Humidity Control Systems for Civil Buildings in Hot Summer and Cold Winter Zone in China

Abstract

In the hot summer and cold winter zone, moisture-laden outside air poses real problems for proper ventilation, air-conditioner sizing, and strategies to overcome the reduced dehumidification capacity of more energy-efficient air-conditioning (AC) systems. Based on our research, this paper further provides the rate and characteristics of moisture resources in civil buildings. Although the ventilation rate is limited with the minimum ventilation rate in the sanitation ventilation mode of the air conditioning period, dehumidifying period and heating period, the ventilation rate is unrestricted in thermal comfort ventilation mode. It is suggested that the operating conditions of the forced ventilation system should be determined on both outdoor air temperature and outdoor air relative humidity (RH). Therefore, the ventilation system should satisfy these requirements during prolonged periods of high ambient humidity. After a detailed presentation of the technical issues, this paper gives specific recommendations for providing adequate ventilation, moisture control and dehumidifying for buildings in hot-humid climates, and takes both the indoor environmental quality (IEQ) and the building energy efficiency into account. Supplying conditioned ventilation air to the buildings appears to be a promising approach to solve the heath problems associated with excessive indoor RH by installation of a separately controlled unit to dry and cool outdoor air.