Photovoltaic-photothermal combined power generation system

Abstract

This invention relates to a photovoltaic-thermal combined power generation system, comprising a hot water storage tank, photovoltaic power generation modules, a first collector, and a second collector. The photovoltaic power generation modules are arranged along a first direction to form a photovoltaic column; multiple first collectors are arranged along the first direction to form a first solar thermal column; multiple second collectors are arranged along the first direction to form a second solar thermal column. The second solar thermal column, the first solar thermal column, and the photovoltaic column are arranged along a second direction. Both the first and second collectors have vacuum tubes. The vacuum tubes of the first and second solar thermal columns are sequentially connected to form a U-shaped solar thermal loop. This photovoltaic-thermal combined power generation system reduces downstream losses from heating demineralized water using steam, reduces boiler energy consumption, and saves energy for the power plant. Furthermore, the combined solar thermal and photovoltaic systems are arranged on the same site, making efficient use of land and increasing the proportion of green and clean energy in the power plant's power generation.

Description

Technical Field

[0001] This invention relates to the field of solar power generation technology, and more specifically to a photovoltaic-thermal combined power generation system. Background Technology

[0002] Back-pressure turbine units are generator sets that adjust their power generation load based on heat load. The unit's power output is constrained by changes in heat load; when the heat load is low, turbine efficiency decreases, thus reducing economic benefits. Thermal power plants using back-pressure turbine units for heating consume large amounts of heating steam, resulting in high energy consumption for steam heating, which is inconsistent with the trend of reducing carbon emission intensity and developing green energy. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a photovoltaic-thermal combined power generation system. By heating demineralized water with solar thermal energy, it can reduce downstream losses from using steam for heating demineralized water, reduce boiler energy consumption, and save energy for the power plant. Furthermore, the combined solar thermal and photovoltaic systems are arranged on the same site, making efficient use of land and increasing the proportion of green and clean energy in the power plant's power generation.

[0005] According to an embodiment of the present invention, a photovoltaic-thermal combined power generation system includes a hot water storage tank, photovoltaic power generation modules, a first collector, and a second collector. The hot water storage tank has a first inlet, a second inlet, a first outlet, and a second outlet. The first inlet is used to connect to a cold demineralized water source, and the first outlet is used to connect to a downstream hot demineralized water user. The photovoltaic power generation modules are arranged along a first direction to form a photovoltaic column. A plurality of the first collectors are arranged along the first direction to form a first solar thermal column. A plurality of the second collectors are arranged along the first direction to form a second solar thermal column. The second solar thermal column, the first solar thermal column, and the photovoltaic column are arranged along a second direction, which is perpendicular to the first direction. Both the first collector and the second collector have vacuum tubes. The vacuum tubes of the first solar thermal column and the second solar thermal column are connected in sequence to form a U-shaped solar thermal circuit. The inlet of the vacuum tube of the first collector located at the beginning of the first solar thermal column is connected to the second outlet, and the outlet of the vacuum tube of the second collector located at the end of the second solar thermal column is connected to the second inlet.

[0006] The photovoltaic-thermal combined power generation system of this invention can reduce the losses of downstream heating of demineralized water by heating it with solar thermal energy, reduce boiler energy consumption, save energy for the power plant, and make efficient use of land by combining solar thermal and photovoltaic power generation on the same site, which can also increase the proportion of green and clean energy in the power plant's power generation.

[0007] In some embodiments, there are multiple first solar thermal arrays, second solar thermal arrays, and photovoltaic arrays. The height of the vacuum tube of the first collector is H3, the height of the vacuum tube of the second collector is H2, and the height of the photovoltaic power generation module is H1. H3 is less than the average water level of the hot water storage tank, and H1 > H2 > H3.

[0008] In some embodiments, the vacuum tubes of the first collector and the second collector are laid flat, and the photovoltaic power generation module has a photovoltaic panel with a tilt angle of 18°-22°.

