Experimental investigation on cooling performance in high radiative temperature of energy-storage radiative cooling panel

As a feasible solution to alleviate global warming, radiative sky cooling technology has been proven to have outstanding energy-saving potential. Considering time mispatch with cooling demand, making efficient use of radiative sky cooling is significant, but the cooling performance of energy-storage radiative coolers in high temperatures is still unclear. One radiative cooling panel with PCM and one without PCM are set up in this study. The impacts of structure factors, including PCM and cover, and operating factors, including inlet temperature and flow rate of refrigerant, on the cooling performance are studied. The results show that energy-storage radiative cooling panel is more beneficial in alleviating the peak demand for building energy during the day, and removing cover is negative for energy storage but positive for cooling. Besides, high radiative temperature is beneficial for radiative cooling panels, and achieving all-day cooling despite of high solar absorbance of 0.9. In the refrigerant inlet temperature of 40 °C, the energy-storage radiative cooling panel achieves a positive net cooling power of 61.70 W/m² during the day. And significantly, excessive flow rate is detrimental for radiative cooling. As the flow rate increases from 0.75 l/min to 1.0 l/min, the net cooling power of the energy-storage radiative cooling panel decreases by 12.94 %.