The sun is a very powerful source of energy which powers natural cycles on earth like wind, water flow and plant growth.. Solar power is the technology of obtaining energy from the sun. There are three approaches to gain maximum benefit of solar energy in our buildings.

Passive Solar

Passive solar technologies convert sunlight into usable heat without the assistance of other energy sources. Passive solar architecture is a design approach which seeks to:

- maximise solar gains in the building (through orientation such as a south-facing site, layout, glazing etc)
- avoid the loss of heat from the building through high quality insulation
- ensure a high degree of comfort by using controlled ventilation and daylighting

Passive solar systems have little to no operating costs, often have low maintenance costs, and emit no greenhouse gases in operation. Passive solar principles can help reduce heating requirements of a home by up to 80%.

The Passive House Standard can be found at www.passive.de

Active Solar Heating

Active Solar technologies are employed to convert solar energy into usable heat, cause air movement for ventilation or cooking or store heat for future use. Unlike Passive Solar, Active Solar uses electrical or mechanical equipment such as pumps and fans to increase the usable heat. The most common use of active solar in Europe is Solar water heating. It is estimated that a correctly sized solar water heating system can provide for up to 60% of your water heating needs. Indeed, studies have shown that one square metre on your roof receives the equivalent of more than 100 litres of oil in free solar energy per year. Solar panels, generally located on a south-facing roof, transform solar radiation into heat which is stored in a large hot water cylinder for whenever you need it.

Solar Photovoltaic (PV) System Photovoltaics, or PV for short, is a solar power technology that uses solar cells or solar photovoltaic arrays to convert energy from the sun into electricity. Solar cells produce direct current electricity from the sun’s rays, which can be used to recharge a battery or to power equipment. When more power is required than a single cell can deliver, cells are generally grouped together to form “PV modules”, or solar panels, that may in turn be arranged in arrays.

Solar arrays are increasingly incorporated into new domestic and industrial buildings as a principal or ancillary source of electrical power. In a typical installation, an array is incorporated into the building (roof or walls). In this way, Solar PV can be used to provide free solar electricity to houses. Recent developments in regulation mean that it will shortly be possible to connect solar PV systems to the grid, opening up a new era for solar PV in Ireland. Arrays can also be retro-fitted into existing buildings, normally by sitting them atop the existing roof. One new feature of note came in August 2006 when Currys, the major high-street retailer decided to stock PV modules at a cost of a thousand pounds sterling per module.