Hygrothermal performance of historic massive wall: when is 2D simulation necessary?

Hygrothermal analysis of historical building envelopes is crucial in ensuring their durability and enhancing their performances. The use of hygrothermal dynamic simulation is the most effective approach to predict moisture related damages or risk of mould growth on ancient masonry envelopes. However, simulating the hygrothermal behaviour of a historic wall composed by stones or bricks and mortar joints, with a detailed two-dimensional (2D) model, is typically a complex and time-consuming process. For this reason, in numerical models, composite walls are often simplified with a one-dimensional (1D) layer, neglecting the mortar joints. An oversimplified numerical model could affect the evaluation of a retrofit intervention and lead to inadequate design choices. This study evaluates when the description of a historic wall as a 1D homogenous layer leads to an acceptable level of accuracy and when it is necessary the use of a more precise 2D model. We quantified the error by comparing 1D and 2D simulations of different massive walls in three Italian climate conditions. We examined a possible retrofit intervention with different internal insulation systems considering vapor tight, vapor retardant and capillary active solutions. Although simplified 1D models are reliable for thermal parameters, we have identified a different behavior regarding the hygric parameters. Whereas for a capillary active insulation system the 1D and 2D simulations show a reasonable agreement, the 1D approximation is no longer acceptable in the case of vapour closed insulation systems as it leads to large deviations. Knowing when it is possible to implement a simplified 1D model and quantifying the introduced error will support architects and energy consultants in the design process. It will guide them in the choice of the most suitable model depending on their specific requirements

Applied Research of the Hygrothermal Behaviour of an Internally Insulated Historic Wall without Vapour Barrier: In Situ Measurements and Dynamic Simulations

The hygrothermal behaviour of an internally insulated historic wall is still hard to predict, mainly because the physical characteristics of the materials composing the historic wall are unknown. In this study, the hygrothermal assessment of an internally thermal insulated masonry wall of an historic palace located in Ferrara, in Italy, is shown. In situ non-destructive monitoring method is combined with a hygrothermal simulation tool, aiming to better analyse and discuss future refurbishment scenarios. In this context, the original U-value of the wall (not refurbished) is decreased from 1.44 W/m2K to 0.26 W/m2K (10 cm stone wool). Under the site specific conditions of this wall, not reached by the sun or rain, it was verified that even in the absence of vapour barrier, no frost damage is likely to occur and the condensation risk is very limited. Authors proposed further discussion based on simulation. The results showed that the introduction of a second gypsum board to the studied technology compensated such absence, while the reduction of the insulation material thickness provides a reduction of RH peaks in the interstitial area by 1%; this second solution proved to be more efficient, providing a 3% RH reduction and the avoidance of further thermal losses

Applied Research of the Hygrothermal Behaviour of an Internally Insulated Historic Wall without Vapour Barrier: In Situ Measurements and Dynamic Simulations

The hygrothermal behaviour of an internally insulated historic wall is still hard to predict, mainly because the physical characteristics of the materials composing the historic wall are unknown. In this study, the hygrothermal assessment of an internally thermal insulated masonry wall of an historic palace located in Ferrara, in Italy, is shown. In situ non-destructive monitoring method is combined with a hygrothermal simulation tool, aiming to better analyse and discuss future refurbishment scenarios. In this context, the original U-value of the wall (not refurbished) is decreased from 1.44 W/m2K to 0.26 W/m2K (10 cm stone wool). Under the site specific conditions of this wall, not reached by the sun or rain, it was verified that even in the absence of vapour barrier, no frost damage is likely to occur and the condensation risk is very limited. Authors proposed further discussion based on simulation. The results showed that the introduction of a second gypsum board to the studied technology compensated such absence, while the reduction of the insulation material thickness provides a reduction of RH peaks in the interstitial area by 1%; this second solution proved to be more efficient, providing a 3% RH reduction and the avoidance of further thermal losses

An Energy Self-Sufficient Alpine Hut: The Refurbishment of an Ex-Tobacco Farm Using Building Integrated Photovoltaics

The abandonment and deterioration of historic rural buildings in Europe raise significant issues, including hydrogeological risks, the loss of productive land, and cultural heritage decline. Despite being underestimated, these structures hold significant potential for cultural and productive activities. Renovating these structures is crucial for local communities committed to preserving their heritage, and it is a more sustainable approach than constructing new buildings. This study explores activities undertaken in the Interreg IT/AT project “SHELTER” in Valbrenta (IT): through a participatory approach involving communities, stakeholders, designers, and researchers, an energy concept is developed for refurbishing an abandoned tobacco farm, chosen by the community, to be an alpine hut. Due to the inability to connect to the city electricity grid, the new energy concept focuses on minimizing consumption through envelope refurbishment, efficient heating, and domestic hot water systems. Additionally, the integration of renewable energy sources, particularly Building Integrated Photovoltaics (BIPV), is emphasized to preserve the building’s original appearance. This study demonstrates the feasibility of meeting seasonal energy needs entirely through renewables and explores the potential integration of biomass for meeting annual energy requirements

Application of the Guidelines for the Integration of Photovoltaics in Historic Buildings and Landscapes to Evaluate the Best Practices of the Historic Building Energy Retrofit Atlas

The challenge of transforming historic buildings and city centers into energy-self-sufficient environments requires innovative solutions. The research project “BiPV meets History” addressed this challenge by providing comprehensive guidelines for assessing the integration of photovoltaic (PV) systems in protected historic architectural contexts. To validate these guidelines, this study conducts a thorough examination of best practices through the mentioned guidelines, developing an application tool. Recognizing the power of well-communicated best practices in overcoming obstacles to integrated photovoltaic adoption, this tool is used to assess PV integration quality with respect to the best practice contained in the HiBERatlas database. The analysis of 17 successful refurbishment cases highlighted the robustness and reliability of the proposed methodology, considering aesthetic, technical, and energy aspects. This study emphasizes the potential of the guidelines for achieving a harmonious integration of renewable energy solutions with historic architectural heritage and landscape and improving usability through the developed tool