Investigation on Human Body Thermal Comfort under Radiative Cooling Air Conditioning System

To explore the human body thermal comfort under radiative cooling air conditioning system, the heat transfer mechanism of radiative cooling air conditioning system is investigated. The relationship of the thermal comfort indicator with the human body's sensible heat loss and the ratio of radiative heat loss to convective heat loss is achieved. Both experimental and numerical results show that the human body thermal comfort index, i.e., predicted mean vote (PMV), is approximately linear with the sensible heat loss of human body under the radiative cooling air conditioning system. Thus, the human body thermal comfort could be directly evaluated by the human body thermal balance according to the obtained linear relationship. Furthermore, it is found that the ratio of radiative heat loss to convective heat loss of human body has no effect on PMV. Therefore, on the basis of maintaining human body thermal comfort, it is conceivable that the higher ratio of radiative heat loss to convective heat loss, which means larger radiative area or higher air supply temperature, could be beneficial to energy conservation. This study may provide a reference for both assessment of human body thermal comfort and system design of radiative cooling air conditioning system.