Comprehensive Cost-benefit Analysis And Evaluation Of Existing Residential Building Retrofit

In China’s northern heating region,due to the poor thermal insulation performance of residential building,heavy burden were added to the society,energy supply companies and households.Nowadays,the implementation of existing residential building energy-saving projects has become an important part of energy-saving emission reduction strategy of our country.Because of the huge investment and long payback time,existing residential building energy-saving projects is so difficult.It is so important to figure out and quantify the benefit of the project scientifically.Allowing for the weather condition,indoor thermal environment,behavior of residents and so on,this paper developed corrected model of energy-savings.Then,the benefit and cost of economic,society and environment were quantified.Based on Life-Cycle-Assessment,Cost-benefit theory,comprehensive cost-benefit analysis model was developed.The model took the initial energy consumption and CO₂emission of the energy saving measures in to account.Three ratio of energy saving benefit to investment cost,ratio of environment benefit to investment cost,ratio of economic benefit to investment cost were introduced to evaluate the effect of renovations.Taking a building in Qingdao as an example,the comprehensive cost-benefit analysis model was applied to study the optimal renovation scheme.Then compare this scheme with the actual one.The verificated comprehensive cost-benefit analysis model was used to evaluate the large-scale renovation project.The result showed that good energy-saving effect was achieved.The energy demand of the building per square meter was 0.28GJ/（m²·a）,and the energy saving per year was 2731tce,the energy saving rate was 57.0%.When one yuan was invested in the existing residential building retrofit project,1.74kgce coal saving,1.19kg SO₂,65g SO₂ and 7g NO₂,20g dust emission reduction will get in the whole life of the project.Even though the investment failed to recovery,but the environment and society benefit was good,Which resulted to the RMB 7600,00comprehensive benefit.