Energy performance simulation of Australian office buildings

Abstract

The initial research focused on evaluation in the field of four office buildings, comparing simulated outcomes with measured performance. From this work and the review of relevant literature, a number of simulation input parameters were chosen for more detailed studies. Occupancy figures typically assumed in Australian building performance simulation were found to be much higher than those measured in the field surveys. A sensitivity analysis found that for some building and climate combinations, using unrealistically high occupancy figures gave rise to increased energy consumption, while for other combinations higher occupancy levels led to decreased energy consumption. Another component of the research included testing a number of Australian office buildings to find out what are typical values of air leakage. The range of measured values was wide. Sensitivity studies of the effects of air leakage on energy performance simulation outcomes found that, generally, increased modelled air leakage resulted in an increase in building energy consumption, although there were exceptions. Another aspect of simulation explored was the difference in modelled energy performance using a file of real time weather data instead of using the Reference Meteorological Year (RMY) weather data. Generally use of real time data produced slightly higher modelled energy consumption than use of RMY data. The research also investigated the simulation of a control strategy not accommodated by building performance simulation software. This study showed that a simple control strategy could appreciably improve modelled energy performance. Finally, the thesis includes a study of microclimate over a week of warm weather. This demonstrated that the use of a weather data file without allowance for effects of vegetation, and soil surface and water-holding capacity can be a significant source of inaccuracy in building performance simulation. A general finding of this thesis is that there are large differences between building performance as modelled in the design stage and the performance of operational buildings. All findings show that to accurately simulate buildings considerably more data is needed than currently available. In particular, more studies are needed to ascertain what are typical occupancy levels and air leakage rates of Australian office buildings. In addition, simulation software needs to provide ways of accommodating control strategies and microclimate considerations; also, the ability to use different weather data files would ensure buildings are not simply designed to suit the RMY. Show more