A heat pump system

Abstract

The application belongs to the technical field of household appliances, and particularly relates to a heat pump system, which comprises a photovoltaic cell panel, an evaporator, a variable frequency controller, a compressor and a water tank; the output end of the photovoltaic cell panel is connected with the direct current bus of the variable frequency controller, the alternating current input end of the variable frequency controller is connected with commercial power, and the variable frequency controller and the photovoltaic cell panel jointly drive the compressor; the evaporator is arranged on the back of the photovoltaic cell panel and is used for heating water in the water tank based on absorbed heat energy; the output end of the photovoltaic cell panel is connected with the direct current bus of the variable frequency controller, thereby supplying power for the compressor, avoiding current loss caused by inversion, and improving the utilization rate of photovoltaic power generation.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic power generation technology, specifically relating to a heat pump system. Background Technology

[0002] Because solar energy is clean and renewable, solar-based power generation and heating methods are widely used.

[0003] Photovoltaic thermal collectors, also known as PVT collectors, combine solar cells and solar collectors into one unit using lamination or adhesive technology. They provide power and heat through photoelectric conversion and photothermal conversion.

[0004] In related technologies, the DC power output from the photovoltaic panels of PVT robots is often converted into AC power by an inverter for power supply. This results in some loss of DC power generated by photovoltaic power generation during the conversion, reducing the utilization rate of photovoltaic power generation. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, namely the low efficiency of photovoltaic power generation based on PVT collectors, this application provides a heat pump system that connects the output end of the photovoltaic panels of the PVT collector to the DC bus of the frequency converter, thereby powering the compressor, avoiding current losses caused by inverters, and improving the utilization rate of photovoltaic power generation.

[0006] This application provides a heat pump system, including: a photovoltaic panel and an evaporator; the output end of the photovoltaic panel is connected to the DC bus of the inverter controller of an air conditioner, and the AC input end of the inverter controller is connected to the mains power, so that the mains power and the photovoltaic panel jointly drive the compressor of the air conditioner; the evaporator is disposed on the back of the photovoltaic panel and is used to heat the water in the water tank of a water heater based on the absorbed heat energy.

[0007] In one possible design, the heat pump system also includes a battery connected to the photovoltaic panel, which is used to charge the battery when the voltage output by the photovoltaic panel is greater than a preset voltage, and to discharge the battery when the voltage output by the photovoltaic panel is less than the preset voltage.

[0008] In one possible design, the heat pump system also includes a photovoltaic maximum power point tracking (MPPT) circuit; the MPPT is used to control the power of the photovoltaic panels charging the battery so that the photovoltaic panels charge the battery at the maximum available power.

[0009] In one possible design, the heat pump system also includes a boost unit; the photovoltaic panels are connected to the DC bus of the frequency converter via the boost unit.

[0010] In one possible design, a condenser is installed inside the water tank, and the evaporator, compressor and condenser are connected in a loop through a pipeline filled with refrigerant.

[0011] In one possible design, the heat pump system also includes a throttling valve located between the evaporator and the condenser.

[0012] In one possible design, the heat pump system also includes an air-cooled evaporator located on the side of the evaporator away from the photovoltaic panel.

[0013] In one possible design, the heat pump system also includes a first switch for controlling the operation of the air-cooled evaporator.

[0014] In one possible design, the heat pump system further includes an ambient temperature sensor, an evaporation sensor, a suction sensor, an exhaust sensor, a water temperature sensor, and a control unit; the ambient temperature sensor is used to detect the external ambient temperature; the evaporation sensor is used to detect the temperature of the gas at the outlet of the evaporator; the suction sensor is used to detect the temperature of the gas at the inlet of the compressor; the exhaust sensor is used to detect the temperature of the gas at the outlet of the compressor; the water temperature sensor is used to detect the temperature of the water in the water tank; and the control unit is used to control the opening of the throttle valve based on the signals output by the ambient temperature sensor, the evaporation sensor, the suction sensor, the exhaust sensor, and the water temperature sensor.

