Photo-thermal-electric coupled photovoltaic hydrogen production system

Abstract

The invention belongs to the technical field of water electrolysis hydrogen production, and relates to a light-heat-electricity coupled photovoltaic hydrogen production system which comprises a collecting lens, a solar Si battery, a semiconductor chilling plate and a proton exchange membrane electrolytic tank, the cold end of the semiconductor chilling plate is attached to the solar Si battery in a heat conduction mode, and the hot end of the semiconductor chilling plate is attached to the proton exchange membrane electrolytic tank in a heat conduction mode. The solar Si battery is electrically connected with a DC-DC converter; the DC-DC converter is electrically connected to a proton exchange membrane electrolytic tank, a gas outlet of the proton exchange membrane electrolytic tank is communicated with a hydrogen storage tank and an oxygen storage tank, and a water supply port of the proton exchange membrane electrolytic tank is communicated with a constant-temperature water tank; the cold end of the semiconductor chilling plate actively refrigerates, so that the photovoltaic working temperature is reduced, the hot carrier recombination effect is inhibited, the photoelectric conversion efficiency is improved, and the photovoltaic power generation efficiency is remarkably improved. And by utilizing the advantage of rapid heat dissipation of the semiconductor chilling plate, the system can support a higher concentration ratio, and the photovoltaic output power density is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production by electrolyzing water, and relates to a photovoltaic hydrogen production system with photo-thermal-electric coupling. Background Art

[0002] With the transformation of the global energy structure towards low-carbonization, solar hydrogen production technology has become a research hotspot due to its clean and sustainable characteristics. The concentrating photovoltaic (CPV) system converges solar radiant energy on a small-area photovoltaic cell through an optical concentrator, which can significantly reduce the cost of photovoltaic materials and improve the power generation efficiency. However, the local high temperature generated by concentration will cause the phenomenon of thermally induced efficiency decay in the photovoltaic cell. When the temperature of the photovoltaic panel exceeds 50°C, the conversion efficiency will lose 0.35%-0.5% for every 1°C increase. The traditional heat dissipation solutions mainly adopt forced air cooling or liquid cooling technologies, both of which require additional energy consumption for driving and cannot recycle the waste heat.

[0003] The PEM electrolyzer stores the fluctuating electric energy in the form of hydrogen due to its advantages such as fast response speed and high hydrogen production purity, and is considered the best device for converting and storing clean energy.

[0004] However, the PEM electrolyzer needs to work within the range of 60-80°C to obtain the best reaction kinetic performance. The existing systems generally use a constant temperature water tank to maintain the temperature, relying on external electric energy for heating, resulting in large heat losses caused by secondary heat transfer and low overall energy efficiency of the hydrogen production system. The existing systems have unidirectional heat transfer and cannot match the energy level requirements of photovoltaic cooling and electrolysis heating. In addition, the coupled system lacks a dynamic coupling mechanism. When the light intensity changes suddenly, the fixed-ratio energy distribution strategy will lead to problems such as unstable operating conditions of the thermoelectric element and the electrolyzer.

[0005] Therefore, a photovoltaic hydrogen production device with high overall energy efficiency and stable operating conditions is needed to solve the above technical problems. Summary of the Invention

[0006] The present invention proposes a new photo-thermal-electric coupled hydrogen production system, which uses a thermoelectric cooler (TEC) to cool the photovoltaic cell and the proton exchange membrane electrolyzer, and improves the photovoltaic power generation efficiency, reduces the energy consumption of electrolytic hydrogen production, enhances the system stability, and increases the service life of the system through the two-way thermal management of the thermoelectric cooler and multi-stage heat recovery.

