Combined heat and power plants driven by renewable energy sources (RES) are becoming more and more popular, given the energy transition towards the integration of more renewable energy sources in the power generation mix. In this paper an innovative micro-solar 2kWe/18kWth Organic Rankine Cycle system, which is being developed by the consortium of several Universities and industrial organizations, with the funding from EU under the Innova MicroSolar project, is considered. In particular, its application to supply electricity and thermal energy for Domestic Hot Water (DHW) in a residential building is investigated by means of simulation analysis. Different Domestic Hot Water supply plant configurations are evaluated and the design parameters are varied in order to determine the best configuration to recover as much energy as possible from the ORC, while maintaining the final users' comfort. It was found out that with the considered plant around 67% of the Domestic Hot Water energy demand of 15 apartments can be satisfied with a water storage tank of 10'000 liters. However, in order to always guarantee the supply water temperature, a back-up boiler, which serves directly the final users when needed, is requested.