oil flows out from the lower oil return pipe.

[0012] Optionally, the heat exchange area of the ribbed micro-channel heat exchanger is calculated according to the following formula:

[0013]

[0014] U -1 = R conv,a-PV + R cond,PV-mic + R conv,a-ri + R cond,ri-mic + R conv,mic-re

[0015] wherein, A eva is the heat collecting evaporator calculation area, m 2 ; U is the heat exchange coefficient of micro-channel structure, W / (m 2 ·K); △T m is the average temperature difference of refrigerant and environment air, K; R conv，a-PV is the air convection heat transfer resistance to photovoltaic panel, (m 2 ·K) / W; R cond，PV-mic is the heat conduction resistance of photovoltaic panel to micro-channel, (m 2 ·K) / W; R conv，a-ri is the air convection heat transfer resistance to micro-channel ribbed surface, (m 2 ·K) / W; R conv，ri-mic is the heat conduction resistance of rib to micro-channel, (m 2 ·K) / W; R conv，mic-re is the micro-channel convection heat transfer resistance to refrigerant, (m 2 ·K) / W.

[0016] Optionally, the rear cover plate is processed into an integrated Ω structure by using iron refrigeration rolling plate, the four sides are bent to form the bonding plane with the photovoltaic panel, and the EVA glue is used to bond with the photovoltaic panel.

[0017] Optionally, a plurality of flow guide grooves are arranged on the two long sides of the rear cover plate as air inlets, two air outlets are arranged on the top surface, the inner top surface of the rear cover plate is attached to the top end of the rib of the ribbed micro-channel heat exchanger, and the air duct is formed.

[0018] The application further provides a heat pump system for comprehensively utilizing solar energy and air energy, which applies the micro-channel PVT heat collecting evaporator, and comprises the micro-channel PVT heat collecting evaporator, a compressor, an indoor unit, an electronic expansion valve, a gas-liquid separator, a reheater, an oil return valve, a reheating valve, a four-way reversing valve, an inverter, a storage battery, a controller and a temperature sensor.

[0019] The micro-channel PVT collector evaporator, the compressor, the indoor unit, the electronic expansion valve, the gas-liquid separator, the reheater, the oil return valve, the reheating valve and the four-way reversing valve form a refrigerant evaporation and condensation loop through refrigerant pipelines; and the micro-channel PVT collector evaporator, the inverter, the battery and the compressor form a power supply and distribution loop through cables.

[0020] In the refrigerant evaporation and condensation loop, the micro-channel PVT collector evaporator is connected with the fourth interface D of the four-way reversing valve, the reheater, the electronic expansion valve and the oil return valve respectively; the second interface B of the four-way reversing valve is connected with the indoor unit; the third interface C of the four-way reversing valve is connected with the gas-liquid separator; the first interface A of the four-way reversing valve is connected with the compressor; the compressor is also connected with the gas-liquid separator; the fourth interface D is also connected with the reheater; the reheater is also connected with the oil return valve; the indoor unit is also connected with the reheating valve and the electronic expansion valve; the reheating valve is also connected with the electronic expansion valve through the reheater; and the temperature sensor is arranged at the outlet of the micro-channel PVT collector evaporator.

[0021] In the power supply and distribution loop, the micro-channel PVT collector evaporator is also connected with the inverter; the inverter is also connected with the compressor, the battery and the indoor unit respectively.

[0022] The controller is connected with the four-way reversing valve, the reheating valve, the temperature sensor, the electronic expansion valve, the oil return valve and the micro-channel PVT collector evaporator respectively, and is used for:

[0023] According to the meteorological environment and the user demand, the corresponding operation mode is switched and the corresponding device parameter is output, so that the user's uninterrupted heating and hot water and cooling demand in winter and summer are met; the operation mode includes a solar-air dual-source heating mode, a single-source heating mode, a single-source cooling mode and an oil return mode.

[0024] Optionally, when the operation mode is switched, the controller specifically includes: controlling the four-way reversing valve to switch the heating or cooling in all modes; controlling the fan to be turned on in the air source heating mode, the solar-air dual-source heating mode and the single-source cooling mode; and controlling the oil return valve and the reheating valve to be turned on in the oil return mode.

[0025] Optionally, when the device parameter is output, the controller specifically includes:

[0026] According to the outlet refrigerant temperature fed back by the temperature sensor, the refrigerant superheat degree is calculated, and the following operations are performed:

[0027] In the heating mode, when the refrigerant superheat is lower than 5 DEG C, the electronic expansion valve is controlled to reduce the opening degree, when the electronic expansion valve reaches the minimum opening degree or the heat pump system cannot meet the indoor heat demand, the fan is controlled to start, and the refrigerant is simultaneously heated from the air and the photovoltaic panel; when the refrigerant superheat is higher than 5 DEG C, the fan is controlled to reduce the wind speed, and when the fan is stopped, the electronic expansion valve is controlled to increase the opening degree;

[0028] In the oil return mode, the oil return valve and the reheating valve are controlled to be opened, the refrigerant flowing out of the micro-channel PVT heat collecting evaporator carries the lubricating oil at the bottom of the evaporator to flow out from the oil return pipe, exchanges heat with the high-temperature refrigerant at the outlet of the indoor unit in the reheater, and then flows to the compressor, so as to realize the oil return function, and meanwhile, the refrigerant flowing out of the indoor unit is divided into two paths, one path directly flows to the electronic expansion valve, and the other path enters the reheater to release heat and then flows to the electronic expansion valve, so as to ensure that the refrigerant flowing out of the oil return pipe can be completely gasified.

