The preventive conservation consists in all activities that allow to mitigate the degradation of cultural heritage. Among these activities, the study of environmental conditions is crucial to assess the degradation process as well as to manage and preserve the cultural heritage. The ageing of an object and the alteration of chemical-physical properties are activated and controlled, directly and indirectly, by the microclimate and its fluctuations. Any departure from the microclimate, especially the relative humidity (RH), that has promoted the conservation of an object (historical climate) might be harmful to its future preservation. For this reason, conservation scientists focus on methodologies able to reduce, predict and prevent the degradation. Combining experimental and modelling approaches in studies of indoor climate proves to be effective (a) to diagnose key factors that determine the microclimate and (b) to predict its dynamic behaviour if boundary conditions change. However, the efficacy of the building dynamic simulation strongly depends on the accuracy of the building model, that should derive both short- and long-term fluctuations of the indoor climate variables, especially those concerning RH, which is, besides, complex to simulate due to its dependence on many factors. Consequently, the use of dynamic simulation can be effective only when the relative humidity is accurately measured, analysed and modelled. This thesis addresses a very important timely topic in the preventive conservation providing a strategy in the control and management of the indoor climate within historic buildings which house permanent collections. To achieve this purpose, the research focused on combining experimental and dynamic simulation studies. Particular attention was paid to moisture modelling as well as to the moisture-induced damage in hygroscopic materials. There were four main reasons to have prompted this research: (1) providing an objective assessment about the quality of indoor climate measurements; (2) developing a damage function specific for mechanical degradation; (3) extending the features of a commercial building dynamic simulation software with a one-dimensional heat and moisture transfer model; (4) easing the set-up of the building model using hourly climate variables instead of energy data. The issues (3) and (4) were needed for using the dynamic simulation as a diagnostic tool. The issue (2) was needed for extending the use of simulation from a diagnostic tool to a predictive tool. The methodology proposed by this research consists of three steps: (i) microclimate monitoring and its characterization for conservation risk assessment based on dose-response model; (ii) creation of a building model and its calibration; (iii) use of calibrated building and dose-response models to predict the microclimate evolution after a new strategy of microclimate control. The specific purposes were achieved using different case studies and the whole strategy (i.e. the general purpose) was successfully exploited in the case of “Archaeological Museum of Priverno”, which might be defined as the pilot case study. The combination of indoor climate measurements jointly with the dynamic simulation has demonstrated to be a powerful tool to assess a climate control solution within historic buildings. The proposed approach results to be completely non-invasive, non-destructive and with zero-costs in terms materials. Indeed, the conservative quality of the exhibition spaces after modification of the indoor climate is directly assessed in the simulation environment. In this way, outcomes can support advantageously decision-making for a better control and management of the exhibition environment.

La conservazione preventiva consiste in tutte quelle attività che consentono di mitigare il degrado dei Beni Culturali. Tra queste attività, lo studio delle condizioni ambientali è fondamentale per valutare il processo di degrado così come per gestire e tutelare il patrimonio culturale. L’invecchiamento di un oggetto e l’alterazione delle sue proprietà chimico-fisiche e strutturali sono processi innescati e regolati in modo diretto e indiretto dal microclima e dalle sue fluttuazioni. Qualsiasi allontanamento dalle condizioni ambientali, in particolar modo dall’umidità relativa (UR), che ha favorito la conservazione del manufatto fino a oggi (clima storico), potrebbe essere deleterio alla sua futura tutela. Per questo motivo, l’interesse dei conservatori scientifici è rivolto a trovare metodologie di studio che consentano di rallentare, prevedere e prevenire il degrado. La combinazione di misure sperimentali e simulazione dinamica del clima interno risulta efficace (a) a diagnosticare le cause che determinano il microclima e (B) a prevedere il suo comportamento in caso di modifiche delle condizioni a contorno. Tuttavia, l’efficacia della simulazione dinamica degli edifici dipende fortemente dall’accuratezza del modello di edificio, che dovrebbe esser in grado di derivare le fluttuazioni a medio e lungo termine, in particolar modo quelle di UR, che è complessa da simulare a causa della sua dipendenza da molti fattori. Di conseguenza, l’uso della simulazione dinamica può essere efficace solo quando l’umidità relativa è misurata, analizzata e modellata accuratamente. Questa tesi affronta un argomento molto importante nel campo della conservazione preventiva, fornendo una strategia per il controllo e la gestione del microclima all’interno di edifici storici che ospitano collezioni permanenti. Per raggiungere questo obiettivo, la ricerca si è focalizzata sull’uso combinato di studi sperimentali e di simulazione dinamica. Particolare attenzione è stata indirizzata alla modellazione dell’umidità così come ai fenomeni di degrado meccanico indotti dall’umidità nei materiali igroscopici. Esistevano quattro ragioni per condurre questa ricercar: (1) fornire una valutazione oggettiva circa la qualità delle misure microclimatiche; (2) sviluppare una funzione di danno specifica per il degrado meccanico; (3) estendere le caratteristiche di una software commerciale di simulazione dinamica degli edifici con un modello monodimensionale di trasferimento simultaneo di calore e vapore attraverso le pareti; (4) facilitare il settaggio dei parametri necessari alla costruzione del modello di edificio a partire dai dati orari di temperatura e umidità relativa. I punti (3) e (4) erano necessaria per usare la simulazione dinamica come uno strumento diagnostico. Il punto (2) era necessario per estendere l’uso della simulazione anche a strumento prognostico. La metodologia proposta da questa ricerca consiste di tre fasi: (i) monitoraggio microclimatico e sua caratterizzazione per la valutazione del rischio di degrado basata un modello dose-risposta; (ii) creazione del modello di edificio e sua taratura; (iii) uso dei modelli tarati di edificio e di degrado per prevedere l’evoluzione del microclima dopo una nuova strategia di controllo microclimatico. Gli obiettivi specifici precedentemente elencati sono stati raggiunti usando differenti casi studio, mentre l’intera metodologia è stata applicata con successo al Museo Archeologico di Priverno che potrebbe essere definito come caso studio pilota. La combinazione di misure microclimatiche insieme alla simulazione dinamica si è dimostrata uno strumento potente and flessibile per la valutazione di una soluzione di controllo microclimatico in edifici storici. L’approccio proposto risulta essere completamente non invasivo, non distruttivo e con costo-zero in termini di materiali (se si esclude il costo del monitoraggio microclimatico). Infatti, le qualità conservative degli spazi da esposizione dopo la modifica del microclima sono direttamente valutate nell’ambiente di simulazione. In questo modo, i risultati possono sostenere vantaggiosamente i processi decisionali riguardanti il controllo e la gestione dell’ambiente espositivo.

