The whole life cycle emission of a building does not only comprise the emissions related to its use phase, but also the embodied carbon comprised along its whole life cycle, from the extraction of raw materials for manufacture of each product to its construction, component replacements, and demolition. The constant growth of the world population and of the construction sector indicate the high relevance of the reducing anthropogenic emissions immediately. The improvement in the environmental performance of a design is a process that is highly dependent on the integration between the professionals involved. Scientific literature has mainly dealt with the optimization of the operational energy of buildings, however, improvements related to the reduction of the embodied emissions are still limited. This thesis presents an overview of the current practice for LCA of building skin related subjects and the limitations found concerning the professionals involved and product availability in the market with a further study in a materiality level, comparing products within the same functionality group as well as the GWP of different ones with similar characteristics. The study then presents an iterative approach of design and carbon footprint reduction applied to the envelope skin of Innovation HUB, a mixed-use building in the MIND district in Milan, Italy. The study is performed in two levels, with a detailed quantification in basis to executive drawings and further modifications. The first level is related to each of the façade typologies applied to the building and their respective impact per square meter, calculating the reduction achieved by either choosing low carbon products or opting for different design alternatives; the second level analyses the application of chosen typologies to the overall building skin, approaching the building carbon footprint reached and performance of the envelope in relation to environmental targets. In this process, the same building skin strategies are compared with both average GWP materials and low carbon ones, and the original design of the building is adapted to a fully glazed one. The main question of this thesis is “how much do design choices impact on a building skin’s embodied carbon and how much are we able to reduce it?” The study demonstrates the possible reduction in GWP associated with the use of low carbon materials applied to the case study and further reductions in basis to a change in modularity and materiality of two different façade typologies: a glazed and a partially opaque one. Within façade typologies, a glazed façade module, with WWR 0.85 was studied and presented a reduction of 25% in its module embodied carbon due to the use of low carbon products instead. The same study, applied to a module with aluminum fins and WWR 0.43, led to a reduction of 21% in the embodied carbon over the whole life cycle. By a change in cladding materiality, such reduction reached 28,4%. Results demonstrate that the use of low carbon products and high recycled content can lead to the reduction of the GWP of the overall building skin of the case study project 24% or more, in comparison to average impact materials, whereas considering further improvements such as substitution of curtain wall profile and change in cladding material, the reduction can be even higher, reaching 28%. By simulating the building design as a fully glazed one with DGUs, the reduction achieved considering low carbon materials was of 22%. The work is concluded demonstrating that as primary structural elements present consistent alternatives for Embodied Carbon reduction, the façade percentage of contribution gets each time higher in relation to the overall building when carbon sequestration is considered, indicating that there is a higher need of integration between sustainability consultants, façade engineers and architects.
L'emissione dell'intero ciclo di vita di un edificio non comprende il solo carbonio relativo alla sua fase di utilizzo, ma anche il carbonio incorporato compreso lungo tutto il suo ciclo di vita, dall'estrazione delle materie prime per la fabbricazione di ciascun prodotto, alla costruzione dell’edificio, sostituzioni di componenti e, alla fine, la sua demolizione. La costante crescita della popolazione mondiale e del settore delle costruzioni indica l'elevata rilevanza della riduzione immediata delle emissioni antropiche. Il miglioramento delle prestazioni ambientali di un progetto è un processo fortemente dipendente dall'integrazione tra i professionisti coinvolti. La letteratura scientifica si è occupata principalmente dell'ottimizzazione dell'energia operativa degli edifici; tuttavia, i miglioramenti legati alla riduzione delle emissioni incorporate sono ancora limitati. Questa tesi presenta una panoramica dello stato dell’arte per il LCA di costruzione di soggetti correlati all’involucro, le limitazioni riscontrate riguardo ai professionisti coinvolti e alla disponibilità dei prodotti sul mercato e un ulteriore studio a livello di materialità che confronta i prodotti all'interno dello stesso gruppo di funzionalità e il GWP di diverse alternative con caratteristiche visuali simili. Lo studio presenta quindi un approccio iterativo di progettazione e riduzione dell'impronta di carbonio applicato all'involucro dell'Innovation HUB, un edificio a uso misto nel distretto MIND di Milano, in Italia. Lo studio si svolge su due livelli, con una quantificazione dettagliata in base a disegni esecutivi e ulteriori modifiche. Il primo livello è relativo a ciascuna delle tipologie di facciata applicate all'edificio e al rispettivo impatto per metro quadrato, calcolando la riduzione ottenuta sia scegliendo prodotti low carbon sia optando per diverse alternative progettuali; il secondo livello analizza l'applicazione delle tipologie scelte all’involucro complessivo dell'edificio, avvicinandosi all'impronta di carbonio dell'edificio raggiunta e alle prestazioni dell'involucro in relazione agli obiettivi ambientali. In questo processo, le stesse strategie di rivestimento dell'edificio vengono confrontate sia con i materiali con GWP medio che con quelli a