Enhancing the internal thermal conductivity of hydrogel for efficient passive heat dissipation: Experimental study of a surface simulating a cooled photovoltaic panel

Abstract

Over 75 % of the absorbed solar energy by photovoltaic (PV) panels is dissipated as heat, leading to a substantial increase in their operating temperature. The temperature rise can adversely affect the energy efficiency and longevity of PV modules. Consequently, efficient cooling technologies are urgently required for PV panels. In this study, an enhanced passive cooling strategy for PV panels was proposed based on evaporative cooling, which employed a composite structure consisting of metal fins and hygroscopic salt hydrogel. The hydrogel demonstrated a water sorption capacity of 1.87 g g−1 after a 16-hour moisture absorption at 25 °C and ∼70 % relative humidity (RH). The fin-hydrogel structure demonstrated an average evaporative cooling power of ∼185 W m−2 over 10 h, resulting in a temperature reduction of ∼16 °C for the simulated PV module under an input heat flux of ∼1000 W m−2. Furthermore, durability and regeneration tests confirmed the feasibility of the fin-hydrogel structure for long-term PV cooling through cyclic water harvesting and release. This innovative cooling strategy offers promising opportunities for effective thermal management and broadens the scope of hydrogel applications, especially in dry areas with low humidity.