Evaluating the influence of thermal mass and window size in a direct gain system on the annual and lifetime energy consumption of domestic Australian light weight construction

Climate responsive design ensures thermal comfort in buildings without using excessive energy for heating and cooling. This study explores how the relationship between the quantity of north (equator) facing window area, the quantity of thermal capacity and the distribution of thermal capacity in a space can improve comfort and energy efficiency in residential buildings in Australia, and optimise lifetime CO2-e emissions. The study concludes that thermal capacity can improve the thermal efficiency of the simulated structure, primarily through its influence on annual cooling loads. A direct gain system is only appropriate for the climate in Penrith. Thermal capacity should be used in Melbourne and Brisbane to mitigate summer overheating. When lifetime CO2-e emissions are calculated no single configuration in any particular climate emerges as the optimal solution. The results suggest that it would be useful to explore further modifications to the fabric and form of the building in each climate.