A system for preparing domestic hot water by off-grid photovoltaic power generation

Abstract

The utility model relates to the field of environmental protection and energy saving technology provides a kind of system for preparing domestic hot water using off-grid photovoltaic power generation, including photovoltaic power distribution unit, mains power distribution unit, heat pump unit, hot water storage tank and water supply tank, and photovoltaic power distribution unit output end is electrically connected with hot water storage tank, mains power distribution unit and heat pump unit input end, and heat pump unit output end connects hot water storage tank, and water tank circulating pump and liquid level control valve are connected between hot water storage tank and water supply tank, and mains power distribution unit output end is electrically connected with water tank circulating pump and water supply tank. The system maintenance cost is low, and service life is longer, can realize hot water system zero carbon operation, and save municipal power consumption.

Description

Technical Field

[0001] This utility model relates to the field of environmental protection and energy conservation technology, and in particular to a system for producing domestic hot water using off-grid photovoltaic power generation. Background Technology

[0002] Photovoltaic power generation is a technology that uses the photovoltaic effect at the semiconductor interface to directly convert light energy into electrical energy. The key component of this technology is the solar cell. Solar cells are connected in series and then encapsulated for protection to form a large-area solar cell module. Combined with components such as a power controller, a photovoltaic power generation device is formed. The advantages of photovoltaic power generation are that it is less restricted by geographical location because sunlight shines on the earth everywhere. Photovoltaic systems also have the advantages of being safe and reliable, noiseless, low-pollution, requiring no fuel consumption or transmission lines to generate electricity locally, and having a short construction period.

[0003] The vast majority of users obtain their domestic water from municipal power supply. For solar energy utilization, solar thermal systems are commonly used, supplemented by electric heating. Solar thermal systems are complex and have high maintenance costs. The heating capacity of solar thermal systems varies greatly with sunlight, which leads to over-reliance on municipal power supply and low utilization efficiency of solar energy resources. Furthermore, the power of distributed photovoltaic power generation systems on building rooftops is difficult to absorb, and the grid load has reached its limit for absorbing the power of distributed photovoltaic power generation.

[0004] Therefore, in order to address the above problems, a system for producing domestic hot water using off-grid photovoltaic power generation is proposed. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by developing a system for producing domestic hot water using off-grid photovoltaic power generation. This invention has low maintenance costs, a longer service life, and can achieve zero-carbon operation of the hot water system, saving municipal electricity.

[0006] The technical solution to the technical problem solved by this utility model is as follows: This utility model provides a system for producing domestic hot water using off-grid photovoltaic power generation, including a photovoltaic power distribution unit, an energy storage module, a mains power distribution unit, a heat pump unit, a hot water storage tank, and a water supply tank. The output end of the photovoltaic power distribution unit is electrically connected to the hot water storage tank, the energy storage module, and the input end of the heat pump unit. The output end of the heat pump unit is connected to the hot water storage tank. A water tank circulation pump and a liquid level control valve are connected between the hot water storage tank and the water supply tank. The output end of the mains power distribution unit is electrically connected to the water tank circulation pump and the water supply tank.

[0007] As an optimization, the mains power distribution unit includes a mains power distribution box and a municipal power supply. The output end of the photovoltaic power distribution unit is connected to the input end of the energy storage module. The output ends of the energy storage module and the municipal power supply are both connected to the input end of the mains power distribution box. The output end of the mains power distribution box is electrically connected to the water tank circulation pump and the water supply tank.

[0008] As an optimization, a second heater is installed inside the water supply tank, and a hot water supply pump is installed at the output end of the water supply tank. The output end of the mains power distribution box is electrically connected to the second heater and the hot water supply pump.

[0009] As an optimization, a first heater is installed inside the hot water storage tank, and the output terminal of the photovoltaic power distribution unit is electrically connected to the first heater.

[0010] As an optimization, the heat pump unit includes a heat pump water heater unit and a heat pump unit circulation pump that are electrically connected to the photovoltaic power distribution unit. The output end of the heat pump water heater unit is connected to the heat pump unit circulation pump. The output end of the heat pump unit circulation pump is connected to the input end of the hot water storage tank through a three-way regulating valve. Both the three-way regulating valve and the input end of the water supply tank are connected to the water supply pipe.

[0011] As an optimization, both the hot water storage tank and the water supply tank are equipped with level sensors and temperature sensors. The level sensors and temperature sensors in the hot water storage tank are electrically connected to the heat pump water heater unit and the heat pump unit's circulating pump. The level sensors and temperature sensors in the water supply tank are electrically connected to the water tank's circulating pump and the level control valve.

[0012] As an optimization, the photovoltaic power distribution unit includes a photovoltaic panel, a photovoltaic busbar, a photovoltaic inverter, and a photovoltaic distribution box that are connected in sequence. The photovoltaic distribution box is electrically connected to the first heater, the heat pump water heater unit, and the heat pump unit circulation pump.

