The Influence Of External Wall Insulation On The Energy Consumption Of Multi-storey Office Building In Changsha

With the increase of the buildings in our country and the improvement of indoorliving qualities, building HVAC energy consumption increases. It’s necessary to find away to reduce HVAC energy consumption without sacrificing the indoor thermalcomfort. China issued a number of design specifications to reduce building energyconservation. Local governments also respond to the needs of improving buildingenergy efficiency, they promulgated some corresponding specifications. Scholars hadput forward their own building energy efficiency improvement measures, such asimproving thermal parameters of the building envelopes, enhancing the heating andair conditioning equipment operating efficiency and using renewable energy. Studieshave shown that outer walls energy consumption account for a large portion ofbuilding HVAC energy consumption, thus reduce exterior walls energy consumptionmay improve building energy efficiency. Therefore, the study of relationship betweenexterior walls energy consumption and building HVAC energy consumption becameparticularly important.In this thesis, multi-storey office building HVAC energy consumption wasstudied. DeST-c energy-consumption simulating program, developed by TsinghuaUniversity, was used. Parameters were set unchanged changing except for the exteriorwalls heat transfer coefficient. The cooling load of the building was simulated. Bychanging the location of the model in three climate zones, ie, the severe cold regions;the hot summer and cold winter region; and the hot summer and warm winterregion,27cases were simulated to evaluate the potential of external wall insulation’senergy saving abilities in different climate zones. The results showed that externalwall insulation in the cold regions has a remarkable energy-saving effect. However, inthe south, where the air conditioning load in summer is the main load, itsenergy-saving effect is not as obvious as that in the cold regions.In addition, this thesis analyzed the multi-storey office building external wallinsulation energy-saving effect in Changsha. All maintain structures except for theexternal walls meet the Design specification for building energy conservationrequirement, several insulation material were used to build the external walls of thesimulated building model. Their energy consumption were simulated to compare withthe base building energy consumption. The results showed that their energy saving rate is around25%compared with base building and has reached the energy-savingratio assumed by building envelope in the building energy efficiency of50%requiredby the energy conservation code. Finally, this thesis tried to optimize the thickness ofthe external wall insulation layer in the multi-storey office building inChangsha.Several simulations were made by changing the thickness of insulationmortar. Life-cycle cost analysis method was used to analyze the economic insulationthickness. The results showed that: Insulation mortar thickness larger40mm will notsignificantly improve the energy-saving effect. The lowest life cycle cost is obtainedwhen the thickness of the insulation mortar is around30~40mm, thus30~40mm canbe considered as the economic insulation thickness.