[0015] In one possible design, the control unit is also used to control the voltage output by the photovoltaic panel based on signals output by the ambient temperature sensor, evaporation sensor, intake sensor, exhaust sensor, and water temperature sensor.

[0016] Those skilled in the art will understand that the heat pump system provided in this application, by connecting the output end of the photovoltaic panel to the DC bus of the frequency converter, and then connecting the AC input end of the frequency converter to the mains power, realizes multi-energy driven compressor to achieve cooling or heating. By directly connecting the output end of the photovoltaic panel to the DC bus to drive the compressor, the loss caused by inverting the DC signal output by the photovoltaic panel to the AC signal is avoided, thus improving the utilization rate of photovoltaic power generation. At the same time, the water in the water tank is heated by the heat energy absorbed by the evaporator set on the back of the photovoltaic panel, realizing a solar-based water heating method that is environmentally friendly, clean, and further improves the utilization rate of photovoltaic power generation energy. Attached Figure Description

[0017] Preferred embodiments of the control method, apparatus, device, and storage medium for household appliances according to this application will now be described with reference to the accompanying drawings. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. The drawings are as follows:

[0018] Figure 1 This is a schematic diagram of the structure of a heat pump system in related technologies;

[0019] Figure 2 This is a schematic diagram of the structure of a heat pump system provided in one embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the structure of a heat pump system provided in another embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the structure of a heat pump system provided in another embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a primary connection, an indirect connection via an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] The terms "first," "second," and "third" (if any) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0026] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or display that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or display.

[0027] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0028] Figure 1 This is a structural diagram of a heat pump system in related technologies, such as... Figure 1 As environmental awareness gradually increases, clean energy, such as solar energy, has received widespread attention, and PVT solar collectors, which generate electricity and provide heat based on solar energy, have become a hot research topic. To achieve heating and power supply based on PVT solar collectors, related technologies often connect the output of the PVT solar collector to an inverter, which in turn connects to the mains power grid via a transformer, thus jointly supplying power to devices such as fans and compressors.

[0029] When the DC power signal output from the PVT collector is converted into an AC signal by an inverter, certain losses occur, thus reducing the utilization rate of photovoltaic power generation. Therefore, to improve the utilization rate of photovoltaic power generation, the heat pump system provided in this application directly connects the output terminal of the photovoltaic panel of the PVT collector to the DC bus of the air conditioner's inverter controller, while the AC input terminal of the inverter controller is connected to the mains power supply. This achieves combined mains power supply to the air conditioner's compressor, while eliminating the inverter process, reducing energy loss, and improving energy utilization.

[0030] Figure 2 This is a schematic diagram of the structure of a heat pump system provided in one embodiment of this application, as shown below. Figure 2 As shown, the heat pump system includes: a photovoltaic panel 210, an evaporator 220, a frequency converter 230, a compressor 240, and a water tank.

[0031] The photovoltaic panel 210 serves as a DC power source, providing a driving power source for the compressor to achieve cooling or heating based on photovoltaic power generation. The evaporator 220 is located on the back of the photovoltaic panel 210, i.e., the side away from the photovoltaic panel 210 that absorbs sunlight, and is used to absorb the heat generated by the photovoltaic panel 210 and heat the water in the water tank based on the absorbed heat energy to provide hot water.

[0032] Specifically, the output terminal of the photovoltaic panel 210 is connected to the DC bus of the frequency converter 230, and the AC input terminal of the frequency converter 230 is connected to the mains power, thereby realizing the combined use of the mains power and the DC power output from the photovoltaic panel 210 to drive the compressor 240.

[0033] The compressor is powered by the DC power output from the photovoltaic panel 210 in conjunction with the mains power, eliminating the need for intermediate conversion stages such as inverters. This reduces costs, improves energy conversion efficiency, and ultimately increases the photovoltaic utilization rate of the photovoltaic panel 210.

[0034] In some embodiments, the photovoltaic panel 210 may be composed of an array of silicon solar cells.

[0035] In some embodiments, compressor 240 is an air conditioner compressor.

