Research On A Pre-assessment Model For Energy Savings Of Energy Efficiency Retrofit For Existing Residential Buildings In Northern Areas Of China

The heat metering and energy efficiency retrofit for existing residential buildings in heating areas are important measures implemented by Chinese central government to reduce energy consumption in building sector.However,the funds provided by governments on different levels,which are dominant among different financing methods,limit sustainable development of the retrofit for existing residential buildings.More and more attention from government officials and researchers has been paid to the clean development mechanism(CDM)which belongs to the market mechanism.The pre-assessment for energy savings is the fundamental work to implement the CDM in the heat metering and energy efficiency retrofit for existing residential buildings.This research came from the project named Improving Energy Efficiency of Buildings in China which was supported by the Ministry of Housing and Urban-rural Development.Main work and conclusions of this research are summarised as follows.First,aiming at improving the data supplement accuracy and avoiding the multicollinearity of input variables when traditional regression method is used to supplement the missing data,an improved data supplement model is built based on statistics methods such as simple regression,partial regression,principal component analysis,multivariable linear regression.At the same time,two contrast models are built to analyse the accuracy and effectiveness of improved model based on two buildings.Second,the meteorological parameters separately in the test implementation year and typical meteorological year are compared to validate the universality of the test implementation year.Indoor dry bulb temperatures of residential buildings at different stage of heating season are analysed based on sampled buildings separately before and after retrofit.Results show that the average indoor dry bulb temperatures of residential buildings before retrofit is 20.1?.It is 22? in the buildings after retrofit.Measured values are both higher than 18? which is widely used.The measured values should be used during the analysis of energy savings instead of 18?.Through comparing the indoor dry bulb temperature separately at different stage,results show that the indoor dry bulb temperature could not be differentiated separately at different stage of heating season.The disparity of sampled buildings heat consumption is obvious under same metrological condition,because of the influence of internal and external disturbance.Therefore,effective pre-assessment of building heat consumption should be implemented before the retrofit.Third,based on the Quantification Theory I,the qualitative and quantitive characteristic indexes of residential buildings which significantly affect the thermal performance are selected and used as the input variables of a model used to differentiate the residential buildings.The percentage of the heating load separately at different stage in a heating season is included in the indexes to classify the residential buildings.Hierarchical clustering method is used to classify the one hundred sampled residential buildings which have been retrofitted.Three groups of residential buildings are achieved.The reasonableness of the classification is analysed.The daily average heat consumption levels of three classifications are compared.Fisher discriminant analysis is used to build the discrimination model for residential buildings.The discrimination model is optimised and validated by measured data based on heat-exchange stations.In the end,the pre-assessment model for energy savings of heat metering and energy efficiency retrofit for existing residential buildings is built based on the clustering model and discrimination model.At the same time,the correction method is proposed.Moreover,the application area and procedure of the pre-assessment model are analysed.