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  • Unraveling the implementation processes of PEDs: Lesson learned from multiple urban contexts
    Publication . Gohari, Savis; Silvia, Soutullo Castro; Ashrafian, Touraj; Konstantinou, Thaleia; Giancola, E.; Prebreza, Bahri; Aelenei, Laura Elena; Murauskaite, Lina; Liu, Mingming
    ABSTRACT: The implementation of Positive Energy Districts (PEDs) is recognized as a promising approach to achieving energy efficiency and reducing the negative environmental impact of climate change through the surplus of local renewable energy generation. However, several barriers to the implementation of PEDs, coupled with the lack of a joint definition and clarity surrounding PEDs, need to be addressed. These barriers include governance, incentives, social, process, market, technology, and context challenges, requiring a profound understanding of the priorities, ambitions, strategies, contextual conditions, administrative conditions, policies, economic and technical resources, and existing solutions of cities. This study explores the creation and implementation of PEDs, seeking to uncover the potential and challenges of this innovative concept in the pursuit of climate neutrality and energy efficiency. Through a peer-to-peer analysis of PED case studies and qualitative interviews with key stakeholders in Brussels, Stockholm, Vienna, Evora, Lisbon, and Salzburg, challenges such as the lack of clarity in the definition of PEDs, diversity of ownership, administrative complexity, resistance to change, limited knowledge exchange, financing constraints, technological limitations, and inadequate involvement of relevant actors are identified. Moreover, success factors and enabling strategies from these case studies are highlighted, including clear roadmaps, stakeholder collaboration, integrated decision-making processes, political commitment, and coordination platforms.
  • Improving the Energy Performance of Public Buildings in the Mediterranean Climate via a Decision Support Tool
    Publication . Gouveia, João Pedro; Aelenei, Laura Elena; Aelenei, Daniel; Ourives, Raquel; Bessa, Salomé
    ABSTRACT: Addressing Europe's decarbonisation challenge involves widespread deployment of nearly zero-energy buildings, deep energy renovations and renewable energy integration in the building sector. Enhancing energy efficiency in public buildings necessitates tailored solutions and strategic planning involving Local Public Administration. This work focuses on advancing insights into the application of the PrioritEE Decision Support Tool in Portuguese public buildings, highlighting the energy and financial savings and carbon dioxide emission reduction potential. Using detailed building characterisation data from energy performance certificates, we applied the tool across 22 public buildings of diverse typologies in three distinct regions of Portugal, representing various public entities. Results demonstrate the tool's adaptability, enabling a comprehensive assessment of energy performance and facilitating the exploration of customised energy efficiency and renewable energy solutions. The research emphasises the critical role of user-friendly tools in aiding policymakers and local administration technicians in meeting national renovation targets and contributing to the broader energy transition objectives.
  • Triggering Deep Renovation of Buildings in Portugal
    Publication . Aelenei, Daniel; Aelenei, Laura Elena
    ABSTRACT: EU and national buildings related regulations are moving towards policies that improve indoor thermal comfort, reduce energy consumption and its environmental impact by establishing very ambitious targets in the emissions reduction in the decades to come. In this context, improving energy efficiency through deep energy renovations is a key action line because of its potential to meet long-term climate and energy targets. However, deep renovations need to become more environmentally friendly, more reliable in terms of performance and more attractive to all concerned stakeholders, in addition of enabling the implementation of the Near Zero -Energy Building (nZEB) assumed by the Energy Performance of Building Directive in 2010. This paper highlights the key aspects related to the strategic pillars of deep renovation and explore ongoing related funding schemes to meet Portugal's carbon neutrality and related sustainability goals.
