5,808 research outputs found
Assessment of energy and cost effectiveness in retrofitting existing buildings
No full textThe construction of buildings and their operation contribute to a large proportion of total energy end-use worldwide; indeed, buildings account for 40% of the total energy consumption and for 36% of CO2 emissions in the European Union. The sector is expanding, which is bound to increase its energy consumption. In order to reduce the growing energy expenditure, the European Directive imposes the adoption of measures to improve the energy efficiency in buildings. The recast of the Directive on the Energy Performance of Buildings defined all new buildings will be nearly zero-energy buildings by the end of 2020. However, the transformation of the EU's building stock will not be completed until well after 2020 and this target can only constitute an intermediate step. Indeed, the recent Commission Roadmap for moving towards a competitive, low-carbon economy showed that emissions in the building sector could be reduced by around 90% by 2050. While new buildings should be designed as intelligent low or zero-energy buildings, refurbishment of existing building stock has many challenges and opportunities because, in the building sector, most energy is consumed by existing buildings. Since the replacement rate of existing buildings by the new-build is only around 1-3% per annum, a rapid enhancement of taking up retrofit measures on a large scale is essential for a timely reduction in global energy use and promotion of environmental sustainability. Consequently, defining minimum energy performance requirements for new and, in particular, for existing buildings represent a key element in European building codes. For this reason, EPBD recast has set out Member States must ensure that minimum energy performance requirements are set with a view to achieve cost-optimal levels for buildings, building units and buildings elements. A cost-optimal level is defined as the energy performance level which leads to the lowest cost during the estimated economic lifecycle. It must be calculated in accordance with a comparative methodology framework that is based on the global cost method. To apply this methodology Member States are expected to define a series of Reference Buildings as baseline and representative models of the national building stock. Additionally, they must define energy efficiency measures to be applied to Reference Building; these ones can be a single measure or constitute a package of measures. Reference Buildings can be exploited as a basis for analysing national building stock and the potential impacts of energy efficiency measures in order to select effective strategies for upgrading existing buildings. Finally, once estimated the Reference Building energy consumptions and the impact of the different energy efficiency measures, the costs of the different packages are estimated in order to establish which of them has the lowest global cost and, consequently, represents the cost-optimal level. Global cost method considers the initial investment, the sum of the annual costs for every year and the final value, all with reference to the starting year of the calculation period. A measure or package of measures is cost-effective when the cost of implementation is lower than the value of the benefits that result, taken over the expected life of the measure. The cost-optimal result represents that retrofit action or combination of actions that minimized the global cost. From the variety of specific results, a cost curve can be derived; the lowest part of this curve represents the economic optimum for the specific set of the analyzed energy efficiency measures. This PhD study deals with complex scenario above described. Its main objective is to examine cost-optimal analysis in order to establish if this methodology can be an appropriate tool to guide and support decisions related with buildings energy performances. In detail, a critical review of the methodology has been developed and some sensitivity analyses have been exploited in order to testing the robustness of the cost-optimal analysis results. Considering the influence that similar outcomes could have on the European energy policies and on the roadmap towards 2050, it is fundamental to evaluate, even before the same outcomes, how these are reliable. Cost-optimality as a theoretical concept is well and clearly established. However, its application is far from easy and straightforward. Indeed, cost-optimal analysis is a complex methodology characterized by an inherent degree of uncertainty in the final outputs; choices of methodology, procedural decision and complexity of much of the input data significantly affect outcomes. In addition, the research highlights that often although a cost-optimal calculation is being developed and some energy efficiency retrofit measures are individualized, there are no effective instruments, in term of energy policies and financial tools, to drive the market to increase the rate of deep renovation
Pursuing occupants’ health and well-being in building management: Definition of new metrics based on indoor air parameters
No full textThe spread of COVID-19 has affected the lives of millions of people. Pandemic has made people more sensitive to health issues. In particular, the growing concern for the virus spread in confined spaces has promoted the necessity to improve indoor air quality. Literature is stressing how buildings must be designed and operated pursuing occupants’ health and well-being, with a particular attention for indoor air parameters. This poses the challenge of monitoring and assessing these aspects through proper metrics. In this paper the approach towards a multi-step assessment procedure embedding in buildings assessment health and well-being related variables and indicators is elaborated. They are intended to inform a building manager of the potential influence of air conditions on human health and well-being. Moreover, a set of monetary metrics (i.e., impacts) is proposed to translate energy and indoor air related building performances into euros, putting the basis for a comprehensive economic evaluation. The application of the set of proposed metrics to an Italian hotel (i.e., Italian pilot of H2020 MOBISTYLE project), enabled to map some indoor air conditions causing health concerns, and to identify clusters of guests with best and worst indoor air conditions, to be targeted by new management strategies. Despite case study specific limitations, the application exemplified how the methodology can expand the traditional energy-based performance assessment for building management towards indoor air domain and the related economic impacts, with implication on results in terms of overall economic performance of the building from both a private and public perspective
Sostenibilità: lo stato dell’arte. La certificazione di sostenibilità: i modelli di riferimento stranieri e l’adeguamento alla realtà italiana