[0007] The technical solution adopted by the present invention to solve the technical problems is: a photo-thermal-electric coupled photovoltaic hydrogen production system, comprising: a condenser, a solar Si cell, a thermoelectric cooler, and a proton exchange membrane electrolyzer. The condensing direction of the condenser faces the solar power generation surface of the solar Si cell, and the solar Si cell and the proton exchange membrane electrolyzer sandwich the thermoelectric cooler in the middle;

[0008] The cold end of the semiconductor refrigeration chip is thermally conductive and abuts against the heat dissipation surface of the backplane of the solar Si cell, and the hot end of the semiconductor refrigeration chip is thermally conductive and abuts against the heat absorption surface of the proton exchange membrane electrolytic cell; the semiconductor refrigeration chip transfers the heat generated on the backplane during the power generation of the solar Si cell to the proton exchange membrane electrolytic cell, reducing the temperature of the backplane of the solar Si cell and improving the power generation efficiency of the solar Si cell, raising and maintaining the temperature of the proton exchange membrane electrolytic cell, reducing the electrolysis energy consumption of the proton exchange membrane electrolytic cell and stabilizing the working condition of the proton exchange membrane electrolytic cell;

[0009] The solar Si cell is electrically connected to a DC-DC converter;

[0010] The DC-DC converter is electrically connected to the power supply port of the proton exchange membrane electrolytic cell. The hydrogen outlet of the proton exchange membrane electrolytic cell is connected to a hydrogen storage tank, the oxygen outlet of the proton exchange membrane electrolytic cell is connected to an oxygen storage tank, and the water supply port of the proton exchange membrane electrolytic cell is connected to a constant temperature water tank; the DC-DC converter transfers the power generated by the solar Si cell to the proton exchange membrane electrolytic cell for use during electrolysis of the proton exchange membrane electrolytic cell.

[0011] Preferably, a circulation water pump is connected in series between the constant temperature water tank and the water supply port of the proton exchange membrane electrolytic cell, and the water pump is used to replenish water to the proton exchange membrane electrolytic cell in real time as needed;

[0012] A gas-liquid separator is connected in series between the oxygen storage tank and the oxygen outlet of the proton exchange membrane electrolytic cell. The gas outlet of the gas-liquid separator is connected to the oxygen storage tank, and the liquid outlet of the gas-liquid separator is connected to the constant temperature water tank.

[0013] Preferably, a capacitor is connected in series between the solar Si cell and the DC-DC converter. The capacitor is used to stabilize the current and electric quantity.

[0014] Preferably, the condenser is connected to a converter for adjusting the condensing angle, and the converter is electrically connected to an intelligent controller;

[0015] The intelligent controller is electrically connected to the solar Si cell through a temperature sensor, and the intelligent controller is electrically connected to the DC-DC converter through a signal converter.

[0016] Preferably, the semiconductor refrigeration chip is sequentially provided with a copper electrode, a thermoelectric pin and a ceramic plate from the cold end to the hot end; heat conductive adhesive films are respectively provided between the cold end of the semiconductor refrigeration chip and the heat dissipation surface of the backplane of the solar Si cell, and between the hot end of the semiconductor refrigeration chip and the heat absorption surface of the proton exchange membrane electrolytic cell.

[0017] More preferably, a plate heat exchanger water supply circuit is provided between the hot end of the semiconductor refrigeration chip and the heat absorption surface of the proton exchange membrane electrolytic cell, and the plate heat exchanger water supply circuit is connected to the constant temperature water tank through a water circulation.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The active refrigeration at the cold end of the thermoelectric cooler of the present invention reduces the working temperature of the photovoltaic cell, inhibits the thermal carrier recombination effect, improves the photoelectric conversion efficiency, and significantly enhances the photovoltaic power generation efficiency. Utilizing the advantage of rapid heat dissipation of the thermoelectric cooler, the system can support a higher concentration ratio and increase the photovoltaic output power density.

[0020] 2. The present invention precisely matches the photovoltaic waste heat with the electrolysis heat supply, improves the heat utilization rate, and enhances the overall energy efficiency of the system. The waste heat at the hot end of the thermoelectric cooler is directionally transported to the electrolytic cell through a circulating water pump, reducing the external energy supply demand of the electrolytic cell and lowering the hydrogen production energy consumption. The three - level utilization of heat energy is achieved through a plate heat exchanger and a circulating water pump, improving the comprehensive heat efficiency.

[0021] 3. The present invention can reduce the fluctuating temperature of the Si cell during irradiation mutation, is suitable for complex working conditions such as fluctuating light resources and day - night alternation, and enhances the adaptability and dynamic stability.