[0029] According to the specific embodiments provided by the present application, the following technical effects are disclosed:

[0030] The present application discloses a micro-channel PVT heat collecting evaporator and a heat pump system for comprehensively utilizing solar energy and air energy, the PVT heat collecting evaporator comprises a photovoltaic panel, a heat-conducting silica gel, a ribbed micro-channel heat exchanger, a back cover plate and a fan which are sequentially arranged from top to bottom; wherein the photovoltaic panel and the ribbed micro-channel heat exchanger are bonded by the heat-conducting silica gel; the back cover plate is bonded with the photovoltaic panel by EVA glue; the fan is installed on the back cover plate by bolts; the ribbed micro-channel heat exchanger is internally provided with low-temperature refrigerant, and an oil return pipe is arranged on one side of the bottom of the heat exchanger close to the outlet, and the oil return pipe is used for collecting and conveying the lubricating oil deposited due to gravity. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor based on these drawings.

[0032] Figure 1 It is a schematic diagram of the micro-channel PVT heat collecting evaporator in the present embodiment;

[0033] Figure 2 It is an exploded view of the micro-channel PVT heat collecting evaporator in the present embodiment;

[0034] Figure 3The heat exchanger operation flow chart of the micro-channel PVT heat collecting evaporator in the embodiment;

[0035] Figure 4 The oil return flow chart of the heat exchanger of the micro-channel PVT heat collecting evaporator in the embodiment;

[0036] Figure 5 The back cover plate view of the micro-channel PVT heat collecting evaporator in the embodiment;

[0037] Figure 6 The principle diagram of the micro-channel PVT heat collecting evaporator for a heat pump system in the embodiment;

[0038] Figure 7 The system principle diagram of the micro-channel PVT heat pump system for a heating mode in the embodiment;

[0039] Figure 8 The system principle diagram of the micro-channel PVT heat pump system for an oil return mode in the embodiment;

[0040] Figure 9 The system principle diagram of the micro-channel PVT heat pump system for a heating mode in the embodiment;

[0041] Figure 10 The system principle diagram of the micro-channel PVT heat pump system for a cooling mode in the embodiment.

[0042] Fig. 1 is a micro-channel PVT heat collecting evaporator; Fig. 2 is a photovoltaic panel; Fig. 3 is a heat-conducting silica gel; Fig. 4 is a ribbed micro-channel heat exchanger; 401 is a gas collecting pipe; 402 is a flat pipe; 403 is a liquid conveying pipe; 404 is a partition piece; 405 is a liquid distributing pipe; 406 is a rib; 407 is an oil return pipe; Fig. 5 is a back cover plate; 501 is an air inlet; 502 is an air outlet; Fig. 6 is a fan; Fig. 7 is a storage battery; Fig. 8 is a four-way reversing valve; Fig. 9 is a compressor; Fig. 10 is a gas-liquid separator; Fig. 11 is a reheater; Fig. 12 is an electronic expansion valve; Fig. 13 is a reheating valve; Fig. 14 is an oil return valve; Fig. 15 is an indoor unit; Fig. 16 is an inverter; Fig. 17 is a temperature sensor; Fig. 18 is a water pump; and Fig. 19 is a heat storage water tank. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0044] The present application aims to provide a micro-channel PVT heat collecting evaporator and heat pump system which comprehensively utilizes solar energy and air energy, and aims to solve or improve at least one of the above technical problems.

[0045] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0046] The present application provides a micro-channel PVT heat collecting evaporator 1 which comprehensively utilizes solar energy and air energy, adopts a multi-layer composite structure design, and is characterized in that it is composed of a photovoltaic panel 2, a heat-conducting silica gel 3, a ribbed micro-channel heat exchanger 4, a back cover plate 5 and a fan 6 from top to bottom; the heat-conducting silica gel 3 bonds the photovoltaic panel 2 and the ribbed micro-channel heat exchanger 4, the back cover plate 5 is bonded on the back of the photovoltaic panel 2 through EVA glue, and the fan 6 is bolted on the back cover plate 5.

[0047] Specifically, the photovoltaic panel 2 realizes photoelectric conversion under solar radiation, generates electric energy which is directly supplied to users for use, and at the same time, transmits solar radiation energy which cannot be converted into heat energy to the back ribbed micro-channel heat exchanger 4 to provide a low-temperature heat source for a heat pump system.

