Breakthrough improves air-con efficiency

CSIRO has unveiled a solar-powered air-conditioning system to cool Australian commercial buildings, achieving greater energy efficiency. Operating at Stockland Wendouree Shopping Centre in Ballarat, Victoria, the system uses concentrating solar thermal technology to produce heat energy used to power the air-conditioning system.

The Australian Renewable Energy Agency (ARENA) provided $520,000 to support the $1.2 million project, jointly managed by CSIRO with Stockland Group and NEP Solar. The system addresses the high energy consumption of large commercial spaces such as shopping centres and hotels due to their heating and cooling energy requirements — around 60% of total energy use.

The closed-loop system uses two ‘desiccant’ wheels to remove moisture from the air, acting as a dehumidifier. A high-temperature wheel uses solar heat for regeneration while a low-temperature wheel functions without any external heat to deliver greater efficiency on a commercial scale.

CSIRO Energy Director Peter Mayfield is extremely pleased with the early results.

"CSIRO's energy research is driving down costs of renewable technologies, accelerating the transition to a lower-emissions future.

"We are pioneering new technologies and this project is a world-first demonstration of a desiccant air-conditioning system using roof-mounted concentrating solar thermal collectors," Mayfield said.

ARENA CEO Ivor Frischknecht said ARENA is happy to have partnered with CSIRO on this technology.

"It has the potential to further improve the efficiency of solar thermal energy systems and storage to provide clean and reliable heating and cooling in commercial buildings.

"ARENA is committed to supporting innovative projects like this and helping to share lessons learned amongst the wider RD&D sector, powering Australian renewable energy innovation well into the future," Frischknecht said.

The air-conditioning system is powered by NEP Solar's trough collectors with heat stored in a thermal oil tank.

The roof space required for the solar air-conditioning technology can be 40% less than a traditional single-stage desiccant system.

Solar heat-driven desiccant air-conditioning systems can provide humidity-controlled fresh air into the buildings and are expected to significantly reduce HVAC electricity usage for commercial buildings.

CSIRO will continue to assess and monitor the technology for the next 12 months to establish long-term commercial operations and further investment as part of CSIRO's commitment to creating a low-emissions future for Australia.