[0022] 4. The present invention dynamically adjusts the refrigeration capacity of the thermoelectric cooler, reduces the risk of thermal damage to the photovoltaic cell, and improves the safety and reliability of the system operation. The waste heat recovery reduces the external energy supply demand and lowers the hydrogen production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a photovoltaic hydrogen production system with photo - thermal - electric coupling of the present invention;

[0024] Figure 2 is a schematic diagram of the temperature dynamic regulation control method of the present invention;

[0025] Figure 3 is a working principle diagram of the Si cell coupled with the thermoelectric cooler of the present invention.

[0026] In the figure, 1. Condensing mirror, 2. Solar Si cell, 3. Thermoelectric cooler, 4. Proton exchange membrane electrolytic cell, 5. Capacitor, 6. DC - DC converter, 7. Constant temperature water tank; 8. Circulating water pump, 9. Hydrogen gas storage tank, 10. Oxygen gas storage tank, 11. Gas - liquid separator, 12. Intelligent controller, 13. Converter, 14. Temperature sensor, 15. Signal converter, 16. Copper electrode, 17. Thermoelectric pin, 18. Ceramic plate, 19. Glass panel, 20. Thermal conductive adhesive film, 21. Plate heat exchanger water supply circuit. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, the relevant technologies in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0028] Referring to Figures 1 to 3 , in this embodiment, the photo-thermal-electricity coupled photovoltaic hydrogen production system includes a concentrating power generation unit, a thermoelectric regulation unit, an electrolytic hydrogen production unit, and an intelligent control unit.

[0029] The concentrating power generation unit includes a parabolic concentrator 1, a solar Si cell 2, a capacitor 5, and a cold-end heat conduction component of a semiconductor refrigerator 3. The concentrator 1 is equipped with a two-axis solar tracker to track the solar azimuth angle and altitude angle, and reflect and focus the incident sunlight onto the surface of the solar Si cell 2 to generate DC electric energy through the photovoltaic effect. The electric energy generated by the solar Si cell 2 is input into the capacitor 5, and is first adjusted to the operating voltage of the proton exchange membrane electrolyzer 6 through a DC-DC converter 6, and the remaining part is supplied to the semiconductor refrigerator 3 to ensure photovoltaic cooling. The cold end of the semiconductor refrigerator 3 is closely attached to the back of the solar Si cell 2, and absorbs excess heat when energized to achieve the purpose of photovoltaic temperature control. When the irradiance increases, the photovoltaic temperature rises, triggering an increase in the power of the semiconductor refrigerator 3, and the heat absorption rate at the cold end matches the heat generation rate of the photovoltaic to ensure that the temperature of the solar Si cell 2 ≤ 50°C. When the photovoltaic power is insufficient, the system automatically switches to the power grid or energy storage battery for energy replenishment.

[0030] The thermoelectric regulation unit includes an array of semiconductor refrigerators 3, a water-cooled plate, a plate heat exchanger, and a circulation water pump 8. The hot end of the semiconductor refrigerator 3 is rigidly connected to the water-cooled plate, and the outlet of the water-cooled plate passes through a water pipeline to preheat the water in the constant temperature water tank 7, improving the energy utilization rate. The cold end of the semiconductor refrigerator 3 is attached to the back of the substrate of the solar Si cell 2. Through detection by a temperature sensor 14, when the temperature of the solar Si cell 2 is higher than 50°C, the semiconductor refrigerator 3 is activated to cool the solar Si cell 2.

[0031] The intelligent control unit includes a temperature sensor 14, an intelligent controller 12, and a DC-DC converter 6. When the solar irradiance suddenly drops, the intelligent controller 12 preferentially reduces the concentration ratio (adjusts the lens inclination angle) and reduces the electrolysis current to avoid temperature runaway caused by the reverse heat absorption of the semiconductor refrigerator 3. When the solar irradiance increases, the photovoltaic temperature rises, triggering an increase in the power of the semiconductor refrigerator 3, and the heat absorption rate at the cold end matches the heat generation rate of the photovoltaic to ensure that the temperature of the solar Si cell 2 ≤ 50°C; at the same time, the waste heat at the hot end is transferred in real time by the water circulation system to avoid heat accumulation.

