Solar XXI building: Proof of concept or a concept to be proved?

Solar XXI building is a low energy office building where passive and active solar strategies have been applied to reduce the use of energy for heating,cooling and lighting, combining also an extensive photovoltaic façade for electricity production. Solar XXI opened in 2006 and is considered a high efficient building, close to a net zero energy building (NZEB), where the difference between the energy consumed and that produced is 1/10th of the energy consumed by a Portuguese standard new office building. Its design includes many energy efficiency concepts, such as a high insulated envelope,south sun exposure, windows external shading, photovoltaic panels heat recovery,ground-cooling system, daylighting, stack effect and cross ventilation. The solar gains of the windows and the effectiveness of shading devices were evaluated in order to correlate solar radiation, external and indoor air temperatures.It was also verified that amplitude-dampening of ground cooled air ranged between 5 and 8 C, following the trend of the analytical solution for heat diffusion of a cylindrical air/soil heat-exchanger

Energy performance certificate: a valuable tool for building-to-grid interaction?

New challenges were opened with the recast of Energy Performance of Buildings Directive, requiring by 2020 that new buildings be “nearly Zero-Energy Buildings” (nearly ZEB). In addition to consumer buildings, Net ZEBs are also producers’ by using as much renewable energy sources as possible to compensate the building energy load. Sustainable cities require energy-efficient buildings, i.e. buildings where the use of energy is minimized without compromising the occupants comfort, namely for heating, cooling, lighting and indoor air quality. But smart cities require energy-efficient ‘interactive’ buildings, which integrate multiplecarrier energy networks and provide up-to-date valuable information for their management, where buildings are simplified to single nodes characterized by their energy load, generation, storage and conversion, applying the load-generation approach. The information currently available in the Energy Performance Certificate is not relevant for estimating the time dependent building energy load, but it can be easily improved by including a few descriptive parameters

Methodological development of sesonal cooling energy needs by introducing ground-cooling systems

In past years, building professionals increased their interest on passive systems as sustainable solutions to reduce energy needs. This has been driven by the building certification program and new Portuguese building thermal code enacted in 2006. For residential and small office buildings, the methodology adopted is a seasonal quasi-stationary approach for calculating cooling energy following EN ISO 13790:2007. However, this method lacks specific recommendations for accounting passive cooling systems, namely ground-cooling systems. In this paper, the ground-heat exchanger contribution is included in the energy needs method. This development is sustained by measurements obtained in the ground-heat exchanger running on Solar XXI office building at LNEG campus, complemented by simplified and Fourier theoretical formulations. The horizontal ground-heat exchanger at Solar XXI is constituted by 32 concrete ducts, with a 30 cm diameter and buried 4.6 m deep. The air entrance is made from a feeding well about 15 m away from the building and its functioning during summer warm days supplies cool air for room offices

University-industry collaboration importance in innovative brazilian industrial firms: a sectorial model

This article examines empirically the university-industry collaboration (UIC) importance in innovative firms on Brazilian industry. This relation is considered an important tool for economic growth in innovation-led firms. It was used a hierarchical regression model for 25.667 innovative industrial firms in the year 2005, the innovation involves product, process, or organizational change. The Total Factor Productivity was introduced as independent variable, because it can be used in all firms as performance measure, and it was average centralized. The TFP is explained by firm’s internal capabilities, and in industry by the UIC importance. The found results are upward average (positive sign), and downward average (negative sign). The sectorial impact of UIC in the TFP is positive, but near zero. The internal capabilities present exchanged signs between the firm and the industry, only innovative labor have both signs positive. The random effects identify nine industries with upward productivity gains, 8,26 % of total Brazilian industry, and these industries are traditional, low-tech intensity, only the automotive industry is medium-technology. Twenty industries have downward productivity gains, 18,35 % of total Brazilian industry, and between them are high-technology industries, as diverse capital tools, and electronics.      Este artículo examina empíricamente la importancia de la colaboración universidad-industria (CUI) en empresas innovadoras en la industria brasileña. Esta relación se considera una herramienta importante para el crecimiento económico en las empresas innovadoras. Se utilizó un modelo de regresión jerárquica para 25.667 empresas industriales innovadoras en el año 2005, la innovación abarca producto, proceso, o cambio organizacional. La Productividad Total de Factores (PTF) se introdujo como variable independiente, ya que puede ser utilizada en todas las empresas como medida de desempeño, y se centró en la media. La PTF se explica por las capacidades internas de la empresa, y en la industria por la importancia de la CUI. Los resultados encontrados son media ascendente (signo positivo) y media descendente (signo negativo). El impacto sectorial de la CUI en la PTF es positivo, pero tiende a cero. Las capacidades internas presentan signos intercambiados entre la empresa y la industria, sólo la mano de obra innovadora tiene ambos signos positivos. Los efectos aleatorios identifican nueve industrias con aumentos de productividad, 8,26 % del total de la industria brasileña, y estas industrias son tradicionales, de baja intensidad tecnológica, solo la industria automotriz es de tecnología media. Veinte industrias tienen aumentos de productividad por debajo de la media, 18,35 % del total de la industria brasileña, y entre ellos son industrias de alta tecnología, como diversas herramientas de capital y electrónica

Theoretical and experimental analysis of beam-to-column composite connections with bottom na web angle-typical floor and isolatec prototypes

Este trabalho apresenta um amplo programa experimental de ligações viga mista-pilar com cantoneiras de alma \ud e assento, incluindo protótipos isolados e ligações inseridas num pavimento tipo de laje pré-moldada com vigotas \ud e lajotas cerâmicas. Os objetivos do trabalho foram avaliar os efeitos da fissuração da laje no comportamento da \ud ligação (rigidez inicial e momento resistente), a influência da variação da taxa de armadura secundária da laje e \ud a eficiência dos detalhes propostos para a ancoragem das armaduras longitudinais.Nos ensaios experimentais, \ud foram analisadas as rotações das ligações, deslocamentos e deformações nos elementos. Para a análise teórica, \ud tomou-se como base o Método das Componentes do EUROCODE 3 e 4. Paralelamente, um estudo numérico via \ud MEF foi desenvolvido com o objetivo de considerar a laje de concreto e as armaduras longitudinais e \ud transversais. De acordo com os resultados, a condição prévia de fissuração da laje mostrou-se menos relevante \ud que a continuidade das vigas na direção do eixo de menor inércia do pilar, no que se refere à determinação da \ud rigidez inicial e resistência das ligações mista inseridas num pavimento tipo. A metodologia de modelagem \ud numérica representou satisfatoriamente os mecanismos plásticos e os estados limites últimos da ligação.This research presents an extensive experimental study of the structural behavior of the beam-to-column \ud composite connections with bottom and web angle, including isolated prototypes and typical floor with slab made \ud of precast joist with lattice and bricks. The objectives were to evaluate concrete slab cracking effects in the \ud composite connections behavior (initial stiffness and resistant moment), the secondary steel ratio increase and the \ud proposed details for the longitudinal steel bars anchorage. In the experimental tests, it was analyzed the \ud connection total rotation, the displacements and deformations in the connection components. The theoretical \ud study was developed based on EURODODE 3 and 4 methodologies. Besides, a numerical study was developed \ud with the purpose of including the concrete slab modeling, the longitudinal and transversal steel bars. The \ud geometrical and material non-linearity it was considerate in the numerical analysis. According to the results, the \ud beam continuity through to the column minor axis showed to be more important than the concrete slab previous \ud cracking, for the initial stiffness and resistant moment composite connections behavior in the typical floor. The \ud numerical models represented satisfactorily the plastic mechanism connection and the ultimate limit state