Cooling CBD hotspots could be a breeze

Surface brightness temperatures of the CBD and North Adelaide in the early hours of 7 March 2011.

A 1C increase in daytime temperature can increase cooling electricity consumption in Adelaide’s CBD by 1.5 million kWh per year, generating an additional 1000 tonnes in carbon dioxide emissions, a Flinders University-led study has found.

The three-year Adelaide Urban Heat Island (UHI) project, which collected and analysed data from 45 points and by remote sensing around the city, also found that heatwaves can boost daytime office building electricity use by 50 per cent from the average.

Project leader Dr Huade Guan, from the School of the Environment and National Centre for Groundwater Research and Training at Flinders, said the report had implications for urban planning and building design in Adelaide.

“It is surprising that not much quantitative research has been done to examine the cooling effects of sea breezes, for example,” Dr Guan said.

“Recent analysis of our data shows that sea breezes in summer from St Vincent’s Gulf can decrease temperatures near the coast by 4C. This cooling effect is reduced in the CBD,” he said.

Adelaide’s unique surrounding parklands also have a significant cooling effect.

“For all weather conditions, on average, the CDB is 0.5C warmer than the surrounding parklands during the day and 1.5C at night. Under some weather conditions, that difference might be as much as 6C,” he said.

Aerial surveys conducted by the University’s Airborne Research Australia and thermal imaging conducted by researchers in the School of the Environment provided additional information to that collected from mini weather stations positioned in a variety of built environments.

The University of Adelaide’s Schools of Chemistry and Physics, and Architecture, Landscape Architecture and Urban Design and consultancy firm Cundall took part in the analysis and modelling of the data.

Two ‘hot spots’ were clearly observed: one in the northwest corner of the CBD, bordered by North and West Terraces, during the day; the other, in the northern section of King William Street, in the evening.

Dr Guan said that further research would be undertaken to better understand how urban planning and building design could mitigate the effects of the UHI.

“Even in the absence of academic publications, some of our colleagues in Japan have already started to modify engineering and design practices to try to take advantage of sea breezes.

“In addition to the energy efficient building methods, measures such as the orientation of buildings, the positioning of tall buildings and provision of surrounding parklands can potentially reduce the urban heat island phenomenon – reducing energy needs to cool buildings.”

The project was funded by the Department of Environment Water and Natural Resources through the South Australian University Sector Agreement Research Fund on Climate Change; the Department of Planning, Transport and Infrastructure; the Department of Premier and Cabinet; and the Adelaide City Council.

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