[0048] Specifically, the ribbed micro-channel heat exchanger 4 is tightly attached to the back of the photovoltaic panel 2 through the heat-conducting silica gel 3. The heat-conducting silica gel 3 has good heat-conducting performance, and its heat-conducting coefficient can reach 6-10 times of that of ordinary EVA glue. Specifically, the ribbed micro-channel heat exchanger 4 includes a flat tube 402, a distribution pipe 405, a fin 406, a liquid conveying pipe 403, a partition 404, a gas collecting pipe 401 and an oil return pipe 407. The flat tube 402 is divided into two regions according to different flow channel directions and is arranged symmetrically along the center line. The upper end of one half of the flat tube 402 is connected with the distribution pipe 405, and the upper end of the other half of the flat tube 402 is connected with the gas collecting pipe 401. The other ends of the flat tubes 402 in the two regions are connected through the liquid conveying pipe 403, forming an efficient "U"-shaped loop system. Further, the oil return pipe 407 is connected to one side of the liquid conveying pipe 403 close to the refrigerant outlet. Further, the fins 406 are welded on the lower surface of the flat tube 402 at equal intervals to increase the air-side heat transfer area of the micro-channel. The structure size of the fin 406 is reasonably designed according to the rib efficiency and wind resistance. Further, the diameters of the gas collecting pipe 401 and the oil return pipe 407 are 1.5 times of that of the distribution pipe 405.

[0049] Specifically, the required heat exchange area of the ribbed micro-channel heat exchanger 4 is calculated according to the building heating load under the most unfavorable condition of winter night, and the relevant calculation formula is formula (1)-(2), and the relevant design parameters refer to “Code for Design of Heating Ventilation and Air Conditioning of Civil Buildings” (GB50736-2012) and “Room Air Conditioner” (GB7725-2022). Further, when the ribbed micro-channel heat exchanger 4 is assembled with the photovoltaic panel 2, the liquid distribution pipe 405 and the gas collection pipe 401 should be placed on the upper side of the inclined panel, and the liquid supply pipe 403 and the oil return pipe 407 should be placed on the lower side.

[0050]

[0051] U -1 = R conv,a-PV + R cond,PV-mic + R conv,a-ri + R cond,ri-mic + R conv,mic-re (2)

[0052] In the formula, A eva is the required area of the heat collecting evaporator, m 2 ; U is the heat exchange coefficient of the micro-channel structure, W / (m 2 ·K); △T m is the average temperature difference between the refrigerant and the ambient air, K; R conv，a-PV is the convective heat transfer resistance of air to the photovoltaic panel 2, (m 2 ·K) / W; R cond，PV-mic is the thermal resistance of the photovoltaic panel 2 to the micro-channel, (m 2 ·K) / W; R conv，a-ri is the convective heat transfer resistance of air to the ribbed surface of the micro-channel, (m 2 ·K) / W; R conv，ri-mic is the thermal resistance of the fin 406 to the micro-channel, (m 2 ·K) / W; R conv，mic-re is the convective heat transfer resistance of the micro-channel to the refrigerant, (m 2 ·K) / W.

[0053] Specifically, the rear cover plate 5 is processed into an integrated "Ω" shape by iron cold-rolled plate, which not only serves as the mounting base of the fan 6, but also provides a channel for air through the flow guide grooves reserved on both sides. Specifically, the rear cover plate 5 is bent around the periphery to form a bonding plane with the photovoltaic panel 2, and is bonded to the photovoltaic panel 2 through EVA glue; the long edges of the rear cover plate 5 are slotted, and a plurality of air inlets 501 are arranged along the length direction, and two air outlets 502 are arranged on the top surface; during installation, the inner top surface of the rear cover plate 5 is attached to the top end of the fins 406 of the ribbed micro-channel heat exchanger 4 to form an air duct, thereby ensuring that air uniformly sweeps over the surface of the fins 406 from the air duct between the ribbed micro-channel heat exchanger 4 and the rear cover plate 5.

[0054] Specifically, the fan 6 should be selected to meet the air volume and air pressure requirements of 2-3 m / s of the wind speed in front of the fins 406.

[0055] Based on the above-mentioned micro-channel PVT heat collecting evaporator 1, a heat pump system equipped with the micro-channel PVT heat collecting evaporator 1 for comprehensive utilization of solar energy and air energy is also provided, which includes the above-mentioned micro-channel PVT heat collecting evaporator 1, a compressor 9, an indoor unit 15, an electronic expansion valve 12, a gas-liquid separator 10, a reheater 11, an oil return valve 14, a reheating valve 13, a four-way reversing valve 8, an inverter 16, a storage battery 7, a controller and a temperature sensor 17.

