Simulations on non-healthy indoor humidity by ventilation rates in nearly zero energy residential buildings in China

Abstract

Indoor humidity can be easily overlooked when discussing building ventilation. However, evidences have shown that moisture-related consequences on health are increasingly common both in China and worldwide. In addition, there is an ongoing debate on what the adequate ventilation rates (VRs) should be for nearly zero energy buildings (NZEBs). Therefore, the effects of VRs for NZEBs in China, on moist environment, are investigated using EnergyPlus in this paper. More than 1100 residential settings have been analysed with different VRs in five major cities, representing all climate zones, in China. Three generally-Agreed humidity levels have been adopted as the thresholds to reduce habitability of microbes. The results indicate that, first, humidity risk decrease with higher VRs in all zones except for some southern regions, and most cities would be free of moisture issues under current VR requirements (∼8 L/s). Second, indoor spaces feature, 1) small per capita area; 2) the ground or top floor; 3) small window-wall ratio and 4) north-orientation, are more prone to risk of high humidity.