Solar technology

General information on solar energy generation

At the end of the 1970s, the first ideas for the development and production of alternative forms of energy generation (i.e. not based on the combustion of coal, oil, gas or wood) in the commercial sense, began to take shape in some European countries (first in Switzerland, later also in Germany). Initial private tinkering was to be developed and engineered professionally.

The then managing director of today's AQSOL GmbH was heavily involved in system and product development in the field of thermal solar technology (solar heat), including the new plant technology required for this, for several years in the early 1980s in Switzerland as part of a large team of engineers at a mechanical engineering company (photovoltaic technology came much later).

The term "solar technology" for electricity and heat generation in practical application includes the following areas in particular:

1. Photovoltaics

Photovoltaic systems generate electricity with glazed modules and have reached a high market volume since China entered the field with subsidised cheap technology. However, since the efficiency per unit area is comparatively low, photovoltaics is only so successful with the help of state subsidies. Without such subsidies, this technology would not have reached market maturity today.

2. Solar heat systems for medium temperature

Solar heat systems for medium temperatures heat domestic hot water or heating water by means of glazed collectors and vacuum tubes in a two- or multi-circuit system. Nowadays, this technology is on the decline, as it does not generate enough energy during the actual period of use, the six colder winter months. Moreover, no convincing storage technology has yet been developed that can distribute the solar energy from the six higher-yield summer months throughout the rest of the year.

3. Solar heat systems for low temperature

Low-temperature solar heat systems use a particularly effective unglazed absorber technology to produce low-temperature water that is used, for example, for swimming pools or in hot water preheating. With annual efficiencies of approx. 55-60%, this technology is considered particularly efficient and the economic useful energy gain is far ahead of any other heating method. The solar energy generated is available immediately and in full when it is needed. The complex storage technology for solar electricity and solar heat described under 1 and 2 is unnecessary here, because the swimming pool serves as a thermal battery.

As with wind energy, energy from biogas or combined heat and power, solar technology was initially promoted with research funds and then with politically determined and ever-changing federal grant programmes.

Only the solar absorber technology mentioned under 3 has managed without government subsidies for more than 20 years, as it is significantly more economical than any other type of heating with oil, gas, PV, biogas or wind and is used with very short payback periods. For this system application, there are only occasional government subsidies for individual applications. This is not justified by the fact that this technology requires state support, but solely for the reason of emission-free, effective environmental technology, which should be used before other heating methods.

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