Photovoltaic cooling and atmospheric water harvesting using a hygroscopic hydrogel

Photovoltaic power generation technology has gained significant attention from researchers due to its advantages of simple structure, environmental friendliness, and high sustainability. However, the photon-to-electron conversion efficiency (PCE) of photovoltaic (PV) panels is limited by the residual heat produced during the solar absorption process. Thus, an effective heat management is vital for the long-term stable and efficient photovoltaic system. In this paper, a novel dual-function device was proposed to realize effective cooling of PV panels and harvest freshwater from the air simultaneously. Through the utilization of evaporative cooling with hygroscopic hydrogel, the photovoltaic cooling-water generator (PVC-WG) device achieves up to 8 °C reduction in the operating temperature of PV panels along with a freshwater generation rate of 122.32 g m−2 h−1 in the laboratory at solar intensity of 1 kW m−2. At night, the hygroscopic hydrogel automatically absorbed moisture from the air to achieve self-regeneration, confirming its excellent reusability. Even in real outdoor environments, a maximum cooling effect of 9.2 °C and a stable freshwater generation of 98.08 g m−2 day−1 could be achieved. The system not only accomplishes thermal management for PV panels but also attains additional freshwater generation, which enhances the efficiency of harnessing the entire spectrum of solar energy.