1. Mechanical Engineering , RWTH Aachen University , Aachen , Germany
2. Jara Energy , Juelich , Germany
3. Institute of Energy and Climate Research: Energy Systems Engineering (IEK-10) , Forschungszentrum Juelich GmbH , Wilhelm-Johnen-Str. , Juelich , Germany
4. Institute of Institute for Energy Efficient Buildings and Indoor Climate at E.ON Energy Research Center , RWTH Aachen University , Aachen , Germany