On an innovative approach for microclimate enhancement and retrofit of historic buildings and artworks preservation by means of innovative thin envelope materials

Abstract

Energy efficiency and environmental sustainability in building has become a key issue since the built environment is nowadays responsible for more than 30% of the total carbon emissions. While new building design and construction reached massive improvements toward net zero energy and high environmental performance standards, existing and historical buildings are still too much energy needy, with a relatively low indoor comfort conditions for both occupants and artworks preserved inside, especially within heritage buildings. Such high architectural value buildings correspond to almost one third of the Italian building stock and they typically need to be re-functionalized for hosting residential, office, or institutional uses, i.e. museums and exhibition areas. In this view, the present research aims at developing a replicable method for assessing and enhancing indoor comfort in historical buildings frequently characterized by too high relative humidity and thermal losses through the envelope. More in details, an innovative envelope material for indoor application, i.e. hygro-adsorbing plaster, has been tested in an ancient Italian castle and its effect has been assessed by means of coupled monitoring and calibrated dynamic simulation. The experimental campaign shows an increase of the Performance Index (PI) in terms of relative humidity acceptable range from 16.1 to 33.3% by applying the new thin plaster. Moreover, the results show that dedicated HVAC systems may support the action of passive strategies for preserving artworks and indoor comfort levels, but at the same time, such passive low-invasive strategies represent a mandatory first step toward energy efficiency, functional, and comfortable cultural heritage architectures. ; Prof. Luisa F. Cabeza would like to acknowledge the Spanish Government for the funding PRX17/00221 that allowed her to visit University of Perugia during 6 months. Prof. Cabeza would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The corresponding author acknowledgements are due to the 'CIRIAF program for UNESCO' in the framework of the UNESCO Chair 'Water Resources Management and Culture', for supporting her research. Also, University of Perugia acknowledgements are due to Centro Edile per la Sicurezza e la Formazione–Perugia (in particular to Dr. Cristiana Bartolucci and Dr. Laura Galli), which provided the case study and supported the project COLO ARTE, also financed by Fondazione Cassa di Risparmio di Perugia ("COLO ARTE - COnservazione e vaLOrizzazione degli edifici storici e delle opere d'ARTE" 2016.0276.021).