Life cycle analysis of energy efficient measures in desert housing designs

Abstract

Paper presented at the XXXIII IAHS World Congress on Housing, 27-30 September 2005,"Transforming Housing Environments through Design", University of Pretoria.

Energy conservation has become an issue of global significance, reflected through the growing status of Environmentally Sustainable Design (ESD) in the Australian housing industry. The objective of ESD is to achieve an efficient balance between social, environmental and economic forces [1]. The Australian Building Codes Board (ABCB) has proposed to increase the stringency of the Building Code of Australia (BCA) in partial recognition of ESD principles, including the enhancement of thermal performance requirements and greater acknowledgement of thermal mass in energy rating schemes. In order to determine its relative merits in desert climates, two standardised house designs utilised by the Indigenous Housing Authority of the Northern Territory (IHANT) were analysed through life cycles, embodied energy, the efficiency of energy saving measures and the resulting active energy consumption. The standardised houses, like others in the NT, are designed for retrofitting within 10 years reducing the time available for savings in operational energy to exceed energy invested in installing these measures. In addition, the spatial distances between population settlements in the NT greatly increase embodied energy values. It was found that adopting the proposed measures would increase the embodied energy within the houses without markedly reducing the energy requirements of evaporative air conditioners that are the primary source of active climate control. The short lifespan of these houses did not permit sufficient time to pay back the energy investment through operational energy savings. Therefore, for these desert housing designs, implementation of the BCA’s proposed energy efficiency measures was found to be out of balance.