Renewable Energy Options for the Home - Part 2 (Solar Energy)
Friday, 07.13.2007, 09:42pm (GMT)
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.
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