Participation of different Swiss reaserch institutions at the international project "Task 52 on Solar Heat and Economics" from the IEA-SHC programme. This Task focuses on the analysis of the future role of solar thermal in energy supply Systems in urban environments. Based on an energy economic analysis - reflecting future changes in the whole energy system - strategies and technical solutions as well as associated tools will be developed. Good examples of integration of solar thermal Systems in urban energy Systems will be developed and documented.