To achieve the national Italian target of cutting by 43% the primary energy consumption and by 39,7% the final energy consumption by 2030 compared to the PRIMES scenario of 2007, it is necessary to take measures to reduce drastically the energy consumption of the building sector. The municipality of Milan is the second most densely populated city of Italy and counts 42980 residential buildings. A bottom-up approach method to assess the current thermal needs of the residential buildings of Milan and the thermal needs after hypothetical retrofit scenarios has been developed in this thesis. The aim of such a bottom-up approach is to be applicable for any detailed scenario of refurbishment. The thermal needs have been approximated as the thermal losses by heat transfer through the building envelope components: the opaque external walls, the windows, the roof, and the external ground floor. The building stock is characterised geometrically, and in terms of thermal performances, in function of the age and the typology of the buildings. Data sets are collected from three main open databases: ISTAT, Geoportale and Cened. The method is first developed and assessed for computing the current thermal needs of the housing stock. For the municipality of Milan, the residential buildings current thermal needs are estimated at 6805 GWh per year. Different retrofit scenarios are defined on the envelope components. The refurbishment hypotheses are applied to estimate the thermal needs post-retrofit focusing on the buildings built between 1961 and 1990 as they are the most likely to be subject to renovation. By comparing the current thermal needs and the ones after refurbishment, it is possible to evaluate the potential energy savings thanks to retrofit actions. A total refurbishment of the envelope components of all the buildings from the construction period 1961-1990 can theoretically save 2314 GWh per year, being 34% of the current thermal needs of the housing stock of Milan. Assessing the potential energy savings thanks to various retrofit scenarios helps policymakers and private owners to take effective measures to encourage investments in buildings renovation.
Per raggiungere l'obiettivo nazionale italiano di ridurre del 43% i consumi di energia primaria e del 39,7% i consumi di energia finale al 2030 rispetto allo scenario di riferimento PRIMES 2007, è necessario adottare misure per ridurre i consumi energetici degli edifici. Il comune di Milano è la seconda città più popolosa d’Italia e conta 42980 edifici residenziali. In questa tesi è stato sviluppato un approccio bottom-up per valutare l’attuale fabbisogno termico degli edifici residenziali di Milano e il fabbisogno termico a seguito di ipotetici scenari di riqualificazione. Lo scopo di un approcio bottom-up è di essere applicabile qualsiasi scenario di restauro dettagliato. I fabbisogni termici sono stati valutati come perdite termiche per trasmissione del calore attraverso i componenti dell’involucro dell’edificio: involucro opaco, serramento, copertura e soletta contro terra. Il parco edilizio è stato dapprima caratterizzato geometricamente, e in seguito in termini di prestazione termica, determinata principalmente sulla base dell’età e della tipologia degli edifici. I dati sono raccolti da tre principali database pubblici: ISTAT, Geoportale e Cened. In primo luogo, il fabbisogno termico attuale del parco edilizio per il comune di Milano è stimato in 6805 GWh per anno. Diversi scenari di riqualificazione sono definiti sui componenti dell’involucro. Le ipotesi di ristrutturazione sono applicate per stimare il fabbisogno termico dopo la riqualificazione, focalizzandosi sugli edifici costruiti tra 1961 e 1990, più promettenti per un retrofit energetico. Confrontando i fabbisogni termici attuali e quelli dopo la riqualificazione, è possibile valutare il potenziale di risparmio energetico grazie alla riqualificazione. Una ristrutturazione totale dei componenti dell’involucro di tutti gli edifici costruiti nel periodo 1961-1990 potrebbe portare in teoria al risparmio dei 2314 GWh per anno, cioè il 34% del fabbisogno termico attuale del parco edilizio milanese. Stimare i fabbisogni termici grazie a vari scenari di riqualificazione aiuta i decisori politici a prendere misure efficaci per incoraggiare gli investimenti per la riqualificazione degli edifici.
Exploring the building stock in Milan : estimation of the thermal losses and of potential energy savings of retrofit scenarios
OBRECHT, LÉNA CHARLOTTE MARIE
2020/2021
Abstract
To achieve the national Italian target of cutting by 43% the primary energy consumption and by 39,7% the final energy consumption by 2030 compared to the PRIMES scenario of 2007, it is necessary to take measures to reduce drastically the energy consumption of the building sector. The municipality of Milan is the second most densely populated city of Italy and counts 42980 residential buildings. A bottom-up approach method to assess the current thermal needs of the residential buildings of Milan and the thermal needs after hypothetical retrofit scenarios has been developed in this thesis. The aim of such a bottom-up approach is to be applicable for any detailed scenario of refurbishment. The thermal needs have been approximated as the thermal losses by heat transfer through the building envelope components: the opaque external walls, the windows, the roof, and the external ground floor. The building stock is characterised geometrically, and in terms of thermal performances, in function of the age and the typology of the buildings. Data sets are collected from three main open databases: ISTAT, Geoportale and Cened. The method is first developed and assessed for computing the current thermal needs of the housing stock. For the municipality of Milan, the residential buildings current thermal needs are estimated at 6805 GWh per year. Different retrofit scenarios are defined on the envelope components. The refurbishment hypotheses are applied to estimate the thermal needs post-retrofit focusing on the buildings built between 1961 and 1990 as they are the most likely to be subject to renovation. By comparing the current thermal needs and the ones after refurbishment, it is possible to evaluate the potential energy savings thanks to retrofit actions. A total refurbishment of the envelope components of all the buildings from the construction period 1961-1990 can theoretically save 2314 GWh per year, being 34% of the current thermal needs of the housing stock of Milan. Assessing the potential energy savings thanks to various retrofit scenarios helps policymakers and private owners to take effective measures to encourage investments in buildings renovation.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/177624