Passive Technology Strategy And Optimal Design Of High Reflective Roof Residential In Guangzhou

As the global population continues to increase,population housing problems have become prominent,and building more houses has become an effective way to alleviate housing problems.In the context of global warming and residents’ pursuit of a better life,the energy demand for residential buildings is increasing day by day.Passive technology can reduce residential energy consumption or contribute to the alleviation of global resource shortages.For example,applying high reflective coatings to the outer surface of the roof can effectively reduce the solar radiation heat of the roof.In addition,residents can also use methods such as opening windows for ventilation and building shading to improve the indoor thermal environment,reduce air-conditioning use time and reduce energy consumption.Therefore,the full combination of passive energy saving technologies(high reflective roofs,natural ventilation and building shading)of buildings has become one of the keys to reducing residential energy requirements.This research adopts methods including questionnaire surveys,experiment and simulation to study the passive energy-saving strategies and optimal design for high reflective roof rooms in Guangzhou residentials.The research content is as follows:Firstly,the effect of high reflective roof,natural ventilation and building shading on indoor thermal environment was analyzed from the mechanism level.Based on the analysis of roof material and reflectance of some residential buildings in Guangzhou,it is found that the reflectance of most residentials is less than 0.4,and the energy-saving effect was bad.Through questionnaire survey,this study analyzes the window opening habit,energy use behavior of residents and shading situation of building in Guangzhou.The survey showed that residents usually open windows in room and use air-conditioner in winter,and balcony is the common building self-shading component.Secondly,three top floor rooms with balconies in panyu district of Guangzhou were selected to build an experiment platform with high reflective roof and natural ventilation.The coatings used in the test were white,blue high reflective coatings,and black base coatings.Through the actual measurement of room window closing conditions,window opening ventilation conditions and air conditioning conditions,it is found that both high reflective roofs and natural ventilation can reduce indoor air temperature in different seasons.That is,high reflective roofs can reduce the energy use of room air-conditioning in summer but increases the energy use in winter.Finally,based on Design Builder software,a residential model was verified with the experiment data.Under the premise of meeting the requirements of indoor light and heat environment,a passive energy saving strategy of natural ventilation combined with natural lighting is proposed,and the energy saving potential of this strategy in high reflective roof rooms of residences is simulated,and the suitable time period for windows to be opened throughout the year is also summarized.Based on the energy saving strategy,the sensitivity method is used to analyze the influence of the passive design parameters of the residential top-floor rooms on the energy consumption.After taking the room energy consumption as the optimization goal,genetic algorithms are used to find the optimal combination of passive design parameters for the top-floor residential rooms to further reduce the room total energy consumption.Through the above research,this article quantitatively analyzes the effect of high reflective roofs and natural ventilation on the indoor thermal environment,establishes a residential model with multiple passive technologies including high reflective roofs,natural ventilation and building shading,explores the passive strategies for existing residentials and optimal design for new residentials,which can provide strong support for the application of passive technology in Guangzhou residential buildings.