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Solar Basics: Types Of Solar Energy
If you are looking to harness the sun to power your home, you are probably looking at 2 very different options:
So, what’s the difference?
Solar Thermal uses the sun’s heat directly to heat up another medium – usually water – without the need to generate any of that pesky electricity. Solar thermal systems use either flat plates or tubes to capture the sun's heat and transfer the heat into a fluid.
Solar thermal is typically used to boost the production of hot water. I use the word boost, because there will always be days when you don’t have enough sun to generate all your hot water needs, and the boosting is performed by either an electric element, a gas fired heater or (less commonly) other fuel heaters such as wood fired stoves.
You will have seen the ‘solar thermal panels’ on roofs they typically look like this:
Storage tanks are most often at the top of the collectors (easy to spot) but sometimes are ground mounted.
These panels don’t generate any electricity. The panels contain rows of water-filled tubes which collect the sun’s heat directly. When the water is hot enough it is stored in the tank ready to flow out of your hot water taps or shower.
If, however, you want to use the sun to generate your own electricity, you are going to need a very different type of technology: Solar Photovoltaics.
Photovoltaic comes from the words photo (meaning light) and volt, a measurement of electricity. As it is a bit of a mouthful, it is usually abbreviated to PV or Solar PV. Solar PV panels are also commonly referred to as ‘solar cells’ (although technically the solar cells are the small squares within the solar PV panel).
Solar PV panels typically look ‘bluey-black’ and they are usually installed in groups called solar arrays. A typical installation is shown here:
You’ll see that there tend to be a lot of individual panels in a single installation. This is because a typical Australian installation is at least 1500 Watts (1.5kW), and a typical panel is 100 to 200W.