Research About Heating And Cooling Periods In Hot Summer And Cold Winter Zone Based On Meteorological Data Analysis

Differences in climate between cities in hot summer and cold winter zone are significant, and the same to heating demand and cooling demand. According to the provisions of 《Design standard for energy efficiency of residentical buildings in hot summer and cold winter zone》 (JGJ 134-2010), all cities in hot summer and cold winter zone must use the same heating period (90d) and colling period (78d). Thus the simulation results of energy saving rate of horizontal external shading in most cities in hot summer and cold winter zone is not in accordance with the actual. A calculation method of heating and cooling periods named B2 was put forward according the analysis of 33 years measured meteorological data of 20 typical cities in hot summer and cold winter zone, 《Design code for heating ventilation and air conditioning of civil buildings》 (GB 50736-2010) and《Thermal design code for civil building》 (GB 50176-93). Further more then measured solar radiation data of the 20 typical cities in hot summer and cold winter zone was analyzed, and a calculation method of heating and cooling periods considering the influence of solar radiation named B3 was put forward. The method B3 corrected the heating and cooling periods by adjusting the heating critical temperature and the cooling critical temperature.This paper studied the effects of different heating and cooling periods on the simulation results of the annual electricity saving rates of horizontal external shading in 20 typical cities in hot summer and cold winter zone. With the heating and cooling periods of the industry standard the simulation results of annual electricity saving rates of 18 typical cities were negative. It seems that the horizontal external shading has no energy saving effect in most cities in hot summer and cold winter zone. With the heating and colding periods calculated by method B2 5 cities’ simulation results of annual electricity saving rate are still negative, but the other 15 cities’are between 0.7% to 6.1%. It means that the horizontal external shading has good energy saving effect in most cities in hot summer and cold winter zone. After the correction by method B3 the annual electricity saving rate of horizontal external shading decreased in cities with scarce solar radiation in winter or summer. Such as Chongqing, after the correction the annual electricity saving rate of horizontal external shading decreased from 6.1% to 3.5%.Effect of the temperature difference between indoor and outdoor and solar radiation on external wall cooling and heating load was studied through full scale experiment. Results show:the cooling load of external wall caused by solar radiation (175 W/m2) and the temperature difference between indoor and outdoor (10℃) together is 3.2 times as much as the value caused by the temperature difference between indoor and outdoor (10℃) singly in summer. In winter the heating load of external wall caused by solar radiation (175 W/m2) and the temperature difference between indoor and outdoor (10℃) together is 0 while the value caused by the temperature difference between indoor and outdoor (10℃) singly is 23.2 W/m2. Therefore, the solar radiation and the temperature difference between indoor and outdoor are all important factors to affect indoor energy consumption. It is really necessary to determine the influence of solar radiation on the calculation of cooling period and heating period.