Experimental and numerical comparative investigation on 24h radiative cooling performance of a simple organic composite film

Radiative cooling technology has broad application prospects because it does not require any energy input, which has drawn much attention from researchers. However, most radiative coolers are expensive and complex. Here, the finite difference time-domain (FDTD) method is used for material selection and film parameter optimization. An organic composite film of polymethyl methacrylate (PMMA) embedded with titanium dioxide (TiO2) particles is proposed, which has a simple structure and low cost. A 24-h continuous experiment was conducted to evaluate the radiative cooling performance of TiO2/PMMA film by using self-made devices. Experimental results show that the temperature of the radiative cooler can be 11 °C lower than the ambient, the average of 4.8 °C and the minimum of 2 °C below ambient during the day. Furthermore, a mathematical model has built to investigate the radiative cooling performance of the TiO2/PMMA device. The effects of environmental parameters, such as wind velocity, ambient temperature, relative humidity and solar irradiance were analyzed. This study can provide a new thinking and some practical guidelines for the design and application of radiative coolers.