[0056] Specifically, the micro-channel PVT heat collecting evaporator 1, the compressor 9, the indoor unit 15, the electronic expansion valve 12, the gas-liquid separator 10, the reheater 11, the oil return valve 14, the reheating valve 13 and the four-way reversing valve 8 form a refrigerant evaporation and condensation loop through refrigerant pipelines. The first interface A and the third interface C of the four-way reversing valve 8, the gas-liquid separator 10 and the compressor 9 are connected in sequence through pipelines; the second interface B of the four-way reversing valve 8 is connected with the inlet of the indoor unit 15, and the outlet of the indoor unit 15 is connected with two paths, one of which is connected with the inlet of the electronic expansion valve 12 through the reheating valve 13 and the reheater 11, and the other of which is directly connected with the inlet of the electronic expansion valve 12. The outlet of the electronic expansion valve 12 is connected with the liquid distribution pipe 405 of the PVT heat collecting evaporator; the fourth interface D of the four-way reversing valve 8 is connected with two paths, one of which is directly connected with the gas collection pipe 401 of the PVT heat collecting evaporator, and the other of which is connected with the oil return pipe 407 of the PVT heat collecting evaporator through the reheater 11 and the oil return valve 14.

[0057] Specifically, the micro-channel PVT heat collecting evaporator 1, the inverter 16, the battery 7, the compressor 9, the fan 6 and other electric equipment form a power supply and distribution loop through cables. The controller is connected with the temperature sensor 17, the fan 6, the electronic expansion valve 12, the four-way reversing valve 8, the oil return valve 14 and the reheating valve 13 respectively to form a control loop. Further, the temperature sensor 17 is installed at the position of the PVT heat collecting evaporator gas collecting pipe 401.

[0058] Specifically, the controller switches the solar heating, air source heating, solar-air dual source heating, air source cooling and oil return mode according to the weather conditions and user demand; the controller controls the four-way reversing valve 8 to realize the switching of the heating / cooling mode; further, the controller controls the fan 6 to be turned on in the air source heating mode, the solar-air dual source heating mode and the cooling mode; further, the controller controls the oil return valve 14 and the reheating valve 13 to be turned on in the periodic oil return mode, so that the lubricating oil accumulated at the bottom of the heat collecting evaporator can be returned to the compressor 9 periodically.

[0059] Specifically, the controller calculates the refrigerant superheat degree according to the outlet refrigerant temperature of the micro-channel PVT heat collecting evaporator 1 fed back by the temperature sensor 17, and makes the following judgments: in the heating mode, when the evaporator outlet refrigerant superheat degree is lower than 5℃, the electronic expansion valve 12 is preferentially controlled to reduce the opening degree, when the electronic expansion valve 12 reaches the minimum opening degree or the heat pump system cannot meet the indoor heat demand, the fan 6 is controlled to be turned on, and the refrigerant absorbs heat from the air and the photovoltaic panel 2 at the same time; when the evaporator outlet refrigerant superheat degree is higher than 5℃, the fan 6 is preferentially controlled to reduce the wind speed, and when the fan 6 is turned off, the electronic expansion valve 12 is controlled to increase the opening degree to adapt to the load size of the evaporator.

[0060] The PVT heat collecting evaporator in the application is installed with a ribbed micro-channel heat exchanger 4 on the back of the photovoltaic panel 2. When the PVT heat collecting evaporator works, the low-temperature refrigerant in the micro-channel absorbs the heat of the photovoltaic panel 2, which reduces the temperature of the photovoltaic panel 2 and improves the power generation efficiency. The generated power preferentially meets the power demand of the system itself, and the surplus power can be connected to the grid. At the same time, the low-temperature refrigerant also absorbs heat from the air, and the heat absorbed by the PVT heat collecting evaporator can be used to meet the heating demand of the user after being upgraded in grade by the heat pump system. Especially at night in summer, the device can be switched to a condenser for use by starting the fan 6 to strengthen heat exchange, realizing the function of refrigeration, and forming a comprehensive energy system integrating power generation, heating and refrigeration.

[0061] The upper side of the microchannel of the PVT heat collecting evaporator in the application is a flat plate, which is attached to the photovoltaic panel 2 through the heat-conducting silica gel 3 with good heat conduction performance, and the lower side is welded with parallel straight ribs with rib efficiency greater than 80%, which is in direct contact with air, two air blowers 6 are arranged on the side of the rib sheet 406 and are installed vertically to the rib sheet 406, and the air heat source can directly perform forced convection heat exchange on the surface of the assembly. Even at night, the system can still exchange heat with air to meet the heat supply demand of the user, expand the application scenario of the PVT heat collecting evaporator, and the specific operation mode is shown in Table 1.

[0062] Table 1 Annual operation mode determination of the microchannel type PVT heat collecting evaporator 1

[0063]

[0064]

[0065] Note: indicates that the operation mode is operable, indicates that the operation mode is inoperable, and indicates that whether the system is operated can be determined according to user demand and climate conditions.

[0066] The refrigerant flow channel of the PVT heat collecting evaporator in the application adopts a parallel microchannel type flow channel, and the parallel flow channels are laid flat on the back of the entire photovoltaic panel 2, and the heat exchange area can be regarded as the area of the entire photovoltaic panel 2, which is increased compared with the tube plate type and the blown type PVT assembly, and the parallel flow channels reduce the local resistance introduced by the honeycomb type, water drop type and other blown type flow channels. Therefore, compared with the tube plate type and the blown plate type evaporator, the PVT heat collecting evaporator has a higher evaporation temperature, thereby improving the heat collecting performance of the heat pump system.

