Indoor Temperature Fluctuation and Cooling Load Reduction Using Thermal Mass and Night Ventilation

The paper presents a qualitative effect of external thermal mass, night ventilation flow on cooling load reduction and indoor air temperature fluctuation at nighttime using thermal mass and night ventilation. A simple residential building model with air-conditioning at daytime and natural or mechanical ventilation at nighttime is chosen to obtain the hourly variation of cooling load at daytime and indoor air temperature at nighttime. It is noted that the temperature distribution of thermal mass material governed by a one-dimensional non-steady heat conduction equation is considered in the paper. The dependence of the cooling load and indoor air temperature at nighttime on the thermal properties of thermal mass, night ventilation flow is further validated. Our results show that only appropriate amount of thermal mass together with suitable outdoor climates and suitable night ventilation flow will benefit most. The present work provides guidance for designing thermal mass and night ventilation.