Influence of building envelope characteristics on the effectiveness of PMV-based controls for schools located in Saudi Arabia

This paper summarizes the results of a comprehensive analysis to investigate the performance of both thermal comfort-based and temperature-based controls for schools in harsh hot climates of Saudi Arabia. The analysis considers the impact of building envelope characteristics including thermal insulation level of exterior walls and air leakage rate on the ability of both control options to maintain indoor thermal comfort while minimizing cooling energy consumption. The analysis utilizes a calibrated energy model for an existing Saudi school with monitored energy consumption data. The analysis results indicated that the thermal comfort-based control is able to maintain the predicted percentage of dissatisfied (PPD) value at 5% throughout the year for any combination of the exterior wall's R-value and air infiltration rate unlike the case of the temperature-based controls that do not maintain acceptable indoor thermal comfort conditions. However, the thermal comfort-based controls consume more cooling energy than the temperature-based controls. The analysis also revealed that the difference between the annual cooling energy of the PMV-based control and the temperature-based controls increases almost linearly with the cooling degree days of the site where the school is located. The analysis results indicate that acceptable indoor thermal comfort levels can be achieved using temperature-based controls when optimal temperature set points are used.