Simulation, design and optimization of a historical building energy retrofit

The climate and energy performance of the case study is modelled through a highly accurate building model realized in IDA ICE 4.8 environment respecting all the listed constraints. Some further realistic assumptions are introduced about the unknown inputs. The Indoor Environmental Quality is assessed by taking into account the total energy demand per year, the annual thermal comfort according to EN 15251:2007, the annual indoor air quality according to ASHRAE 2011 and the visual comfort according to mbox{ASHRAE 90.1}. Three retrofit configurations avoiding all the measures that may be conflicting and/or incompatible with conservation are tested: Passive, Active and Passive + Active (P + A). The results show that all the retrofit strategies are able to improve the overall building indoor environmental quality. A multi-objective optimization allowed identifying the P + A retrofit configuration as the most efficient in minimizing energy consumption whilst maintaining thermal comfort conditions. This retrofit design brings together roof and ground floor insulation, windows enhancement, simple fan-coils installation and increased ventilation. The P + A retrofit measures markedly enhance the thermal comfort and the indoor air quality, meeting the comfort requirements for almost $75%$ and $70%$ of the occupancy time, respectively. Moreover, a new control strategy of the internal shading devices is proposed to reduce the visual discomfort due to too high illuminance.