[0036] In some embodiments, the water tank is the water tank of a water heater.

[0037] In some embodiments, a transparent cover is provided above the photovoltaic panel 210 to reduce heat loss.

[0038] In some embodiments, the transparent cover can be a low-emissivity glass cover.

[0039] In some embodiments, a heat-absorbing plate is disposed below (or on the back) of the photovoltaic panel 210 to absorb solar energy that has not been converted by the photovoltaic panel 210.

[0040] In some embodiments, the photovoltaic panel 210 can absorb sunlight with wavelengths of 0.3 micrometers to 1.1 micrometers, while the heat absorber can absorb sunlight with wavelengths of 1.1 micrometers to 3 micrometers, thereby improving the utilization rate of solar energy and enabling the PVT collector composed of the photovoltaic panel 210 and the heat absorber to absorb sunlight across the entire solar spectrum.

[0041] In some embodiments, the heat-absorbing plate can be an aluminum plate, which is the back plate of the photovoltaic panel 210.

[0042] In some embodiments, an evaporator 220 is provided on the side of the heat absorber away from the photovoltaic panel 210. The evaporator 220 consists of multiple heat-collecting evaporation tubes arranged in a serpentine manner on the heat absorber to cool the photovoltaic panel 210 and prevent the photovoltaic panel 210 from reducing its output power due to excessive temperature.

[0043] In some embodiments, the heat-collecting evaporator tube of the evaporator 220 forms a passage with the heat exchanger pipe of the water heater, and the pipe is filled with refrigerant, so that the water in the water tank of the water heater is heated by the heat absorbed by the evaporator 220, thereby further improving the energy utilization rate of the heat pump system.

[0044] In some embodiments, an insulation layer is provided below the heat absorber to reduce heat loss from the heat absorber.

[0045] In some embodiments, the heat collection evaporation tube is tightly bonded to the heat absorption plate with thermally conductive adhesive, and after the insulation layer is applied, they are installed together in an aluminum alloy frame to complete the encapsulation of the PVT collector assembly.

[0046] In some embodiments, a condenser 260 is provided in the water tank of the water heater, and a loop is formed between the evaporator 220, the compressor 240 and the condenser 260 through a pipeline, and the pipeline is filled with refrigerant.

[0047] In some embodiments, condenser 260 is a microchannel condenser.

[0048] In some embodiments, the refrigerant may be Freon 12 (R12, CF2CL2), Freon 22 (R22, CHF2CL), Freon 502 (R502), Freon 1341a (R134a, C2H2F4), etc.

[0049] The heat pump system provided in this application connects the output end of the photovoltaic panel to the DC bus of the frequency converter, and then connects the AC input end of the frequency converter to the mains power, realizing multi-energy driven compressor to achieve cooling or heating. By directly connecting the output end of the photovoltaic panel to the DC bus to drive the compressor, the loss caused by inverting the DC signal output by the photovoltaic panel to the AC signal is avoided, thus improving the utilization rate of photovoltaic power generation. At the same time, the heat energy absorbed by the evaporator on the back of the photovoltaic panel is used to heat the water in the water tank, realizing a solar-based water heating method that is environmentally friendly, clean, and further improves the utilization rate of photovoltaic power generation energy.

[0050] Figure 3 This is a schematic diagram of the structure of a heat pump system provided in another embodiment of this application, see below. Figure 2 and Figure 3 As can be seen, the heat pump system provided in this embodiment also includes a storage battery 250.

[0051] The storage battery 250 is connected to the photovoltaic panel 210 and is used to charge the storage battery 250 when the voltage output by the photovoltaic panel 210 is greater than a preset voltage, and to discharge the storage battery 250 when the voltage output by the photovoltaic panel 210 is less than the preset voltage.

[0052] In some embodiments, the preset voltage can be 24V, 48V, or other values.

