EAC - Artigos em revistas internacionais
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- Assessement of the Portuguese building thermal code: Newly revised requirements for cooling energy needs used to prevent the overheating of buildings in the summerPublication . Panão, Marta Oliveira; Camelo, Susana; Goncalves, HelderIn this paper, cooling energy needs are calculated by the steady-state methodology of the Portuguese building thermal code. After the first period of building code implementation, re-evaluation according to EN ISO 13790 is recommended in order to compare results with the dynamic simulation results. From these analyses, a newly revised methodology arises including a few corrections in procedure. This iterative result is sufficiently accurate to calculate the building’s cooling energy needs. Secondly, results show that the required conditions are insufficient to prevent overheating. The use of the gain utilization factor as an overheating risk index is suggested, according to an adaptive comfort protocol, and is integrated in the method used to calculate the maximum value for cooling energy needs. This proposed streamlined method depends on reference values: window-to-floor area ratio, window shading g-value, integrated solar radiation and gain utilization factor, which leads to threshold values significantly below the ones currently used. These revised requirements are more restrictive and, therefore, will act to improve a building’s thermal performance during summer. As a rule of thumb applied for Portuguese climates, the reference gain utilization factor should assume a minimum value of 0.8 for a latitude angle range of 40-41ºN, 0.6 for 38-39ºN and 0.5 for 37ºN.
- Design issues for net zero-energy buildingsPublication . Aelenei, Laura Elena; Aelenei, Daniel; Goncalves, Helder; Lollini, Roberto; Musall, Eike; Scognamiglio, Alessandra; Cubi, Eduard; Noguchi, MassaNet Zero-Energy Buildings (NZEBs) have received increased attention in recent years as a result of constant concerns about energy supply constraints, decreasing energy resources, increasing energy costs and the rising impact of greenhouse gases on world climate. Promoting whole building strategies that employ passive measures together with energy efficient systems and technologies using renewable energy became a European political strategy following the publication of the Energy Performance of Buildings Directive recast in May 2010 by the European Parliament and Council. However designing successful NZEBs represents a challenge because the definitions are somewhat generic while assessment methods and monitoring approaches remain under development and the literature is relatively scarce about the best sets of solutions for different typologies and climates likely to deliver an actual and reliable performance in terms of energy balance (consumed vs generated) on a cost-effective basis. Additionally the lessons learned from existing NZEB examples are relatively scarce. The authors of this paper, who are participants in the IEA SHC Task 40-ECBCS Annex 52, “Towards Net Zero Energy Solar Buildings”, are willing to share insights from on-going research work on some best practice leading NZEB residential buildings. Although there is no standard approach for designing a Net Zero-Energy Building (there are many different possible combinations of passive and efficient active measures, utility equipment and on-site energy generation technologies able to achieve the net-zero energy performance), a close examination of the chosen strategies and the relative performance indicators of the selected case studies reveal that it is possible to achieve zero-energy performance using well known strategies adjusted so as to balance climate drivendemand for space heating/cooling, lighting, ventilation and other energy uses with climate-driven supply from renewable energy resources.
- Eco-efficiency in Portuguese companies of marble sectorPublication . Catarino, Justina; Henriques, José João M. Silva; Maia, AnabelaThe activities developed within an eco-efficiency project in mineral industries located in the largest area for marble extraction in Portugal, in Alentejo region, in the Estremoz – Borba and Vila Viçosa anticline are presented in this paper. The project was designed to apply the sustainability concept in seven companies of marble extraction and transformation. The adopted strategy used new cleaner production models together with sustainable value (SV) improvement, leading to the rationalization of the industrial process, the involvement of economic agents and the orientation of the management of production processes towards eco-efficiency. The challenge was to have the mineral industry managing efficiently the resources on which the business depends, according to sustainability principles. Different opportunities for improvement, related to the minimization of materials, water and energy use, were identified in the companies. Some proposals mainly related to social improvement and small and medium-sized enterprise competitiveness benefits were also selected and discussed. This approach allows the integration of sustainability at company's and region's levels by combining in the entrepreneurial activity the creation of wealth together with the environment protection and the achieving of social benefits. Highlights: The involvement of different stakeholders in the project (Eco-efficiency in Portuguese companies of marble sector) was positive in the discussion and search of solutions for companies. It is possible to involve marble extraction and processing companies in eco-efficiency improvement towards sustainability. Companies from the marble sector improved environmental and social performance and reduced the costs of their production processes by applying SV methodology.
- Enhancing Market Readiness for nZEB ImplementationPublication . Aelenei, Laura Elena; Croitoru, C.; Korczak, K.; Petran, H.; O'Rourke-Potocki, H.; Tzanev, D.; Goncalves, Helder; Duarte, Ana Paula; Trindade, Paula; Loureiro, DavidABSTRACT: 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.
- From solar building design to Net Zero Energy Buildings: performance insights of an office buildingPublication . Aelenei, Laura Elena; Goncalves, HelderNet Zero-Energy Buildings Performance has gained more attention since the publication in 2010 of the EPBD recast [1]. Successful implementation of such an ambitious target depends on a great variety of factors. With a literature full of theoretical advice and a building industry rife with myths about the value of technologies, the present study intend to unveil an sustainable framework for sharing insights into NetZEB methodology applied in an Portuguese office building, Solar XXI, based on the authors experience in the ongoing research carried out within International Energy Agency SHC Task 40 - ECBCS Annex 52, "Towards Net Zero Energy Solar Buildings”.