[0009] In some embodiments, the photovoltaic panel is a monocrystalline silicon solar cell panel.

[0010] In some embodiments, in the second direction, the distance between the photovoltaic column and the adjacent second photothermal column is greater than the distance between the first photothermal column and the adjacent second photothermal column.

[0011] In some embodiments, the photovoltaic-thermal combined power generation system further includes a regulating valve, which is provided at the inlet of the vacuum tube of the first collector located at the first end of the first solar thermal array.

[0012] In some embodiments, the photovoltaic-thermal combined power generation system further includes an exhaust pipe and an automatic exhaust valve, wherein the exhaust pipe is connected to the vacuum tube of every 7-10 first or second collectors, and the automatic exhaust valve is provided on the exhaust pipe.

[0013] In some embodiments, the photovoltaic-thermal power generation system further includes a water-stop bend disposed between the exhaust pipe and the outlet of the adjacent vacuum tube.

[0014] In some embodiments, the photovoltaic-thermal combined power generation system further includes a controller, a first temperature detector, a second temperature detector, a third temperature detector, a collector circulation pump, and a water supply pump. The first temperature detector is located at the outlet of the vacuum tube of the second collector at the end of the second solar thermal array. The second temperature detector and the collector circulation pump are both located between the inlet of the vacuum tube of the first collector at the beginning of the first solar thermal array and the second water outlet. The third temperature detector is located inside the hot water storage tank to detect the liquid temperature inside the hot water storage tank. The water supply pump is located at the first water outlet. The first temperature detector, the second temperature detector, the third temperature detector, the collector circulation pump, and the water supply pump are all connected to the controller. Attached Figure Description

[0015] Figure 1This is one of the schematic diagrams showing the arrangement of the second solar thermal column, the first solar thermal column, and the photovoltaic column in a photovoltaic-thermal combined power generation system according to an embodiment of the present invention;

[0016] Figure 2 This is a second schematic diagram of the arrangement of the second solar thermal column, the first solar thermal column, and the photovoltaic column in the photovoltaic-thermal combined power generation system of this invention.

[0017] Figure 3 This is a schematic diagram of a photovoltaic-thermal combined power generation system according to an embodiment of the present invention;

[0018] Figure label:

[0019] 100 photovoltaic-solar thermal power generation system;

[0020] Hot water storage tank 1, first water inlet 101, second water inlet 102, first water outlet 103, second water outlet 104;

[0021] Photovoltaic power generation module 2, photovoltaic column 20, first collector 3, first solar thermal column 30, second collector 4, second solar thermal column 40, solar thermal circuit 34, regulating valve 5, controller 6, first temperature detector 7, second temperature detector 8, third temperature detector 9, collector circulation pump 10, water supply pump 11. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] like Figures 1 to 3As shown, the photovoltaic-thermal combined power generation system 100 of this embodiment includes a hot water storage tank 1, photovoltaic power generation modules 2, a first collector 3, and a second collector 4. The hot water storage tank 1 has a first inlet 101, a second inlet 102, a first outlet 103, and a second outlet 104. The first inlet 101 is used to connect to a cold demineralized water source, and the first outlet 103 is used to connect to a downstream hot demineralized water user. The photovoltaic power generation modules 2 are arranged along a first direction to form a photovoltaic column 20. Multiple first collectors 3 are arranged along the first direction to form a first solar thermal column 30. Multiple second collectors 4 are arranged along the first direction to form a second solar thermal column 40. The second solar thermal column 40, the first solar thermal column 30, and the photovoltaic column 20 are arranged along a second direction, which is perpendicular to the first direction. Both the first solar collector 3 and the second solar collector 4 have vacuum tubes. The vacuum tubes of the first solar collector 30 and the second solar collector 40 are connected in sequence to form a U-shaped solar thermal circuit 34. The inlet of the vacuum tube of the first solar collector 3, located at the beginning of the first solar collector 30, is connected to the second water outlet 104, and the outlet of the vacuum tube of the second solar collector 4, located at the end of the second solar collector 40, is connected to the second water inlet 102. The first solar collector 30 and the second solar collector 40 connected in series form the solar thermal circuit 34.

