The use of solar thermal energy for process heat especially in developing countries is still little known, although the market and application potential are very large. The aim of this project is the planning, development, design and optimization of a decentralized, mobile system for the continuous use of process heat in the medium temperature range. For the investigations, a solar thermal plant system was planned, developed, designed and built. By changing the parameters, the operating conditions of the plant system can be adapted for operation in developing countries.