Thinking Outside The Square

Canberra Times
Wednesday 18/3/2009 Page: 10

Scientists and engineers are thinking outside the square to fight climate change in Canberra. They are working to improve existing technologies and create new ones to reduce our reliance on fossil fuels. Nyssa Skilton reports on three technologies being developed in Canberra.


Wind power
Finding the best spot for a wind turbine can be tricky. There has to be lots of wind, but also wind has to flow smoothly. Windlab Systems has developed software tools to improve windfarm efficiency. The Canberra-based company's latest offering will be a computational model to predict turbulence on wind energy sites.

Turbulent air can inflict different forces on the turbine blades and structure, increasing wear and also decreasing the amount of energy the turbine can extract. The model uses computational fluid dynamics to calculate and predict levels of turbulence in air passing through the disc of the turbine blades, so engineers can avoid placing turbines in areas of turbulent air flow.

Windlab's chief technology officer Keith Ayotte said one of the major challenges was that one turbulence analysis could require hundreds of billions of computer calculations. "Because the amount of power we have with computers is increasing fairly rapidly, we're only really now getting to the point where we can consider doing these things," he said. Wind lab plans to release the model commercially at the end of the year or beginning of next.


Angled Buried Contact Cell
A solar cell with hidden metal contacts may be another step in the efforts to improve solar efficiency. Canberra-based company Spark Solar Australia is working to develop the technology, called the Angled Buried Contact cell or ABC cell. Metal contacts act to draw electrical current from the cell. But they also shade about 7% of the surface of the cell from sunlight, reducing the cell's ability to convert sunlight into electricity. Hiding the contacts can improve cell efficiency by about 7% .

Spark directors Michelle McCann and Peter Fath, together with colleagues at the University of Konstanz in Germany, first developed the technology in 2005. But creating the ABC cell grooves into the surface of the cell at an angle. Surfaces that face upwards are covered in an insulating layer of silicon nitride and the metal is deposited on the exposed surfaces.

The contacts are hidden away underneath the surface of the cell, increasing the surface area that can collect sunlight. Spark Solar Australia plans to spend several years in further research, development and commercialisation of the technology.


Solar-powered air-conditioner
A team of engineers and scientists are developing a solar energyed air-conditioner, which can cool or heat a home and provide hot water year round.

The Australian National University design replaces the electrical compressor in a conventional air-conditioner with a solar energyed thermal compressor. Solar energy is provided in the form of heat, not electricity, from conventional solar water heater panels. Dr Mike Dennis, from the college of engineering and computer science, said the air-conditioner was similar to a traditional household split-system, except for the power source.

"The whole idea is to make it as seamless as possible, so it's very similar in look and feel to a conventional air conditioner," Dennis said. "In fact, the only difference people will see is the solar panel on the roof." Dennis said the refrigerants circulating in traditional air conditioning units were several thousand times more potent greenhouse gases than carbon dioxide.

He predicts the manufacture cost will be low as it has only one moving part. A two-year commercially driven development program started this year at ANU.