The problem that needs to be resolved is the fact that there is too little knowledge about the energetically optimal application of photovoltaic thermal collectors (PVT) in an energy system configuration as well as its integration in a building envelope. A solution for this problem could eventually entail an optimisation in the use and storage of solar energy. The technology of PVT is very promising in relation to the current energy transition, most certainly as an incentive to foster the use of renewable energy sources and technologies. That is why the development of a PVT system configuration with additional envelope-integration is treated in this thesis. The main purpose of this thesis is to expound the energy concept of PVT, its role in the system configuration and its facade-integrational aspects, all this in relation to the application of PVT on a multi-family case study building. The accompanying research question is: How can an energy concept with PVT be optimised or maximised in terms of renewable energy and be integrated in the envelope of a multi-family building? In order to give an unambiguous answer to this question, the energy concept of PVT and other relevant technologies will be explained in a literature and background study upfront. This is followed by the description of the case study building. After that, the development of the PVT output types, configurations and the development of the system configuration and operation modes are discussed. The energy requirements of the multi-family building together with the energy output of the PVT collector results in an energy balance. Finally, the facade-integration aspects of PVT are described, where the amount of collectors on the roof and in the facade are determined by the energy balance. It was shown that a PVT collector that is glazed on the top and insulated at the back is the most effective type in the light of this thesis, that is to say in combination with this specific multi-family building. In addition to this, several collectors in series will lead to an effective configuration. Besides, for an efficient utilisation of the (collected) energy, it is wise to apply low-temperature heating as well as an energy storage in the system configuration. For the integration of PVT into a multi-family building, it is first of all recommended to design a proper layout for the in- and outcoming distribution pipes. Finally, in order to improve the integrational flexibility, it is advised to introduce multiple dimensions of PVT collectors in the future.