- How low should be the energy required by a nearly Zero-Energy Building? The load/generation energy balance of Mediterranean housingPublication . Panão, Marta Oliveira; Rebelo, Miguel P.; Camelo, SusanaDirective 2010/31/EU adopted that by the end of 2020 all new buildings should be nearly Zero-Energy Buildings (nZEB) and Member States should achieve cost-optimal levels by ensuring minimum energy performance requirements for buildings. This paper discusses how low should be the energy required by a nZEB, in the context of housing energy consumption in a Mediterranean climate (Lisbon). For selected houses built after 1990, the calculated primary energy loads for regulated uses – heating, cooling and domestic hot water – are found to be below 90 kWh/(m2 year). Applying the cost-optimal solutions of thermal insulation and glazing type and considering energy efficiency improved systems, this study concludes that housing energy loads are ‘low’ for the indicative range of 70 kWh/(m2 year) for regulated uses or 100–110 kWh/(m2 year) for total uses, taking primary energy indicators (PEI) from EN 15603. Assuming PEI from Passive House Planning Package or those to be assumed in Portugal for 2013, the threshold decreases to 60 kWh/(m2 year) for regulated uses or 90–100 kWh/(m2 year) for total uses. Only the first nZEB condition is explored by this paper. The second condition requires that the nZEB energy load is covered by a ‘significant’ part of renewable energy sources produced on-site or ‘nearby’.
- Implementing cost-optimal methodology in existing public buildingsPublication . Aelenei, Laura Elena; Paduos, S.; Petran, H.; Tarrés, J.; Ferreira, Ana R.; Corrado, V.; Camelo, Susana; Polychroni, E.; Sfakisnaki, K.; Goncalves, Helder; Salom, J.; Riva, G.; Murano, G.This study presents some preliminary results of an on-going European Project, RePublic_ZEB, where an analysis is conducted for identifying the cost optimal levels for the existing buildings, towards nearly Zero Energy Buildings (nZEB) performance. The analysis is applied to the reference building for an existing office building in five different countries: Italy, Portugal, Romania, Spain and Greece. The evaluation tool uses a new cost optimization procedure based on a sequential search- optimization technique considering discrete options is applied and the results will be presented in terms of optimal “package of measures”, energy consumption and global costs. Finally a cross-country analysis will be performed.
- Improving the Energy Performance of Public Buildings in the Mediterranean Climate via a Decision Support ToolPublication . Gouveia, João Pedro; Aelenei, Laura Elena; Aelenei, Daniel; Ourives, Raquel; Bessa, SaloméABSTRACT: 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.
- Investigating the potential for energy flexibility in an office building with a vertical BIPV and a PV roof systemPublication . Aelenei, Daniel; Lopes, Rui Amaral; Aelenei, Laura Elena; Goncalves, HelderABSTRACT: Building Integrated Photovoltaics (BIPV) are becoming an attractive solution in the context of high penetration of photovoltaics (PV) in buildings caused by the strive to achieve net or nearly zero energy status. Besides retrieving solar radiation to produce electricity, BIPV also offers aesthetical advantages because of its architectural feature. This paper reports on the electrical energy performance of a passive solar office building, Solar XXI, located in Lisbon, Portugal, which has installed on the South façade a BIPV (12 kWp) and an additional photovoltaic roof system in a nearby car park facility (12 kWp) for electricity generation. The main objective is to investigate the potential to increase load matching between energy generation and consumption and improve grid interaction for two scenarios using the energy flexibility enabled by the integration of Battery Energy Storage Systems (BESS) with capacities ranging from 13.5 kWh to 54 kWh. To collect the required results, real consumption and generation data are used, together with numerical simulations related to the integration of the BESS. The results show that load matching and grid interaction related metrics can be significantly improved by using the energy flexibility provided by a BESS and that the implementation of such system can be economically viable for a 10-year period.
- Mapping flexibility of urban energy systems (FIRST) project: rationale and study design of an exploratory projectPublication . Aelenei, Daniel; Lopes, Rui Amaral; Silva, Carlos; Costa, F.; Majdalani, N.; Simões, Teresa; Goncalves, Helder; Aelenei, Laura ElenaABSTRACT: With the publication of the new Energy Performance of Buildings Directive, a large number of buildings are expected to become high energy performance and explore more the availability of renewable energy resources. Such buildings are often described in literature as nearly Zero-Energy Buildings (nZEB). Because renewable energy sources, such as wind and solar power, have an intrinsic variability, the zero-energy annual balance of nZEBs is difficult to reach at short time resolution (e.g. hourly). Thus, since electricity generation from small-scale solar renewable (typical case in Portugal) in individual households has limited capacity to be adjusted according to the power system needs, it is relevant to consider the demand flexibility potential, specially at community level (cluster of buildings). Unfortunately, there is a lack of studies on the impact of changes in electricity use at urban level on the future energy systems. Therefore, an approach addressing the energy flexibility (EF) in buildings may allow obtaining useful exploratory directions for the construction sector and related markets, policy makers and regulatory bodies. For these reasons, an exploratory project aimed at examining the potential of EF at the level of an existent neighbourhood in Lisbon was initiated. In this article we describe the objectives, design, and methods of the FIRST project, designed to map out the potential for EF in terms of benefits and costs in Lisbon.