Evaluating retrofit options in a historical city center: Relevance of bio-based insulation and the need to consider complex urban form in decision-making

Abstract

Historical dwellings make up a significant fraction of the French building stock and require substantial retrofitting to reduce their energy consumption and improve their thermal comfort. In the city center of Cahors, France, the old medieval dwellings are considered as valuable cultural heritage and internal insulation is often the only insulation technique that can be used when the architectural value of the exterior façade is to be preserved. However, internal insulation may have an impact upon the hygrothermal performance of the wall, leading to lowered drying capacity, with possible interstitial condensation and mold growth. Hygrothermal models may be used to assess the risk of failure, but the accuracy of the results depends on how reliable the input data is, including external boundary conditions, which may vary significantly in dense medieval cities such as Cahors. In this study, a Geographical Information System model of Cahors is used to develop EnergyPlus models of individual dwellings. The boundary conditions output by these models are, in turn, used to model the hygrothermal performance of façades with different internal insulations, using the hygrothermal tool Delphin. The Delphin outputs are then analyzed with the VTT model, a mold growth assessment model. Results highlight a quantitative correlation between some urban morphology characteristics and the hygrothermal performance of refurbished walls, with some configurations raising the risk of damage patterns. We find that bio-based insulation presents a better hygrothermal performance than mineral wool in most of the configurations.

From Smelly Buildings to the Scented Past: An Overview of Olfactory Heritage

“…A systems approach has been applied to study various aspects of cultural heritage, including decision-making concerning historic buildings (Claude et al, 2019) and heritage values and conservation (Fouseki et al, 2020). The study of smells as part of cultural heritage can be related to the "sensory turn" in the humanities in the 1980s and 1990s, which involves "a cultural approach to the study of the senses and a sensory approach to the study of culture" (Howes, 2013).…”

A Discussion on Winter Indoor Hygrothermal Conditions and Hygroscopic Behaviour of Plasters in Southern Europe

“…Nonetheless, modelling hygroscopic materials requires some simplifications, in particular concerning their sorption isotherm. Building materials can show a residual moisture content at the end of desorption, due to the effect of capillary forces which make the uptake of water molecules in the porous network easier than their removal [56]. This behaviour is also known as moisture hysteresis [57].…”

Energy Retrofitting Opportunities Using Renewable Materials—Comparative Analysis of the Current Frameworks in Bosnia-Herzegovina and Slovenia

“…In contrast, the bottom-up approach extrapolates the estimated energy consumption of a representative set of individual houses to regional and national levels [62]. However, as pointed out by Claude et al, building in a very dense area should not be treated in the same way as a stand-alone building, especially in terms of thermal radiation [63].…”