Research On Energy Saving Potential And Technology Roadmap Of Nearly Zero Energy Building

How to lead building toward net zero energy through reducing 70% to 80% energy demand by passive & active design and use renewable energy to supply the remaining 20% to 30% is a long term goal of the energy efficiency work internationally.Developed countries had already set up mid-long term goal on this topic and had a clear R&D roadmap,also the feasbility of nearly zero energy building had already been approved by demonstration projects.The energy efficiency work launched in China early in late 1980 s,but the maximum energy reduction potential of typical building in different climate zones according to the latest building energy codes,definition and index system of nearly zero energy building and pilot building demonstration is not enough,further,China don’t have a long term goal of nearly zero energy building.To solve this problem,author finalized the related reserach:1.Set up 10 typical building by investigation and analysis of existing projects,whichcould represent majority of China’s various type of building.Take five national building energy efficiency standards(“Design standard for energy efficiency of rurall residential buildings” GB/T 50824-2013,“Design standard for energy efficiency of residential buildings in severe cold and cold zones” JGJ 26-2010,“Design standard for energy efficiency of residential buldings in hot summer and cold winter zone” JGJ134-2010,“Design standard for energy efficiency of residential buldings in hot summer and warm winter zone” JGJ 75-2012,“Design standard for energy efficiency of public buildings” GB50189-2005)as the reference basis.Meanwhile,through comparison of the U value of widows and walls of nearly zero energy building best practices internationally,the heating and cooling load that will be influenced by the high performance envelope is studied.10 typical building in 4 climate zones was re-classified according to the heating and cooling demand.2.Analyze the advantages and disadvantages of 9 kinds of multi-objective evaluationmethodology that could be used in building energy system selection : principal contradiction,linear weighting method,ideal point method,the effectiveness of the system,gray matter element method,entropy method,value analysis,AHP,and fuzzy optimization,with 7 evaluation indicators: the integrity of the decision-making process,systematic problem analysis,the objective accuracy of the evaluation,the number of samples required for decision-making,decision-making basis for the required amount of information,decision-making process on the basis of utilization of information and decision the complexity of the calculation of seven evaluation.Thus the determination of hierarchical structure of energy system selection decision factors could be achieved and the Analytic Hierarchy Process Based Fuzzy Comprehensive Optimization is proposed with the basis of 4 first class indicators and 11 second class indicators.3.Set up 4 nearly zero energy building reference model in various climate zones by using high performance envelope,high efficiency energy system,heating recovery,and renewable energy system.With the energy consumption using paramenters in building codes as a reference,the energy reduction potential and technology roadmap of nearly zero energy building is given.4.By testing and monitoring of the pilot projects,the parameter selected as the simulation input(high performance external wall heat transfer coefficient 0.12 W/(m2·K),high performance external window heat transfer coefficient 0.12 W/(m2·K),air tightness n50 ≤ 0.6h-1,etc.)and energy reduction potential simulation result was verified.The energy consumption monitoring of a 4 floor pilot project which located in cold zone shows that the actual annual heating and cooling consumption,together with lighting,is 22.32 k Wh/(m2a),which is 75% lower than similar buildings in this climate zone(100k Wh/(m2a)in average).The monitoring result of a residential building in cold zone shows that the annual energy consumption of the pilot is 22.61 k Wh/(m2a),which saves more than 80% of the heating cost comparing with the use of central heating system.The innovation of this thesis are:(1)Breaking the traditional method of climate-basis building energy system determination,proposed the building that use high-performance envelope into four new classifications,which are "heating dominant","cold heat balance" "cooling-dominant,needs heating","cooling only".(2)Proposed the Analytic Hierarchy Process Based Fuzzy Comprehensive Optimization that could be applied in nearly zero energy building energy source selection in four climate zones.(3)On the basis of current building energy efficiency standards,proposed the goal of nearly zero energy building development: 70% energy reduction in severe cold region,70% energy reduction in cold zone,and 50% reduction in hot summer and cold winter zone.The output of this thesis could(1)support the set up of national building energy efficiency long term goal;(2)support the building energy codes upgrading;(3)as a guidance of technology roadmap of nearly zero energy building in all climate zones;(4)the manufacture could use the parameter as a reference to upgrading the related materials and equipments.