Triggering Deep Renovation of Buildings in Portugal

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.info:eu-repo/semantics/publishedVersio

The nZEBs in the near Future: Overview of definitions and guidelines towards existing plans for increasing nZEBs

Zero-energy performance buildings have gained significant attention since the publication in 2010 of the recast of the EPBD recast which requires all new buildings to become nearly zero-energy by 2020. Buildings are requested to meet higher levels of energy performance and to explore more the alternative energy supply systems available locally on a cost-efficiency basis. Since the directive does not specify minimum or maximum harmonized requirements as well as details of energy performance calculation framework, it is up to the member states to define the exact meaning of “high energy performance” and “amount of energy from renewable sources” according to their own local conditions and strategic interests. Nearly zero-energy building (nZEB) performance derives from net zero-energy concept (Net ZEB) which in case of buildings is usually defined as a high energy performance building that over a year is energy neutral. The successful implementation of such an ambitious target, however, needs to be planned out diligently. The critical steps are a) a correct picture about the existing state and trends, b) clear definitions and targets, c) dynamic building codes and energy efficient technologies and d) rules for testing and verification. The nZEBs or NetZEBs built in the near future therefore may play a critical role in implementing any ambitious plan as its success on long-term relies on setting best practice examples, in addition of the supporting policies and initiatives. The purpose of this paper is to review existing definitions, terms and policies on strategic planning of nZEBs at national and international level

Investigating the potential for energy flexibility in an office building with a vertical BIPV and a PV roof system

ABSTRACT: 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.info:eu-repo/semantics/publishedVersio

The use of attached-sunspaces in retrofitting design: the case of residential buildings in Portugal

This study addresses the energetic performance of an attached-sunspace applied to an existing residential building in Portugal. Four configurations (two attached, one integrated and one partially integrated) are studied in six different climatic zones. In addition other key parameters are considered such as ventilation (with or without natural ventilation), shading devices (one external and two internal configurations), number of glazed surface layers (single glazed and double glazed) and orientation (South, East and West). The thermal performance analysis, carried out using a dynamic simulation code, proved that energy savings for retrofitting design can be very important and that in climates with warm summers the risk of overheating can be considerably diminished through an accurate analysis based on modeling

Standard Unretrofitted Buildings and Net Zero-Energy Concept

There are many different possible combinations of building envelope, utility equipments and onsite energy generation equipments that can lead to net zero-energy performance. For instance, a building with standard design can offset its energy demand by adding a large amount of photovoltaic cells or by improving its energy efficiency rating first and then adding a smaller amount of photovoltaic cells. Despite the second strategy being considered the roadmap to net zeroenergy status, the first scenario is also possible in the actual Portuguese context where laws favor conditions for the installation of PV´s and solar thermal systems. This paper intends to discuss the implications of this fact from a national perspective coupled with the IEA SHC Task 40 - ECBCS Annex 52 vision where authors are active participants

Design strategies for non-residential zero-energy buildings: lessons learned from Task40/Annex 52: towards net zero-energy solar buildings

Net zero-energy buildings (Net ZEBs) have been the object of various studies in recent years as various countries have set this performance as long-term goal of their energy policies. Designing successful Net ZEBs represents a challenge since the definitions are yet generic, the assessment method and monitoring approach are 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 (used consumed vs. generated) on a costeffective basis. The International collaborative research initiative between the Solar Heating and Cooling (SHC) and the Energy Conservation in Buildings and Community Systems (ECBCS) through Task 40/Annex 52 - Towards Net-Zero Energy Solar Buildings-, summarises most of the recent developments in this field. The authors of this article, who are participants in this task, are providing insights from on-going research work on some best practice leading projects which have been the object of an exploratory cross-case analysis in order to facilitate identification of the set of relevant design strategies. The close inspection of the strategies and indicators of the relative performance of the projects revealed interesting features about the combination of design challenges with techniques and technologies responsible for delivering the Zero Energy performance

Edifícios de balanço energético nulo: uma síntese das características principais

Os edifícios de balanço energético nulo têm recebido uma atenção crescente desde a publicação da nova Directiva sobre o Desempenho Energético dos Edifícios em 2010 (EPBD, 2010). A nova EPBD, vai obrigar todos os edifícios novos construídos a partir de 2020 serem caracterizados por níveis mais elevados de desempenho energético, procurando explorar mais as fontes de energia renováveis disponíveis localmente numa base economicamente equilibrada e sem prejuízo para o conforto dos ocupantes. Para este fim, a partir 2020 todos os novos edifícios deverão ser caracterizados por um balanço energético “quase nulo”. Um edifício de balanço energético quase nulo, ou nearly-zero, refere-se a um edifício com necessidades energéticas muito baixas, devido à adopção de medidas de eficiência, em que as necessidades serão supridas por fontes renováveis de energia. De acordo com referências bibliográficas recentes, vários Estados-Membros da UE já definiram os seus objectivos nacionais com base nas exigências da nova EPBD, enquanto estratégias semelhantes são consideradas pelos governos dos EUA e do Japão (Yokoo, 2009). A partir de 2020, todos os novos edifícios serão caracterizados por um balanço energético positivo em França (ECEEE, 2011) ao passo que o governo Britânico aponta na direcção duma estratégia baseada num balanço em termos de emissões de CO2 nulo (zero-carbon) (DSLG, 2009). Ainda o governo dos EUA promove “casas comercializáveis” e edifícios não residenciais de balanço energético nulo a partir de 2020 e de 2025, respectivamente (DOE, 2008). Com cada vez mais países a apontar na direcção deste novo padrão, em todo o mundo são conhecidos a volta de 300 edifícios que alegam um desempenho energético nulo ou perto do nulo (Musall et al., 2010)