An effective strategy for preventive conservation in historic buildings coupling dynamic simulation and experimental data of indoor climate / Frasca, Francesca. - (2019 Feb 15).

An effective strategy for preventive conservation in historic buildings coupling dynamic simulation and experimental data of indoor climate

FRASCA, FRANCESCA
15/02/2019

Abstract

The preventive conservation consists in all activities that allow to mitigate the degradation of cultural heritage. Among these activities, the study of environmental conditions is crucial to assess the degradation process as well as to manage and preserve the cultural heritage. The ageing of an object and the alteration of chemical-physical properties are activated and controlled, directly and indirectly, by the microclimate and its fluctuations. Any departure from the microclimate, especially the relative humidity (RH), that has promoted the conservation of an object (historical climate) might be harmful to its future preservation. For this reason, conservation scientists focus on methodologies able to reduce, predict and prevent the degradation. Combining experimental and modelling approaches in studies of indoor climate proves to be effective (a) to diagnose key factors that determine the microclimate and (b) to predict its dynamic behaviour if boundary conditions change. However, the efficacy of the building dynamic simulation strongly depends on the accuracy of the building model, that should derive both short- and long-term fluctuations of the indoor climate variables, especially those concerning RH, which is, besides, complex to simulate due to its dependence on many factors. Consequently, the use of dynamic simulation can be effective only when the relative humidity is accurately measured, analysed and modelled. This thesis addresses a very important timely topic in the preventive conservation providing a strategy in the control and management of the indoor climate within historic buildings which house permanent collections. To achieve this purpose, the research focused on combining experimental and dynamic simulation studies. Particular attention was paid to moisture modelling as well as to the moisture-induced damage in hygroscopic materials. There were four main reasons to have prompted this research: (1) providing an objective assessment about the quality of indoor climate measurements; (2) developing a damage function specific for mechanical degradation; (3) extending the features of a commercial building dynamic simulation software with a one-dimensional heat and moisture transfer model; (4) easing the set-up of the building model using hourly climate variables instead of energy data. The issues (3) and (4) were needed for using the dynamic simulation as a diagnostic tool. The issue (2) was needed for extending the use of simulation from a diagnostic tool to a predictive tool. The methodology proposed by this research consists of three steps: (i) microclimate monitoring and its characterization for conservation risk assessment based on dose-response model; (ii) creation of a building model and its calibration; (iii) use of calibrated building and dose-response models to predict the microclimate evolution after a new strategy of microclimate control. The specific purposes were achieved using different case studies and the whole strategy (i.e. the general purpose) was successfully exploited in the case of “Archaeological Museum of Priverno”, which might be defined as the pilot case study. The combination of indoor climate measurements jointly with the dynamic simulation has demonstrated to be a powerful tool to assess a climate control solution within historic buildings. The proposed approach results to be completely non-invasive, non-destructive and with zero-costs in terms materials. Indeed, the conservative quality of the exhibition spaces after modification of the indoor climate is directly assessed in the simulation environment. In this way, outcomes can support advantageously decision-making for a better control and management of the exhibition environment.
15-feb-2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1261291
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