Using a Novel and Easy-to-Use Sandwich Structure Device to Evaluate the Cooling Properties of Cool Materials

A number of cool materials have been designed and used in hot weather to minimize the heat coming from sunlight. Traditionally, solar reflectance and infrared emittance were measured to characterize the cooling properties of cool materials. However, these methods could represent the cooling property only indirectly. In this work, a sandwich structure device that can straightforwardly measure the cooling properties of cool materials was designed. Two cool materials, including high-density polyethylene (HDPE) and polyvinyl chloride (PVC), were selected to verify the device. For the purpose of comparison, UV-vis-NIR spectral characterization was also used to evaluate the cooling properties of the selected materials. The results, especially for the HDPE/Green 260 composite sample, which presents much lower solar reflectance but better cooling property, indicated that the cooling properties cannot be entirely represented by only the reflectance or transmittance, and the sandwich structure device was able to make up for this deficiency.