Harnessing the Sun

Harnessing the Sun

The sun is an extraordinary powerful form of energy. In fact, the Earth receives 20,000 times more energy from the sun than we currently use. If we used much more of this source of heat and light, it could supply all the power needed throughout the world. We can harness energy from the sun, called “solar energy”, in many ways. Satellites in space have large panels covered with solar cells that change sunlight directly into electrical power.

Some buildings have solar collectors that use solar energy to heat water. These panels are covered with glass and are painted black inside to absorb as much heat as possible. Some electric cars are even powered by solar panels. Solar energy is a clean fuel, but fossil fuels, such as oil or coal, release harmful substances into the air when they are burned. Fossil fuels will run out eventually, but solar energy will continue to reach the Earth long after the last coal has been mined and the last oil well has run dry.

Saving energy

An energy-efficient house is designed to minimize energy waste. It generates its own electricity, but it is still connected to the national power grid. If it generates more electricity than it needs, the excess is supplied to the grid. If it needs more electricity, this supplied by the grid.

Keeping warm

Most of the heat lost by a house escapes through the roof. The roof of an energy-efficient house is lined with insulation material to stop heat from escaping.

Solar panels

When the sun shines on a solar panel, solar energy is converted into electricity to power electrical appliances in the house, such as water heaters or cooling fans.

The Sunny Side

Many houses are built today with one long side facing the sun so that it can absorb as much solar energy as possible during the day.

Harnessing the Sun. Photo by Elena.

Small windows

Windows that do not face the sun are smaller, to reduce heat loss.

Water tanks

Hot water from the roof-top solar collectors is stored in tanks for later use. The tanks are insulated to stop the heat from escaping.

Cover Up

Awning shield windows from the excessive heat and glare of the sun.

Skylights

These let in natural light and can be opened to let war air escape.

Walls

The walls are filled with insulating materials to stop heat from escaping through them.

Large Windows

Windows facing the sun are large so that plenty of solar energy can pass through and warm the rooms inside. In the evening, when the sun sets, heavy curtains or shutters are closed over the windows to stop the heat from escaping.

Warming Up

Greenhouse are made of glass and have slanted roofs to allow the maximum amount of sunlight to enter. The sun's heat is trapped inside, which raises the temperature inside the greenhouse and helps the plants to grow. Plants in a greenhouse can be grown all year around.

Solar Cells

Solar cells convert light directly into electricity. Light reaches the cell through a transparent protective coating. The first layer is made from a material called N-type silicon (silicon is one of the most plentiful elements in the Earth's crust). N-type silicon is specially treated so that it has more electrons than normal silicon. This has gaps in its structure because it has less electrons. Sunlight gives electrons enough energy to jump from the N-type silicon to the P-type to fill the gaps. When electrons move, they make an electric current. The tiny currents made by hundreds of thousands of solar cells are added together to make an electric current that is large enough to power equipment.