  • Enhancing Market Readiness for nZEB Implementation
    Publication . Aelenei, Laura Elena; Croitoru, C.; Korczak, K.; Petran, H.; O'Rourke-Potocki, H.; Tzanev, D.; Goncalves, Helder; Duarte, Ana Paula; Trindade, Paula; Loureiro, David
    ABSTRACT: Despite transposing the 2010/31/EU Directive's requirements creates legal responsibilities at the national level, the nearly Zero energy building (nZEB) principle does not appear to be widely adopted just yet in many nations. Previous studies have shown that the most significant barriers include determining the cost-effective ideal integration of the technologies appropriate for nZEB and the skills constraints faced by the construction industry. In order to meet the challenge of an efficient nZEB implementation, existing certification courses and training programs are still insufficient and inadequate, and hiring experienced specialists for building retrofit and new construction is not common practice. The traditionally conservative real estate industry is nevertheless hesitant to adopt the new building standards and practices, notably in the residential sector, despite a significant movement towards nZEB and extensive energy renovation. In this specific situation, this paper provides a preliminary analysis of the European project nZEB Ready Enhancing Market Readiness for nZEB Implementation, which aims to address the issue of the effective implementation of the nZEB and make use of new possibilities to act at the market level in order to boost the market's readiness for a successful implementation of the nZEB and to encourage demand for energy-related skills among construction workers and specialists in the countries involved and beyond.
  • Ten questions concerning positive energy districts
    Publication . Sareen, Siddharth; Albert-Seifried, Vicky; Aelenei, Laura Elena; Reda, Francesco; Etminan, Ghazal; Andreucci, Maria-Beatrice; Kuzmic, Michal; Maas, Nienke; Seco, Oscar; Civiero, Paolo; Gohari, Savis; Hukkalainen, Mari; Neumann, Hans-Martin
    ABSTRACT: Positive Energy Districts (PEDs) constitute an emerging energy transition paradigm, with an ambitious timeline for rapid upscaling to match the urgency of climate mitigation and adaptation. Increasingly networked and coordinated actors aim to realise 100 PEDs across Europe by 2025. This resonates with the mission orientation turn of the European Green New Deal, to inspire and enable target-driven innovation. Yet it raises questions that have long perplexed scholars and practitioners in energy transitions: how can rapid diffusion be achieved in a sustained and replicable manner in diverse socio-technical contexts? Identifying the key questions to address and implement fit-to-purpose solutions within short-term project timescales is essential in order to mainstream PEDs. Such solutionism must be accompanied by a healthy dose of scepticism, in order to avoid undesirable outcomes such as exacerbated inequalities, societal backlash, and spatial displacement of invisible burdens. But it also requires proactive sharing of experiences, responsive learning and dissemination, and cooperation across sectors and disciplines. In this timely contribution, thirteen researchers from nine European countries flag ten questions concerning PEDs, and offer preliminary responses in line with cutting-edge insights informed by science and practice. This contribution draws on multidisciplinary competence in steering the Positive Energy Districts Eu-ropean Network, and aims to make emerging knowledge widely available, while also inviting constructive critique and engagement within the PED arena which features a broad range of diverse stakeholders. Authors highlight key pathways forward for a rapid, far-reaching translation of the ambitious PEDs agenda into multi-sited, district-scale beacons of sustainable energy transition.
  • Retrofit measures evaluation considering thermal comfort using building energy simulation: two Lisbon households
    Publication . Gomes, Ricardo; Ferreira, Ana R.; Azevedo, Luís; Neto, Rui C.; Aelenei, Laura Elena; Silva, Carlos
    ABSTRACT: Retrofit measures for buildings are in general evaluated considering the energy savings and life cycle cost. However, one of the main benefits, the increase of users comfort is very seldom analysed. In this work, two residential households representative of a large share of households in Portugal, were monitored and its thermal behavior was modeled using Energy Plus. The thermal evaluation of the pre-retrofit households shows that the winter season is problematic due to construction solutions and low availability for heating. The retrofit measures analysis was performed considering different retrofit solutions regarding envelope improvement and efficient systems implementation. In order to work around the question of comparing households that do not use energy for acclimatization and therefore have very low energy consumption, in the retrofit scenarios it was considered the thermal comfort evaluation value for the real case (pre-retrofit) and compared the energy consumption to achieve that same average comfort level (in this case avoiding high discomfort peaks). The measures that more rapidly pay the investment are those related with implementing active systems. The approach used in this paper, should be used in more calibrated models in order to have overall conclusions about the retrofit process at a larger scale.
