In Italy, buildings requirements in both public and private buildings’ field (established by the Ministerial Decree 26/06/2015), raises the question about energy calculation methods reliability, due to the possibility to choose between asset rating and tailored method.
This research aims to present a study carried out on a XVIII century public building in Lombardy region (Rebecco houses) which is without HVAC system, testing both a quasi-steady state simulation tool (CENED+ freely provided by Lombardy Region for building certification) and a dynamic simulation tool (EnergyPlus) to investigate different retrofit options.
Outcomes allow to demonstrate that better results can be reached in the performance assessment adopting a dynamic model although its complexity: it is demonstrated a low reliability of the quasi-static model, due to the presence of uncertainties in input data (as the obligation to insert a plants) and also in the impossibility to modify final output (as including comfort evaluations); on the contrary, a dynamic method allows to obtain the trend of the internal temperatures (operating, radiating and air) and the thermal load required to the system, leaving rooms also to make decisions on non-standard conditions, such as lower indoor temperature, seasonal use and conservation heating. For heritage buildings, even if decisions on national level do not require the detailed approaches, a tailored energy performance calculation method is finally recommended.
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