[0013] The effects provided in the utility model description are merely those of the embodiments, and not all the effects of the utility model. The above technical solution has the following advantages or beneficial effects:

[0014] 1. This system, by setting up photovoltaic power distribution units, has low maintenance costs and a longer service life. When the area of ​​photovoltaic power generation meets the overall hot water energy consumption requirements, the hot water system can achieve zero-carbon operation.

[0015] 2. Both the municipal power distribution box and the photovoltaic distribution box are powered by photovoltaics, which can realize the zero-carbon operation of the hot water system. The hot water storage tank and the water tank circulation pump are powered by the battery of the energy storage module. The municipal power supply can only be used as a backup in case of failure, thus saving municipal electricity. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0017] Figure 1 This is an overall structural diagram of the present invention;

[0018] Figure 2 This is a structural diagram of the hot water storage tank of this utility model;

[0019] Figure 3 This is a structural diagram of the water supply tank of this utility model.

[0020] In the diagram, 1. Hot water storage tank; 2. Water supply tank; 3. Heat pump water heater unit; 4. Heat pump unit circulation pump; 5. Hot water supply pump; 6. Water tank circulation pump; 7. Liquid level sensor; 8. Temperature sensor; 9. First heater; 10. Second heater; 11. Three-way regulating valve; 12. Liquid level control valve; 13. Photovoltaic panel; 14. Photovoltaic distribution box; 15. Mains power distribution box; 16. Control box; 17. Photovoltaic busbar; 18. Photovoltaic inverter; 19. Energy storage module; 20. Municipal power supply; 21. Water supply pipe. Detailed Implementation

[0021] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and / or letters in different examples. This repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. The present invention omits descriptions of well-known components and processing techniques and processes to avoid unnecessarily limiting the present invention. The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] like Figures 1 to 3As shown, a system for producing domestic hot water using off-grid photovoltaic power generation includes a photovoltaic power distribution unit, an energy storage module 19, a mains power distribution unit, a heat pump unit, a hot water storage tank 1, and a water supply tank 2. The output of the photovoltaic power distribution unit is electrically connected to the hot water storage tank 1, the energy storage module 19, and the input of the heat pump unit. The output of the heat pump unit is connected to the hot water storage tank 1. A water tank circulation pump 6 and a level control valve 12 are connected between the hot water storage tank 1 and the water supply tank 2. The output of the mains power distribution unit is electrically connected to the water tank circulation pump 6 and the water supply tank 2. Both the photovoltaic power distribution unit and the mains power distribution unit are equipped with fault protection devices such as short-circuit, overload, and grounding protection devices. This is an existing structure and will not be described in detail. By setting up a photovoltaic power distribution unit, this system has low maintenance costs and a longer service life. When the area of ​​photovoltaic power generation meets the overall hot water energy consumption requirements, the hot water system can achieve zero-carbon operation.

[0023] In this embodiment, the mains power distribution unit includes a mains power distribution box 15 and a municipal power supply 20. The output end of the photovoltaic power distribution unit is connected to the input end of the energy storage module 19. The output ends of the energy storage module 19 and the municipal power supply 20 are both connected to the input end of the mains power distribution box 15. The output end of the mains power distribution box 15 is electrically connected to the water tank circulation pump 6 and the water supply tank 2.

[0024] A second heater 10 is installed inside the water supply tank 2, and a hot water pump 5 is installed at the output end of the water supply tank 2. The output end of the mains power distribution box 15 is electrically connected to the second heater 10 and the hot water pump 5. When the photovoltaic power distribution unit cannot work properly, the second heater 10 is activated for temporary heating when the water temperature in the water supply tank 2 is below 50°C.

[0025] A first heater 9 is installed inside the hot water storage tank 1, and the output terminal of the photovoltaic power distribution unit is electrically connected to the first heater 9.

[0026] In this embodiment, the heat pump unit includes a heat pump water heater unit 3 and a heat pump unit circulation pump 4 electrically connected to the photovoltaic power distribution unit. The output end of the heat pump water heater unit 3 is connected to the heat pump unit circulation pump 4, and the output end of the heat pump unit circulation pump 4 is connected to the input end of the hot water storage tank 1 through a three-way regulating valve 11. The three-way regulating valve 11 and the input end of the water supply tank 2 are both connected to the water supply pipe 21. The heat pump unit has a built-in wired controller with two operating modes: energy saving and rapid heating. The temperature setting range of the hot water storage tank 1 is 45~55℃, the maximum outlet water temperature of the heat pump unit circulation pump 4 is 60℃, and the operating ambient temperature of the heat pump water heater unit 3 is -10~48℃. The heat pump water heater unit 3 is powered by the photovoltaic power distribution unit and can realize dual power supply switching. When the solar power generation is sufficient, it is given priority to supply the heat pump water heater unit 3 to produce hot water. The surplus power is used to charge the battery of the energy storage module 19, and any remaining surplus is used for the first heater 9 of the hot water storage tank 1 until the water temperature of the hot water storage tank 1 rises to 95°C.

