What is solar thermal?

Solar thermal is the technical name for solar energy which is used to heat your hot water. Solar thermal uses a solar panel or solar tubes to heat your hot water.

How does a solar thermal system work?

Solar thermal hot water heating works by heating a liquid that is pumped through the panels or tubes and around to your hot water cylinder where it indirectly heats the water in the hot water cylinder. It only pumps the liquid around when there is enough sun to heat up the solar panels or solar tubes.

My house faces North, are solar panels or tubes right for me?

The best outlook for such a heating system is directly south although it can still work for an outlook of south east through to south west. If your house faces north, then the back of the house would usually face south so the panels or tubes could possible be installed at the back of the house.

Will solar panels or tubes work with my combination boiler?

No. Combi boilers are not compatible with solar heating in their own right, you have to have a hot water store. It is possible to add a thermal store, or to convert the boiler to a system boiler by the use of zone valves. In either case a hot water cylinder will need to be installed.

How much gas will it save?

While fuel prices will vary across Ireland and the UK solar water heating will still save approximately 50-60% of your gas bill needed to heat your hot water. This is not to be confused with central heating. Solar thermal does not contribute to your central heating.

Does using solar panels or tubes cut carbon emissions?

Yes. By installing a solar hot water heating system, you are actively contributing to cutting carbon emissions responsible for global warming. On average a typical domestic system will cut 500kg- 1 Tonne of carbon emissions a year.

In the summer will it heat up the all of my hot water?

Even in Ireland, yes. Generally in the summer your solar hot water heating will provide up to 100% of your hot water heating, and in most cases, apart from a few cloudy or rainy days you should be able to turn off your normal hot water controls.

Will it still work in the winter?

Yes, even a sunny day in November will contribute to your hot water, as the system works on sunlight rather than heat. In Ireland and the UK December and January are usually the only two months that your system will rely on the boiler to heat your hot water as these are the two months with least sunlight.

Does the solar thermal system need much maintenance?

No. Generally the system is maintenance free. Some systems installed in the 1970s are still running. It may be necessary to exchange the antifreeze every few years. It may also be necessary to exchange the pump as it wears, but it’s a normal off the shelf heating pump, and is inexpensive. As with all systems concerned with heating, it is advisable to have them checked out on an annual basis by a suitable qualified person.

Is it possible to obtain a grant from the government for a solar thermal system in Ireland and the UK?

Yes. At the moment you can apply for a grant from the SEAI for existing houses in Ireland and from the Low Carbon Buildings Program in the UK. We can assist you in obtaining the small grants available for these installations.

Solar works every day even in Ireland

Solar power is available all year round, it even works on hazy and overcast days. The chart opposite indicated the average level of sunlight in W per square metre across Ireland and the UK.

From solar tubes to panels: different solar thermal solutions

There are basically two types of solar collectors available for water heating: flat plate glazed collector panels and evacuated tubes. Both systems collect the radiant heat from the sun to heat water.

The flat plate collector panels are more aesthetically pleasing, but they can only operate at maximum efficiency when the sun is directly overhead at midday. At other times, the suns rays are striking the collector at varying angles, reducing efficiency.

Evacuated tube solar hot water systems overcome this problem. Because the collector consists of a series of tubes, the suns rays are perpendicular to the tubes for most of the day, allowing the system to operate at high efficiency for much longer than flat-plate units.

Roof inclination and direction

Even though almost every roof type is suitable, the inclination and direction are very important. Pure south facing and an inclination of 40 C are ideal and will achieve optimal performance of your solar product. The direction can be from east to west but after pure south southwest or southwest are preferred. Both panels and tubes can be mounted at an angle between 20 C and 90 C.

70% of hot water needs from the sun

When averaged over the year, a correctly sized solar system - installed in Ireland or the UK - can provide up to 70% of a household's hot water needs at almost no cost to the homeowner.

Solar simulation calculations

Evolve Technical Solutions is able to provide to all their customers in Ireland and the UK solar simulations and system layouts (for both panels and tubes) including solar fraction analysis and energy performance for our various solar systems. This is a valuable tool for engineers and consultants for the planning of solar thermal systems such as solar panels or tubes.