Experimental investigation of the effect of clothing insulation on thermal comfort indices

Abstract

Clothing insulation is one of the six parameters used to calculate the predicted mean vote (PMV) and the new standard effective temperature (SET*). Various studies have confirmed the effects of airspeed, wind direction, and posture on clothing insulation. However, there is a lack of clarity on how these factors affect the prediction of thermal comfort by impacting clothing insulation. This study presents the clothing insulation of eight sets of current typical clothing ensembles under various airspeeds and wind directions using a manikin experiment. Furthermore, the effects of airspeed, wind direction, and posture on the calculation of PMV and SET* were investigated. The results of the study highlight that (1) the clothing insulation for the standing posture was 10% higher than that of the sitting posture; The clothing insulation decreased with the increase in airspeed. (2) The PMV and SET* for the standing posture were higher than those of the sitting posture. The PMV value under the crosswind was, at the maximum, 0.23 larger than that under other wind directions. The SET* for the crosswind was, at a maximum, 0.85 °C higher than that under other wind directions. (3) The PMV and SET* values considering the reduction of clothing insulation due to airspeed had smaller values than those that do not consider the reduction of clothing insulation. Thus, it is essential to consider the conditions of wind direction, posture, and reduction of clothing insulation caused by airspeed to achieve reliable prediction of thermal comfort.