Energy sources for sustainable buildings
Use of green energy from the nature
Renewable energy sources are not the subject of construction itself, but foreseen and meaningfully used, lead to significant reduction in operation costs and are means of preserving the environment and preserving exhaustible natural resources. This is the main feature that turns the building into "green" and "sustainable" - leaving a smaller ecological footprint. A similar source, for example, is the solar hot water system, which is a popular solution.
The major renewable sources, widely used today, are solar and geothermal energy.
Opportunities delivered by the sun energy
The larger renewable energy sources is the Sun. In Bulgaria, among of the sunniest countries in Europe, we can not boast rational use of that energy source, unlike countries with a less favorable climate than ours. For one year, the Sun delivers 8500 times the energy we consume on Earth for the same period of time, and today we have many opportunities to take advantage of it. Due to the advanced level of technologies nowadays, the Sun is widely used for domestic hot water and for electricity production. Two solar panels (5 sq.m. can cover more than half of the yearly hot water demand (55° C) of a family of four, consuming 200 liters hot water a day. The investment payback period is about 5 years.
High efficiency for heating and cooling
Geothermal energy is used for heating and cooling of buildings. The temperature of the soil and water is almost constant below the fifth meter, about 10° C, which makes it warmer than the outside air in the winter and colder than it in the summer. Combined with a heat pump system, geothermal energy provides possibility for high efficiency heating and cooling, where for each 1 kWh of used electricity you can get 5 kWh of heat. By comparison, a conventional electric stove for each 1 kWh of electricity consumed provides 1 kWh of heat.