Study On The Thermal Design For Night Ventilation Building

The air-conditioning energy consumption in summer gradually became the focus ofthe modern social energy consumption with the rapid development of social economyand the improvement of people’s living standard. Meanwhile, the global energy problemwhich made passive building design has gradually become to the focus problem ofArchitecture industry was also on the rise. Night ventilation technique could greatlyreduce the energy consumption of building cooling energy consumption on one hand; italso can improve indoor air quality. Therefor, the night ventilation technique graduallybecame the one of the important research projects domestic and overseas. However, thenight ventilation cooling technique wasn’t generalization due to various limitations inpractical application. Therefor, how to make the night ventilation technique used inbuilding the preliminary design stage is the important develop direction for thetechnique, which was also the major problem in the paper.The night ventilation building thermal physical model was established based on thenight ventilation cooling mechanism. The influence of related parameters for nightventilation was analysed, especially for building thermal parameters and ventilationparameters which were analyzed and concluded. The theoretical model was verifiedthrough the field measured. The main parameters were abstracted to obtain thecongruent relationship of meteorological parameter, building parameter and coolingeffect. Comprehensive above conclusion, a relatively simple night ventilation buildingthermal design method was given to provide guidance reference data for the applicationof night ventilation cooling technique in the initial stage of architectural design.The mainly task and conclusion as follows:First of all, the night ventilation research is divided into three categories on the basis of the integration of literatures including research on the external environment,research on the building performance and research on the building thermal environment.Secondly, the night ventilation ideal building thermal physical model was establishedand difference solution to obtain the computing method of hourly indoor air temperatureand inner surface temperature. Consider the night ventilation as two different air rateventilation periods, indoor temperature was affected by periodic external thermalenvironment. The concept of lag time and attenuation coefficient were introduced tosolve the the indoor air temperature variation law with time. And put forward thethermal mass (Mc m) as the building thermal performance parameters to system analysisthe parameters that influence building night ventilation effect.The veracity of the model was proved through a measurement in Xi’an for two weeks.The testing results and the calculate results were compared and consequently shows agood match in the overall trend.Finally, present a night ventilation building thermal design method on the basis ofthe ideal building thermal physical model and the different night ventilation coolingclimate suitability in north China. Each step of the method was elaborate in detail. Thedesign and calculation steps of this thermal design method were simple and clear, aswell as the calculated result which could be used to contrast and evaluation. And alsothe thermal design method was quite easy to use for the architecture designers. Buildingthermal design and calculation were done in four different cities using this method. Theindoor thermal comfort situation was analysed and the thermal mass standard for all daylong thermal comfort was also disscused.