Naturally ventilated classrooms: An assessment of existing comfort models for predicting the thermal sensation and preference of primary school children

Abstract

Current thermal comfort models are based on studies with adult subjects, mainly in offices. There is no assurance however that these models apply to children. This paper presents findings from thermal comfort surveys and measurements of indoor environmental variables in naturally ventilated classrooms in Hampshire, England. School children aged 7–11 were surveyed regarding their thermal sensation and preference in repeated survey runs outside the heating season, gathering about 1300 responses in total. The results were compared to predictions achieved with the two common approaches used in existing comfort standards, the heat balance and the adaptive comfort model. The heat balance model indices PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for the survey periods, using the measured physical parameters, estimated values for clothing insulation and four different approaches for determining the metabolic rate. The applicability of the adaptive comfort model was investigated by comparing the comfort temperature equation derived from the survey with the equation used in the European Standard EN 15251. The results suggest that children are more sensitive to higher temperatures than adults with the comfort temperatures being about 4°C and 2°C lower than the PMV and the EN 15251 adaptive comfort model predictions respectively.