Assessing the solar irradiation potential for solar photovoltaic applications in buildings at low latitudes ¿ Making the case for Brazil

In Brazil, a low-latitude country characterized by its high availability and uniformity of solar radiation, the use of PV solar energy integrated in buildings is still incipient. However, at the moment there are several initiatives which give some hints that lead to think that there will be a change shortly. In countries where this technology is already a daily reality, such as Germany, Japan or Spain, the recommendations and basic criteria to avoid losses due to orientation and tilt are widespread. Extrapolating those measures used in high latitudes to all regions, without a previous deeper analysis, is standard practice. They do not always correspond to reality, what frequently leads to false assumptions and may become an obstacle in a country which is taking the first step in this area. In this paper, the solar potential yield for different surfaces in Brazilian cities (located at latitudes between 0° and 30°S) are analyzed with the aim of providing the necessary tools to evaluate the suitability of the buildings’ envelopes for photovoltaic us

Performance of passive application of PCM in Spain

Contemporary construction systems tend to be thinner, lighter and better insulated than ever, but usually lack thermal mass. In order to improve the indoor temperature and reduce the energy consumption in the lightweight building it is necessary to add thermal energy storage capacity to the construction elements. Phase change materials (PCM) have high a heat of fusion so they can absorb a lot of thermal energy before melting or solidifying without adding physical mass. The stored energy can be released later when it is necessary. The main purpose of this study is to quantify the effectiveness of PCMs as interior temperature stabilizers in the Spanish construction. Another goal was to identify the influence of the windows sizes and their shading factor in a PCM´s passive application, and find out the most convenient combinations. A comparative study has been made, simulating a Test Room, with and without PCM, to predict the annual interior temperature behavior in each case. The thermal performance of the test rooms was evaluated on an hour to hour basis, in several Spanish climate zones with diverse combinations of facade glazing ratio and window shadow factors (Fs). The results indicate that the addition of PCM to building partitions help to maintain the interior thermal comfort, reducing the high and low temperature peaks in all Spanish climates studied. The PCM thermal stabilizing capacity is more noticeable in summer. However, the Test Room in the warmer climate falls behind in the overall results. The PCM passive application has demonstrated to help to maintain a uniform interior temperature and to save energy, but its use is not a cost effective solution for all the cases in the study. This study helps to identify when, and where, the use of this PCM application should be more appropriate

Methodology in research on photovoltaic cogeneration integrated in building

There are currently various universities and institutions developing research into the integration of photovoltaic systems in buildings, internationally known by its abbreviation in English, BIPV (Building Integrated Photovoltaics). Within this technology, one aspect stands out, considered innovative, the integration of hybrid models or cogeneration. This technology, which we shall call BIPVT (Building Integrated Photovoltaics Thermal), integrates a hybrid module in the building, which not only generates electricity, but also uses residual energy that is lost in the form of heat or light, to increase the energy efficiency of the building, in applications with low temperature. However, the methods to test the efficiency of this investigation and evaluate its cost benefit, are not clear, and constitute a challenge for the investigation within an architectural framework

El proceso constructivo de los teatros del canal del arquitecto Juán Navarro Baldeweg

El artículo que se presenta estudia y valora el sistema constructivo, y su desarrollo, de las obras de los Teatros del Canal, obra del Catedrático de Proyectos de la Escuela de Arquitectura de Madrid, Prof. Navarro Baldeweg, que se están llevando a cabo en Madrid, siendo la Promotora y Propietaria el Canal de Isabel II de la Comunidad Autónoma de Madrid. Se trata de un conjunto de tres edifi cios, dos teatros y un centro coreográfi co, cada uno con soluciones constructivas diferenciadas. Este artículo es el resultado del trabajo llevado a cabo durante el Curso 2006- 07 en el Seminario de “Industrialización de la Construcción”, que bajo la dirección del Catedrático Prof. del Águila se desarrolla dentro del Programa de Doctorado del Departamento de “Construcción y Tecnología Arquitectónicas” de la Universidad Politécnica de Madrid. El trabajo comprende dos partes bien diferenciadas: La primera de introducción, prólogo (redactado por el Prof. Navarro) y una descripción general de los edifi cios; la segunda, desarrollando las diferentes partes constructivas del mismo, desde los distintos tipos de estructuras utilizados, pasando por las fachadas “colgadas” a modo de telones, a los aspectos múltiples de interior, desde la acústica, al mobiliario especial y a los acabados y todo ello no puramente descriptivo, sino también de una manera crítica para que sirva como una consecuencia con valor didáctica para los alumnos-autores. - This present article studies and chriticizes the building system and the developement of the theater and dance complex of Canal (Teatros del Canal, Madrid), designed by Juan Navarro Baldeweg, Principal Professor of Architectural Design at Madrid School of Architecture Polytechnic University. These theaters are being built in the center of Madrid city. The owner and developer of this complex is Canal de Isabel II (the water supply company of Madrid regional Government). The project consist in a three building complex, two theatres and a choreographic centre, put together by a back service block, each of them with it’s own different building solutions. This article is the result of the work done during the term 2006-07 of the Seminar of “Industrialization of Building Process” that, under the direction of the Principal Professor Alfonso del Águila, takes place within the Ph. D. Program of the Department of Construction and Architectural Technology set in Madrid School of Architecture Polytechnic University. The work includes two different parts: the fi rst one, which introduces is a prologue written by Prof. Navarro and a general description of the building. The second part describes its different construction areas, ranging from the different structural solutions, the hung façades pretending to be theatre curtains, some aspects of the interior design, as acoustics, special furniture and fi nishes, not in a mere descriptive way, but also from a critical manner with the intention to be a consequence with didactical value for the students/ authors

