The Research On Thermal Performance Indexes Of Low Energy Consumption Reconstruction Of Existing Residential Buildings In Changsha

China’s"the 13th Five-Year Plan"has set a clear target for the energy-saving renovation of existing residential buildings in hot summer and cold winter areas.As a representative city of this region,Changsha has a large existing building stock and great potential for energy-saving renovation.At present,Changsha region of the existing building energy efficiency design standard,evaluation standard,the energy saving measures of reform most are based on the new building energy efficiency design standards as a benchmark,the working condition of such standards are based on continuous use for setting,emphasizes building palisade structure of"efficient",in the region can actually use situation is different,make the region reaches index difficulty in the practical renovation project.Therefore,this paper combined with the actual situation of energy use and its impact on the thermal performance index of the envelope,and then put forward the thermal performance index value of the envelope that is suitable for the low-energy transformation of the existing residential buildings in this area.In this paper,the current situation of envelopment structure and energy-using behavior questionnaire were investigated in this area,and the calculation period of actual heating and air conditioning in this area was calculated according to the climate characteristics,and the typical housing types and actual energy-using conditions were summarized.Secondly combing the palisade structure and calculation of the heat transfer process,,the use of the Design Builder building Energy consumption simulation software to dynamic simulation for the whole year of construction,can study with different Energy saving effects of the retaining structure under the condition of different indicators.Finally,the index is screened and improved in combination with economic and daylight requirements to obtain the thermal performance index of the enclosure structure suitable for the transformation of low-energy residential buildings in this region,and the practical case is applied to verify its scientificity.Finally,the author proposed that,under intermittent energy use,internal insulation should be selected for exterior wall insulation.Heat transfer coefficient is suggested to be 1.5W/m~2·K,roof heat transfer coefficient 1.0W/m~2·K,floor and partition heat transfer coefficient1.8W/m~2·K,exterior window heat transfer coefficient 3.2W/m~2·K,and solar heat gain coefficient 0.2.The heat transfer coefficient is suggested to be 0.9w/m~2·K.The value of roof,floor,partition wall and window is the same as that of intermittent energy.It is of certain reference significance to the study of building energy conservation in Changsha.