[0027] In this embodiment, a level sensor 7 and a temperature sensor 8 are installed in both the hot water storage tank 1 and the water supply tank 2. The level sensor 7 and the temperature sensor 8 in the hot water storage tank 1 are electrically connected to the heat pump water heater unit 3 and the heat pump unit circulation pump 4. The level sensor 7 and the temperature sensor 8 in the water supply tank 2 are electrically connected to the water tank circulation pump 6 and the level control valve 12.

[0028] The system also includes a control box 16, which is electrically connected to the photovoltaic power distribution unit, the mains power distribution unit, and the heat pump unit, and is used to control the operation of the entire system. Its control logic is as follows: on the demand side, the system heating is activated when the water temperature in the water supply tank 2 is lower than the set temperature; on the power supply side, the priority order is: heat pump unit heating—energy storage module 19 charging—hot water storage tank 1 electric heating—supply to the mains power distribution box 15.

[0029] Heat pump unit control:

[0030] When the temperature of the hot water storage tank 1 is ≤44℃ (automatically adjusted according to the ambient temperature), the hot water supply pump 5 is turned on, and the heat pump water heater unit 3 is turned on in sequence.

[0031] When the temperature of the hot water storage tank 1 is ≥54℃ (automatically adjusted according to the ambient temperature), the heat pump water heater 3 and the heat pump unit circulation pump 4 are shut down.

[0032] When the heat pump unit's circulating pump 4 is operating at low flow rate and large temperature difference, one water pump will be turned on; when the flow rate is large and the temperature difference is small, two water pumps will be turned on and running simultaneously.

[0033] When the water level in the hot water storage tank 1 is lower than the set water level, port B of the three-way regulating valve 11 opens, and the corresponding hot water supply pump 5 and heat pump unit circulation pump 4 are turned on. When the water level in the hot water storage tank 1 reaches the set water level, port B of the three-way regulating valve 11 closes.

[0034] When the temperature of water supply tank 2 is ≤44℃ (natural cooling during low water usage), the liquid level control valve 12 opens and the water tank circulation pump 6 starts.

[0035] When the temperature of water supply tank 2 is ≥54℃ (automatically adjusted according to ambient temperature), the electric three-way ball valve 12 closes and the water tank circulation pump 6 closes.

[0036] The photovoltaic power distribution unit includes photovoltaic panels 13, photovoltaic busbars 17, photovoltaic inverters 18, and photovoltaic distribution boxes 14, which are connected in sequence. The photovoltaic distribution box 14 is electrically connected to the first heater 9, the heat pump water heater unit 3, and the heat pump unit circulation pump 4. The photovoltaic panels 13 of the photovoltaic power distribution unit should meet the total demand for hot water supply and be able to drive the heat pump unit circulation pump 4 to work normally.

[0037] The system uses photovoltaic power generation to directly supply the heat pump unit's circulating pump 4 and hot water storage tank 1 for heating. The water tank circulating pump 6 and water supply tank 2 are heated by the battery of the energy storage module 19 and the municipal power supply 20. When the energy storage capacity of the energy storage module 19 is insufficient, the municipal power supply 20 can independently provide hot water heating and system operation.

[0038] Both distribution boxes, the mains power distribution box 15 and the photovoltaic distribution box 14, are powered by photovoltaics, which can achieve zero-carbon operation of the hot water system. The hot water storage tank 1 and the water tank circulation pump 6 are powered by the battery of the energy storage module 19, and the municipal power supply 20 is only used as a backup in case of failure.

[0039] Control of the first heater 9 and the second heater 10: When both the hot water storage tank 1 and the water supply tank 2 reach the set water level and set temperature (55°C), the power generation system is still running, prioritizing the charging of the energy storage module 19. After the energy storage module 19 is fully charged, the first heater 9 is activated to heat the water in the hot water storage tank 1 until the water temperature reaches 95°C. When the photovoltaic system cannot work due to weather conditions, the energy storage module 19 is released to replenish the system. When the energy level drops to a low point, the system switches to municipal power supply 20, and the second heater 10 of the water supply tank 2 is activated for temporary water supply. The second heater 10 of the water supply tank 2 is supplied by the battery of the energy storage module 19 and municipal power supply 20. When the battery cannot supply power, the system sequentially switches to municipal power supply 20.

[0040] Defrosting control: When the unit reaches the conditions for entering defrosting, the heat pump unit circulation pump 4 and the heat pump water heater unit 3 are turned on; when the unit reaches the conditions for exiting defrosting, the heat pump unit circulation pump 4 and the heat pump water heater unit 3 are turned off.

