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Energy for the future. Most of the UK’s energy is supplied by fossil fuel power stations. There are two main reasons why we need to become less reliant on this sources of energy:. Fossil fuels are non-renewable and supplies of some are likely to run out in your lifetime.
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Energy for the future Most of the UK’s energy is supplied by fossil fuel power stations. There are two main reasons why we need to become less reliant on this sources of energy: • Fossil fuels are non-renewable and supplies of some are likely to run out in your lifetime. • Burning fossil fuels produces greenhouse gases which cause global warming. This means we need to find alternative ways of powering our homes and businesses. We also need to think of ways to reduce the amount of energy we use.
The roof of the Ecohouse The roof of the Ecohouse is designed to make the most of the Sun’s energy. There are five square metres of photovoltaic cells in the centre of the roof which provide the house with electricity. Solar hot water panels on the edges provide hot water using passive solar heating The sunspace at the front acts like a greenhouse, trapping the Sun’s energy in the house. How do you think the energy gathered varies over the day?
The photovoltaic roof The photovoltaic panels are the main source of electricity for the house. They generate about 3200 kWh of electricity each year. The Ecohouse only uses about 3000 kWh per year, so the roof generates more electricity than the house uses. However, too much electricity is produced in the summer, and too little during the winter. To remedy this, energy is bought from and sold to the national grid, depending on the season.
The solar hot water collector On either side of the roof, there are solar hot water collectors. These contain sheets of copper which are painted dark grey. Tubes containing water run underneath the panels. The Sun heats the copper panels, which transfer the heat to the water in the tubes. The hot water convects upwards into the hot water tank. Why do you think the panels are painted a dark colour? Why do you think they are made from copper?
The sunspace The windows in the Ecohouse make it possible for the Sun to provide passive solar heating. During the day, sunlight enters through the windows and is absorbed by the inside of the house. This energy is stored in the walls, floors and windows. During the night this energy is slowly re-radiated. Even during a cool evening, the sunspace is hot as it continues to radiate heat absorbed during the day.
Kacheloven The kacheloven is located in the centre of the house. It is a type of wood-burning oven that is far more efficient than a traditional fireplace. It burns wood chopped from softwood trees in the garden of the Ecohouse. Wood is a much better source of energy than fossil fuels, because the trees absorb carbon dioxide while they are living. This means that wood is carbon neutral.
Kacheloven Kachelovens are “heat sinks”. This means that they are made from materials that are very good at storing heat and release it slowly over time. The wood burns for only a few minutes, but the walls of the oven absorb the heat and release it into the room over several hours. You use the flue to create a hot core in the centre of the house. The smoke escapes through the coiled “flue” – these tightly-coiled ducts ensure as much heat is absorbed into the bricks as possible before the smoke escapes from the house.
Roman heating The kacheloven makes use of many of the same principles as a Roman hypocaust. Rich Romans used a system of under-floor heating. Beneath the floor they built a stone chamber (or hypocaust), with stone pillars supporting the house above. A fire was lit in the hypocaust which set up convection currents in the space under the floor. The stone pillars and walls absorbed the heat and then released it gradually to the room above.
