Quantify the magnitude and energy impact of overcooling in a sub-tropical campus building

Overcooling leads to unnecessary energy wastes and low thermal satisfaction rate. This study investigates the magnitude and energy impact of overcooling in a sub-tropical university campus. We deployed an environmental sensing network with 577 temperature sensors across the campus, collecting data every 30 min for 2 years. We derived the suitable temperature set-point using heat balance model and adaptive comfort model. We compared the actual temperature measurements with the set-point recommended by thermal comfort theories and standards in different jurisdiction. We found the indoor temperature measured in the campus buildings are averagely 2.5 °C lower than the comfort temperature recommended by the heat balance and adaptive comfort theories. The magnitude of overcooling are inhomogeneous: offices and interiors thermal zones suffer more from overcooling compared with other functional spaces and exterior thermal zones. And overcooling is more severe in the morning and during working days. Next, we use building energy simulation engine EnergyPlus to quantify the energy impact of overcooling. The simulation results show that overcooling in the campus lead to 34% more annual cooling energy consumption and 20% higher peak cooling load. Considering the increasing demand for space cooling due to global warming, mitigating overcooling provides a non-negligible opportunity to reduce cooling energy consumption and associated carbon emissions without compromising comfort. •We quantify the magnitude and energy impact of overcooling in a subtropical campus.•577 temperature sensors were deployed across the campus, collecting data for 2 years.•The indoor temperature are averagely 2.5 °C lower than the recommended comfort temperature.•Overcooling leads to 34% more cooling energy consumption and 20% higher peak load.