No full textLivelli di prestazione energetica ottimali per edifici a energia quasi zero: il caso di un edificio multifamiliare
No full textIl livello di prestazione energetica ottimale in funzione dei costi (cost optimal level of energy performance) è la quantità di energia necessaria per il soddisfacimento del fabbisogno energetico dell'edificio, che richiede il costo più basso durante il ciclo di vita economico stimato dell'edificio stesso. Il concetto è stato definito dalla Direttiva Europea 2010/31/UE del 19 maggio 2010 (EPBD recast) che richiede agli Stati Membri l'applicazione di un quadro comparativo metodologico per il calcolo del livello ottimale di prestazione energetica su edifici di riferimento. Tale quadro metodologico prevede lo sviluppo, da parte di ciascuno Stato Membro, di una serie di edifici di riferimento a livello nazionale o regionale (Reference Building), da utilizzare come edifici tipo rappresentativi del patrimonio edilizio, ed ai quali applicare ipotesi di misure per il miglioramento dell'efficienza energetica per determinare i target prestazionali degli edifici ad energia quasi zero. L'obiettivo di questa ricerca è l'individuazione per un edificio residenziale esistente del livello di prestazione energetica ottimale in funzione dei costi, attraverso l'applicazione del quadro metodologico comparativo della Direttiva europea EPBD recast. L'edificio di riferimento è un edificio multifamiliare per appartamenti realmente esistente (Real Building), costruito negli anni ‘60 e selezionato dal database di archetipi del progetto europeo IEE TABULA. All'edificio sono state applicate differenti misure di efficientamento energetico, valutate a livello energetico attraverso l'uso di un software di simulazione dinamica (EnergyPlus) ed a livello economico attraverso l'applicazione del metodo del costo globale secondo la norma UNI EN 1545
Combining energy dynamic simulation and multi-criteria analysis for supporting investment decisions on smart shading devices in office buildings
No full textIn the framework of the current energy transition, the building sector is experiencing a smart revolution, recognizing how the adoption of advanced control strategies and smart management systems can increase buildings energy efficiency and improve occupants’ comfort. As a key element for smart buildings, solar shading devices coupled with effective control systems need to be strategically assessed. The investment decision-making process for selecting the proper shading systems is influenced by the existence of potential conflicts from economic, environmental, social, and energy standpoints, thus asking to be supported by innovative methodological approaches able to include all these aspects in the decisional framework. To this purpose, the work aims to propose a multi-disciplinary methodological framework to support decision-makers in ranking a set of solar shading device and relative control strategy, integrating energy dynamic simulations with multi-criteria decision analysis techniques. The analysis focuses on office buildings, recognizing their huge impact in terms of energy consumptions and the need to guarantee proper indoor conditions to increase employees’ productivity and well-being. To test the applicability of the multi-step methodology for this building category, the proposed approach is applied to an office building located in the North-West of Italy, aiming to assess and compare different alternative combinations of shadings devices and management strategies. The advanced features of building energy modelling and simulation and the application of PROMETHEE II (Preference Ranking Organization METHod for Enrichment Evaluation II) method as multi-criteria analysis allows to provide recommendations to decision-makers to identify the systems to be installed, able to guarantee the best trade-off between internal comfort, operational energy, and environmental costs for the building under investigation
Metodologie di calcolo del fabbisogno di energia annuale per la climatizzazione: risultati a confronto
No full textTowards Post-Carbon Cities: Which retrofit scenarios for hotels in Italy?
No full textThe building sector plays a crucial role in the advocated transition towards a carbon-free economy, and thus the zero-carbon building concept is taking hold. The paper focuses on the issue of existing hotels, with the aim of investigating the possibility of meeting the ambitious zero-carbon targets for this category of buildings, in which guests’ comfort and satisfaction is the core business. A reference hotel and different retrofit scenarios are assessed in two Italian climatic zones. Models are evaluated with a multiobjective approach, by introducing a set of hotel-related Key Performance Indicators (KPIs), to evaluate the simulated models on three main dimensions: thermal comfort, energy and environmental impacts.
The obtained results have emphasized the difficulty to achieve the zero-carbon targets, due to the high energy consumptions caused by the comfort-based nature of hotels and of the space constraints for onsiterenewable sources. These outcomes help highlighting the need to shift the focus from single buildingto district or city scale, proving that the zero-carbon building definition must go hand-in-hand with the Post-Carbon City concept
New evaluation metrics: the H2020 Mobistyle project contribution
No full textIn energy planning for the building sector, it is possible to identify two needs: i) considering the multiple benefits of renovation strategies in evaluation procedures; ii) educate occupants about their impacts on buildings energy consumptions to control the performance gap. In this paper the H2020 Mobistyle project contribution is underlined
Verso gli edifici zero-carbon: scenari di retrofit per un hotel in Italia (Towards zero-carbon buildings: retrofit scenarios for a reference hotel in Italy)
No full textIl settore degli edifici sta vivendo una progressiva transizione energetica verso la sua decarbonizzazione, necessaria per raggiungere l’ambizioso obiettivo di riduzione delle emissioni di gas serra del 90% entro il 2050 definito dalla Commissione Europea. Oltre al ben noto concetto di edificio ad energia quasi zero, si sta diffondendo quello di edificio zero-carbon, che via via sta interessando tutte le tipologie edilizie, tra cui gli hotel, oggetto della ricerca. Con l’obiettivo di valutare la possibilità di raggiungere gli obiettivi zero-carbon per questa categoria, il cui impatto energetico-ambientale è significativo, un hotel di riferimento e diversi scenari di retrofit sono stati simulati tramite il software EnergyPlus, in due località italiane, Milano e Bari. Il lavoro, proponendo i risultati nella forma di indicatori energetici e ambientali, ha messo in luce le difficoltà incontrate nel raggiungere gli obiettivi zero-carbon per gli hotel
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