Self-healing passive cooling utilizing endothermic reaction of NH4NO3/H2O driven by moisture sorption for photovoltaic cell

Power efficiency of photovoltaic (PV) cell is significantly affected by the cell temperature. Herein, a passive cooling unit comprising inexpensive materials is developed for perfromance improvement of the PV cell. The water-saturated zeolite 13X is coated on the back side of the PV cell, and ammonium nitrate is dispersed as a layer. When thermal radiation is supplied, water is desorbed from zeolite 13X (primary latent cooling), and also dissolves ammonium nitrate to induce secondary endothermic reaction cooling. The cooling unit is operated based on the moisture sorption performance of mesoporous materials, which is inversely proportional to the cell temperature, and the solubility of endothermic reaction pairs increases proportionally with temperature. It is a reversible process in which ammonium nitrate is crystallized when the temperature is low at night, and water is adsorbed back to zeolite 13X. The average temperature of the PV cell can be reduced by approximately 14.9°C during the day, and the cooling energy density reaches 2,876 kJ/kg. Based on the life cycle cost analysis, the cost of power generation can be reduced by 5.1%, and the power efficiency is improved by 7.5%. A PV cell with the passive cooling unit will be a solution for efficient PV electric generation.