Heat Transfer And Load Analysis Of External Walls With Different Thermal Insulation Forms In Residential Buildings Of Hot Summer And Cold Winter Zone

The improvement of indoor thermal and humidity environment in Hot Summer and Cold Winter Zone(HSCW)in China involves many factors such as demand,construction,equipment and regulation.During the 12 th and 13 th five-year plans in China,such as "integration and demonstration of key technologies for building energy conservation in HSCW" and "solutions for building heating and air conditioning in the Yangtze river basin" supported by the national science and technology were successively launched.Due to the poor thermal performance of building envelope,more than 95% of residential buildings in HSCW are high-energy buildings.In recent years,countries have made improvements to the enclosure structure,but there are still gaps between China and developed countries.At the same time,based on the climate difference,the form of external wall insulation in HSCW is different from that in the north China and Hot Summer and Warm Winter zone,so it is necessary to consider the heat protection in summer,ventilation and cooling,as well as proper winter protection.Therefore,it is of great significance to study the dynamic heat transfer characteristics of the building's external walls and the impact of different forms of external walls on the load to optimize the thermal performance of the envelope structure in the zone to achieve building energy efficiency.In this paper,the room model is built with the EnergyPlus,and the dynamic heat transfer simulation model of the wall is solved by Conduction Finite Difference(CondFD).For a certain winter working condition,the "wall dynamic heat transfer performance test platform" was used for experimental comparison.The results show that the temperature deviation of the inner and outer surfaces of the wall is less than 4.2%.Under natural conditions,comparison natural room temperature distribution of 13 different exterior wall structure in different cities(Shanghai,Changsha,Chongqing)in HSCW,decrease the Uvalue is conducive to improve the indoor comfort,but under the condition of the room ventilation rate constant promotion effect is limited.Study a typical meteorological year in chongqing on July 20(sunny)under the condition of heat transfer coefficient is 0.77(W/m2 K)insulation,exterior insulation and heat preservation of three kinds of insulated wall under natural room temperature,wall temperature and building orientation is the change of the direction of heat transfer,heat transfer and heat storage found that three wall day and throughout the period of time are characterized by accumulation of heat,night is exothermic.Study a typical meteorological year in Chongqing on July 20(sunny day)under the condition of heat transfer coefficient is 0.77(W/m2 K),when three kinds of insulated wall are under natural room temperature,comparing the wall temperature in different orientation,heat transfer direction,heat transfer and heat storage found that All the three types of wall show heat storage during the day and the whole day,and heat release at night.For heat storage,the internal insulation wall is 1.4 times of the selfinsulation wall and 2.6 times of the external insulation wall.After the HVAC equipment is turned on or off,the inner wall surface temperature of the internal insulation responds fastest,and the change of inner wall surface temperature in winter living room is greater than in summer.This paper discusses the influence of different insulation methods on room load under different meteorological conditions by reforming the outer wall of old buildings without insulation.