Thermal comfort in Italian classrooms under free running conditions during mid seasons: Assessment through objective and subjective approaches

This work shows the results of a field study about indoor thermal comfort, based on investigations in Italian classrooms. The surveys were carried out in Turin, in the North–West of Italy. The monitoring campaigns were performed during the mid season, in free running conditions. This study follows a previous one based on a monitoring campaign performed during the heating season. The responses from these two different configurations were integrated, analyzed and compared. The field study was conducted by physical observations, survey questionnaires and behavioral observations. Both field measurements and subjective surveys were performed at the same time during the regular lesson period. Thermal environment parameters were measured: indoor air temperature, mean radiant temperature, air relative humidity, air velocity and outdoor air temperature. Through these data, Fanger’s comfort indices were calculated (predicted mean vote and predicted percentage of dissatisfied people), the actual people clothing and metabolic rate being known; furthermore an adaptive model was applied to obtain acceptable ranges for the indoor operative temperature, in function of the outdoor climatic conditions. The subjective survey investigated the thermal sensation, the thermal acceptability and the thermal preference, using subjective scales. The subjective judgments about the thermal environment were compared with the results of the field measurements. Moreover, the thermal sensation votes were compared with the votes of acceptability and preference. The responses from this study and from the previous one, performed during the heating season, were compared. The results show a trend characterized by a gradual change in the thermal preference from the heating season to the mid and warm season. In fact, the results show a preference for environments judged slightly warm or warm during the heating period and a preference for neutral environments in the mid season.