Experimental evaluation of thermal environment built by decoupled radiant cooling system with low radiant cooling temperature

Abstract

Decoupled radiant cooling system (DRCS)1, which utilizes an infrared-transparent membrane to isolate the radiant surface from the ambient air, can provide radiant cooling temperature below the dew point to prevent condensation and increase cooling capacity. However, whether the thermal environment built by DRCS with low radiant cooling temperature meets thermal comfort needs further investigation. This includes: 1) Do the environment parameters meet the comfort standard? 2) How do subjects evaluate the environment's comfort? Thus, environmental monitoring and questionnaire surveys were conducted to evaluate the thermal environment of DRCS in summer. Initially, the environment parameters were measured and 32 subjects were recruited to perform subjective and physiological response tests. Further, the environment was evaluated using thermal comfort models and thermal sensation votes. Finally, the applicability of the predicted mean vote (PMV) model was examined by comparing actual and predicted thermal sensations. The results confirmed that thermal environment built by DRCS satisfied the ASHRAE Standard criteria. The neutral operative temperature was around 24.8°C and the comfort environment was achieved between 23.3°C and 26.5°C. Moreover, PMV model has a high accuracy in predicting the thermal sensation of DRCS.