CFD modeling and moisture dynamics implications of ventilation scenarios in historical buildings

The importance of historical buildings preservation is constantly increasing due to damage concerns to cultural property. In these buildings, conservation should be a priority in the evaluation of indoor conditions. If adequate, a natural microclimate, to which artworks have been adapted over centuries, should be maintained to avoid sudden microclimatic changes and take into account the main features of the site. A three dimensional (3D) computational fluid dynamics (CFD) model. has been developed to investigate the adequacy of natural ventilation in a historical building located in the South of Italy. The model was validated with experimental data to analyze the microclimatic conditions obtained inside the building by five ventilation scenarios and twenty computational models. The aim of the study was to find a solution able to provide a proper microclimate for the conservation of the building. The influence of wind direction was considered in opposite seasonal conditions, and the microclimatic variations caused by the walling over of two windows with bricks, were verified. The scenario providing the most stability in time and uniformity in space microclimate was checked by the simulations considering the compatibility with the safety range of the materials. Simulation outputs were then used to model physical quantities linked to moisture dynamics and salt crystallization (i.e. evaporation rates, height of rise, water stored, and water flow). The model determined a great variability of the thermo-hygrometric parameters among the tested ventilation solutions and allowed to establish how to improve the indoor microclimate in the building.