Field study on energy economic assessment of office buildings envelope retrofitting in southern China

Energy consumption of buildings accounts for more than 37.3% of total energy consumption while the proportion of energy-saving buildings is just 5% in China. In this paper, in order to save potential energy, the building envelope retrofitting is considered. An office building in Southern China was selected as a test example for energy consumption characteristics. The base building model was developed by TRNSYS software and validated against the recorded data from the field work in six days out of August-September in 2013. In addition, with a design of numerical simulation, sensitivity analysis was conducted for energy performance of building envelope retrofitting; six envelope parameters were analyzed for assessing the thermal responses. Results show that significant energy savings are obtained for the thermal transmittance (U-value) of exterior walls, infiltration rate, ventilation and shading coefficient, of which the sum relative sensitivity is about 91.06%. The results are evaluated in terms of energy and economic analysis. On the other hand, it appears that the cost-effective method improves the efficiency of investment management in building energy.