A NEW form of solar panel that warms air and water as well as generating electricity is being developed by Sydney researchers.

The twist in the University of NSW project is that the solar cells are integrated into the structural fabric of a building, so rather than being attached to a roof, they are the roof.

It is part of a wider project to investigate future energy efficiency projects, and check how effective current methods really are.

''I'm a harsh marker,'' Associate Professor Alistair Sproul said. ''You can show me a 'green building' in Australia and I bet I can find a few ways it could be improved.

''Australia has this perception that we are blessed with limitless energy, but by the time we have filtered it through the system and into buildings in the form of electricity, there is enormous waste. So we are gathering the data to make informed decisions about that.''

Researchers at the university's ''low carbon living'' project are tinkering with several renewable energy systems, to work out how practical and expensive they are likely to be when offered for commercial development.

Among the successful experiments so far are the prototype solar panels, which capture the heat that builds up behind the solar cell and uses it to heat air or water.

The solar cells convert photons of sunlight into electricity, but generate a lot of waste heat as a by-product, and this can be harnessed by having an insulated space behind the panel where the air is heated to a comfortable 25 degrees.

By making the panels extra-durable, they also function as the roof itself.

''We want to take the building performance to the next level,'' the head of the research group, Professor Deo Prasad, said.

''In the past we have had separate experts working on solar panels, on energy efficiency, water efficiency, but what we are looking at now is total integration from the start.''

The project is also looking at carving out a place for Australian manufacture of some products if possible, with several firms monitoring the progress of the research.

''A lot of lower-tech forms of photovoltaics seem to be finding their way into countries where there are cheaper labour costs, so we want to concentrate on developing these high-tech, high-end forms,'' Professor Prasad said.

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