[0067] The PVT heat collecting evaporator in the application adopts a flow channel scheme that can consider complete gasification of the refrigerant and effective return of the lubricating oil, the inlet and the outlet are both arranged on the upper side to form a U-shaped circuit layout, the gaseous refrigerant with smaller density can be smoothly discharged, and the complete gasification of the refrigerant in the evaporator is ensured. At the same time, the evaporator is connected with the oil return pipe 407, and when the oil return pipe 407 is opened, the system can realize regular oil return, thereby prolonging the service life of the compressor 9. In order to prevent incomplete gasification of the refrigerant during the oil return process, the system is provided with a reheater 11, and the refrigerant in the oil return pipe 407 is fully heat exchanged with the high-temperature refrigerant flowing out of the indoor unit 15, thereby further preventing the problem of wet compression of the compressor 9.

[0068] As a specific embodiment, an embodiment as shown in Figures 1-10 is provided.

[0069] As shown in Figure 1 and Figure 2As shown, the micro-channel PVT heat collecting evaporator 1 proposed in the embodiment comprehensively utilizes solar energy and air energy, adopts a multi-layer composite structure design, and comprises, from top to bottom, a photovoltaic panel 2, a heat-conducting silica gel 3, a ribbed micro-channel heat exchanger 4, a back cover plate 5, and a fan 6. Specifically, the heat-conducting silica gel 3 is used to bond the photovoltaic panel 2 and the ribbed micro-channel heat exchanger 4; the back cover plate 5 is bonded to the back of the photovoltaic panel 2 through EVA glue; and the fan 6 is bolted to the back cover plate 5, and should be selected to meet the air volume and air pressure requirements of the wind speed of 2-3 m / s between the fins 406.

[0070] As shown in the figure, Figure 3 The ribbed micro-channel heat exchanger 4 comprises a gas collecting pipe 401, a flat tube 402, a liquid conveying pipe 403, a partition 404, a liquid distribution pipe 405, a fin 406, and an oil return pipe 407. Specifically, the flat tube 402 is divided into two regions according to the flow direction, and is arranged symmetrically along the center line. The upper end of one half of the flat tube 402 is connected to the liquid distribution pipe 405, and the upper end of the other half of the flat tube 402 is connected to the gas collecting pipe 401. The other ends of the flat tubes 402 in the two regions are connected through the liquid conveying pipe 403, forming an efficient "U" type loop system. Further, the oil return pipe 407 is connected to one side of the liquid conveying pipe 403 close to the refrigerant outlet. Further, the fins 406 are welded on the surface of the flat tube 402 at equal intervals to increase the air side heat transfer area of the micro-channel, and the structure size of the fin 406 is designed according to the rib efficiency and wind resistance. Further, the diameters of the gas collecting pipe 401 and the oil return pipe 407 are 1.5 times the diameter of the liquid distribution pipe 405. Further, when the ribbed micro-channel heat exchanger 4 is assembled with the photovoltaic panel 2, the liquid distribution pipe 405 and the gas collecting pipe 401 are placed on the upper side of the inclined plate, and the liquid conveying pipe 403 and the oil return pipe 407 are placed on the lower side. At this time, the gaseous refrigerant flows out from the upper gas collecting pipe 401, and the lubricating oil flows out from the lower oil return pipe 407 periodically.

[0071] When the micro-channel PVT heat collecting evaporator 1 works, the oil return pipe 407 is always closed. The low-temperature liquid refrigerant flows into the liquid distribution pipe 405, and then flows into the flat tube 402 after distribution, and then flows into the liquid conveying pipe 403, and then flows into the other half of the flat tube 402 through the liquid conveying pipe 403, and finally flows into the gas collecting pipe 401 to leave the PVT heat collecting evaporator. High-temperature environmental air uniformly flows over the surface of the fin 406 from both sides of the ribbed micro-channel heat exchanger 4, and then flows out through the fan 6, and the air flow direction is perpendicular to the refrigerant flow direction. The low-temperature liquid refrigerant absorbs heat from the photovoltaic panel 2 and the air while flowing in the pipeline, and gradually evaporates, and the dryness increases, and finally flows out of the PVT heat collecting evaporator as superheated gas. When the solar radiation is good, the fan 6 can be closed, and the low-temperature refrigerant absorbs heat from the photovoltaic panel 2 and the natural convection heat transfer amount from the air.

[0072] As shown in the figure, Figure 4As shown, when the PVT heat collector evaporator regularly returns oil, the oil return pipe 407 is opened. The refrigerant in the infusion pipe 403 carries the lubricating oil at the bottom of the evaporator and directly flows to the compressor 9 through the oil return pipe 407, thereby realizing the recovery of the lubricating oil.

