Solar Panel For Heating Hot Water

A Solar Panel and Hot Cars

Solar panel for heating water installed on a slate roof facing south

Solar Panel system for heating hot water in Ireland

A Solar panel really works in Ireland – solar panels are tried and tested but many people can still be unsure so we’ve tried to explain how they work using something that we all know – a hot car on a sunny day.   If you're happy with the technicalities and just want to look at prices you could just go straight to have a look at our range of solar panels prices.



All solar panels work on the same basic principal as a car getting hot on a sunny day. The car will warm up throughout the day as solar radiation passes through the windows heating the internal parts of the car which are usually dark in colour. The heat inside cannot escape not until someone comes along and opens the door. This solar heat is effectively trapped raising the temperature inside far above what it is outside. Solar panels work in a similar but optimized way, the solar energy passes through glass and heats up a dark material raising the temperature so it can heat water and our homes in a carbon-free, cost free and renewable way.

How Solar Panels Work

Installing solar panels - the basics

We can organise a site survey is to find out the technical aspects of installing any renewable energy source or solar panels into your building or home and to inform you of the process involved. If you agree, we will contact you later with a no obligation quotation - no hard sell just common sense figures
To install solar panels for heating water you need to consider the following:

Installing solar panels will take approximately 1-2 days to complete. This is possible if your house is like the vast majority of houses in Ireland and satisfies the following simple criteria:

1. There is access to a South facing roof (anything between South East and South West is fine) with room to install the solar panels. If your property faces east or west that is also no problem but needs a slightly larger system.
2. You have attic space with reasonable access to run the solar pipework.
3. Your hot press or plant room has space big enough to take a new solar cylinder

How solar panels work in more detail

So how do you know if the solar panels you are considering are any good? There are three things to look out for - First the efficiency; the car described above is functioning as a solar panel. Solar panels are designed specifically to exploit this heating up effect. Solar radiation strikes the solar panel, entering through a glass shield before meeting a dark-coloured solar absorber. As anyone who’s ever worn black on a sunny day knows, dark colours are great at absorbing heat. A solar panel left sitting in the sun during the day will see its temperature steadily rise until it is far hotter than the ambient air temperature. Good solar panels are better at absorbing this heat and this can be assessed by looking at the solar panel absorber efficiency factor (n0). This is a measure of the quantity of solar energy the solar panel is capable of absorbing, for a certain amount of solar radiation.

Secondly the size; the aperture area of solar panels is the area of the solar panel absorber that is exposed to solar radiation and capable of collecting sunlight. The total amount of energy collected by the solar panel is therefore dependent both on the efficiency of the absorber, and the aperture area of the solar panel. The higher the efficiency (n0) and the bigger the area that can absorb the energy (Aperture Area), the more energy that will be produced.

The third thing that makes good solar panels is its ability to retain the energy that it has collected and not lose it back to the air surrounding it. Heat energy always travels from hot to cold (thermodynamic basics..). The rate of energy movement depends on how easy it is for the energy to move from hot to cold and the temperature differential between them. Therefore, to prevent the ambient air from cooling the solar panel down again, the absorber must be insulated and sealed to prevent energy loss. Vacuum tubes use a vacuum to limit this energy loss so they are typically better at retaining heat. The A0 value of solar panels indicates how good a panel is at retaining heat. The lower the A0 value, the more efficient the solar panel is.

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