Analysis and comparison of thermal comfort indicators based on a long-term campaign in low energy residences

Abstract

There is a large number of thermal comfort indicators in the literature. However, their description is generally ambiguous since there is no single and clear way to calculate them. This article evaluates thermal comfort using steady state and adaptive approaches according to 9 temperature-based indicators, 8 RH-based indicators and 1 proposed temperature-RH-based indicator. All of them are calculated using 3–4 years of measurements in the living room and the parental bedroom of 3 new and occupied nearly-zero energy houses in France, with and without occupancy scenario, during 3 seasons (winter, summer and interseason). All the measurements come from low-cost probes sampling every minute, except the outdoor temperature of one house, which comes from the nearest meteorological station. The threshold values selected correspond to current standards and the occupancy scenario is based on the habits of the inhabitants of these specific houses. Results show that the difference between the data distribution using 1-h and 10-min as time steps for the same season and year is 0–1% in the three houses. This suggests that 1-h time step is enough for the calculation of temperature-based and RH-based comfort indicators in low energy houses, even using low-cost sensors. All indicators tested are sensitive to the occupancy scenario and season. The absence of an occupancy scenario in the calculation of the “degree-hour” using the EN 16798 lower limits leads to an overestimation of up to 93% in these houses. In the case of the “percentage of time outside the RH range [25%; 60%]”, the difference range between results with and without scenario is [-57%; 52%] depending on the house and season considered.