The following thesis analyses and compares the performance of combined DHW and space heating and cooling systems driven by district or solar heating and evaluates the energetic savings of using a small scale absorption chiller to produce cold in the household. A reference system, composed of a compression chiller and space heating and DHW driven by district heating, is used in the analysis. The different con gurations have been modelled using the Modelica modelling language and simulated as being in two different locations, Berlin and Madrid. These simulations have been carried out for a week in summer and a week in winter in order to identify the optimal con gurations and energetic performance in each location. The resulting analysis has shown that a system can be deemed unpro table when not well dimensioned and that pressure losses in the circuits are an important issue which is seldom unaccounted for.