Abstract：

Taking the dry-bulb temperature and specific enthalpy of outdoor air to judge whether using an air-side economizer, by analysing the energy saving status of fresh air free cooling, puts forward an energy saving evaluation index for fresh air free cooling—energy saving rate for fresh air free cooling. Adopting the index, analyses the energy saving status of fresh air free cooling applied to three types of buildings in six typical cities with different climate conditions. The result shows that the energy saving rate is higher in the northern severe cold and cold areas, followed by the hot summer and cold winter and hot summer and warm winter areas, and the lowest in the warm area. The rate for hotel buildings is lower than that for office buildings and shopping buildings.