Solar heat pump heat supply system capable of efficiently utilizing solar energy

Abstract

The invention provides a solar heat pump heat supply system capable of efficiently utilizing solar energy. The solar heat pump heat supply system comprises a heat collection unit and a heat supply unit. Main components include an inverter, a PV / T heat collector, a heat storage water tank, a phase change energy storage element, a compressor, a throttling valve, a stop valve, a water pump and the like. The heat collection unit comprises two energy storage elements, and different heat collection operation modes can be selected according to the intensity of solar radiation to store heat for the energy storage elements, so that full utilization of solar energy is realized; moreover, the condenser and the evaporator of the heat pump are respectively coupled with the heat storage water tank and the phase change heat storage element, so that the system structure is more compact, and the occupied area is greatly reduced. The system is high in comprehensive utilization rate of solar energy and is a clean and efficient heat pump air conditioning system. By means of the control method of the system, solar energy can be fully utilized, and a stable heat supply source and domestic hot water are provided for residences.

Description

Technical Field

[0001] This invention relates to the field of solar heat pump technology. Specifically, it relates to a solar heat pump heating system that efficiently utilizes solar energy. Background Technology

[0002] Currently, the energy market faces tremendous opportunities and challenges, and energy conservation and carbon reduction have become a hot topic of social concern. Traditional fossil fuels, due to their non-renewability, low utilization efficiency, and severe environmental pollution, can no longer meet the needs of today's sustainable development. Against this backdrop, accelerating energy transition, developing clean energy, promoting the cascade utilization of energy systems, and improving energy efficiency are imperative.

[0003] Clean heating methods in northern my country include electric heating, gas heating, solar energy, heat pumps, and biomass heating. Among these, electric heating and gas-fired boilers are expensive to operate and have low cost-effectiveness. Solar energy suffers from insufficient sunshine and reduced radiation intensity in winter, making it unsuitable for room heating. Heat pumps also have relatively low energy efficiency in low winter temperatures. Solar heat pumps, however, can achieve energy complementarity and improve energy efficiency. How to fully utilize solar energy while ensuring system stability and reliability is a crucial issue that must be addressed for solar heat pump systems to achieve practical application.

[0004] Current solar heat pumps add energy storage devices to enhance system stability, which increases system complexity, reduces reliability, and does not fully utilize the energy storage devices. Therefore, this paper proposes a compact solar heat pump system that can fully utilize the energy storage devices.

[0005] Application content

[0006] To address the aforementioned problems and the shortcomings of existing technologies, this invention proposes a solar heat pump heating system that efficiently utilizes solar energy. This system enables more complete utilization of solar energy and has the advantages of simple structure, high solar energy utilization rate, and high housing comfort.

[0007] A high-efficiency solar heat pump heating system that utilizes solar energy includes an inverter, a PV / T collector 2, a hot water storage tank, a phase change energy storage element, a compressor, a throttling valve, a filter, etc.

[0008] The photovoltaic thermal module has multiple thermal storage cycle modes, allowing for the selection of a suitable operating mode based on the intensity of solar radiation to better match heating demands. During the heating season, when solar radiation intensity is high, the outlet water temperature of PV / T collector 2 is higher than the building's required heating temperature, and solar thermal collection cycle 1 operates. PV / T collector 2 transfers heat sequentially to the hot water storage tank and the phase change energy storage element. When solar radiation intensity is low, and the outlet water temperature of PV / T collector 2 is lower than the building's required heating temperature, solar thermal collection cycle 3 operates, and PV / T collector 2 transfers heat to the phase change energy storage element. During the non-heating season, solar thermal collection cycle 2 operates, and PV / T collector 2 transfers heat to the hot water storage tank for heating domestic hot water.

[0009] The hot water storage tank and phase change energy storage element are coupled to the condenser and evaporator of the heat pump, respectively, which saves space and reduces heat transfer loss.

[0010] The hot water supply first passes through a water pump and then through a Y-type filter to prevent excessive scale buildup in the first hot water storage tank and extend its service life. The filtered water is first heated by a low-temperature phase change energy storage element, and then enters the first hot water storage tank for a second heating. After being heated in stages, the water is supplied to residents for domestic hot water.

[0011] Preferably, the first hot water storage tank includes two inlets and two outlets, and has two built-in heat exchange coils; the phase change energy storage element is a three-channel heat exchange element.

[0012] As a preferred option, water in the hot water storage tank is the heat storage material. Water has a large specific heat capacity, cools down slowly, and can store heat well. In addition, water has little pollution to the environment and is safe to use.

[0013] Preferably, the phase change temperature of the phase change energy storage element is 15-20℃, which is beneficial to the overall efficiency of the system during the heating season as a low-grade energy supply.

