On the use of a novel nanoporous polyethylene (nanoPE) passive cooling material for personal thermal comfort management under uniform indoor environments

Passive cooling materials such as specially designed nanoporous microfibers are nearly transparent to infrared thermal radiation emitted from the human body. Hence, such passive cooling materials have the potential to help indoor occupants attain thermal comfort through regulating the radiative body heat in indoor conditions. In this work, a regular fit women's business shirt made of the nanoporous polyethylene (nanoPE) material was designed and its cooling performance under four uniform indoor conditions was examined. A cotton shirt (CO) with the same size and pattern as the nanoPE shirt was designed and selected as the control. Eighteen female participants underwent eight 80-min trials at four indoor temperatures: 23, 25, 27 and 29 °C. Trials were performed in simulated indoor environments where RH = 60% and the air velocity was kept below 0.10 m/s. Results have demonstrated that participants had significantly lower mean skin temperatures, mean upper torso temperatures and forearm temperatures in nanoPE as compared to CO at 23, 25 and 27 °C. Participants showed the maximum satisfaction with the thermal environment while wearing the CO clothing at 25 °C, whereas they were mostly satisfied with the thermal environment while wearing the nanoPE clothing at 27 °C. Thus, the acceptable air conditioning setpoint temperature could be extended by 1.5 °C from 25.5 to 27 °C while using the nanoPE clothing and thereby, this saves about 9-15% cooling energy. Finally, it was concluded that the nanoPE passive cooling clothing contributes to enhancing indoor thermal comfort under uniform environments and saving significant cooling energy.