• Air handling unit
• Artworks preservation
• Dynamic simulation
• Energy efficiency
• Heat pump
• HVAC systems
• Matlab
• Microclimate
• Monitoring campaign
• Multi-objective optimization
• Museums
• Sensors
• Suitability indexes
• TRNSYS
• Visitors' comfort

In the last years, the attention on the correct use of energy in the building sector has grown, as this sector is responsible for a large amount of the total primary energy requirements.
In some categories of buildings, such as museums and galleries, the reduction of energy consumption is an important aspect that, however, cannot be separated by the strict microclimatic requirements.
In this framework, this thesis proposes a procedure which takes concurrently in account several goals in existing museums (i.e. indoor microclimate maintenance for artwork preservation, human comfort, energy efficiency, preservation of historic value of the building, robustness of the system, possibility of application on an urban scale). To pursue these targets, dynamic simulations are useful tools for the control of the suitability of current building-plant systems and for the correct choice of possible retrofit solutions. Moreover, the procedure is based on monitoring campaigns for the evaluation of current microclimate, identifying possible criticalities and verifying if there is room for improvement. Easy-to-evaluate indexes are defined, which estimate the effectiveness of the current system for the maintenance of optimal microclimate. Indexes evaluate instantaneous values, temporal and spatial differences of temperature and relative humidity.
The use of these indexes can give hints to professionals and experts in conservation on a better management of the systems. Moreover, if benchmark values are identified for these indexes, they can be useful also in the comparison of several retrofit solutions, choosing the measure that provides the best internal conditions.
In the second part of the thesis, after a preliminary analysis of the museum stock in Pisa, a case study is identified as the most representative of the stock: the museum hosted in Palazzo Blu, in Pisa. The museum houses important exhibitions and attracts several thousands of visitors every year.
First, two monitoring campaigns have been carried out in the most important halls of the museum: values of temperature and relative humidity were recorded, highlighting the appropriateness of current HVAC system in the maintenance of suitable microclimate in the rooms.
The current system has been simulated by means of a dynamic model with in-house developed routines, using TRNSYS and MatLab software. Each of the routines has been validated, finding a good agreement between simulation results and monitoring data. Then, several retrofit solutions have been simulated, verifying the improvement of both thermal human comfort, energy efficiency, and internal microclimate indexes. The proposed solutions are appropriate to solve the identified criticalities and to decrease the sensitivity of the system to critical boundary conditions: the indoor air quality remains high also in case of an increased number of visitors or more dangerous external climate.
Future developments can be the evaluation of other retrofit actions, involving also renewable energy sources, or a better management of the HVAC system, based upon the prediction of external climate and visitors' presence in the rooms.
The proposed systemic approach can be useful for multi-objective retrofit actions of existing museums: on one hand it can promote a better conservation of our cultural heritage; on the other hand it can be responsible for a major attention of the energy issue among citizens.