Modeling and Measurements in Natural Ventilation of Massive Buildings: A Case Study

Numerical simulations are widely used to evaluatethe thermal comfort and energy savings in the retrofitof historic buildings. In most cases, however,no detailed data are available on the materials andstratigraphy of the building envelopes, and on-sitemeasurements can be expensive and time consuming.The present work uses as a case study a universitybuilding characterized by a high thermal capacityin the city of Rome to verify whether the use ofnatural ventilation can be a practice of use in orderto guarantee energy saving and natural comfort.To this end, in the summer of 2020, an experimentalcampaign was carried out aimed at acquiringthermofluximetric measurements through thevertical walls, the air temperature inside and outsidethe analyzed environment and the air velocity.Measurements were conducted under three differentusage protocols, including night ventilationand 24-hour continuous ventilation.These measurements made it possible to identifythe thermophysical characteristics of a wall considered"equivalent" to the real wall, allowing the realizationof thermofluidodynamic computationalmodels. In particular, in the study, 3 different stratigraphieswere considered and compared, correspondingin the first case to the equivalent wall, inthe second to that available from the Comsol softwarelibrary, and, finally, in the third and last case,from literature data (Tabula project) for the buildingtypology analyzed.From the analysis, it emerged that the 3 groups ofparameters do not have a significant impact interms of variation of internal comfort, confirmingthe reliability of the use of the literature values forthese types of modeling.