The 3 Types of Solar Hot Water
There are 3 types of solar hot water system to choose from:
Collector based systems
The first two types both use a solar collector that is placed on your roof. This absorbs the sun’s rays and transfers the heat from those sunrays directly to your household water which is pumped through the collectors.
The water heats up as the sun hits it. When the sun isn’t shining, you obviously can’t heat the water with solar energy, so you need to have a backup fuel source, usually gas or electricity. Of course to avoid using this electricity or gas you store the hot water in a well insulated tank.
Generally these systems can provide from 50 to 100% of your home’s hot water – depending on where you live and how efficient your solar hot water panels are.
In Hobart, you’ll get about 50% of your water heated by the sun. In Darwin, you may get 100%.
Here’s a typical collector based system that uses a ‘flat panel’ style collector. This one has its hot water tank integrated with the panels.:
Heat Pump Systems
A lot of people believe that the heat pump – isn’t a proper ‘solar’ powered system because it does not use collectors. These people are wrong! Heat pump systems don’t need any solar collectors because they use a different type of solar energy. Where ‘conventional’ solar hot water systems need sun light to heat the water, heat pumps pull solar heat out of the air around us and use this heat to increase your water temperature. Although it sounds unlikely there is actually enough heat in the surrounding air – even on a winter’s day – to heat your water right up to boiling!
Heat pump systems do use electricity to remove the heat from the air and transfer it to your water (they are basically air conditioners in “heating-mode”), but they use around 75% less electricity heating your water in this way – compared to a conventional electric water heater.
Here is a typical heat pump system – you can see the similarities to an air conditioner!
And if aesthetics are important to you, don’t worry, you can get really sexy looking ones (to an engineer like me anyway!) with the heat pump integrated into the cylinder so it is almost invisible.