Seasonal division of HVAC in cities of hot summer and cold winter zone

The hot summer and cold winter zone has the common features of high temperature and high humidity, as well as obvious climate differences between east and west regions. In order to understand the seasonal difference of HVAC among the cities in hot summer and cold winter zone, analyses the thermal and humid states of outdoor air and the seasonal change of the representative cities of Nanjing in the east and Chongqing in the west, and finds that the transition period of HVAC in eastern and western cities is different from each other in terms of time, length and complexity. Further analysis shows that the key points and difficulties of HVAC operation and regulation in eastern and western cities as well as the time periods with great energy saving potential are different. The eastern cities are the ventilation period before and after heating seasons, while the western cities are the ventilation period before and after dehumidification and air conditioning seasons.