[0024] Specifically, in the photovoltaic-thermal combined power generation system 100 of this embodiment of the invention, the first direction is east-west and the second direction is north-south.

[0025] In the photovoltaic-thermal combined power generation system 100 of this embodiment, under operating conditions, cold demineralized water is fed into the hot water storage tank 1 through the first inlet 101. The cold demineralized water is discharged from the second outlet 104, flows into the vacuum tube of the first collector 3 of the first solar thermal array 30, and then flows into the vacuum tube of the second collector 4 of the second solar thermal array 40. The cold demineralized water is heated by solar energy as it flows through the collectors of the first solar thermal array 30 and the second solar thermal array 40, and then flows back to the hot water storage tank 1 through the second inlet 102.

[0026] Photovoltaic power generation module 2 generates electricity using solar energy, adopts 6kV grid connection, and is automatically consumed as power for the thermal power plant.

[0027] The vacuum tubes of the first collector 3 and the second collector 4 are large-diameter vacuum tubes, with an inlet and outlet diameter of 50 mm. The first collector 3 of the first solar thermal array 30 has 11 units, and the second collector 4 of the second solar thermal array 40 has 11 units.

[0028] After being circulated and heated by the photovoltaic-thermal combined power generation system 100 of this invention, the demineralized water can be discharged through the first outlet 103 and supplied to downstream users. For thermal power plants, the heated demineralized water is supplied to the boiler, where it is further heated and vaporized to form steam, which is then supplied to the back-pressure steam turbine generator set.

[0029] Therefore, the photovoltaic-thermal combined power generation system 100 of this invention can reduce the losses of downstream heating of demineralized water by heating demineralized water with solar thermal energy, reduce boiler energy consumption, save energy for thermal power plants, and the combination of solar thermal and photovoltaic power generation in the same site can make intensive use of land and increase the proportion of green and clean energy in the power generation of thermal power plants.

[0030] If there are multiple first solar thermal arrays 30, second solar thermal arrays 40, and photovoltaic arrays 20, then there are multiple solar thermal circuits 34.

[0031] In some embodiments, the height of the vacuum tube of the first collector 3 is H3, the height of the vacuum tube of the second collector 4 is H2, and the height of the photovoltaic power generation module 2 is H1. H3 is less than the average water level of the hot water storage tank 1, and H1 > H2 > H3. The height of the photovoltaic power generation module 2 is higher than the height of the second collector 4 of the second solar thermal array 40, and the height of the second collector 4 of the second solar thermal array 40 is higher than the height of the first collector 3 of the first solar thermal array 30. The photovoltaic power generation module 2, the second collector 4, and the first collector 3 are spaced apart in this second direction. Since roads are needed between the solar thermal circuits of different arrays for passage and equipment maintenance, arranging the photovoltaic power generation modules 2 in the vertical space above the roads to form a photovoltaic array 20 can conserve land and avoid the problem of shading between the first collector 3, the second collector 4, and the photovoltaic power generation module 2 in the north-south direction. Furthermore, the height of the first collector 3 is lower than the average water level of the hot water storage tank 1 to ensure that the collector will not suddenly fill with water due to water shortage under any circumstances, causing thermal shock that could cause the vacuum tube to burst.

[0032] Furthermore, the vacuum tubes of the first solar collector 3 and the second solar collector 4 are laid flat, and the photovoltaic power generation module 2 has a photovoltaic panel with a tilt angle of 18°-22°.

[0033] In this embodiment, the tilt angle of the photovoltaic panel is 20°.

[0034] In some embodiments, the photovoltaic panel is a monocrystalline silicon solar panel. Based on site resources, climate, and construction conditions, crystalline silicon solar panels with relatively high photoelectric conversion efficiency are selected. Considering module efficiency, economics, technological maturity, market share, and available capacity, a monocrystalline silicon module with a rated power of 445W is specifically chosen.

