Investigating the Gap between Simulated and Measured Performance of a Low Energy House in Sydney

Abstract

In the last few decades, the world has seen a significant increase in low energy residential housing development and a growing use of pre-construction simulation model to predict and rate the energy performance. However, a number of studies have found that many buildings were not performing as good as what has been predicted, and more researches were looking into the underlying causes for this performance gap. Based on the "CSR house", an energy efficient detached two-storey residential house in Sydney, Australia, the thesis aims to show how knowledge acquired from the blower door test, thermal imaging test and coheating test can be used to identify the causes of the performance gap and improve the accuracy of a post-construction simulation model. The influence of air-tightness, insulation defects, thermal mass and ground temperature on the performance gap has been analysed and presented. The significance of the performance gap not only demonstrates the importance of post-construction thermal performance diagnostics, but also underlines the lack of systematic methodology and characteristic indicators in thermal performance analysis and estimation. In this context, transfer and self admittance have been studied to explore new thermal performance indicators that combine the effect of thermal mass and thermal conductivity.