[0053] Since the voltage of the DC power signal output by the photovoltaic panel 210 is easily affected by the intensity of sunlight, a storage battery 250 is added in order to provide a stable voltage source to the air conditioner compressor 240, fan, etc. When the photovoltaic panel 210 has sufficient power, that is, when the output voltage is greater than the preset voltage, the photovoltaic panel 210 charges the storage battery 250. When the photovoltaic panel 210 has insufficient power, that is, when the output voltage is less than the preset voltage, the storage battery 250 discharges, so that the photovoltaic panel 210 can work together to supply power to the air conditioner.

[0054] In some embodiments, the charging and discharging control of the battery 250 can be achieved by designing a charging and discharging management module, so that the power output of the power module composed of the battery 250 and the photovoltaic panel 210 is stabilized at a preset voltage.

[0055] In some embodiments, in order to improve the photovoltaic utilization rate of the photovoltaic panel 210, a maximum power point tracking (MPPT) circuit can be added to the heat pump system. The MPPT is used to control the power of the photovoltaic panel 210 to charge the battery 250.

[0056] Specifically, the MPPT is used to monitor the voltage and current at the output terminal of the photovoltaic panel 210, and to track the highest voltage and highest current at the output terminal of the photovoltaic panel 210, thereby controlling the photovoltaic panel 210 to charge the battery at the maximum available power.

[0057] In some embodiments, the heat pump system further includes a boost unit or boost circuit, and the photovoltaic panel 210 is connected to the DC bus of the frequency converter 230 through the boost unit.

[0058] In some embodiments, the boost unit is a PWM (Pulse Width Modulation) boost circuit.

[0059] In some embodiments, the MPPT can adjust the duty cycle of the PWM drive signal of the boost unit according to the changes in the current and voltage of the photovoltaic panel 210, thereby controlling the photovoltaic panel 210 to charge the battery 250 at the maximum available power.

[0060] Figure 4 This is a schematic diagram of the structure of a heat pump system provided in another embodiment of this application, see below. Figure 2 and Figure 4 In this embodiment, the heat pump system also includes a throttling valve 270 and an air-cooled evaporator 280.

[0061] The throttling valve 270 is located between the evaporator 220 and the condenser 260. The air-cooled evaporator 280 is located on the side of the evaporator 220 furthest from the photovoltaic panel, used to blow the vaporized refrigerant inside to the compressor 240. When the refrigerant is compressed into a high-temperature, high-pressure gas in the compressor 240, it is condensed into a low-temperature, high-pressure liquid in the condenser 260. The heat released by the refrigerant heats the water in the tank. The high-pressure liquid condensed in the condenser 260 is then depressurized through the throttling valve 270 into a two-phase state and enters the evaporator 220, completing one heat pump cycle. The air-cooled evaporator 280 includes a fan and a baffle plate, such as a cross-flow fan.

[0062] In some embodiments, the fan or blower of the air-cooled evaporator 280 may be powered by the photovoltaic panel 210.

[0063] In some embodiments, the heat pump system also includes an expansion valve.

[0064] Specifically, the opening degree of the throttle valve 270 can be controlled based on factors such as light intensity, water temperature in the tank, and ambient temperature, thereby controlling the flow rate of the refrigerant flowing into the evaporator 220 to achieve cooling control of the photovoltaic panel 210.

[0065] In some embodiments, the heat pump system further includes one or more of the following sensors: an ambient temperature sensor, an evaporation sensor, a suction sensor, an exhaust sensor, and a water temperature sensor, as well as a control unit; the ambient temperature sensor is used to detect the ambient temperature; the evaporation sensor is used to detect the temperature of the gas at the outlet of the evaporator; the suction sensor is used to detect the temperature of the gas at the inlet of the compressor; the exhaust sensor is used to detect the temperature of the gas at the outlet of the compressor; the water temperature sensor is used to detect the temperature of the water in the water tank; and the control unit is used to control the opening degree of the throttle valve based on the signals output by one or more of the ambient temperature sensor, the evaporation sensor, the suction sensor, the exhaust sensor, and the water temperature sensor.