[0073] As shown in Figure 1 and Figure 5 , the rear cover plate 5 is processed into an "Ω" integrated structure with iron refrigeration rolling plate, which not only serves as the mounting base of the fan 6, but also provides a channel for air through the flow guide grooves reserved on both sides. Specifically, the rear cover plate 5 is bent around to form a bonding plane with the photovoltaic panel 2, and is bonded to the photovoltaic panel 2 through EVA glue; the long sides of the rear cover plate 5 are slotted, and a plurality of air inlets 501 are arranged along the length direction, and two air outlets 502 are arranged on the top surface; during installation, the inner top surface of the rear cover plate 5 is attached to the top end of the rib 406 of the ribbed micro-channel heat exchanger 4 to form an air duct, thereby ensuring that air uniformly sweeps across the surface of the rib 406 from the air duct between the ribbed micro-channel heat exchanger 4 and the rear cover plate 5.

[0074] As shown in Figure 6 , a micro-channel PVT heat collector evaporator 1 heat pump system for comprehensive utilization of solar energy and air energy includes the micro-channel PVT heat collector evaporator 1, the compressor 9, the indoor unit 15, the electronic expansion valve 12, the gas-liquid separator 10, the reheater 11, the oil return valve 14, the reheating valve 13, the four-way reversing valve 8, the inverter 16, the battery 7, the controller and the temperature sensor 17.

[0075] Specifically, the micro-channel PVT heat collector evaporator 1, the compressor 9, the indoor unit 15, the electronic expansion valve 12, the gas-liquid separator 10, the reheater 11, the oil return valve 14, the reheating valve 13 and the four-way reversing valve 8 form a refrigerant evaporation and condensation loop through refrigerant pipelines. Specifically, the first interface A and the third interface C of the four-way reversing valve 8, the gas-liquid separator 10 and the compressor 9 are connected in sequence through pipelines; the second interface B of the four-way reversing valve 8 is connected with the inlet of the indoor unit 15, and the outlet of the indoor unit 15 is connected with two paths, one of which is connected with the inlet of the electronic expansion valve 12 through the reheating valve 13 and the reheater 11, and the other of which is directly connected with the electronic expansion valve 12. The outlet of the electronic expansion valve 12 is connected with the liquid distribution pipe 405 of the PVT heat collector evaporator; the fourth interface D of the four-way reversing valve 8 is connected with two paths, one of which is directly connected with the gas collection pipe 401 of the PVT heat collector evaporator, and the other of which is connected with the oil return pipe 407 of the PVT heat collector evaporator through the reheater 11 and the oil return valve 14.

[0076] Specifically, the micro-channel PVT heat collector evaporator 1, the inverter 16, the battery 7 and the power supply and use equipment such as the compressor 9 and the fan 6 form a power supply and use loop through cables.

[0077] Specifically, the controller is connected with the temperature sensor 17, the fan 6, the electronic expansion valve 12, the four-way reversing valve 8, the oil return valve 14 and the reheating valve 13 respectively to form a control loop. Further, the temperature sensor 17 is installed at the outlet of the PVT heat collecting evaporator.

[0078] Specifically, the controller switches the solar heating, the air source heating, the solar-air dual source heating, the air source cooling and the oil return mode according to the weather condition and the user demand; specifically, the controller controls the four-way reversing valve 8 to realize the switching of the heating / cooling mode; further, the controller controls the fan 6 to be turned on in the air source heating mode, the solar-air dual source heating mode and the cooling mode; further, the controller controls the oil return valve 14 and the reheating valve 13 to be turned on in the regular oil return mode.

[0079] Specifically, the controller calculates the superheat degree of the refrigerant according to the outlet refrigerant temperature of the micro-channel PVT heat collecting evaporator 1 fed back by the temperature sensor 17, and makes the following judgment: in the heating mode, when the outlet refrigerant superheat degree of the evaporator is lower than 5℃, the electronic expansion valve 12 is preferentially controlled to reduce the opening degree; when the electronic expansion valve 12 reaches the minimum opening degree or the heat pump system cannot meet the indoor heat demand, the fan 6 is controlled to be turned on, and the refrigerant absorbs heat from the air and the photovoltaic panel 2 at the same time; when the outlet refrigerant superheat degree of the evaporator is higher than 5℃, the fan 6 is preferentially controlled to reduce the wind speed, and when the fan 6 is turned off, the electronic expansion valve 12 is controlled to increase the opening degree to adapt to the load size of the evaporator.

[0080] Figure 7 The system principle diagram of the heat pump system with the micro-channel PVT heat collecting evaporator 1 of the application for the heating mode is shown, at this time, the indoor unit 15 is used as the condenser of the heat pump system, when the heat pump system works, the low-temperature liquid refrigerant flows into the PVT heat collecting evaporator along the pipeline, absorbs heat from the photovoltaic panel 2 and the air in the PVT heat collecting evaporator at the same time, and then vaporizes to flow into the D port of the four-way reversing valve 8, flows out from the C port to enter the compressor 9, the low-temperature gaseous refrigerant is compressed into high-temperature and high-pressure refrigerant in the compressor 9, and then flows into the indoor unit 15 through the A port and the B port of the four-way reversing valve 8, the indoor air and the refrigerant in the indoor unit 15 are fully heat exchanged, high-temperature hot air is blown out to the indoor, and the refrigerant releases heat to condense, then flows into the electronic expansion valve 12 to be throttled into low-temperature liquid refrigerant to continue the circulation. At the same time when the heat pump system works, the temperature of the photovoltaic panel 2 is reduced, and the power generation efficiency is improved, the direct current generated by the photovoltaic panel 2 is converted into alternating current by the inverter 16, and then is used to power the fan 6, the compressor 9 and the indoor unit 15, and the remaining electricity can be stored in the battery 7 or fed into the grid.

