Renewable energy and sustainable buildings
- SUN WARMS UP
THE SUN IS A SOURCE OF FREE ENERGY – THE BILLS DO NOT HAVE TO BE PAID
1 kW – such a stream of energy from solar radiation lands on each m2 of the surface of the land during a sunny summer day! This is a lot: a 1 kW electric heater is sufficient to heat a large room in winter time.
Why do we not use this energy? We do it very often especially in summer when we sunbathe...
- SOLAR ENERGY FOR HEATING BUILDINGS
HEAT FROM THE SUN
During one summer month, the solar radiation landing on the roof of a typical house has a lot of energy – about 5 000 kWh. The equivalent amount of electricity costs ca. 300 Euro. So, it is worth saving. Part of this energy can be caught by solar collectors and then effectively used. In summer, heating of water for households is the most convenient and common option for the use of solar energy. During the winter solar energy can be used to help heat the building, which can cut energy bills.
Solar collectors (also called solar thermal collectors) are appliances which use solar energy to produce heat. They are usually applied for the provision of warm water in households, hospitals etc., for warming up water in swimming pools, for drying crops, and sometimes for heating and conditioning of rooms. Solar collectors used in a typical water heating system in our climate zone can provide up to 450 kWh of heat from each square metre of collector surface over the course of a year.
- PHOTOVOLTAIC - ELECTRIC ENERGY FROM SUN
Solar radiation may also be converted to electric energy.
Photovoltaic (PV) cells are used for this purpose. Photovoltaic cells (PV) are appliances which convert sunlight directly into electric energy. The efficiency of energy conversion is comparatively low and depending on, amongst other things the manufacturing process, equals between a few percent to about a dozen percent. Despite this PV is a useful source of electricity for many applications.
- HEAT PUMPS USE SHALLOW SOURCES OF GEOTHERMAL ENERGY
Heat pumps are appliances used for heating or conditioning of rooms. Heat pumps collect heat from low-temperature sources (e.g. from soil around the house) and transfer it to high-temperature sources (e.g. heated room). Heat pumps available on the market transfer in this way four times more heat energy compared to the amount of supplying them electricity. Currently heat pumps often replace traditional boilers.
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