Contribution of thermal resistance and thermal mass to the energy demand of walling systems / Beitrag des Wärmedurchlasswiderstandes und der thermischen Masse zum Energiebedarf von Wandsystemen

This paper describes an experimental investigation of the thermal performance of four common walling systems for Australian housing having a range of thermal resistance (R-values) and varying degrees of external and internal thermal mass (i. e. inherent property of masonry constructions). The comparison is based on the energy demand under controlled conditions to maintain internal thermal comfort. The R-values of each wall were first determined using a Guarded Hot Box Apparatus. The walls were then incorporated into four housing test modules built on the University of Newcastle campus and the detailed thermal performance of each system was observed under a range of seasonal conditions. The interior of each module was controlled within a comfort range by a heating/cooling system with the energy consumption being measured. Comparison of the energy requirements clearly show that internal comfort levels and energy demands are influenced by both the thermal resistance of the walls as well as the extent and location of the thermal mass, with neither being the sole predictor. The best thermal performance is therefore obtained by an appropriate combination of thermal mass and resistance, rather than focussing on the wall thermal resistance (R-value) alone.