Ecological Life Cycle Assessment And Application Of Building Energy Supply System

With the acceleration of Chinese urbanization,building energy consumption continues to rise.In 2017,building energy consumption reached 947 million tons of standard coal and accounted for 21% of total energy consumption,of which public building energy consumption accounted for 38%,building carbon emissions accounted for 19.5% of national energy carbon emissions,how to choose suitable building energy system has been a hot issue for designers.This article relies on the Sino-Dutch International Science and Technology Cooperation Project of the Ministry of Science and Technology "Key Technology and Collaborative Drive of Smart Energy-saving Industrial Park"(2015DFG62270).Ecological-based life cycle assessment(Eco-LCA)method is used to study the ecological sustainability of the building energy supply system,and Eco-LCA evaluation model for the building energy supply system is established.The ecological cumulative exergy consumption(ECEC i.e.sum of the ECEC of natural resource cost,socio-economic cost and environmental impact)of each scheme in the stages of production,operation and transportation were calculated and discussed.By investigating the operation status of the energy supply system of two actual engineering projects in Chongqing,collecting operating data,and analyzing the actual operation effect of the energy supply system,it is found that energy utilization ratio of two system meet the standard requirements,but energy saving ratio is less than 0.System fails to take advantage of energy saving.Based on the design load of the second building,Eco-LCA evaluation model is used to determine the appropriate installed capacity of the CCHP system with gas internal combustion engine(GICE).By calculating the ECEC of different installed capacity of the CCHP in the stage of equipment production,system operation,and equipment transportation,it is found that the system with 600 k W GICE consumes the least amount of ECEC in a typical year,and has the best ecological sustainability.At this time,the GICE’s equivalent full-load running hours in one typical year is about 3289 h.By further analysis of the percentages of each ECEC,it can be seen that the ECEC in the stage of operation accounts for about 97% of the total ECEC,and the ECEC of non-renewable resource is more than 80% of ECEC in the stage of operation.Therefore,the simplified Eco-LCA evaluation model is proposed,and used to analyze the ecological sustainability of different scheme in actual load conditions,it is found that the CCHP system with a400 k W GICE has reduced better ecological sustainability.Second,based on the design load of the second building,Eco-LCA evaluation model is used to analyze the ecological sustainability of various building energy supply systems.It is found that the scheme containing CCHP in the system form has obvious advantages in terms of ecological sustainability compared with the traditional building energy system,and CCHP system combines with electric-driven air-conditioning equipment can expand the ecological sustainability advantage.By further analysis of the percentages of each ECEC,and propose a simplified Eco-LCA evaluation model for determining the form of building energy supply system.The simplified model is used to analyze the ecological sustainability of different scheme in actual load conditions.It is found that the scheme equipped with CCHP still has better ecological sustainability than the traditional air conditioning system.The ecological sustainability of CCHP system equipped with electrically driven air conditioning equipment is affected by the reduced cooling and heating loads is greater than system equipped with direct-fired machine.This article provides a new perspective for engineering technicians to analyze the ecological impact of building energy supply systems.The simplified Eco-LCA evaluation model is more convenient for engineering designers to choose suitable building energy systems.