TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesconsumption is strongly climate dependent due to the impact of cooling towers.The derivation of the National Australian Built Environment Rating System(NABERS) rating thresholds has been presented. Separately conducted datacollection in tropical Australia has been compared against the temperate-basedrating bands and sufficient alignment has been found to justify extrapolation of thescheme into tropical areas.The results of thirty one water audits of office buildings have been used to derivesub-category benchmarks for water use. Highlighted in this data is the presence ofa high level of leakage, estimated to be on average 13% of water consumption oftypical buildings in Sydney, but more than 50% in some individual cases. Theaudit results have been used to derive a range of water consumption benchmarksrepresenting good practice, economic best practice and market leadingperformance. The results indicate that improvements of 25% are economicallyviable above and beyond the correction of leaks.Extrapolating these results to Hong Kong and tropical Asia, the water consumptionof water cooling should be expected to be a major end use, while a level of waterleaks comparable to that seen in Australia should be expected. This indicates thatkey policy objectives in this area should relate to the improvement of energyefficiency, in order to reduce cooling tower water requirements, and theelimination of leakage flows.7. ACKNOWLEDGEMENTThe studies reported in this paper were funded by and with the assistance of theNew South Wales Department of Energy Utilities and Sustainability, NorthernTerritory Department of Planning and Infrastructure and Sydney Water. Theassistance of individuals within these organisations and specifically Matthew Clark,Jo Kieboom and Lyndall Pickering is specifically and gratefully acknowledged181