[0081] Figure 8The system principle diagram of the heat pump system with the micro-channel PVT collector evaporator 1 of the present application for the regular oil return mode is shown, and the working principle is similar to that of the heating mode. The difference is that in the regular oil return mode, the oil return valve 14 and the reheating valve 13 are opened, the refrigerant flowing out of the PVT collector evaporator carries the lubricating oil at the bottom of the evaporator to flow out from the oil return pipe 407, and after heat exchange with the high-temperature refrigerant at the outlet of the indoor unit 15 in the reheater 11, the refrigerant flows to the compressor 9, thereby realizing the oil return function. At the same time, the refrigerant flowing out of the indoor unit 15 is divided into two paths, one directly flows to the electronic expansion valve 12, and the other enters the reheater 11 to release heat and then flows to the electronic expansion valve 12, so as to ensure that the refrigerant flowing out of the oil return pipe 407 can be completely gasified.

[0082] Figure 9 The system principle diagram of the heat pump system with the micro-channel PVT collector evaporator 1 of the present application for the hot water mode is shown, and the working principle is similar to that of the heating mode. The difference is that the heat storage water tank 19 is used as the condenser of the heat pump system, and the water in the heat storage water tank 19 absorbs the heat in the high-temperature refrigerant, which is delivered to the user by the water pump 18 to meet the user's demand for domestic hot water.

[0083] Figure 10 The system principle diagram of the heat pump system with the micro-channel PVT collector evaporator 1 of the present application for the cooling mode is shown, and the working principle is similar to that of the heating mode. The difference is that the PVT collector evaporator and the indoor unit 15 are interchangeable in function, and the circulation of the refrigerant is reversed. Specifically, when the system is working, the fan 6 is opened, the PVT collector evaporator is used as the condenser, and the high-temperature gaseous refrigerant can be fully cooled and condensed into liquid refrigerant in the PVT collector evaporator due to the large heat dissipation area of the photovoltaic panel 2; the indoor unit 15 is used as the evaporator, and the indoor air and the refrigerant in the indoor unit 15 are fully heat exchanged, and the cold air is blown out to the indoor, thereby realizing the cooling function.

[0084] The embodiments in the present specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0085] The principles and implementation manners of the present application are described by using specific examples in the present specification, and the above description of the embodiments is only used to help understand the core idea of the present application; meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application. In conclusion, the content of the present specification should not be understood as a limitation of the present application.

Claims

1. A microchannel PVT collector evaporator that comprehensively utilizes solar energy and air energy, characterized in that, include: The components, arranged sequentially from top to bottom, include a photovoltaic panel, thermally conductive silicone, a ribbed microchannel heat exchanger, a rear cover plate, and a fan. The photovoltaic panel and the ribbed microchannel heat exchanger are bonded together using the thermally conductive silicone. The rear cover plate is bonded to the photovoltaic panel using EVA adhesive. The fan is bolted to the rear cover plate. The ribbed microchannel heat exchanger contains a low-temperature refrigerant and has an oil return pipe at its bottom near the outlet. This oil return pipe collects and transports lubricating oil deposited due to gravity. The ribbed microchannel heat exchanger specifically includes: a gas collecting pipe, a flat pipe, a liquid conveying pipe, a dividing component, a liquid dispensing pipe, fins, and an oil return pipe; The ribs are welded at equal intervals onto the flat tube, dividing the flat tube into two conveying areas. Both conveying areas are symmetrically arranged along the center line. One end of one conveying area is connected to the liquid distribution pipe, and one end of the other conveying area is connected to the gas collecting pipe. The other ends of both conveying areas are connected to the liquid delivery pipe, forming a U-shaped loop. The oil return pipe is connected to the side of the liquid delivery pipe near the refrigerant outlet. The dividing element is used to separate the liquid distribution pipe and the gas collecting pipe. The liquid distribution pipe and the gas collecting pipe are located on the upper side of the inclined photovoltaic panel, with gaseous refrigerant flowing out from the upper gas collecting pipe. The liquid delivery pipe and the oil return pipe are located on the lower side of the inclined photovoltaic panel, with lubricating oil flowing out from the lower oil return pipe. Multiple air inlets are provided on the long sides of the rear cover plate, and two air outlets are provided on the top surface. The inner top surface of the rear cover plate is attached to the top of the fins of the ribbed microchannel heat exchanger to form an air duct.