[0035] In some embodiments, in the second direction, the distance between the photovoltaic column 20 and the adjacent second solar thermal column 40 is greater than the distance between the first solar thermal column 30 and the adjacent second solar thermal column 40. This avoids the photovoltaic column 20 affecting the light-gathering of the second solar thermal column 40 to its north, and avoids shading the second solar thermal column 40.

[0036] The photovoltaic-thermal combined power generation system 100 of this embodiment further includes a regulating valve 5, which is provided at the inlet of the vacuum tube of the first collector 3 located at the first end of the first solar thermal array 30. The regulating valve 5 can adjust the inflow of water to each solar thermal loop 34, thereby compensating for and balancing the difference in demineralized water pressure drop in different solar thermal loops 34, ensuring that each solar thermal loop 34 of the photovoltaic-thermal combined power generation system 100 of this embodiment has the same or similar flow rate, thereby ensuring the operational stability of the photovoltaic-thermal combined power generation system 100 of this embodiment.

[0037] The photovoltaic-thermal combined power generation system 100 of this embodiment further includes an exhaust pipe and an automatic exhaust valve. An exhaust pipe is connected to the vacuum tube of every 7-10 first collectors 3 or second collectors 4, and an automatic exhaust valve is installed on the exhaust pipe. The automatic exhaust valve can automatically discharge the gas in the photovoltaic-thermal circuit, preventing the gas generated in the photovoltaic-thermal circuit from adversely affecting the circuit.

[0038] The photovoltaic-thermal combined power generation system 100 of this embodiment further includes a water-stop bend, which is located between the exhaust pipe and the outlet of the adjacent vacuum tube, thereby preventing the demineralized water circulation in the solar thermal circuit from stopping, and further ensuring the operational stability of the photovoltaic-thermal combined power generation system 100 of this embodiment.

[0039] The photovoltaic-thermal combined power generation system 100 of this embodiment further includes a controller 6, a first temperature detector 7, a second temperature detector 8, a third temperature detector 9, a solar collector circulation pump 10, and a water supply pump 11. The first temperature detector 7 is located at the outlet of the vacuum tube of the second solar collector 4 at the end of the second solar thermal array 40. The first temperature detector 7 detects the temperature of the demineralized water at the outlet of the solar thermal circuit, denoted as T1. The second temperature detector 8 and the solar collector circulation pump 10 are both located between the inlet of the vacuum tube of the first solar collector 3 at the beginning of the first solar thermal array 30 and the second water outlet 104. The second temperature detector 8 detects the stability of the demineralized water at the inlet of the solar thermal circuit, denoted as T2. The third temperature detector 9 is located inside the hot water storage tank 1 to detect the liquid temperature inside the hot water storage tank 1, denoted as T3. The water supply pump 11 is located at the first water outlet 103. The first temperature detector 7, the second temperature detector 8, the third temperature detector 9, the solar collector circulation pump 10, and the water supply pump 11 are all connected to the controller 6.

[0040] When T1-T3 > 8℃ (adjustable) and T3 ≤ 75℃ (adjustable), the solar collector circulation pump 10 is turned on, allowing the demineralized water to circulate in the solar thermal circuit. When T1-T3 ≤ 4℃ (adjustable) or T3 > 75℃, the solar collector circulation pump 10 is turned off.

[0041] When downstream users need water, the first outlet 103 opens and the water supply pump 11 starts; otherwise, it closes.

