A study on the relationship between thermal cognition of room space controlled by high-temperature radiant cooling panel combined with natural ventilation and human-body exergy balance

Abstract

This paper discusses the relationship between the indoor thermal conditions provided by a high-temperature radiative cooling system mounted on the ceiling and thermal cognition given by the subjects experiencing its thermal environment in an experimental room simulating common living conditions in residential buildings. The subjects accepted the indoor thermal environment with high relative humidity over 70 % provided that both of the mean radiant and air temperatures kept at 29°C and the air movement exceeds 0.15m/s. We also calculated the human-body exergy balance for indoor thermal conditions that the subjects voted most for "comfort". Under such a condition, the cool radiant exergy received by the human body was approximately 30mW/m2 and thereby the warm exergy was emitted efficiently from the human body by radiation and convection into the room space. This amount of warm exergy emissions was are larger than that in an air-conditioned room space. Therefore, radiant cooling is not to provide a large amount of cool radiant exergy with occupants, but to provide a sufficient amount in order for the human body to release warm exergy smoothly from the human body surface; that is for spontaneous entropy disposal.