The sun is an inexhaustible source of energy. Photovoltaic systems use the sun and transform its radiation into energy via solar cells: direct, clean, emission-free, noiselessly. They require energy only in their production. Thereafter photovoltaic systems produce electricity for free. A photovoltaic system can be mounted easily on a roof or facade.
- The radiation of the sun at the earth’s surface on a clear day attains 1000 watts per square meter; on a cloudy winter day some 20 W/m².
- Seasonal fluctuation is great.
- Before deciding on a thermal or photovoltaic system, determine how much solar energy is available at the planned site.
- Solar cells are the core components of a photovoltaic system.
- They transform radiant solar energy directly into electrical energy.
- There are mono- and polycrystalline as well as amorphous cells.
- Solar systems consisting of monocrystalline cells energetically amortize in ca. 85 months; amorphous cells in only 30 months.
- The lifetime of a solar module at today’s state of the art is 20 years.
Solar modules and solar generators
- A single solar cell provides an electrical voltage of about 0.6 V and a maximum current of about 3 A.
- To achieve higher currents, individual cells are combined to solar modules.
- 36 solar cells are switched in series in a common frame behind special hardened glass.
- A solar generator consists of multiple such solar modules.
Autonomous photovoltaic systems (isolated systems)
- Autonomous operation involves the supplying of devices and properties without a grid connection.
- A constant autonomous energy supply is achieved with batteries, which supply power at times when solar energy does not suffice (night, cloudy, foggy).
- Decentralized power supply for properties is economically possible today with photovoltaic systems (alpine huts, broadcast stations, etc.).
Photovoltaic systems with grid connection
- You can generate power for your own needs on your roof with a solar plant.
- The grid is used as a buffer.
- Unneeded solar electricity is fed into the grid.
- At night or during bad weather, you can draw power from the grid.
- Today many companies offer the main components of grid-connected photovoltaic systems as standard packages, whereby the heart is an inverter that converts the DC current of the solar module into AC.
Photovoltaic systems transform sunlight into electric power.