[0014] As a preferred option, the phase change material of the phase change energy storage element is KF·4H2O. The phase change material has a phase change temperature of 18.5℃. This phase change energy storage material is an inorganic hydrated salt, which has a wide range of applications, is relatively inexpensive, and has a large heat storage density per unit volume. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a solar cascade heat pump system that combines energy storage;

[0016] Figure 2 It is a solar thermal energy storage cycle 1;

[0017] Figure 3 It is solar thermal storage cycle 2;

[0018] Figure 4It is a solar thermal storage cycle 3

[0019] Figure 5 It is a heat pump heating cycle;

[0020] Figure 6 It is a water tank heating circulation

[0021] Figure 7 It is a domestic hot water supply cycle.

[0022] In the diagram: 1. Inverter; 2. PV / T collector 2; 3-1-3-3. First to third shut-off valves; 4-1 to 4-2. First and second water pumps; 5. Three-way valve; 6. Hot water storage tank; 7. Phase change energy storage element; 8. Compressor; 9. Throttling valve; 10. Filter; 11. Domestic hot water. Detailed Implementation

[0023] The system has the following operating modes:

[0024] Solar thermal storage mode 1: During the heating season when there is ample sunlight, open port a of the three-way valve and the second shut-off valve. The circulating working fluid absorbs heat generated by solar radiation on the solar collector panels. The hot water enters the first pair of inlets of the hot water storage tank 6 from the outlet of the heat exchange channel of the PV / T collector 2. The cooled working fluid enters the heat exchange channel of the phase change energy storage element 7, heating the phase change energy storage element 7. The working fluid then returns from the phase change energy storage element 7 to the inlet of the heat exchange channel of the PV / T collector 2. At this time, the heat in the PV / T collector 22 is transferred to the hot water storage tank 66 and the phase change energy storage element 77, serving as a low-temperature heat source for house heating and the heat pump.

[0025] Solar thermal storage mode 2: In summer, when there is sufficient sunlight and the water temperature at the outlet of PV / T collector 2 meets the heating demand, the a port of the three-way valve and the first shut-off valve are opened. The circulating working fluid absorbs the heat generated by solar radiation on the solar collector panels. The hot water enters the first pair of inlets of the hot water storage tank 6 from the outlet of the heat exchange channel of PV / T collector 2. The hot water transfers the heat generated by solar energy to the hot water storage tank 6. The cooled circulating working fluid enters the inlet of the heat exchange channel of PV / T collector 2 from the first pair of outlets of the hot water storage tank 6. Since the temperature of the photovoltaic thermal module is high in summer, affecting the power generation efficiency, this circulation can both reduce the temperature of the photovoltaic thermal module and provide domestic hot water for residents.

[0026] Solar thermal storage mode 3: When sunlight is insufficient during the heating season, and the water temperature at the outlet of PV / T collector 2 cannot meet the heating demand, the b port of the three-way valve and the second shut-off valve are opened. The circulating working fluid absorbs the heat generated by solar radiation on the solar collector panel. The hot water enters the heat exchange channel of phase change energy storage element 7 from the outlet of the heat exchange channel of PV / T collector 2, heating the phase change energy storage element 7. After being cooled, the circulating working fluid enters the inlet of the heat exchange channel of PV / T collector 2. In this circulation mode, solar energy only supplements the heat of phase change energy storage element 7, serving as a low-temperature heat source for the heat pump to heat the water in the hot water storage tank 6 for room heating. When sunlight is insufficient, priority is given to meeting the heating demand, and only after ensuring the heating demand is met is domestic hot water heated.

[0027] Water tank heating operation mode: When the water temperature at the water tank outlet is sufficient to supply the building's heating requirements, water pump 4-2 is turned on to directly utilize the heat in the water tank for building heating.

[0028] Heat pump heating operation mode: During the heating season, when the building needs heating, compressor 8 is started. At this time, the refrigerant flowing through the internal heat exchanger of phase change energy storage element 7 absorbs heat from phase change energy storage element 7 and evaporates, entering the compressor as a low-temperature, low-pressure superheated gas. After being heated and pressurized by the compressor, the superheated gas enters the internal heat exchanger of hot water storage tank 6 and releases heat to the water in hot water storage tank 6. At the same time, the refrigerant is condensed, becoming a high-pressure liquid at the outlet. After passing through the throttling valve 9 to reduce the pressure drop, it becomes a low-temperature, low-pressure liquid and returns to phase change energy storage element 7. After this cycle, the heat in phase change energy storage element 7 is upgraded, and the high-temperature hot water is stored in hot water storage tank 6 for building heating and providing domestic hot water.

