Experimental evaluation on asymmetrical thermal sensation in modular radiant heating system

Modular radiant heating system has been widely used for heating during winter with the advantage of energy saving and meet thermal requirement. However, the asymmetry issues about thermal sensation would be often occurred because of the thermal radiation characteristics, and human thermal comfort would be affected by the position in relative to the radiant plate. How to solve asymmetrical thermal sensation will be an essential challenge to the popularization of radiant heating systems. This paper tries to evaluate the asymmetric thermal sensation of human body indoor at different exposure positions. Twenty volunteers were employed to investigate physiological and psychological situations during typical winter conditions. The experiment has assumed that the volunteers located at different positions to the radiant plate with different angles and vertical distance. Results illustrated that volunteers at different positions had different asymmetric thermal sensation because one side of the human body indoor was facing the radiant plate but the other was not. Besides, experimental data showed that the skin temperature difference was the biggest in upper arm, of 3°C–4 °C. An asymmetric thermal sensation votes (ATSVs) was proposed to supplement the evaluation of the asymmetric thermal comfort, the highest difference values of all volunteers’ ATSVs would get to 0.21, which were different with TSVs. Moreover, asymmetric skin temperature difference has a clear linear relationship with asymmetric thermal sensation vote, reflecting sensitivity of personnel at different positions to asymmetric thermal environments. The experimental results of this study can serve as a reference for thermal designs of buildings.