| Work Detail |
A team of UK researchers have developed a concept photovoltaic sheet capable of producing electricity, water and thermal energy in a single device. The leaf-inspired system relies on a biomimetic (BT) transpiration layer that cools the built-in photovoltaic unit and uses excess cell heat to produce water and thermal energy.
Researchers at Imperial College London have developed a new concept of photovoltaic leaf (PV-leaf) capable of producing electricity, thermal energy and water.
In the “ High-efficiency bio-inspired hybrid multi-generation photovoltaic leaf ” study , published in nature communications , the research team describes the system as a structure-based multi-generation hybrid photovoltaic leaf. of biomimetic perspiration made of bamboo fibers and stacked hydrogel cells.
The 1mm thick Biomimetic Transpiration Layer (BT) passively moves water from a separate water reservoir to a 10cm × 10cm solar cell positioned atop the structure. The water flowing over the cell is able to reduce its operating temperature, thus increasing its efficiency, and the excess heat is used to produce water and thermal energy. The photovoltaic sheet is only protected by a 0.7 mm thick layer of high transmittance glass.
The structure uses bundles of vascular hydrophilic fibers that evenly distribute water across the photovoltaic sheet. Hydrogel cells are used to mimic vascular bundles and cancellous cells. “In the BT layer, about 30 branches of bamboo fiber bundles are homogeneously embedded in the potassium polyacrylate (PAAK) superabsorbent polymer (SAP) hydrogel cells, distributing water throughout the area covered by the BT layer. ”, explain the scientists, who add that the edges of the fiber branches come together and become soaked with water.
The scientists measured the performance of the system under standard lighting conditions and compared it to a reference stand-alone photovoltaic cell cooled by natural air convection. They verified that the photovoltaic sheet reached a temperature of 43.2 ºC, while that of the reference cell reached 68.8 ºC. “The temperature of the non-insulated water tank is close to room temperature and has a slight influence on the cooling performance,” they say.
The photovoltaic sheet achieved an energy conversion efficiency of 15.0%, an open circuit voltage of 0.63 V, and a fill factor of 0.77. The reference cell, on the other hand, achieved an efficiency of 13.2%, an open circuit voltage of 0.58 V, and a fill factor of 0.75.
The academics also noted that the capital cost of the additional components required by the PV sheet is about $1.1/m2, which is about 2% of the cost of conventional solar panels. The payback time of the additional components is estimated to be less than half a year. “The PV sheet concept can be extended to larger-scale collectors, beyond which even the largest commercial-sized solar plants can be divided into several small areas allocated to separate and interconnected PV sheets,” they added, referring to their potential project applications. real.
“Compared to previous studies on transpiration cooling, the solution in this paper does not require a pump, control unit or expensive porous materials, and is capable of cooling the target surface to a significantly lower temperature, making it suitable for multi-generation applications. as well as thermal management applications for photovoltaic cells,” the British group said, noting that the system can also use seawater instead of freshwater. “The simulation results show that the FV sheet has better transpiration performance in hot and dry climates.”
The academics also claim that the device may be capable of generating an additional 1.1 L/h/m2 of fresh water under 1000 W/m solar irradiance. They also believe that the system could use seawater instead of freshwater. "The simulation results show that the FV sheet has a better transpiration performance in hot and dry climates," they underlined. |
