Energy-saving Design Of Ultra-low Energy Residential Buildings In Zhengzhou Area

Energy conservation of buildings is an important part of sustainable development and it plays a vital role in the domain of energy conservation in the world.With the development of modern science and technology and the improvement of living standards,people are eager to achieve indoor thermal comfort through manual adjustment,accompanied by huge building energy consumption and air pollution.China is a country scare of natural resource,reducing energy consumption of buildings through effective technical measures in the precondition of guaranteed indoor comfort becomes urgent in our country.The ultra-low-energy residential building refers to the combination of regional climate characteristics and living behavior habits,adopting passive technical means,specifically optimizing the thermal performance of the envelope structure and the building energy-saving operation mode,etc.,to ensure the indoor environment is comfortable and reduce the heat and cold load as much as possible.The ultra-lowenergy residential buildings in Zhengzhou are just in their initial stage,and the study of passive design schemes applicable to the climate environment of Zhengzhou is of great significance for the development of ultra-low-energy residential buildings.Based on the climatic conditions in Zhengzhou,this thesis uses the building energy simulation software DesignBuilder to conduct energy-saving design research on ultra-low-energy residential buildings in Zhengzhou.Main findings of this thesis are shown as below:(1)Combine the energy-saving design elements of ultra-low-energy buildings and summarize the design points and node practices.Coupled with the ultra-low-energy building design standards issued by the German PHI,the Ministry of Housing and Urban-Rural Development and the Department of Housing and Urban-Rural Development of Henan Province,we analyzed the recommended values of the thermal performance parameters of the building envelope and the area ratios of the facing windows to walls.The ranges of the energy-influencing factors are given in this thesis.(2)On-site monitoring of the ultra-low energy demonstration project in Zhengzhou area during winter and summer,and analyzing the thermal response characteristics of ultra-low energy buildings under extreme weather conditions.The analysis shows that the outdoor temperature ranges from 16.2 to 39.8 ℃ during summer,while the indoor temperature is 23.4 to 29.5 ℃.During winter,the outdoor and indoor temperatures are-9.5 to 6.8 ℃ and 13.2 to 20.6 ℃,respectively.Compared with the outdoor temperature,the highest temperature in the room on the same day lags 3–4 h,and the lowest temperature lags 2 h.(3)Using the DesignBuilder software to establish a physical model and verify the Zhengzhou area ultra-low energy demonstration project,based on the model to conduct a single energy-saving design strategy research.The analysis shows: for the ultra-lowenergy residential buildings in Zhengzhou,the influence of factors such as occlusion between buildings are neglected.The best orientation of the building is between 3 degrees east of south and 7 degrees west of south.The area ratios of east-west window to wall have the largest influence on building air-conditioning energy consumption,followed by the south window,with minimum inpacts for the north window.Hence,we recommended to use the full-heat fresh air heat recovery system and reduce the building energy consumption when the outdoor climate is suitable,with natural ventilation.In this way,the highest energy saving rate may reach 79.72% in October.(4)Based on the physical model,a number of energy-saving design strategy combinations are studied.The analysis shows that the influence of the ground heat transfer coefficient and the external wall heat transfer coefficient on the energy consumption of building air-conditioning is mainly determined by the area ratios of the east-west window to wall,less by the south window and least by the north window;However,the area ratio of the south facing window to wall affects the heat transfer coefficient of the outer window to the energy consumption of the building airconditioning most,the north direction does less and the east-west direction does the least.The influence of the thermal performance parameters of the building envelope on the building load and air-conditioning energy consumption is as follows: external wall heat transfer coefficient > outside window heat transfer coefficient > ground heat transfer coefficient > roof heat transfer coefficient.(5)Based on the research and summary of the existing residential buildings in Zhengzhou area,the typical residential building model in Zhengzhou area was established by combining the “Design Standard for Energy Efficiency of Residential Buildings in Henan Province(75%+ in Cold Areas)”(DBJ41/T184-2017).Using the orthogonal test method,the optimal design scheme is obtained by the range analysis based on the building energy consumption.Compared with the basic building,the energy saving rate of the optimization scheme can reach 93%.The results of this thesis have certain reference value and theoretical guiding significance for the development of ultra-low energy residential buildings in Zhengzhou.