A very significant parameter for solar thermal plants is the temperature level of a process; it has a major influence on the energy supply system. The second important characteristic number of a process is the energy consumption. The combination of these two values for all important processes in a single sector of industry has not been investigated yet and was thus the innovative part of this project.

Results

Those industry sectors which were actually to be examined for solar thermal use more closely, were

• food and beverage industry,

• textile industry,

• chemical industry and

• production of plastic goods.

One important result from all investigations in industry sectors and in enterprises is that the analysis for solar thermal supply also depends strongly on location and specific parameters (e. g. power supply, product range, mode of operation).

General statements about the appropriateness of the solar thermal process heat within an industry sector do not permit conclusions on individual enterprises.

The total annual requirement for energy of the Austrian industry is approx. 264 PJ (incl. approx. 67 PJ for steam generation). The low-temperature heat ratio (under 100 °C) is slightly over 10 PJ. After consideraton of possible heat recovery a little more than 4 PJ for solar thermal process heat remain of interest.

Conclusions

There are some industry sectors, in which solar thermal process heat seems to be of interest as an auxiliary system to supply energy. But only after all aspects of energy
efficiency (insulation, power supply system, heat recovery) have been regarded in detail, follows as last step the replacement of fossil sources of energy by renewable forms of energy. The supply by renewable forms of energy in an energetically inefficient system is economically and ecologically useless.

How an individual enterprise is able to assess and optimize its existing energy system and how during this optimization the integration of solar process heat takes place, is topic of the follow-up project SolProBat.

The result of this study the potential for the solar thermal supply of industrial processes in the Austrian industry — has only to be seen as an intermediate result. The results and pilot plants focused in the follow-up projects can initiate a new market for solar plants in the industry within the next years.

The interest of the producing trade and also the solar technique industry is however already very large and demands in consequence further development in the areas of the collector development (costs and/or higher temperatures), the integration of solarthermal plants into existing heat supply systems as well as the development of financing concepts, which make a conversion possible by the industry. At present a broad conversion is braked by solar plants for the process heat supply particularly by the short amortization periods of maximally three years, demanded by the industry. The first estimations of the potentials for solar thermal plants in industry and trade result in a portion of 3,0 % of the industrial for Austria. This corresponds to a demand of over 4 PJ on basis of the energy consumption of 1998, for their covering a collector surface of approx.. 2,5 million is square meters necessary. As comparison to the fact it is marked that the entirely installed collector surface in Austria in the year 2001 approx.. 2 million square meters amounted to.