The Italian building stock consists of buildings mainly constructed until the mid-20th century using pre-industrial construction techniques. These buildings require energy refurbishment that takes into account the preservation of their architectural heritage. In this view, this work studies an innovative integrated modelling and simulation framework consisting of the implementation of Historical Building Information Modeling (HBIM) for the energy retrofit of historical buildings with renewable geothermal HVAC system. To this aim, the field case study is part of a medieval complex in Central Italy (Perugia), as representative ancient rural offshore architecture in the European countryside. The system involves of a ground source heat pump, a water tank for thermal-energy storage connected to a low-temperature radiant system, and an air-handling unit. The building heating energy performance, typically influenced by thermal inertia in historical buildings, when coupled to the novel HVAC system, is comparatively assessed against a traditional scenario implementing a natural-gas boiler, and made inter-operative within the HBIM ad hoc platform. Results show that the innovative renewable energy system provides relevant benefits while preserving minor visual and architectural impact within the historical complex, and also in terms of both energy saving, CO2 emissions offset, and operation costs compared to the traditional existing system. The integrated HBIM approach may effectively drive the path toward regeneration and re-functioning of heritage in Europe.

In Europe, near zero energy buildings (NZEBs) represent the new frontier of energy efficiency in the built environment. Shifting the scale from NZEBs to net zero energy (NZE) settlements represents the opportunity to achieve further energy, environmental, and cost benefits, thanks to shared energy management, optimization of renewable energy systems, and microclimate mitigation. In particular, the last aspect takes advantage of the implementation of local microclimate mitigation strategies at a larger scale to improve settlements outdoor environmental conditions and citizens’ wellbeing. Furthermore, this inter-building scale mitigation involves relatively less severe working boundary conditions for buildings, able to both reduce building energy demand and improve HVAC (heating, ventilation, and air conditioning) system’s efficiency. In this study, this potential extra-energy saving, achievable without additional costs, is explored within the framework of a NZE settlement built in Italy thanks to an ongoing Horizon 2020 project. Improved working conditions for the operating air conditioning system and building energy savings thanks to settlement scale opportunities for microclimate mitigation are assessed. Findings show how this effect represents a further non-negligible energy-efficient and environmentally sustainable benefit achievable through the design and construction of NZE settlements. Potential energy savings are up to 24% when considering the double effect of microclimate mitigation.

Italian cities are mainly constituted by buildings constructed until the mid-20 th century by pre-industrial construction techniques. A HVAC system for the energy retrofit of historical buildings is evaluated when applied in the case study of Sant'Apollinare. It consists of a ground source heat pump a water tank for thermal energy storage connected to a low-temperature radiant system and air handling unit. The building thermal-energy behavior, typically influenced by thermal inertia in historical buildings, and the novel HVAC system performance interactions are comparatively assessed together with more traditional scenarios. Energy demand decreases by about one third compared to the pre-retrofit situation.

Net zero energy buildings (NZEB) represent reality of new constructions in Europe for environmentally sustainable energy efficiency. The shift to net zero energy settlements represents a further opportunity to achieve extra-energy saving, thanks to utilities sharing, renewables optimization, and microclimate mitigation. This last aspect concerns the opportunity to improve settlements outdoor microclimate conditions in both hot and cold seasons, in a variety of climate conditions, with the purpose to improve occupants’ wellbeing. At the same time, microclimate mitigation at inter-building scale may also involve relatively less severe boundary conditions able to reduce both cooling and heating demand of buildings and better working conditions for HVAC systems, e.g. heat pumps and air-to-air heat exchangers. This extra-energy saving, achievable with no extra costs, may represent an interesting opportunity to be taken into account in net zero energy settlements design and construction. This study analyzes this energy saving in a net zero energy settlement in Italy, built thanks to an on-going Horizon 2020 project. The influence of microclimate mitigation strategies is assessed in terms of energy saving benefits for the heat pump working conditions. Results demonstrate that this further benefit represents a non-negligible, environmentally sustainable, strategy for energy efficiency of NZEB in new inter-building scale developments.

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