How Solar Heating Works

A solar water heating system uses collector panels that are usually situated on your roof to absorb energy from the sun. This energy is transferred into water stored in a hot water cylinder.

What about cloudy days

On days when there isn't enough sunlight to heat the water to the desired temperature, backup or 'booster' heating is utilised, which is typically gas, electricity or a wetback. The water is heated from a cool temperature of 5 - 15 º C to a minimum of 60 degrees (to comply with the Building Code). But, for safety reasons the water is also mixed with cold water so that it comes out of the taps at 55º C.

Solar Panels (flat plates)

A flat plate panel looks very similar to a common household skylight, but the difference is that this panel utilises the sunlight by absorbing it and then transfering the heat to the water or fluid in the collector panel. A flat plate system typically has a total surface area of between 2.5 and 6 metres² depending on the application and hot water requirements.

Heating Process

The heating process varies from manufacturer to manufacturer, but the Nova Energy SolarElite system we install effectively pre-heats the water before it goes to your hot water cylinder. It keeps pre-heating the water by circulating it through the sun-heated solar collectors until you require it.

If there is not enough sun to heat the water to the required temperature, or if you use all the water in your cylinder quickly, then the system uses another energy source (like electricity or gas) to bring the cylinder water up to the desired heat.

Water Circulation

The water in a solar water heating system can be circulated using a pump (an active system) or naturally using a method known as thermosiphon (a passive system). By integrating an active, pumped water circulation system, the location of the hot water cylinder is not restricted to the roof (as with a passive system) and can be sited at any suitable location inside (or outside) the home. A highly efficient electric pump is used to circulate water in conjunction with a controller used to ensure that the pump only operates when it is required.

As you can imagine, an active system is more favoured as not only is it more cost effective when utilising an existing hot water cylinder, it is also more aesthetically pleasing.

Hot Water Cylinders

A hot water cylinder is required to store the water heated by the solar panels until it is required for use.

Controllers

A solar water heating system also uses a system of controllers, which manage the use of backup (booster) gas or electric heating and can be used to control the pump. The controller ensures that you always have hot water, no matter what the weather outside is like.

Controllers fall generally into two categories; a time trigger controller and a minimum temperature controller. The time trigger controller keeps the booster heating turned off during the day so that you are not paying for electricity or gas to heat your water when the sun can be used, while a minimum temperature controller simply works by triggering the supplementary heating sytem into life whenever the water temperature drops below a pre-set minimum.