2,571 research outputs found

    Solar XXI: A Portuguese Office Building towards Net Zero-Energy Building

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    Solar Building XXI, built in 2006, at LNEG Campus in Lisbon, pretends to be an example of a low energy building using passive systems both for heating and cooling (ground cooling) towards a Net Zero-Energy Building (NZEB). The main fa√ßade has a PV system with heat recovery which assists the heating in winter time. In summer a ground cooling system (earth tubes)is used to cool the building, together with night cooling strategies. Net Zero-Energy Buildings Performance has gained more attention since the publication in 2010 of the EPBD recast. Successful implementation of such an ambitious target depends on a great variety of factors. For designers and code writers these include: balancing climate driven-demand for space cooling and heating with climate-driven supply for renewable energy resources. With a literature full of theoretical advice and a building industry rife with myths about the value of technologies,the present paper intends to unveil a sustainable framework for sharing insights into NZEB methodology applied to a Portuguese solar office building, SOLAR XXI, currently underway to reach the Net Zero-Energy Goal. Under the common work which is developed also in SHC Task 40-ECBCS Annex 52, ‚ÄúTowards Net Zero Solar Energy Buildings‚ÄĚ, the authors of this paper are currently engaged in studying possible strategies for ‚Äúupgrading‚ÄĚ Solar XXI to NZEB status

    The Road Towards ‚ÄúZero Energy‚ÄĚ in Buildings: Lessons Learned from SOLARXXI Building in Portugal

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    In this paper the authors intend to share the lessons learned in the designing process of a solar office building currently underway to reach the Net Zero-Energy performance. Solar XXI building was built in Lisbon in 2006 as a demonstration project [1]. The building, which design is based on a combination of passive design techniques with renewable energy technologies (PV, solar collectors), may be currently considered, from this perspective, a near Net Zero Energy Building. Despite Solar XXI falling short the NZEB status, it is believed that the experience acquired and lessons learned in the designing phase are worth noting. The demonstration of the building energy performance is done by means of experimental monitoring data and energy modelling results using the simulation engine EnergyPlus [2]. In addition of this, it is important to stress out the fact that the authors of this paper, who are participants in the SHC Task 40-ECBCS Annex 52, ‚ÄúTowards Net Zero Solar Energy Buildings‚ÄĚ are currently engaged in studying possible strategies for ‚Äúupgrading‚ÄĚ Solar XXI to NZEB status [3]

    Analysis Of Load Match and Grid Interaction Indicators in NZEB with High-Resolution Data

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    A Net Zero Energy Building (Net ZEB) is succinctly described as a grid-connected building that generates as much energy as it uses over a year. The ‚ÄúNet Zero‚ÄĚ balance is attained by applying energy conservation and efficiency measures and by incorporating renewable energy systems. The main objective of this report is to analyze the usefulness and relevance of proposed Load Match and Grid Interaction (LMGI) for Net Zero Energy Buildings. The methodology is based in the analysis of available high-resolution data (mainly hourly) both from simulated and monitored Net ZEBs (Net Zero Energy Buildings) or nZEB (nearly Zero Energy Buildings). The central question is to find a limited set of indicators which provide relevant information to building owners, local grid Distribution System Operators (DSO) when information from building simulations are available at design stage

    ‚ÄúNET ZERO BUILDINGS‚ÄĚ ‚Äď APLICA√á√ÉO DO CONCEITO A UM EDIF√ćCIO EXISTENTE

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    Os edif√≠cios de balan√ßo energ√©tico nulo (NZEB - Net-Zero Energy Building) e/ou quase nulo (nZEB), t√™m vindo a ganhar crescente aten√ß√£o desde a publica√ß√£o da diretiva europeia 2010/31/EU [15]. Em Portugal, com a introdu√ß√£o do Decreto-Lei n.¬ļ118/2013, d√° o primeiro passo para os edif√≠cios com necessidades quase nulas de energia. Os novos edif√≠cios licenciados ap√≥s 31 dezembro de 2020, ou ap√≥s 31 de dezembro de 2018 no caso de edif√≠cios p√ļblicos, ser√£o edif√≠cios com necessidades quase nulas de energia. O objetivo do trabalho descrito neste artigo consiste na aplica√ß√£o do conceito ‚ÄĚNet Zero Energy Building‚ÄĚ, ao edif√≠cio existente do Instituto Superior Polit√©cnico Gaya (ISPGaya), em Vila Nova de Gaia, com o intuito de analisar a viabilidade de otimiza√ß√£o de energia e a metodologia deste conceito ao edif√≠cio, com recurso a ferramentas de simula√ß√£o. Neste trabalho efetu√°mos uma simula√ß√£o energ√©tica do edif√≠cio, atrav√©s do DesignBuilder¬ģ, que servir√° como termo de compara√ß√£o para outras simula√ß√Ķes. Ser√£o delineadas as especifica√ß√Ķes a implementar no edif√≠cio por forma a ser considerado Net Zero Energy Building, com altera√ß√Ķes na simula√ß√£o do mesmo de acordo com as novas especifica√ß√Ķes. Por √ļltimo, ser√° feita a compara√ß√£o t√©cnica, financeira e ambiental da solu√ß√£o NZEB encontrada. Atrav√©s das v√°rias simula√ß√Ķes energ√©ticas ao edif√≠cio, conclui-se que √© poss√≠vel baixar as necessidades energ√©ticas do edif√≠cio atrav√©s de medidas de efici√™ncia energ√©tica, em especial na ilumina√ß√£o e que os resultados obtidos, apesar de ser vi√°vel a implementa√ß√£o do conceito Net Zero Energy Building, traduzem um esfor√ßo financeiro e algumas condicionantes para a sua concretiza√ß√£o

