Solar heated water has been around for a long time – remember the sun-warmed swimming pool in your back yard; waiting for the sea to warm up in spring before taking that first dip; or the good old camp shower – a plastic bag full of water hung in the sun to heat up for your daily wash?
The earliest record of an Australian solar water heating system was at Meringa Station (near Cairns) in 1941. It was relatively crude, but was still able to provide hot water for the household for about ten months of each year.
Today, solar water heating has advanced into streamlined systems which can save you money at the same time as helping the environment. The Australian government has invested heavily into sustainable energy forms that reduce greenhouse gas emissions, and with Australia’s high rate of sunshine, solar energy is an excellent alternative to fossil fuels and unsustainable resources. Solar hot water is here to stay.
So what does this mean for you? The news is good – as solar hot water systems continue to be improved, the savings for you, the consumer, are increasing. Not only can you reduce your power bill by using the sun’s energy to heat your household water, you will also help the environment. Over a quarter of household greenhouse gas emissions are caused by traditional methods of water heating – there are no greenhouse emissions from solar water heating!
Solar water heating is pretty simple – in a nutshell, it exposes water to heat from the sun by pumping it through a system of photo-voltaic (PV) panels (or collectors) which capture the suns energy and using it to heat the water, then the hot water is stored in your hot water cylinder ready for use.
As solar heating is reliant on having regular sunlight, the efficiency of your system will depend on where it is placed (generally this will be on a north-facing part of your roof, away from the shade of trees and the like), and of course, how much the sun shines! To ensure a constant hot water supply, a back-up system such as gas or a heat pump is used, which will kick in when your solar system is not getting enough sun, for example during heavy cloud and at night.
In most cases, a solar system will provide between 50% and 90% of your household hot water requirements, depending on the system you choose and the amount of direct sun hitting it each day. Given that water heating accounts for more than a quarter of the power costs in an average home, this means big savings and a positive impact on the environment.
The parts that make it all happen
The components of a solar hot water system work in a circular loop, constantly feeding cold water in and pumping hot water out through interconnecting pipes. There are three main parts of the system that help with this process:
• Solar thermal collectors (the panels) – Used to capture the solar thermal energy from the sun and heat the water.
• Gas or electric water storage tank – Used to house your property’s water, pumping any cold water past the solar thermal collectors for heating, and sending this heated water around your home.
• Electric or gas booster – Used to maintain a constant level of heat in your storage tank so you always have a ready supply of hot water, even if there’s no sun.
Electric water heaters are being phased out in some parts of Australia and it is a requirement for new homes to have sustainable energy systems for water heating. Solar systems will not only meet legal requirements, but will make your home more desirable when it comes to resale. Depending on where you live, there are also government incentives and sometimes financial bonuses for making the change.
So when you are thinking about water heating, think solar. After all, nature has been using it for millions of years!