Solar Air-Conditioning
Cool air on hot days
Peak Load
We have a looming issue with our electricity grid - the demand on very hot days has been rapidly increasing since domestic air-conditioning (A/C) became popular, placing pressure on the grid. This issue is known as "peak load".
On very hot days when everyone has retreated inside and turned on the A/C, our current electricity generation capacity can struggle to meet the demand. Further, the entire grid must be designed to meet this peak load, which may only occur on a few days per year.
Designing the grid to meet peak load is inefficient and much research has gone into reducing the peak load.
One of the most promising technologies is solar air-conditioning. You can see by the following graph that if we could use solar to provide our hot water and heating/cooling needs we would cut average household energy use by over half.
Solar A/C Theory
There are two branches of solar air-conditioning:
- Sorption chillers
- These systems use heat energy like solar to drive the cooling system rather than mechanical energy like a traditional compressor-based system.
- Desiccant coolers
- Removing the humidity from the air greatly reduces the effort required to cool the air down. Desiccant coolers remove the humidity from the air with a liquid desiccant, which then needs to be regenerated by heating the desiccant up.
In both situations, heat energy forms an integral part of the overall process. This allows us to use solar thermal technology, such as the same evacuated tubes used in some of our solar hot water systems, to efficiently run the solar air-conditioning system.
Use of solar energy instead of mechanical energy greatly reduces the electricity requirements and the running costs, effectively reducing the peak load demand.
Solar A/C Systems
The Solar Guys are actively researching solar air-conditioning systems that can be brought to the market in Australia. We attended the 2nd International Solar Air-Conditioning Conference in Spain, October 2007 to learn more about this exciting technology.