Do solar panels work here?
Friday September 19 2008
Q: I really want to improve the eco design of my house and I've been looking at the possibility of installing solar panels to heat my water supply. But given the summer we've been having, is there any point in putting them in?
A: Many people equate solar heating with strong direct sunlight and imagine, with our changeable Irish weather, that solar panels are an inefficient badge of eco friendliness.
However, solar panels work during daylight hours, meaning that they use the sun's heat to provide warm water even if the sky is overcast and there is no direct sunlight. It is estimated that you can receive up to 60pc of your hot water required during the year from a well-designed solar hot water system. With the cost of heating spiralling, it is something to seriously consider including in your house.
When installing a solar panel hot water system, bear in mind that the panels should be orientated facing roughly south and an optimal inclination of 30-45° to the horizontal. The panels should not be overshadowed by structures or trees and you should consider that space will be required for the positioning of the solar tank, probably in the attic.
At present, the installation of roof-mounted solar panels in your home is exempt from planning permission up to 12sqm or 50pc of your roof area, but it is worthwhile contacting your local planning authority to make sure that your proposal complies with this exemption. The SEI provides a list of recommended suppliers and installers, which is useful to consult. See www.sei.ie.
Q: I'm thinking of changing my boiler and have heard about something called a wood pellet boiler and stove. Would it be a good idea to install one?
A: Wood pellets are a biomass product made from sawdust and wood shavings. They are a carbon-neutral form of fuel, meaning that when the material is burned, the CO2 released is the same as that absorbed by the plant over its life cycle.
Essentially, a wood pellet boiler or stove uses this product for heating purposes by either providing heat directly to the immediate area, or feeding it back into the central heating system. A wood pellet stove does not necessarily have to feed into the central heating system and can be used as a pleasant form of heating for the room, while not incorporating the polluting aspects of an open fire or old-fashioned stove.
Filling the pellet stove usually allows for aproximately 30 hours of continuous heating and, unlike a traditional fireplace, they are self cleaning.
If, however, you propose to use a wood pellet boiler to run the main heating system of the house, it is very important to consider the amount of pellets needed to run the boiler efficiently, as bulk dry storage is necessary. By bulk storage, I mean in the region of 80pc of annual pellet requirements. If not, Murphy's Law may find you running out of fuel on the coldest day of the year!
Wood pellets are a cheap form of energy when compared with solid fuel and, while the initial capital costs may be quite high, this can be quickly offset against its cheaper running costs. Various designs are available and further information on design and installation can be found on www.sei.ie.
- Ruth Kealy
