Photovoltaic thermal management with highly transparent evaporative hydrogel

The temperature effect deteriorates the energy conversion efficiency of photovoltaic system, necessitating effective cooling methods for thermal management. The evaporation process of hydrogel provides a substantial cooling capacity, while its transparency allows for effective heat removal from the front surface of photovoltaic cells. Investigations on the thermal management of photovoltaic panels using highly transparent and evaporative hydrogels are conducted numerically and experimentally. The effects of the optical characteristics and evaporation rate of hydrogels on the temperature profiles and energy conversion efficiency of PV systems are elucidated. The findings suggest that hydrogels must exhibit transparency across the entire solar spectrum to lower the PV temperature and introduce more short-wavelength solar energy for electricity production. A high evaporation rate of hydrogel is preferable for effective temperature control, resulting in a system's average temperature decrease by 19.3 K as the evaporation rate increases from 0.5 to 1.3 kg m⁻² h⁻¹. Under a standard one sun illumination, a temperature reduction of 18 K has been experimentally achieved. The combination of temperature effect and increased short-circuit current results in a hydrogel-cooled PV system surpassing the standalone PV system in solar-electrical conversion efficiency by 1.96 percentage points.