Renewable Energy Requirements
Water Solar Heating
The building regulations call as a minimum requirement of 10 kWh/m2/annum of renewable energy for hot water.
A typical well sized solar thermal system should provide around 50-70% of the domestic hot water requirements of the home, representing a worthwhile saving on hot water heating costs.
The remaining hot water requirement is provided by the boiler.
A common question about solar water heating is whether there’s enough sunshine available to make solar worthwhile.
Contrary to popular belief the amount of solar radiation received in this area is enough for solar water heating to be a viable supplement to existing domestic water heating.
The map on the right shows typical annual solar radiation falling within a square metre of
Solar Radiation Map of Ireland
ground in the Ireland.
Perhaps surprisingly, Ireland in particular receives 65% of the amount of solar radiation that is received by the south of Spain.
The radiation in Ireland is made up of direct radiation on sunny days, which accounts for around 40%, and diffused radiation on cloudy days, accounting for 60% of the total.
Solar water heating panels have been developed with this typical weather in mind and make the most of both direct and diffused sunlight to give a useful annual contribution wherever you are in Ireland.
Summer will provide the largest amount of solar radiation over the year but a useful contribution will also be provided by other seasons.
As an indication, a well sized typical solar water heating installation will provide the
Solar water Heating
following proportion of the household’s domestic hot water requirement:
Solar energy provides on a well sized and installed sytem
Summer up to 85%
Spring and Autumn 45%
Winter 20%
Photovoltaic Solar Panels
For renewable energy generating electricity a 4 kWh/m2/annum is required.
This method of renewable energy is in many ways better as it cuts down on the amount of
Photovoltaic solar panels
electricity being generated.
It is leaner in that it generates electricity which can be used in the home.
It is expensive relative to solar water heating.
It has a big drawback as the payments for any power going back to the grid is too small standards and as such is not used extensively.
hightechhouses 