## 2 Material and Methods
### Methodology
#### 2.2.4 Strategies and Impact Assessments  
Based on the yearly microclimatic analysis concerning thermo-hygrometric parameters and indoor air quality (CO\({}_{2}\) concentration), some strategies were defined and assessed. Some critical issues were taken into account in planning the strategies, such as economic and structural factors, linked to the conformation of the Hall, making the study very complex (very high, decorated arched ceilings and the presence of the bookcases on the mezzanine level narrowing the passage for people). A simulated model was also used as an instrument to evaluate the effectiveness of some of them in order to help the decisions made by the librarians. The strategies considered in this work concern mainly management and passive actions aimed at reducing and mitigating risk conditions, in particular the optimal management of the existing shutters and opening windows for natural ventilation; finally, the installation of solar control films on the windows was investigated. Management actions specifically involving the librarians adopt a curative method, providing for direct actions such as stabilization, consolidation, and disinfestation of the cultural property, and also the correct handling and consultation of books. In addition, great importance was given in this study to the control of the number of visitors during events, their duration and the management of the natural ventilation given by opening the windows. Management of the solar shading (shutters) was important for defining guidelines and good practices for the librarians in order to obtain a balance between thermal comfort (reduction of thermal gains) and visual comfort (reduction of natural daylight). The installation of solar films, instead, referred to envelope intervention (windows): this was a more complex strategy than the others, because it was also linked to structural, aesthetic (technical feasibility of their installation) and economic aspects. No other passive actions were considered for this case study, because of the presence of some important limits, mainly related to the fact that the entire building is heritage listed. This means that strategies which involve the envelope (such as the walls' insulation) cannot be carried out. Both these strategies were defined, simulated and assessed with a dynamic calibrated thermal model evaluated by means of EnergyPlus v.8.7 in order to predict hourly indoor temperature in the Hall [35]. To create the model, in addition to the thermophysical properties of the building envelope, thermal loads and HVAC system characteristics were set: as internal gains, human occupancy (5.5 m\({}^{2}\)/person), lights (2 W/m\({}^{2}\)) and office equipment (5 W/m\({}^{2}\)) for all zones used as offices (first and ground floor, except for the hall and atrium) were considered. The presence of occupants in these zones was set from 7 a.m. to 6 p.m. for each workday; the heating period was instead from 15 October to 15 April, as established by Italian law for this climatic zone. Set-point temperature of room air, based on occupancy schedules, was assumed equal to 20 \({}^{\circ}\)C for all zones [36; 37]. The hall was simulated in the conditions of \"non-occupancy\", with the shutters partially closed. A weather file [23] was created based on the data collected from a weather station (dry bulb temperature, relative humidity, wind speed, solar radiation), which is located on the roof of a university building about 1 km away from the investigated building. To validate the energy model, a calibration process was followed: this was an important phase, to allow a reliable simulation model to be created for the purpose of analysing indoor climate to support preventive conservation [38; 39; 40; 41]. The energy model was calibrated to consider only the hall zone: the quality of the model was assessed adopting indoor temperature as the calibration control variable [42; 43].