[0042] When the water level in the hot water storage tank 1 is less than 60%, cold demineralized water is added to the hot water storage tank 1. When the water level in the hot water storage tank 1 is 100%, the water supply to the hot water storage tank 1 is stopped.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A photovoltaic-thermal combined power generation system (100), characterized in that, include: A hot water storage tank (1) has a first inlet (101), a second inlet (102), a first outlet (103), and a second outlet (104). The first inlet (101) is used to connect to a cold demineralized water source, and the first outlet (103) is used to connect to a downstream hot demineralized water user. A photovoltaic power generation module (2), wherein the photovoltaic power generation module (2) is arranged along a first direction to form a photovoltaic column (20); First solar collector (3), a plurality of first solar collectors (3) are arranged along the first direction to form a first solar thermal array (30); The second solar collector (4) is arranged in a second solar thermal array (40) along the first direction. The second solar thermal array (40), the first solar thermal array (30) and the photovoltaic array (20) are arranged in a second direction perpendicular to the first direction. The first solar collector (3) and the second solar collector (4) both have vacuum tubes. The vacuum tubes of the first solar thermal array (30) and the second solar thermal array (40) are connected in sequence to form a U-shaped solar thermal circuit (34). The inlet of the vacuum tube of the first solar collector (3) located at the beginning of the first solar thermal array (30) is connected to the second water outlet (104). The outlet of the vacuum tube of the second solar collector (4) located at the end of the second solar thermal array (40) is connected to the second water inlet (102).

2. The photovoltaic-thermal combined power generation system (100) according to claim 1, characterized in that, The number of the first solar thermal array (30), the second solar thermal array (40) and the photovoltaic array (20) is multiple. The height of the vacuum tube of the first collector (3) is H3, the height of the vacuum tube of the second collector (4) is H2, and the height of the photovoltaic power generation module (2) is H1. H3 is less than the average water level of the hot water storage tank (1), and H1 > H2 > H3.

3. The photovoltaic-thermal combined power generation system (100) according to claim 2, characterized in that, The vacuum tubes of the first collector (3) and the second collector (4) are laid flat, and the photovoltaic power generation module (2) has a photovoltaic panel with a tilt angle of 18°-22°.

4. The photovoltaic-thermal combined power generation system (100) according to claim 3, characterized in that, The photovoltaic panel is a monocrystalline silicon solar cell panel.

5. The photovoltaic-thermal combined power generation system (100) according to claim 2, characterized in that, In the second direction, the distance between the photovoltaic column (20) and the adjacent second photothermal column (40) is greater than the distance between the first photothermal column (30) and the adjacent second photothermal column (40).

6. The photovoltaic-thermal combined power generation system (100) according to claim 1, characterized in that, It further includes a regulating valve (5), which is provided at the inlet of the vacuum tube of the first collector (3) located at the first end of the first photothermal column (30).

7. The photovoltaic-thermal combined power generation system (100) according to claim 1, characterized in that, It further includes an exhaust pipe and an automatic exhaust valve, with the exhaust pipe connected to the vacuum tube of every 7-10 of the first collector (3) or the second collector (4), and the automatic exhaust valve is provided on the exhaust pipe.

8. The photovoltaic-thermal combined power generation system (100) according to claim 7, characterized in that, It further includes a water-stop bend, which is disposed between the outlet of the exhaust pipe and the outlet of the adjacent vacuum pipe.

9. The photovoltaic-thermal combined power generation system (100) according to claim 1, characterized in that, The system further includes a controller (6), a first temperature detector (7), a second temperature detector (8), a third temperature detector (9), a heat collection circulation pump (10), and a water supply pump (11). The first temperature detector (7) is located at the outlet of the vacuum tube of the second collector (4) at the end of the second solar thermal array (40). The second temperature detector (8) and the heat collection circulation pump (10) are both located between the inlet of the vacuum tube of the first collector (3) at the beginning of the first solar thermal array (30) and the second water outlet (104). The third temperature detector (9) is located in the hot water storage tank (1) to detect the liquid temperature in the hot water storage tank (1). The water supply pump (11) is located on the first water outlet (103). The first temperature detector (7), the second temperature detector (8), the third temperature detector (9), the heat collection circulation pump (10), and the water supply pump (11) are all connected to the controller (6).

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