Frequently Asked Questions
What is solar thermal?
Solar thermal is the specialist term for heat produced using solar energy. Thermal collectors convert sunlight into heat which is used for hot water and to supplement conventional heating systems or to heat swimming pools. It may also be used to heat air directly using air collectors.
What is meant by "photovoltaic"?
Photovoltaic (photo = light, volt = unit of electrical voltage) is the specialist term for electricity produced using solar energy. Photovoltaics concerns the direct conversion of sunlight into electric current using solar cells.
What components go to make up a solar thermal system?
Solar thermal systems consist of a collector array, storage cylinder, solar circuit and a control unit with pump. The whole system is connected together by pipes in which solar fluid circulates as a heat transfer medium.
What components go to make up a photovoltaic system?
Photovoltaic solar systems generally consist of photovoltaic modules and a device called an inverter. The direct current generated by the system is transformed by the inverter into alternating current as per electricity supplied by the grid. If the system is connected to the grid, this electricity is fed into the public grid via an export meter. In the case of a stand-alone system, solar electricity is mainly stored in batteries for use at a later time.
When is a house suitable for solar power?
Almost any building is suitable for a solar installation. The roof or façade on which the solar collectors are installed must face south, east or west. Shading caused by trees or houses should be avoided. A solar thermal system also requires a suitable location for the hot water storage cylinder.
Is the United Kingdom sufficiently sunny?
Every year the Earth receives 10,000 times as much solar energy as the human race currently needs. In Germany alone, an annual total of 300 billion kilowatt hours of solar energy is available. There is an average of 1,000 W of direct and indirect solar radiation per square meter. This is the fuel equivalent to almost 100 litres of heating oil.
What proportion of my hot water requirements can I cover with a solar thermal system?
Solar thermal systems are generally dimensioned so that over 60% of energy requirements are met by the solar installation. When used to supplement a conventional heating system, approximately the same amount of energy can also be saved.
What is a sensible size for a photovoltaic solar energy system?
Due to the subsidy for solar generated electricity paid for by the utility companies (as laid down in the Renewable Energies Act), the system should be dimensioned according to the size of the roof and the amount of money available, in order to obtain as high a return as possible.
How can a solar energy system help save the environment?
A solar installation generates energy and therefore reduces energy requirements from conventional energy like oil, gas, coal or uranium. CO2 emissions are reduced accordingly (not in comparison with nuclear power). Furthermore, environmental damage through transport, extraction and processing of raw materials or through the final storage of spent fuels is avoided.
In what ways can solar thermal systems be used?
There are four main types of use:
- Systems for hot water
- Solar energy systems for hot water and auxiliary heating
- Systems for heating swimming pools (mostly in conjunction with the above)
- Systems for air heating
In what ways can photovoltaic systems be used?
For private homes, there are two main types of use:
- Grid coupled photovoltaic systems for returning electricity to the grid
- Off-grid (stand-alone) photovoltaic systems for own consumption
How much energy can I really save?
A solar thermal system will generally allow you to save over 60% of the energy required to generate hot water. If used to supplement a conventional heating system, roughly the same percentage saving can be made in addition. As a rule of thumb, at our latitudes the energy yield per year and per system is between 750 and 850 kWh per kWp of installed output. This means that a 2kWp photovoltaic system roughly 20 square meters in size produces approximately 1.500 - 1.700 kWh of electricity per annum.
Do you need planning permission to install a system?
No planning permission is required to install a solar energy system. However, if a building is listed then the relevant authority will have to decide.
How do I fit a solar energy system?
There are the following installation types:
- On-roof installation
- Flat-roof installation
- Integrated/complete roof installation system
- Canopy installation
- Façade installation