Dynamic simulation and analysis of a Passive House case study with direct PV system for heating and domestic hot water production

Different heating systems for space heating and domestic hot water (DHW) preparation are investigated with respect to their energy efficiency. In particular, a case study of a multi-storey Passive House (called An-der-Lan) is analysed by means of dynamic simulations. The first part of dynamic simulations focuses on the comparison of the UA and RC models for a simple office located in Rome. This is a case study from the project IEA SHC T56 – System Simulation Models. In particular, attention is put on the influence of the thermal capacity. Assuming the RC model as the reference case, variants of the UA model with different percentages of the thermal capacity are simulated, in order to find out the most similar to the RC model. The same investigation is carried out for the An-der-Lan building. In general, it is not possible to identify the best UA model, because for every considered quantity, the minimum difference between the UA and RC model is got for a different percentage of the thermal mass. The second part of dynamic simulation focuses on the comparison among different systems for heating and DHW preparation. The realized system is direct electric heating for both space heating and DHW preparation. It is denoted as the reference Case1 and it is compared against alternative solutions. Case2 is based on a central air/water heat pump system for both heating and DHW production. A sensitivity analysis study is conducted. Finally, Case3 and Case4 are a mix of the previous two cases. Results show that Case2 is the best in terms of electric energy required from the grid, although it is the system with the highest thermal losses. Furthermore, the PV system only in the south façade is not sufficient to cover the energy required in neither of the cases. Finally, annual, monthly, daily, hourly and 10 minutes balances are compared. Results show the importance of smaller time step in balances between required and produced energy, in order to have more precise results.