basse emissioni di carbonio e il design originale dell'edificio viene adattato a uno completamente vetrato. La domanda principale di questa tesi è "quanto incidono le scelte progettuali sul carbonio incorporato nell’involucro di un edificio e quanto siamo in grado di ridurlo?" Lo studio dimostra la possibile riduzione del GWP associato all'uso di materiali a basse emissioni di carbonio applicato al caso di studio e ulteriori riduzioni in base a un cambiamento di modularità e materialità di due diverse tipologie di facciata: una vetrata e una parzialmente opaca. All'interno delle tipologie di facciata, è stata studiata una facciata vetrata con WWR 0.85 che ha presentato una riduzione del 25% nel carbonio incorporato del modulo a causa del cambiamento per alternative a basse emissioni. Lo stesso studio, applicato a un modulo con pinne in alluminio e WWR 0.43, ha portato a una riduzione del 21% del carbonio incorporato nell'intero ciclo di vita. Al variare della materialità del rivestimento, tale riduzione ha raggiunto il 28,4%. I risultati dimostrano che l'uso di prodotti a basse emissioni di carbonio e ad alto contenuto riciclato può portare alla riduzione del carbonio incorporato dell'involucro edilizio complessivo del progetto di studio del caso del 24% o più, rispetto ai materiali a impatto medio, considerando ulteriori miglioramenti come la sostituzione del profilo della facciata continua e del cambio del materiale di rivestimento, la riduzione può essere anche maggiore, raggiungendo il 28%. Simulando il progetto dell'edificio come un edificio completamente vetrato con DGU, la riduzione ottenuta considerando i materiali a basse emissioni di carbonio è stata del 22%. Il lavoro si conclude dimostrando che poiché gli elementi strutturali primari presentano alternative coerenti per la riduzione del carbonio incorporato, la percentuale di contributo della facciata aumenta ogni volta rispetto all'edificio complessivo quando si considera il sequestro del carbonio, indicando una maggiore necessità di integrazione tra consulenti di sostenibilità, ingegneri di facciata e architetti.
Low embodied carbon pathways in façade design : a case study
Cassol Pasqualotto, LuÃsa
2021/2022
Abstract
The whole life cycle emission of a building does not only comprise the emissions related to its use phase, but also the embodied carbon comprised along its whole life cycle, from the extraction of raw materials for manufacture of each product to its construction, component replacements, and demolition. The constant growth of the world population and of the construction sector indicate the high relevance of the reducing anthropogenic emissions immediately. The improvement in the environmental performance of a design is a process that is highly dependent on the integration between the professionals involved. Scientific literature has mainly dealt with the optimization of the operational energy of buildings, however, improvements related to the reduction of the embodied emissions are still limited. This thesis presents an overview of the current practice for LCA of building skin related subjects and the limitations found concerning the professionals involved and product availability in the market with a further study in a materiality level, comparing products within the same functionality group as well as the GWP of different ones with similar characteristics. The study then presents an iterative approach of design and carbon footprint reduction applied to the envelope skin of Innovation HUB, a mixed-use building in the MIND district in Milan, Italy. The study is performed in two levels, with a detailed quantification in basis to executive drawings and further modifications. The first level is related to each of the façade typologies applied to the building and their respective impact per square meter, calculating the reduction achieved by either choosing low carbon products or opting for different design alternatives; the second level analyses the application of chosen typologies to the overall building skin, approaching the building carbon footprint reached and performance of the envelope in relation to environmental targets. In this process, the same building skin strategies are compared with both average GWP materials and low carbon ones, and the original design of the building is adapted to a fully glazed one. The main question of this thesis is “how much do design choices impact on a building skin’s embodied carbon and how much are we able to reduce it?” The study demonstrates the possible reduction in GWP associated with the use of low carbon materials applied to the case study and further reductions in basis to a change in modularity and materiality of two different façade typologies: a glazed and a partially opaque one. Within façade typologies, a glazed façade module, with WWR 0.85 was studied and presented a reduction of 25% in its module embodied carbon due to the use of low carbon products instead. The same study, applied to a module with aluminum fins and WWR 0.43, led to a reduction of 21% in the embodied carbon over the whole life cycle. By a change in cladding materiality, such reduction reached 28,4%. Results demonstrate that the use of low carbon products and high recycled content can lead to the reduction of the GWP of the overall building skin of the case study project 24% or more, in comparison to average impact materials, whereas considering further improvements such as substitution of curtain wall profile and change in cladding material, the reduction can be even higher, reaching 28%. By simulating the building design as a fully glazed one with DGUs, the reduction achieved considering low carbon materials was of 22%. The work is concluded demonstrating that as primary structural elements present consistent alternatives for Embodied Carbon reduction, the façade percentage of contribution gets each time higher in relation to the overall building when carbon sequestration is considered, indicating that there is a higher need of integration between sustainability consultants, façade engineers and architects.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/192574