[0032] The electrolytic hydrogen production unit includes a proton exchange membrane electrolytic cell 4, a constant temperature water tank 7, a circulating water pump 8, and a plate heat exchanger water supply circuit 21. The waste heat released from the hot end of the semiconductor refrigeration sheet 3 is transferred to the constant temperature water tank 7 through the circulating water path for preheating. The high-temperature water flows through the flow channels of the proton exchange membrane electrolytic cell 4 to maintain the temperature of the proton exchange membrane electrolytic cell 4 within the optimal working range of 60-80°C. A one-way valve and an expansion tank are provided in the circulation pipeline to prevent the reverse impact of the water flow on the semiconductor refrigeration sheet 3 module, and the rotational speed of the circulating water pump 8 is dynamically adjusted through a pressure sensor to maintain the stability of the system pressure.

[0033] Embodiment

[0034] The hydrogen production system of this embodiment includes: a condenser 1, a solar Si cell 2, a semiconductor refrigeration sheet 3, and a proton exchange membrane electrolytic cell 4. The cold end of the semiconductor refrigeration sheet 3 is closely attached to the backplane of the solar Si cell 2. The capacitor 5 stores the electric energy generated by the solar Si cell 2, and the stable electric energy is transmitted to the proton exchange membrane electrolytic cell 4 through the DC-DC converter 6, and the overshoot electric energy caused by the light intensity fluctuation is transmitted to the semiconductor refrigeration sheet 3. After the semiconductor refrigeration sheet 3 is powered on, the cold end absorbs heat, reduces the temperature of the solar Si cell 2, and improves the power generation efficiency. The circulating water pipeline passes through the hot end of the semiconductor refrigeration sheet 3, and the preheated water is introduced into the constant temperature water tank 7 and then sent to the proton exchange membrane electrolytic cell 4 by the circulating water pump 8 for electrolysis reaction. The generated hydrogen enters the hydrogen storage tank 9 through the cathode outlet of the electrolytic cell, and the generated oxygen enters the oxygen storage tank 10 through the gas-liquid separator 11. The water stored in the gas-liquid separator 11 is mixed with the circulating water circuit of the hot end of the semiconductor refrigeration sheet 3 through the circulating water circuit and circulates in the constant temperature water tank 7 together.

[0035] As Figure 2 shown, the temperature sensor 14 monitors the temperature of the solar Si cell 2. When the solar radiation irradiance increases and the temperature of the solar Si cell 2 rises, the temperature sensor 14 transmits the signal to the intelligent controller 12. The intelligent controller 12 transmits the control signal to the DC-DC converter 6 through the signal converter 15. While ensuring the stable power supply of the solar Si cell 2, the semiconductor refrigeration sheet 3 is started to consume the fluctuating electric energy. When the solar irradiance suddenly drops, the intelligent controller 12 transmits the signal to the DC-DC converter 6 to turn off the semiconductor refrigeration sheet 3, and at the same time adjusts the irradiation angle of the condenser through the converter 13 to increase the concentration ratio and maintain the stable transmission of electric energy.

[0036] As Figure 3As shown in the figure, the semiconductor refrigeration chip 3 includes a copper electrode 16, a thermoelectric pin 17, and a ceramic plate 18. A glass panel 19 is provided on the semiconductor refrigeration chip 3. When a direct current flows through an electric couple composed of N-type (electron-rich) and P-type (hole-rich) semiconductor materials, electrons flow from the N-type material to the P-type material, and holes move in the opposite direction. At the junction of the two, when electrons and holes combine, they absorb the surrounding heat to form a cold end, which plays a refrigeration role. At the other end, when electrons and holes separate, they release heat to form a hot end, and the heat needs to be discharged through a radiator. By adjusting the current direction, the functions of the cold and hot ends can be switched to achieve two-way temperature control; and by changing the current magnitude, the intensity of refrigeration or heating can be precisely controlled. The cold end of the semiconductor refrigeration chip 3 is closely attached to the thermal conductive adhesive film 20 to reduce the temperature of the solar Si cell 2. The hot end is closely attached to the water supply circuit 21 of the plate heat exchanger to provide preheated water for the constant temperature water tank 7.

