Analysis Of The Applicability Of Membrane-based Energy Recovery Ventilators In Different Climatic Zones Of China

People's concern over indoor air quality problems has led to new standards that specify higher outdoor ventilation air flow rates. As a consequence, lager amounts of energy must be consumed to condition outdoor ventilation air so that building space conditions remain within the thermal comfort zone, at the same time, the same amount of indoor air which has already been conditioned to indoor set point will be exhausted to outside directly and cause a lot waste of energy.The air-to-air energy recovery ventilator can recover a fraction of the energy from the exhaust air to the supply air. There are presently two kinds of technique available for air-to-air energy recovery ventilators: heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs).Although under the same conditions, ERVs can recover more energy than HRVs, ERVs still should not be select unconditionally, but should be carefully chosen according to the proportion of sensible and latent energy cost for conditioning fresh air, since for ERVs, not only good heat conductivity, but also perfect moisture permeability are necessary, so both the first cost and run cost are lager than HRVs.In our country, the climates vary from south to north, east to west. In different climatic zone, or in different seasons of the same area, the proportion of latent and sensible energy cost for conditioning fresh air are different. So, air-to-air energy recovery system should be chosen according to characteristics in different climatic zone.In this paper, the efficiency of energy recovery was tested on hourly basis, the general relation between the efficiency of ERVs and outdoor temperature and humidity was found. The characteristics of energy costs for conditioning the fresh air in different climatic zones and different seasons in China are analyzed by analyzing the climate and calculating the load of fresh air on the basis of hourly temperature and humidity data of some cities located in various climatic zones and with specific weather characteristics. The effects of energy recovery in different cities under 3 conditions are further compared, that is, use HRV only, ERV only and use the different combinations of the two ventilators, so that a general proposal of choosingair-to-air energy recovery system is put forward. In view of the influence of hot island effect, the temperature and humidity of outdoor air were sampled hour by hour for 3 months in summer season and winter season in Shanghai and Datong respectively, and the variations in the amount of energy requirements for conditioning ventilation air calculated on the basis of sampled data are compared. The possible energy savings of ERV(energy recovery ventilator) and SERV(sensible only energy recovery ventilator) for typical outdoor conditions in the hot summer cold winter zone and the cold zone are studied to get the applicability of ERV and SERV in these two areas in different seasons.