[0066] In some embodiments, the control unit is also used to determine the operation of each switch or valve of the heat pump system based on the signals output by the ambient temperature sensor, evaporation sensor, intake sensor, exhaust sensor and water temperature sensor, thereby controlling the heat pump system to operate in different working modes to optimize the COP (Coefficient of performance) of the heat pump system.

[0067] In some embodiments, the heat pump system further includes a first switch for controlling the operation of the air-cooled evaporator 280. When the first switch is closed, the air-cooled evaporator 280 operates; when the first switch is open, the air-cooled evaporator 280 stops operating. The control unit described above can control the opening and closing of the first switch based on the light intensity and the temperature of the water in the tank collected by the water temperature sensor.

[0068] Specifically, when the light intensity is greater than the first intensity, the first switch is turned off; when the light intensity is less than the second intensity, the first switch is turned on.

[0069] In some embodiments, the heat pump system further includes a refrigerant pump, a second switch, a third switch, and a first check valve. The second switch controls the operation of the refrigerant pump, which is connected to the condenser 260 and the expansion valve 270. When the second switch is closed, the refrigerant in the condenser 260 enters the evaporator 220 through the refrigerant pump and the expansion valve 270. When the second switch is open, the refrigerant in the condenser 260 enters the evaporator 220 through the check valve and the expansion valve 270. The first and second switches can be controlled by a control unit based on the light intensity and the water temperature in the water tank collected by a water temperature sensor. One end of the third switch is connected to the compressor, and the other end is connected to the output terminal of the photovoltaic panel 210. When the third switch is open, the photovoltaic panel 210 does not supply power to the compressor 240; when the third switch is closed, the photovoltaic panel supplies power to the compressor 240.

[0070] Specifically, when the light intensity is greater than the first intensity and the water temperature is lower than the first water temperature, the second switch is closed, the third switch is opened, and the throttle valve 270 is fully opened. This prevents the photovoltaic panel 210 from supplying power to the compressor, allowing more solar energy to be converted into heat energy, which is then absorbed and vaporized by the refrigerant in the evaporator 220. The vaporized refrigerant condenses into a liquid in the condenser 260 and then enters the evaporator 220 through the refrigerant pump and the throttle valve 270, completing one cycle. When the light intensity is greater than the first intensity and the water temperature is higher than the second water temperature, the second switch is opened, the third switch is closed, and the throttle valve 270 is in a throttling state. Part of the solar energy is converted into electrical energy by the photovoltaic panel 210 to power the compressor 240, and part of the solar energy is converted into heat energy, which is absorbed and vaporized by the evaporator 220. The vaporized refrigerant condenses into a liquid in the condenser 260 and then enters the evaporator 220 through the first one-way valve and the throttle valve 270, completing one cycle. The second water temperature is higher than the first water temperature.

[0071] In some embodiments, the heat pump system further includes a working fluid pump, a first switch, a second switch, a third switch, and a first check valve.

[0072] For example, the first water temperature can be 30℃, 35℃, 40℃ or other values, and the second water temperature can be 45℃, 50℃, 55℃ or other values.

[0073] In some embodiments, the evaporator 220 is a liquid storage evaporator.

[0074] In some embodiments, the control unit is also used to control the opening degree of the throttle valve 270 and the closing of the third switch based on the liquid level of the liquid refrigerant in the evaporator 220, the light intensity and the water temperature, so as to meet the heating and cooling needs under various operating conditions.

[0075] Specifically, when the liquid refrigerant level in the evaporator 220 is higher than the preset height, the light intensity is greater than the first intensity, and the water temperature in the water tank is lower than the first water temperature, the third switch is opened and the throttle valve is fully opened, so that the photovoltaic panel 210 does not supply power to the compressor 240, and more energy is used to heat the water in the water tank; when the light intensity is greater than the first intensity and the water temperature in the water tank is higher than the second water temperature, the third switch is closed and the throttle valve 270 is in a throttling state, so that part of the energy generated by the photovoltaic panel 210 is used to supply power to the compressor 240 and part of the energy is used to heat the water in the water tank.