[0041] The water level control of hot water storage tank 1 and water supply tank 2 is as follows: when hot water storage tank 1 reaches the set water temperature (55-95°C) and water supply tank 2 supplies water, the water tank circulation pump 6 supplies high-temperature water from hot water storage tank 1 to water supply tank 2. When the water supply temperature exceeds 60°C, cold water is added through water supply pipe 20 to mix the water to the set water supply temperature. When the water level of hot water storage tank 1 drops to the lower protection water level (150mm above the first heater 9), the three-way regulating valve 11 is opened to replenish water to hot water storage tank 1 to the set water level.

[0042] With the development of solar photovoltaic power generation technology, the efficiency of solar power generation has reached over 24%, and the cost has decreased by more than 90% in the past 10 years. Combined with the average COP of 4.2 for heat pump units, the overall efficiency of solar photovoltaic systems in producing domestic hot water reaches 100%, which is much higher than the average heating efficiency of 42% for solar thermal systems. Moreover, the system has less loss and higher stability. Since electric heating can be used, hot water at any temperature can be obtained. This system adopts an off-grid system, and the self-consumption of photovoltaic power generation can effectively reduce the impact on the power grid. It can utilize solar energy resources more efficiently, and use heat storage and energy storage to balance the imbalance between the power generation side and the demand side, thereby maximizing the utilization of solar energy resources and solving the problem of solar power consumption. For the same heating capacity, the construction cost of this system is lower, and zero-carbon operation can be achieved during the operation phase. Therefore, it has technical and economic advantages. This off-grid photovoltaic power generation system for producing domestic hot water can completely replace the solar photovoltaic hot water system.

[0043] Although the specific embodiments of the utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the utility model. Based on the technical solution of the utility model, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the utility model.

Claims

1. A system for producing domestic hot water using off-grid photovoltaic power generation, characterized in that: It includes a photovoltaic power distribution unit, an energy storage module (19), a mains power distribution unit, a heat pump unit, a hot water storage tank (1), and a water supply tank (2). The output end of the photovoltaic power distribution unit is electrically connected to the hot water storage tank (1), the energy storage module (19), and the input end of the heat pump unit. The output end of the heat pump unit is connected to the hot water storage tank (1). A water tank circulation pump (6) and a liquid level control valve (12) are connected between the hot water storage tank (1) and the water supply tank (2). The output end of the mains power distribution unit is electrically connected to the water tank circulation pump (6) and the water supply tank (2).

2. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 1, characterized in that: The mains power distribution unit includes a mains power distribution box (15) and a municipal power supply (20). The output end of the photovoltaic power distribution unit is connected to the input end of the energy storage module (19). The output ends of the energy storage module (19) and the municipal power supply (20) are both connected to the input end of the mains power distribution box (15). The output end of the mains power distribution box (15) is electrically connected to the water tank circulation pump (6) and the water supply tank (2).

3. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 2, characterized in that: A second heater (10) is installed inside the water supply tank (2), and a hot water supply pump (5) is installed at the output end of the water supply tank (2). The output end of the mains power distribution box (15) is electrically connected to the second heater (10) and the hot water supply pump (5).

4. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 1 or 2, characterized in that: A first heater (9) is installed inside the hot water storage tank (1), and the output end of the photovoltaic power distribution unit is electrically connected to the first heater (9).

5. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 4, characterized in that: The heat pump unit includes a heat pump water heater (3) and a heat pump circulating pump (4) that are electrically connected to the photovoltaic power distribution unit. The output end of the heat pump water heater (3) is connected to the heat pump circulating pump (4). The output end of the heat pump circulating pump (4) is connected to the input end of the hot water storage tank (1) through a three-way regulating valve (11). The three-way regulating valve (11) and the input end of the water supply tank (2) are both connected to the water supply pipe (21).

6. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 5, characterized in that: A level sensor (7) and a temperature sensor (8) are installed in both the hot water storage tank (1) and the water supply tank (2). The level sensor (7) and the temperature sensor (8) in the hot water storage tank (1) are electrically connected to the heat pump water heater unit (3) and the heat pump unit circulation pump (4). The level sensor (7) and the temperature sensor (8) in the water supply tank (2) are electrically connected to the water tank circulation pump (6) and the level control valve (12).

7. The system for producing domestic hot water using off-grid photovoltaic power generation according to claim 5, characterized in that: The photovoltaic power distribution unit includes a photovoltaic panel (13), a photovoltaic busbar (17), a photovoltaic inverter (18), and a photovoltaic distribution box (14) connected in sequence. The photovoltaic distribution box (14) is electrically connected to the first heater (9), the heat pump water heater (3), and the heat pump unit circulation pump (4).

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