The Institute for Thermal Engineering (TU Graz – Institut für Wärmetechnik) is part of Faculty of Mechanical Engineering at the Graz University of Technology (TU Graz). The institute employs a scientific staff of currently 35 researches and covers the research areas Thermal Energy Systems and Biomass, Bioenergy Clean and Sustainable Systems, Solar Thermal Energy Systems, Heating Ventilation and Air Conditioning, Heat Pump Technology, District Heating and Utilization of Waste Heat and Energy Efficient Buildings. The experts of IWT have a long-term experience in heat pump technology and solar thermal systems. IWT has been and is active in many international projects, e.g. several Tasks of the IEA-SHC, Annexes of the IEA-HPP, and in European projects like MacSheep and COMTES and did a lot of research in the context of energy supply for urban regions and the development and integration of heat pump systems. IWT has a long tradition in simulation competence and thermal system calculation. It is possible to cover many problem areas, from analytical calculation models to numerical 3D simulations using commercial or proprietary software.