[0076] In some embodiments, the control unit is also used to control the voltage output from the photovoltaic panel 210 to the frequency converter 230 based on signals from one or more of the ambient temperature sensor, evaporation sensor, intake sensor, exhaust sensor, and water temperature sensor.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the protection scope of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this application.

Claims

1. A heat pump system, characterized in that, include: Photovoltaic panels, evaporator, frequency converter, compressor, water tank, battery, photovoltaic maximum power tracking circuit (MPPT), boost unit, air-cooled evaporator, first switch, working fluid pump, second switch, third switch, first check valve, throttle valve, control unit, and water temperature sensor; The output of the photovoltaic panel is connected to the DC bus of the frequency converter through the boost unit, and the AC input of the frequency converter is connected to the mains power so that the mains power and the photovoltaic panel work together to drive the compressor. The evaporator consists of multiple heat-collecting evaporation tubes arranged in a serpentine manner and tightly attached to the back of the photovoltaic panel with thermally conductive adhesive. It is used to absorb the heat generated by the photovoltaic panel and heat the water in the water tank based on the absorbed heat energy. The MPPT is used to adjust the duty cycle of the PWM drive signal of the boost unit according to the changes in the current and voltage of the photovoltaic panel, so as to control the photovoltaic panel to charge the battery with the maximum available power. A condenser is installed inside the water tank. The evaporator, compressor, and condenser form a loop through pipes filled with refrigerant. The air-cooled evaporator is located on the side of the evaporator furthest from the photovoltaic panel. A first switch controls the operation of the air-cooled evaporator. The refrigerant pump is connected between the condenser and the throttling valve. A second switch controls the operation of the refrigerant pump. A third switch is connected between the output end of the photovoltaic panel and the compressor to control whether the photovoltaic panel supplies power to the compressor. The throttling valve is located between the evaporator and the condenser. The water temperature sensor is used to detect the temperature of the water in the water tank; The control unit is configured to control the closing of the first switch, the second switch, and the third switch, as well as the opening of the throttle valve, based on the detected light intensity and the water temperature in the water tank detected by the water temperature sensor. When the light intensity is greater than the first intensity, the first switch is opened and the air-cooled evaporator stops operating; when the light intensity is less than the second intensity, the first switch is closed and the air-cooled evaporator starts operating. When the light intensity is greater than the first intensity and the water temperature is lower than the first water temperature, the second switch is closed, the third switch is opened and the throttle valve is fully opened, so that the refrigerant is driven to circulate via the refrigerant pump. When the light intensity is greater than the first intensity and the water temperature is higher than the second water temperature, the second switch is opened, the third switch is closed, and the throttling valve is in a throttling state, so that the refrigerant is driven to circulate through the first one-way valve and the photovoltaic panel supplies power to the compressor; wherein, the second water temperature is higher than the first water temperature.

2. The system according to claim 1, characterized in that, The storage battery is connected to the photovoltaic panel and is used to charge the storage battery when the voltage output by the photovoltaic panel is greater than a preset voltage, and to discharge the storage battery when the voltage output by the photovoltaic panel is less than the preset voltage.

3. The system according to claim 1, characterized in that, It also includes a throttling valve, which is disposed between the evaporator and the condenser.

4. The system according to claim 1, characterized in that, It also includes ambient temperature sensors, evaporation sensors, intake sensors, and exhaust sensors; The ambient temperature sensor is used to detect the external ambient temperature. The evaporation sensor is used to detect the temperature of the gas at the outlet of the evaporator; The intake sensor is used to detect the temperature of the gas at the compressor inlet; The exhaust sensor is used to detect the temperature of the gas at the compressor outlet. The control unit is used to control the opening degree of the throttle valve based on the signals output by the ambient temperature sensor, evaporation sensor, intake sensor, exhaust sensor and water temperature sensor.

5. The system according to claim 4, characterized in that, The control unit is also used to control the voltage output from the photovoltaic panel to the frequency converter based on the signals output by the ambient temperature sensor, evaporation sensor, intake sensor, exhaust sensor and water temperature sensor.

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