By Electricity is expensive on hot days
Summertime in Australia is expensive. As one of the sunniest countries in the world, Australians need to keep their businesses and homes cool.
Have you ever noticed your electricity rates (not to mention consumption) are more expensive in summer? Many commercial electricity bills will actually state “summertime demand” charges. This is because almost every building is running air conditioning, putting an enormous demand on the electricity grid. It is much more difficult and energy-intensive to cool something than to heat it.
Roof-mounted solar power is popular in Australia for good reason; it generates a lot of electricity and cost savings. It does this through an active process, i.e. the sun’s UV radiation creates free electrons that produce a current. This can be consumed before drawing expensive power from the grid.
Another cost reduction benefit often not considered, is the secondary passive reduction solar panels can have in reducing cooling costs.
The science behind PV passive cooling
Back in 2011, the UC San Diego Jacobs School of Engineering published the first peer-reviewed study of the cooling effects solar panels have on a building.
Since solar panels are designed to attract as much sunlight as possible, they are efficient at absorbing heat. The more efficient the solar panels, the greater the cooling effect. This is great news in today’s age of 500W+ solar panel modules.
The passive solar cooling effect works like this:
Panels are mounted several inches above the roof line. The black silicon cells absorb heat, which is transmitted through the panel. This process is known as conduction.
Solar panels are installed on rail several inches above a commercial roof. The air gap between the panel and the roof also heats up. This is a process called convection. Rather than transferring all this heat to the roof, air flow beneath the panels cause much of the heat to be removed. This keeps the roof significantly cooler during hot days.
The opposite effect occurs at night. Solar panels prevent the roof from losing all its heat rapidly to the cool night air. This provides insulation and keeps the building warmer for longer.