Renewable energy sources
In the energy planning of buildings, important stage is the integration of renewable energy sources (R.E.S). As renewable energy sources are configured the energy sources that exist in abundance in the natural environment. The renewable energy sources are inexhaustible; their use does not pollute the environment, while their utilization is limited only by the development of reliable and economically acceptable technologies aimed at the freezing of their potential.
The types of renewable energy are from:
- The Sun: where the solar energy is converted into heat via thermal solar systems or into electricity via photovoltaics. Those two methods are mostly used in residences and that’s why areanalysed below.
- The wind: where the wind energy is converted into electricity using wind turbines.
- Waterfalls: Conversion of the kinetic energy of the water into electricity.
- Biomass: Thermal or chemical energy to produce bio-fuels, solid, liquid or gas form, with the use of forestry and the use of industrial agribusiness (plant and animal) and municipal waste.
- The Sea: where wave energy, tidal energy from temperature difference of the water on the surface and in great depth.
The R.E.S.In sustainable development have the following advantages in the following areas:
- R.E.S are environmentally friendly since they contribute to reducing carbon dioxide emissions.
- Under specific conditions can be lucrative for the small investor.
- They have low operating costs which are not affected by international developments.
- Contribute to economic and social development of their region.
- Constitute an alternative solution to strengthening the security of energy supply in the country by reduce dependence on fossil fuels.
In our country (Cyprus)due to the sunshine, the heating water is the most efficient and economical application of solar energy. Thermal solar panels are collectingthe sunlight and converting it to heat, which is transferred through air or water into storage tanks, in order to be used in various parts of the building. Thermal solar systems are consisted of solar thermal collectors, storage tank, pipes and control system.
At the designing of solar systems, the main elements that must be identified are: the surface of solar panels, the correct positioning in relation to the orientation that should be the South and the storage tank capacity depending on the use of the building.
Another application of solar energy which now is applying more often in new and existing buildings is the use of Photovoltaics due to thegrantsfrom government and their simple installation.
Photovoltaic systems are collecting solar energy and convert it into electricity by using semiconductors. Semiconductors are connected to each other and assembled together on a metal base, creating a PV array.
Photovoltaic systems can be installed in three different ways:
- Independently on the roof of the building
- Autonomously in a plot of channelling the generated energy to the electric network.
- Can be integrated in the shell of the building (on the facades of the building or stick systems or in prefabricated curtain walls).
The generated electricity can be used in 3 ways:
- To be used to cover a portion of the building’s electrical needs.
- To be stored in accumulators (batteries) for use in the evening.
- To be pushed into the electricity network of the city.
There are 3 types of photovoltaic cells:
- monocrystalline silicon cells
- polycrystalline silicon cells
- By amorphous silicon.
In order to maximize the performance of the photovoltaic cells the best orientation is the South. The Photovoltaics must be installed tilted towards the horizontal plane is equal to the latitude of the area within ± 15 °, to optimize nook of incidence of solar radiation and thus to maximize energy production.
Renewable Energy has entered our lives, at last. More and more households decide to benefit from the net-metering system and install photovoltaics. Therefore, different obstacles found on the roof, threaten the optimal operation of a PV system.
The worst enemy of a PV system, of any technology, is shading. It only requires partial shading of a PV panel in order to decrease considerably the production of the whole PV system. Therefore, PV manufacturers take this problem into serious consideration and are trying to find ways to minimize the consequences of shading. And the indisputable leader in this case is SolarEdge. SolarEdge systems allow module-level optimization on a PV system, which gives a better system performance. By connecting a SolarEdge power optimizer to a PV panel it becomes a smart panel, which this allows: a) Harvest up to 25% more energy from each panel b)Constant feedback on the performance of each panel and c) Automatic shutdown of each panel for maximum safety in case of an emergency.