Analysis On Load Of Nearly Zero Energy Buildings In Severe Cold And Cold Zones

As a high energy consumption country,building energy conservation has become a key part of China Energy saving.Because the heating energy consumption in Severe Cold and Cold Zones accounts for about a quarter of the building total energy consumption,reducing heating energy consumption has an important impact on China’s building energy efficiency.“nearly zero energy buildings”can greatly reduce or even eliminate the use of traditional heating equipment in winter,reducing the dependence of fossil fuels greatly.It is an effective way to reduce heating energy consumption in China.At present,China mainly refers to the design standards of passive houses in Germany to construct“nearly zero energy buildings”.However,due to the differences in climate conditions between Germany and China,the building load cannot be identical.Therefore,it is necessary to analyze the load of“nearly zero energy buildings”that are built in the Severe Cold and Cold Zones and determine the feasibility of applying passive house standards in China.the current research focus mostly on the calculation of the energy saving rate.Few articles have carefully analyzed the he changes in building loads and heating time,and not verified whether“nearly zero energy buildings”can only rely on heat recovery system to maintain indoor temperature within the set range.To solve these problem,author conducted the related studies:First of all,set up the basic model of residential buildings and public buildings.Due to the diversity of public buildings,this article takes office buildings as the representative.The parameter setting of typical building is mainly based on“Design standard for energy efficiency of residential buildings in Severe Cold and Cold Zones”JGJ 26-2010 and "Design standard for energy efficiency of public buildings"(GB50189-2015).The parameter setting of“nearly zero energy buildings”is mainly based on the design standard of passive house in Germany and the“Design Standard for energy efficiency of passive low-energy residential buildings”(DB 13(J)/T177-2015).Secondly,Harbin,Shenyang,and Beijing are selected as the representative cities in the Severe Cold and Cold Zones.Using DeST to simulate the full-year load of the benchmark building and the“nearly zero energy buildings”,taking into account the impact of heat recovery devices.According to the simulation results,the energy saving rate and economy of“near-zero-energy buildings”are summarized,the variation of accumulated values of cooling and heating loads is analyzed,and the principle of determining the heating time is formulated,the heating time of the“nearly zero energy buildings”is reset,which is much shorter than the legal one.Thirdly,the paper analyzes and explains the changes of winter and summer load in each room of“nearly zero energy buildings”after adopting an efficient heat recovery system.In addition,the paper also compares the annual average heating and cooling average load indicators of“nearly zero energy buildings”between three regions,and analyzes the impact of the orientation,building envelope area,and floors on building load.Finally,the article compares the climate conditions and energy demand in China and Germany,using 15kWh/(m~2?a)as the limit for annual heating or cooling demand per unit area,and judge whether the simulation result meets the energy consumption limit.The possibility of whether“nearly zero energy buildings”do not rely on traditional heating equipment was analyzed.In addition,the paper also compares the changes in the energy saving rate of residential buildings and office buildings and summarizes the rules.