Dr Lisa Guan has discovered that buildings
and air conditioning systems will need to
be redesigned in order to cope with
climate change.

Office air conditioning systems face collapse under the pressure of global warming unless steps are taken now to reduce both the internal and external heat affecting buildings, a QUT engineering researcher says.

Dr Lisa Guan, from Queensland University of Technology's School of Engineering Systems, said her PhD computer modelling study of indoor thermal environment and the cooling load faced by air-conditioners in office buildings showed most units would not cope with global warming.

"If the outdoor temperature increases by two degrees, the risk of overheating in an air-conditioned office building will increase significantly," Dr Guan said.

"The cooling load by air-conditioners will increase by up to 47 per cent in some Australian cities, based on CSIRO projections of potential temperature increase due to climate change."

She said designing air-conditioning systems to cope with climate change had to take account of heat generated inside buildings as well as heat from the sun.

The number of people in office buildings, lighting and machines all produced a significant amount of heat for air conditioners to deal with.

"For example, an adult male generates 140 watts of heat, and a woman 85 per cent of that. Heat generated from lights, computers, printers and copiers all contribute to the internal load," Dr Guan said.

"Cutting the internal load or heat generated inside the building will become as important as shielding buildings externally from the sun to reduce the future load on air-conditioning."

Dr Guan said it was time to adapt to the new environment by reducing the internal and external load on existing buildings and build new ones that took account of the increased load on air-conditioners.

"If we do nothing to reduce the internal and external heat load, the cooling capacity of air-conditioners will need to increase by up to 59 per cent," she said.

"This will require more energy for the operation of larger capacity air-conditioning units than we have now.

"Obviously, this is not feasible and we need to find ways to reduce both the amount of sun falling on our buildings and the heat generated within buildings."

Dr Guan's on-going research focuses on finding alternative and environmentally friendly design and operation of air-conditioning systems.

She is investigating automatic control of outdoor air intake for free cooling, automated systems to turn off unnecessary lights and ways to use innovative design to utilise natural light as much as possible to improve building energy efficiency.