  • Thermal behavior of a BIPV combined with water storage: an experimental analysis
    Publication . Lourenço, José Marco; Aelenei, Laura Elena; Sousa, Miguel; Facão, Jorge; Goncalves, Helder
    ABSTRACT: Buildings play an active role in the global energy consumption and are required to not only minimize their energy use, but also generate energy in a sustainable manner. The integration of renewable energies in building elements can improve their overall performance, as they are able to replace common construction materials, while offering both electrical and thermal energy. The scope of this paper is to present the first results of an experimental study of a Building-Integrated Photovoltaic system combined with a water storage tank (BIPV-WS), a combined integration not extensively studied yet. Both layers are separated by a ventilated air cavity, and the thermal behavior of the system was analyzed experimentally in real functioning conditions. The water tank performs as a thermal storage, maintaining a regular temperature of about 20-30 degrees C during a typical winter day of Lisbon for a period of 11 h. Moreover, through the ventilation of the air cavity, the heat provided by the solar panel was naturally recovered to the indoors of the building, while keeping the temperature high enough to heat up the water. During summer, the ventilated BIPV-WS enabled beneficial nocturnal heat loss while delaying diurnal space heating.
  • The use of key enabling technologies in the nearly zero energy buildings monitoring, control and intelligent management
    Publication . Lourenço, José Marco; Aelenei, Laura Elena; Facão, Jorge; Goncalves, Helder; Aelenei, Daniel; Pina, João Murta
    ABSTRACT: The 2018 revision of the European Performance Building Directive (EPBD) requires that from the year 2020 onwards, all new buildings will have to be "nearly zero energy buildings". It also further promotes smart building technologies, raising awareness amongst building owners and occupants of the value behind building automation. The European Commission also identified, in 2011, Key Enabling Technologies (KETs), which provide the basis for innovation in the EU. In the frame of the SUDOKET project, the Solar XXI building was used as a pilot case, as innovative integrated solutions and technologies are monitored and controlled. The objective of this paper is to validate a simulation of the laboratorial test room in EnergyPlus with data obtained experimentally and determine the impact of the control systems on energy needs and on thermal comfort. Two systems, in particular, were studied: the Building-Integrated Photovoltaic (BIPV) and the earth tubes. Once validated, the simulation of the test room without the systems was created, allowing their impact to be determined. The results show that, for the analysed periods, BIPVs reduced the heating consumption by 22% while also increasing thermal comfort, and the earth tube system would reduce the cooling needs by 97%.
  • Performance assessment of a building-integrated photovoltaic thermal system in a Mediterranean climate: an experimental analysis approach
    Publication . Bot, Karol; Aelenei, Laura Elena; Goncalves, Helder; Gomes, Maria da Glória; Silva, Carlos Santos
    ABSTRACT: The experimental investigation of building-integrated photovoltaic thermal (BIPVT) solar systems is essential to characterise the operation of these elements under real conditions of use according to the climate and building type they pertain. BIPVT systems can increase and ensure energy performance and readiness without jeopardising the occupant comfort if correctly operated. The present work presents a case study's experimental analysis composed of a BIPVT system for heat recovery located in a controlled test room. This work contribution focuses on the presentation of the obtained measured value results that correspond to the BIPVT main boundary conditions (weather and room characteristics) and the thermal behaviour and performance of the BIPVT system, located in the Solar XXI Building, a nZEB exposed to the mild Mediterranean climate conditions of Portugal.
  • Performance assessment of a building integrated photovoltaic thermal system in Mediterranean climate : a numerical simulation approach
    Publication . Bot, Karol; Aelenei, Laura Elena; Gomes, Maria da Glória; Silva, Carlos
    ABSTRACT: This study addresses the thermal and energy performance assessment of a Building Integrated Photovoltaic Thermal (BIPVT) system installed on the facade of a test room in Solar XXI, a Net Zero Energy Building (NZEB) located in Lisbon, Portugal. A numerical analysis using the dynamic simulation tool EnergyPlus was carried out for assessing the performance of the test room with the BIPVT integrated on its facade through a parametric analysis of 14 scenarios in two conditions: a) receiving direct solar gains on the glazing surface and b) avoiding direct solar gains on the glazing surface. Additionally, a computational fluid dynamics (CFD) analysis of the BIPVT system was performed using ANSYS Fluent. The findings of this work demonstrate that the BIPVT has a good potential to improve the sustainability of the building by reducing the nominal energy needs to achieve thermal comfort, reducing up to 48% the total energy needs for heating and cooling compared to the base case. The operation mode must be adjusted to the other strategies already implemented in the room (e.g., the presence of windows and blinds to control direct solar gains), and the automatic operation mode has proven to have a better performance in the scope of this work.