[0037] In summary, the present invention can realize the dual utilization of photovoltaic waste heat. The cold end of the semiconductor refrigeration chip actively refrigerates to ensure the photovoltaic efficiency, and the waste heat at the hot end precisely matches the requirements of the electrolytic cell to achieve the cascade utilization of energy grades. The present invention can also alleviate the decomposition and aging of the solar cell panel materials caused by the high volatility of light, extend the service life; reduce the external energy consumption required by the electrolytic cell, open up a new path for the utilization of low-grade heat energy, and accelerate the process of the electrolytic hydrogen production industry.

[0038] It should be emphasized that: the above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification made to the above embodiments based on the technical essence of the present invention also belongs to the protection scope of the present invention. Other equivalent changes and modifications are still within the scope of the technical solution of the present invention.

Claims

1. A photovoltaic hydrogen production system coupling light, heat and electricity, characterized in that Including: A condenser (1), a solar Si cell (2), a semiconductor refrigeration sheet (3), and a proton exchange membrane electrolytic cell (4). The condensing direction of the condenser (1) faces the solar power generation surface of the solar Si cell (2), and the solar Si cell (2) and the proton exchange membrane electrolytic cell (4) sandwich the semiconductor refrigeration sheet (3) in the middle; The cold end of the semiconductor refrigeration sheet (3) is thermally conductive and abuts against the backplane heat dissipation surface of the solar Si cell (2), and the hot end of the semiconductor refrigeration sheet (3) is thermally conductive and abuts against the heat absorption surface of the proton exchange membrane electrolytic cell (4); The solar Si cell (2) is electrically connected to a DC-DC converter (6); The DC-DC converter (6) is electrically connected to the power supply port of the proton exchange membrane electrolytic cell (4). The hydrogen outlet of the proton exchange membrane electrolytic cell (4) is communicated with a hydrogen storage tank (9), the oxygen outlet of the proton exchange membrane electrolytic cell (4) is communicated with an oxygen storage tank (10), and the water supply port of the proton exchange membrane electrolytic cell (4) is communicated with a constant temperature water tank (7).

2. The photo-thermal-electricity-coupled photovoltaic hydrogen production system according to claim 1, wherein A circulation water pump (8) is connected in series between the constant temperature water tank (7) and the water supply port of the proton exchange membrane electrolytic cell (4); A gas-liquid separator (11) is connected in series between the oxygen storage tank (10) and the oxygen outlet of the proton exchange membrane electrolytic cell (4). The gas outlet of the gas-liquid separator (11) is communicated with the oxygen storage tank (10), and the liquid outlet of the gas-liquid separator (11) is communicated with the constant temperature water tank (7).

3. A photo-thermal-electricity coupled photovoltaic hydrogen production system according to claim 1, wherein A capacitor (5) is connected in series between the solar Si cell (2) and the DC-DC converter (6); 4. A photo-thermal-electricity coupled photovoltaic hydrogen production system according to claim 1, characterized in that, The condenser (1) is connected to a converter (13) for adjusting the condensing angle, and the converter (13) is electrically connected to an intelligent controller (12); The intelligent controller (12) is electrically connected to the solar Si cell (2) through a temperature sensor (13), and the intelligent controller (12) is electrically connected to the DC-DC converter (6) through a signal converter (15).

5. The photovoltaic hydrogen production system with photo-thermal-electric coupling according to claim 1, wherein The semiconductor refrigeration sheet (3) is sequentially provided with a copper electrode (16), a thermoelectric pin (17), and a ceramic plate (18) from the cold end to the hot end; Heat conductive adhesive films (20) are respectively provided between the cold end of the semiconductor refrigeration sheet (3) and the backplane heat dissipation surface of the solar Si cell (2) and between the hot end of the semiconductor refrigeration sheet (3) and the heat absorption surface of the proton exchange membrane electrolytic cell (4).

6. The photo-thermal-electricity coupled photovoltaic hydrogen production system according to claim 5, wherein, A plate heat exchanger water supply circuit (21) is provided between the hot end of the semiconductor refrigeration sheet (3) and the heat absorption surface of the proton exchange membrane electrolytic cell (4), and the water circuit of the plate heat exchanger water supply circuit (21) is circulated and communicated to the constant temperature water tank (7).

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