The recent heatwave conditions in Australia’s southern states has highlighted the fragility of the country’s mains electricity supply during extreme weather events. In hot conditions, a blackout is more than an inconvenience that impacts on a local economy. It can mean death for the very young and elderly if they are not able to keep cool.
With the likelihood of extreme weather events becoming more frequent and the demand for air-conditioning during heatwaves continually increasing, Australia’s electricity infrastructure faces dire challenges.
Dr Mike Dennis, a senior research fellow in the Centre for Sustainable Energy Systems in the Australian National University College of Engineering and Computer Science, somewhat prophetically recently stated that peak period power blackouts are imminent for Australia. Dr Dennis is currently developing extremely efficient solar-powered air-conditioning systems that will not only lighten the load on the mains transmissions grid, but also address the huge amount of greenhouse gas emissions generated by the use of air conditioners.
His research goes beyond the carbon emissions associated with coal-fire generated electricity use in favour using clean solar energy and extends to the refrigerants used in air conditioning units. According to Dr. Dennis, for every kilogram of refrigerant in a split air conditioning systems, there’s two to three thousand kilograms of carbon dioxide equivalent in refrigerant chemicals – around the average car emits in a year. While evaporative air conditioners use far less electricity, they only work effectively in dry areas – the same areas where water is becoming increasingly scarce.
Dr. Dennis’s solar powered air conditioner design replaces the electrical compressor in a conventional air-conditioner with a solar-powered thermal compressor. Solar power is provided in the form of heat, not electricity, from conventional solar hot water collectors.
The technology, known as ejector cooling, operates using compressed air expanding out of a jet that sucks refrigerant and air into a line and then expels the air at a much cooler temperature. The refrigerant is recirculated back and then recompressed. The closed loop system can utilise any form of refrigerant, including water.
A two-year development program is due to begin this year, with the units expected to be available commercially in Australia during 2010. While an approximate price is not yet available, with only one moving part and no dangerous chemicals, Dr. Dennis predicts the cost to manufacture the system will be low.
Solar Energy – A Solution To Australia’s Heatwave Blackouts