Solar thermal energy and photovoltaics

  • Photovoltaikanlage


  • Solaranlagen

    Solar thermal energy

Why do we attach importance to the ecology?

Ecology is a subject that concerns everyone. We count on sustainability at all our services – for us and the next generation.

With recyclable, low-emission and environmentally friendly materials, we do our bit for the environment protection

Not only during the production, but also at further processing.

The inclines the professional disposal of polluted old stockings at renovations and material waste.

We install solar energy systems and photovoltaics and build your green rooftop. For the sake of the environment.


Andreas Strunz

master roofer and manager of dach & fach strunz GmbH

Definition Solar thermal energy

This means establishments, that use the solar radiation directly and transform it into usable energy (heat). The significant parts of a thermal solar system are the collector, the storage and the regulation system. Collectors for the heating of a house are funded by the government.

How does a solar thermal energy system work?

The black collectors compel the sunlight, so that the special liquid will be heated up to 95°C. This liquid circulates to a heat exchanger, in order that the heat is saved in the solar storage (buffer storage). Connected to this buffer is the heating system, so that the warm water can be used. The buffer works like a battery to have warm water available, even if the sun isn’t shining. 

Definition photovoltaics

Photovoltaics is a procedure to transform the light energy with the help of solar cells directly into electrical energy (solar power). This can be used as an isolated supply or can be fed into the public power supply, if the self-consumption is covered.

How do the photovoltaics work?

Photovoltaics consist of solar cells, that are composed of numerous silicon layers. Every layer shows different electrical conductivity qualities. Electrical fields are formed that build up voltage through metal contacts, when hit with light. With solar radiation arises a field of tension, that leads to DC. This can be transformed in the so-called inverter to AC, that can be fed into the power supply. The electricity meter records the income of the electrical energy.

What is to be considered in the planning phase?

The ideal conditions for the installation of a solar thermal energy system or a photovoltaics are named with the slope of 25 – 50 ° in the southern direction. More than that should your house be located at a spot with the annual greatest possible sunshine duration (statistically). But even with not the most ideal conditions (up to ca. 60° deviation of the ideal southern orientation and 30° deviation of the roof slope) is the loss of earnings mostly small and allows different characteristics of the rooftop.

Important is that there is no shadow effecting the solar radiation, because that leads to enormous loss of earnings.

You also have to consider the snow load and that the attachment points have to be constructed for that matter. For the detachment on metal rooftops there are special requirements.

For a preferably exact calculation of the given circumstances you should arrange a meeting with the installer on site, who can name the advantages and disadvantages of the location and the rooftop structure.

A parallel launch of both systems is possible, but not a constructional combination.

Who installs photovoltaics?

We build exclusively in-roof photovoltaics. For that you need the know-how of a roofer. The on-roof elements are built from installers.

Is a solar thermal energy system/ photovoltaics rewarding?

This depends on certain factors. A personal consultation with a specialist is recommended in any case. For the first orientation, there is a calculator, that offers an overview over the benefits.

Photovoltaics are mostly rewarding for businesses with a high power consumption.

How much power generates the solar system?

That depends on the size. The power is used in the domestic supply or can be fed into the public power supply.

What does a photovoltaics cost?

The size is here a factor as well. To inform yourself beforehand us the calculator. The installation costs vary from one firm to another, you should consider multiple offers.

Do I have to insure my solar systems?

Yes, an insurance is recommended in any case. Only the damage that the system does is insured in your liability insurance, not the damage to the system itself.

Do I have to clean the system?

The modules are protected against hail up to 2,5 cm. Dirt will be washed of, because of the rain (because of the slanting installation). If moss or lichens form (after many years), you have to clean the surface, because they lower the solar radiation.

What is kWP?

The acronym kWp stands for “Kilowatt peaks”. This state the performance of the photovoltaics and solar thermal energy Systems under normal circumstances. This is also called the rated output.

Can I install photovoltaics on landmarked buildings?

No, you can’t install them on landmarked buildings, because the alter the view of the rooftop.