2. The microchannel PVT collector evaporator for comprehensively utilizing solar and air energy as described in claim 1, characterized in that, The heat exchange area of ​​the ribbed microchannel heat exchanger is calculated according to the following formula: ； in, A eva Calculate the area of ​​the solar collector evaporator, in meters. 2 ; U The heat transfer coefficient of the microchannel structure is W / (m²). 2 ·K); △ T m K represents the average temperature difference between the refrigerant and the ambient air. R conv，a-PV The convective heat transfer resistance of the photovoltaic panel to the air is (m) 2 ·K) / W; R cond，PV-mic The thermal resistance of the photovoltaic panel to the microchannel is (m 2 ·K) / W; R conv，a-ri The convective heat transfer thermal resistance between air and the ribbed surface of the microchannel, (m 2 ·K) / W; R cond，ri-mic The thermal resistance of the fins to the microchannel is (m 2 ·K) / W; R conv，mic-re The convective heat transfer thermal resistance between the microchannel and the refrigerant, (m 2 ·K) / W.

3. The microchannel PVT collector evaporator for comprehensively utilizing solar and air energy as described in claim 1, characterized in that, The rear cover plate is made of iron cold-rolled plate into an Ω-shaped integrated structure, with the four sides bent to form an adhesive plane with the photovoltaic panel, and is bonded to the photovoltaic panel with EVA adhesive.

4. A heat pump system that comprehensively utilizes solar energy and air energy, employing the microchannel PVT collector evaporator as described in any one of claims 1-3, characterized in that, include: Microchannel PVT evaporator, compressor, indoor unit, electronic expansion valve, gas-liquid separator, reheater, oil return valve, reheat valve, four-way reversing valve, inverter, battery, controller and temperature sensor; The microchannel PVT evaporator, the compressor, the indoor unit, the electronic expansion valve, the gas-liquid separator, the reheater, the oil return valve, the reheat valve, and the four-way reversing valve form a refrigerant evaporation-condensation loop through refrigerant pipelines; the microchannel PVT evaporator, the inverter, the battery, and the compressor form a power supply loop through cables; In the refrigerant evaporation-condensation loop, the microchannel PVT collector evaporator is connected to the fourth port D of the four-way reversing valve, the reheater, the electronic expansion valve, and the oil return valve, respectively; the second port B of the four-way reversing valve is connected to the indoor unit; the third port C of the four-way reversing valve is connected to the gas-liquid separator; the first port A of the four-way reversing valve is connected to the compressor; the compressor is also connected to the gas-liquid separator; the fourth port D is also connected to the reheater; the reheater is also connected to the oil return valve; the indoor unit is also connected to the reheat valve and the electronic expansion valve; the reheat valve is also connected to the electronic expansion valve through the reheater; the temperature sensor is located at the outlet of the microchannel PVT collector evaporator. In the power supply and distribution loop, the microchannel PVT collector evaporator is also connected to the inverter; the inverter is also connected to the compressor, the battery and the indoor unit respectively. The controller is connected to the four-way reversing valve, the reheat valve, the temperature sensor, the electronic expansion valve, the oil return valve, and the microchannel PVT evaporator, respectively, and is used for: The system switches between the corresponding operating modes and outputs the corresponding equipment parameters according to the meteorological environment and user needs, so as to meet the user's needs for uninterrupted heating and hot water in winter and cooling in summer. The operating modes include solar-air dual-source heating mode, single-source heating mode, single-source cooling mode and oil return mode.

5. The heat pump system for comprehensively utilizing solar energy and air energy according to claim 4, characterized in that, The controller, when switching operating modes, specifically includes: controlling the four-way reversing valve to switch between heating and cooling in all modes; controlling the fan to start in air source heating mode, solar-air dual source heating mode, and single source cooling mode; and controlling the oil return valve and reheat valve to start in oil return mode.

6. The heat pump system for comprehensively utilizing solar energy and air energy according to claim 4, characterized in that, The controller specifically includes the following when outputting device parameters: Based on the outlet refrigerant temperature fed back by the temperature sensor, calculate the refrigerant superheat and perform the following operations: In heating mode, when the refrigerant superheat is below 5°C, the electronic expansion valve is controlled to reduce its opening. When the electronic expansion valve reaches its minimum opening or the heat pump system cannot meet the indoor heat demand, the fan is controlled to turn on, and the refrigerant absorbs heat from the air and the photovoltaic panel at the same time. When the refrigerant superheat is above 5°C, the fan is controlled to reduce its speed. When the fan stops, the electronic expansion valve is controlled to increase its opening. In oil return mode, the control oil return valve and reheat valve are opened. The refrigerant flowing out of the microchannel PVT collector evaporator carries the lubricating oil from the bottom of the evaporator and flows out through the oil return pipe. In the reheater, it exchanges heat with the high-temperature refrigerant at the indoor unit outlet and then flows to the compressor, thus realizing the oil return function. At the same time, the refrigerant flowing out of the indoor unit is divided into two paths: one path flows directly to the electronic expansion valve, and the other path enters the reheater to release heat and then flows to the electronic expansion valve, so as to ensure that the refrigerant flowing out of the oil return pipe can be completely vaporized.

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