Low Energy House - Renewable Energy
Renewable energy is generated from natural resources, such as sunlight, wind, rain, tides and geothermal heat, all of which are naturally replenished
Renewable energy occurs naturally and repeatedly in the environment and can be energy from water, wind, sun or geothermal heat from the ground. Renewable energy can also be produced from biomass, plant sources, such as wood or crops grown specifically as a fuel.
Most renewable energy production is large scale but some renewable technologies are suited to small off-grid applications. The Low Energy House website concentrates on renewable energy applications that are appropriate to the construction of individual houses.
Renewable Energy - Solar PV Panels
Solar photovoltaics, or solar pv for short, is a technology with which daylight is converted into electrical power. It uses energy from the sun to create electricity that will operate electrical appliances and lighting.
Solar power requires only daylight, not necessarily sunlight, and is therefore capable of generating electricity on a cloudy day. Solar panels work equally well in urban or rural locations. They can be installed on the roofs of most homes and can easily be connected to a building's electricity supply.
Renewable Energy - Solar Roof Tiles
Solar tiles operate on the same principle as solar pv panels. The advantage of solar tiles is that they are manufactured to the same modular size as large format roof tiles. They can be integrated into a new roof at the time of construction or into an existing roof when the roof covering is replaced.
Renewable Energy - Small Wind Generators
Small wind turbines harness the power of the wind and use it to generate electricity. Small wind turbines can produce electricity to power lighting and domestic appliances in a typical home. When considering whether to invest in a wind turbine system to provide electricity for a home, it is important to know if there are any significant nearby obstacles such as buildings or trees that are likely to reduce the wind speed or increase wind turbulence.
Renewable Energy - Solar Heating Panels
A well designed system of solar heating panels can provide half the heat required to supply a household's domestic hot water throughout the year. Where there is a shortfall, the temperature of the water can be raised to the required level using hot water from a wood burning boiler or a condensing central heating boiler, in the conventional way.
Renewable Energy - Ground Source Pumps
Radiation from the sun heats the earth all the year round. In the UK winter, the temperature of the earth, close to its surface, is between 8°C and 12°C. Ground source heat pumps transfer heat from the ground into a building to provide space heating or to pre-heat domestic hot water. From every unit of electricity used to power a ground source heat pump system, between 3 and 4 units of heat are extracted and distributed. At this high level of efficiency, there are less carbon dioxide emissions than for a gas boiler system.
Carbon Neutral Biomass Burners - Wood Burning Stoves
Biomass fuel is one of the most environmentally friendly ways of heating individual rooms or a whole house because wood is a carbon neutral fuel. Wood fuel is readily available as logs, wood chips, bark, sawdust and wood pellets. Wood fuel can also be obtained by coppicing, whereby wood is removed in rotation from young willow and poplar trees.
Wood burning stoves and boilers are typically sealed units manufactured from either cast iron or steel. They operate at around 75 per cent efficiency whereas an open fire operates at only 15 to 20 per cent efficiency. To provide heating and domestic hot water a log fired stove with a combined water boiler is required. Wood burning stoves with a back boiler can provide most of the required domestic hot water in a house. Larger models are capable of supporting domestic central heating systems and are very cost effective.
Before considering renewable energy for an existing house, it is advisable to improve the energy efficiency of the house through improved draught proofing, low energy lighting and more sophisticated heating controls
Low Energy House - Renewable Energy