[0029] Hot water supply mode: In summer, the replenished water for domestic use has a certain amount of cold water. This water is first filtered through a Y-type filter 10, and then its cold energy is absorbed by the phase change energy storage element 7, serving as a low-level cold source for the cooling heat pump. The heated replenished water can be used for daily domestic use, or it can be reheated by the hot water storage tank 6 for domestic hot water supply. In winter, the replenished water is heated in stages by the phase change energy storage element 7 and the hot water storage tank 6 for residential domestic use.

[0030] The above modes can be combined according to the intensity of solar radiation and heating demand to achieve the best results.

Claims

1. A solar heat pump heating system that efficiently utilizes solar energy, characterized in that: The system mainly includes PV / T collector 2, inverter, hot water storage tank, phase change energy storage element, compressor, throttle valve, filter, shut-off valve and water pump, etc. The PV / T collector 2 can absorb part of the solar radiation and convert it into electrical energy, and part of it can be converted into heat to provide to the hot water storage tank and the phase change energy storage element. The hot water storage tank and phase change energy storage element are used to store the heat generated by solar radiation and provide a stable heat source for the heat pump; the compressor and throttle valve are components of the heat pump, which can upgrade low-grade heat to high-grade heat to meet the heating needs of the room. The shut-off valve and water pump are opened and closed according to the controller output, which flexibly adjusts the system to adapt to different intensities of solar radiation and achieves a high solar energy utilization rate.

2. The solar heat pump heating system for high-efficiency utilization of solar energy according to claim 1, characterized in that, The solar photovoltaic thermal element includes a solar panel with a heat exchange channel below it. One end of the heat exchange channel has a water inlet, and the other end has a water outlet. The heat from the solar panel is transferred to a first hot water storage tank through the heat exchange channel. The water outlet of the heat exchange channel is connected to the inlet 1 of the hot water storage tank. The outlet 1 of the first hot water storage tank is connected to the inlet of the phase change energy storage element. The outlet of the phase change energy storage element is connected to the water inlet of the heat exchange channel, thus completing the solar thermal storage cycle 1.

3. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 2, characterized in that, The solar photovoltaic thermal element includes a solar panel with a heat exchange channel below it. One end of the heat exchange channel has a water inlet, and the other end has a water outlet. The heat from the solar panel is transferred to a hot water storage tank through the heat exchange channel. The water outlet of the heat exchange channel is connected to the inlet 1 of the first hot water storage tank, and the outlet 1 of the first hot water storage tank is connected to the water inlet of the heat exchange channel, thus completing the solar thermal storage cycle 2.

4. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 3, characterized in that, The solar photovoltaic thermal element includes a solar panel with a heat exchange channel below it. One end of the heat exchange channel has a water inlet, and the other end has a water outlet. The heat from the solar panel is transferred to a phase change energy storage element through the heat exchange channel. The water outlet of the heat exchange channel is connected to the inlet of the phase change energy storage element, and the outlet of the phase change energy storage element is connected to the water inlet of the heat exchange channel, thus completing the solar thermal storage cycle 3.

5. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 4, characterized in that, The PV / T collector 2 has an optimal operating temperature. Its power generation efficiency first increases with the increase of temperature. When the temperature of the PV / T collector 2 is higher than the optimal operating temperature, the heat collection efficiency decreases. The circulating working fluid of the system flows through the PV / T collector 2 and carries away its heat, which can reduce the temperature of the PV / T collector 2 and improve its power generation efficiency.

6. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 5, characterized in that, The PV / T collector 2 can store heat for the hot water tank and the phase change energy storage element alone, or store heat for both energy storage elements at the same time.

7. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 6, characterized in that, The energy storage material inside its phase change energy storage element is a low-temperature energy storage material with a melting point of 15-18℃. During the heating season, its temperature is higher than the outdoor temperature, making it more effective than air source heat pumps.

8. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 7, characterized in that, The hot water storage tank has two inlets and two outlets, and the internal heat exchange coil serves as the condenser of the heat pump. The hot water storage tank is coupled with the condenser of the heat pump, and the phase change energy storage element is coupled with the evaporator of the heat pump. The heat pump evaporator directly absorbs heat from the heat storage element, reducing heat exchange losses, making the structure more compact, and reducing the footprint.

9. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 8, characterized in that, The hot water supply unit first passes through a water pump, then through a Y-type filter to prevent excessive scale buildup in the first hot water storage tank and extend its service life. The filtered water is first heated by a low-temperature phase change energy storage element, then enters the first hot water storage tank for a second heating, and finally supplied to residents for domestic hot water after being heated in stages.

10. A solar heat pump heating system for high-efficiency utilization of solar energy according to claim 9, characterized in that, In summer, the system can provide domestic hot water to the building, and in winter, in addition to supplying domestic hot water, it can also provide heating to the building.

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