Transmittance analysis for materials suitable as radiative cooling windshield and aging study for polyethylene

Nowadays space conditioning with renewable energy is one of the highest challenges of our society. Solar collection is a suitable source of energy for domestic hot water and space heating, but there is no green source to cool the spaces during hot periods or for hot climates. Radiative cooling seems to be a feasible solution for it. Elsewhere the Radiative Cooler Emitter (RCE) is presented, a device with an adaptive cover concept that combines both functionalities: solar collection during daytime and radiative cooling during nighttime. In this study, the solar and IR transmittances are analyzed for five samples: polycarbonate, methacrylate, and three commercial samples of low density polyethylene (LDPE): 17 mu m, 50 mu m and 200 mu m). The aging of 50 mu m low density polyethylene film is also studied during two months of environmental exposure in a RCE prototype (summer 2019). Presence of double bonds and C=O groups are detected, which implies a degradation of the polyethylene during the experimental campaign.