    A Portuguese study on building renovation towards a nearly zero energy building (nZEB)

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    The social and environmental urgency of large-scale integrated retrofitting of the European residential building stock is widely acknowledged and supported by all Member States. However, the European building sector is currently still not able to offer an integral solution for deep renovation toward nearly Zero Energy Building (nZEB) for reasonable costs. MORE-CONNECT project aims to tackle this issue by developing cost optimal solutions to renovate buildings towards nZEB. In this project, the optimal solutions include the development of prefabricated, multifunctional renovation elements for the total building envelope (façade and roof) and installation/building services. This paper presents the first stage of the project, namely the analysis and comparison of three scenarios following the current national requirements in Portugal i) 80% reduction of the current primary energy consumption of the building, ii) cost optimal solution (nZEB) and iii) net zero energy (NZEB). The optimization of the building envelope will be the main driver for the three scenarios as well as the inclusion of renewable energy strategies. Overall, results suggest that it is possible to achieve cost-effective solutions for the renovation of Portuguese residential buildings. Moreover, the cost-optimal solution (scenario ii) matches approximately with the 80% reduction of energy scenario (scenario i).MORE-CONNECT is funded by the European Commission within the framework of the Horizon 2020 progra

    Is the NZEB benchmarking approach suitable for assessing energy retrofit design?

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    Currently, many effort have been done to enable energy saving issues in building design and many definitions have been introduced for most performing constructions based on energy balance between energy demand and supply. Recently, the Net Zero Energy Building theory has bypassed old Passive House concept but many questions still remain open. Present work aims to estimate how NZEB requirements matching could be affected by the choice of their definition and the choice of weighting factor system, to be count in the energy balance. NZEB concept is mainly referred to new buildings design. Its application to existing buildings is for sure an hard task provided the architecture and physical constraints are often problematic. Nevertheless, the benchmarking approach able to assess the building performance according to the NZEB objective can be utilized for other two purposes. The first one is to assess how an existing building is far from the performances of a NZEB. The second one is to assess the contribution of a conventional retrofit in improving its energy balance

    Temperature, Relative Humidity, and Carbon-Dioxide Modulation in a Near-Zero Energy Efficient Retrofit House

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    The concept of Net Zero Energy Buildings (NZEB) has reached a phase where countries all around the world are encouraging its implementation into mainstream construction. In the United States, both private and public sector buildings are incorporating energy efficient technologies to reduce their environmental impact, while increasing the productivity and comfort of its occupants. A Net Zero Energy Building (NZEB) performs as expected only when the building√Ę‚ā¨‚ĄĘs envelope, HVAC and other mechanical/electrical systems work in unison. Subsequently, once these buildings are occupied, the behavior of its occupants significantly influences the buildings energy performance.√ā The authors have captured the modulation of temperature, relative humidity, and carbon-dioxide within one such Near-Net Zero Energy Building during the heating season. This house is a Deep-Energy Retrofit Home completed as a marketing and demonstration home for a joint neighborhood stabilization project and U.S. Department of Energy funded community-wide retrofit grant program in Lafayette, Indiana. The house includes an internet based real-time home energy monitoring system, which facilitates reviewing the changes in the houses energy performance as a consequence of fluctuating internal temperature settings and external climate conditions. Post retrofit blower-door test result conform that the house has been made fairly air-tight during the retrofit. Hence ventilation within the house is achieved via an Energy Recovery Ventilator (ERV) with multiple stages of operation. To this end, the paper is an exploratory examination of the inter-relationships between occupancy, interior temperature, relative humidity, carbon-dioxide levels and energy consumption within the retrofitted residential Near-Net Zero Energy Building

    Net-Zero Energy Buildings: Principles and Applications

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    Global warming and climate change are rising issues during the last couple of decades. With residential and commercial buildings being the largest energy consumers, sources are being depleted at a much faster pace in the recent decades. Recent statistics shows that 14% of humans are active participant to protect the environment with an additional 48% sympathetic but not active. In this chapter, net-zero energy buildings design tools and applications are presented that can help designers in the commercial and residential sectors design their buildings to be net-zero energy buildings. Case studies with benefits and challenges will be presented to illustrate the different designs to achieve a net-zero energy building (NZEB)

    Potential reconstruction design of an existing townhouse in Washington DC for approaching net zero energy building goal

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    The concept of the Net Zero Energy Building (NZEB) has received more interest from researchers due to global warming concerns. This paper proposes to illustrate optional solutions to allow existing buildings to achieve NZEB goals. The aim of this study is to investigate factors that can improve existing building performance to be in line with the NZEB concept and be more sustainable. An existing townhouse in Washington, DC was chosen as the research target to study how to retrofit or reconstruct the design of a building according to the NZEB concept. The methodology of this research is modeling an existing townhouse to assess the current situation and creating optional models for improving energy efficiency of the townhouse in Revit and utilising renewable energy technology for energy supply. This residential building was modeled in three versions to compare changes in energy performance including improving thermal efficiency of building envelope, increasing thickness of the wall, and installing smart windows (switchable windows). These solutions can reduce energy and cost by approximately 8.16%, 10.16%, and 14.65%, respectively, compared to the original townhouse. Two renewable energy technologies that were considered in this research were photovoltaic and wind systems. The methods can be applied to reconstruct other existing buildings in the future
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