Solar system combines technologies - Cells to heat, cool, generate power

Canberra Times
Friday 21/8/2009 Page: 5

Solar cells immersed in liquid are set to boost our ability to harvest energy from the sun in a joint research project between Australia and China. Researchers at the Australian National University and Tianjin University have started a 2.5 year project to pioneer a new technology, expected to deliver both solar heat and power to achieve up to 70% combined efficiency.

The director of the ARC Centre for Solar Energy Systems at the ANU, Professor Andrew Blakers, said the system could be on the market within two years. "You get the complete home energy solution: the solar electricity, the solar hot water, the solar space heating and the solar space cooling," Professor Blakers said.

"A typical solar panel just sheds its heat to air, it's completely wasted. A typical solar hot-water panel doesn't collect any electricity at all; it just makes hot water. So putting them together and using the waste heat from the solar cell to heat your water just makes a lot of sense I think." The technology involves submerging the solar cells in a channel of liquid. Sunlight reaches the cells through a glass window and the liquid, a transparent mineral oil, flows past them, carrying away their heat. As the cells cool down, the efficiency of sunlight conversion to electricity increases while the heat is harvested for other uses.

The work began last year when the two universities came together to develop a new generation of efficient and cheap solar concentrator receivers in a multimillion dollar project, involving Anna University in India and solar company Chromasun in the United States. The Australian Government will invest $380,000 in this new phase of the project, which will be matched by the Chinese Government.

Professor Blakers said he expected manufacturing to take place in the market countries, because "shipping steel and glass collectors around the world did not make a lot of sense". ANU college of engineering and computer science business development manager Igor Skryabin said they had received "many, many inquiries" from commercial partners about manufacturing the technology.

But he said it was unlikely Australia could build manufacturing capabilities at this stage. "I really think it will be industrialised in China and commercialised in Australia," he said. "Our contribution will be in the development and supply of the key component of this system, the photovoltaic cell." The project brings together the ANU's expertise in building cost effective solar cells and Tianjin University's capabilities in chemical engineering and heat transfer.

Diplomatic tensions arising out of the recent detention of Rio Tinto executive Stern Hit in China did not have any influence on the collaboration, the researchers said. Tianjin University Green Technology Centre director Professor Piping Wang, who attended the launch of the new project yesterday, said they tried to smooth relationships in such collaborations.

"The people between the two countries are trying to get closer and closer and that's what we are doing now," he said, speaking through a translator. The researchers have built a 300sgm combined system on the roof of Bruce Hall at the ANU and the next step is to create smaller systems, which are lightweight, low-profile and only rise 30cm from a roof.