Cerramientos multicapas ligeros en el concurso solar Decathlon 2007

El constante crecimiento de consumo energético en todos los sectores, siendo el caso particular el de las edificaciones que consumen una tercera parte del consumo total. Todo ello surge como consecuencia del crecimiento económico y del aumento de las exigencias de las condiciones de confort, además de utilizar energías fósiles. Si se estudia el consumo energético en las edificaciones, se puede ver que el mayor consumo se genera en climatización con un 46%, luego el agua caliente con 21%, electrodomésticos 16%, cocina 10% e iluminación 7%. Desde la década de los setenta, ha surgido una creciente demanda social por un crecimiento sostenible, originado por una parte por la crisis energética iniciada con el conflicto de Medio Oriente y por otra parte por un cada vez mayor y mejor análisis de la repercusión en el ambiente de nuestras actividades. Esto ha llevado a actuaciones de ámbito mundial como son: El Protocolo de Montreal, AGENDA 21, propone el desarrollo de las energías renovables, disminuir los impactos sobre la salud y el medio ambiente de la producción y consumo de energía y el fomento de una educación hacia el desarrollo sostenible. El Programa 21 de la ONU, plantea el control de aquellas substancias que producen el agotamiento de la capa de ozono. El Protocolo de Kyoto, cuyo objetivo es la disminución de las emisiones de Gases de Efecto Invernadero, en especial del CO2. Dando respuesta a estas actuaciones mundiales la Unión Europea ha desarrollado normativas, tendentes a la mejora de la eficiencia energética y a la seguridad y diversificación de los suministros. Así ha desarrollado: La Directiva 93/76 de 13.09.93 (SAVE), El Libro Verde, La Directiva 2002/91. En España las actuaciones se han presentado con: Código Técnico de la Edificación, Documento Básico “Ahorro de Energía” y Real Decreto 47/2007, por el que se aprueba el procedimiento básico para la certificación de eficiencia energética de edificios. Este certificado deberá incluir información objetiva sobre las características energéticas de los edificios de forma que se pueda valorar y comparar su eficiencia energética, con el fin de favorecer la promoción de edificios de alta eficiencia energética y las inversiones en ahorro de energía. Como respuesta a toda esta serie de normativas para la mejora del consumo energético se tiene, por un lado es el empleo de las energías renovables, como la solar fotovoltaica, solar térmica, eólica, hidráulica, biomasa, geotérmica,… y por otro mejorar el diseño y construcción de los edificios usando cerramientos eficientes, como los multicapa y aún mejor los multicapa ligeros, ya que generan mejores prestaciones en término de confort y ahorro energético

Integración de sistemas fotovoltaicos en edificios de oficinas en bajas latitudes: estudio del balance energético aplicado a Brasil

La hipótesis que inspiró esta tesis sostiene que la integración de componentes fotovoltaicos en los cerramientos opacos y sombreamientos de huecos acristalados de edificios de oficinas en sitios ubicados en bajas latitudes, tomando como el ejemplo el caso concreto de Brasil, podría incrementar su eficiencia energética. Esta posibilidad se basa en el bloqueo de una parte significativa de la irradiación solar incidente en estos edificios, reduciendo así las cargas térmicas para la climatización y a la vez transformándola en energía eléctrica, a tal punto que se amortizan los costes de inversión en plazos aceptables a través de los ahorros en la demanda de energía. Para verificar esta hipótesis de partida se ha propuesto como objetivo general analizar la integración de elementos fotovoltaicos en cubiertas, muros opacos y sombreamiento de huecos acristalados desde la óptica del balance energético térmico y eléctrico. Inicialmente se presenta y analiza el estado del arte en los temas estudiados y la metodología de investigación, de carácter teórico basada en cálculos y simulaciones. A partir de un modelo tipo de edificio de oficinas situado en Brasil, se definen cuatro casos de estudio y una serie de parámetros, los cuales se analizan para siete latitudes ubicadas entre -1,4° y -30°, separadas las unas de las otras por aproximadamente 5°. Se presentan y discuten los resultados de más de 500 simulaciones para los siguientes conceptos: - recurso solar, desde la perspectiva de la disponibilidad de irradiación solar en distintas superficies de captación apropiadas para la integración de sistemas solares fotovoltaicos en edificaciones en bajas latitudes; - análisis de sombras, con objetivo de identificar los ángulos de sombras vertical (AVS) para protección de huecos acristalados en edificios de oficinas; - balance energético térmico, para identificar el efecto térmico del apantallamiento provocado por componentes fotovoltaicos en cubiertas, muros opacos y parasoles en ventanas en las cargas de refrigeración y consecuentemente en las demandas de energía eléctrica; - balance energético eléctrico, contrastando los resultados del balance térmico con la energía potencialmente generada en las envolventes arquitectónicas bajo estudio; - análisis económico, basado en un escenario de precios de la tecnología fotovoltaica de un mercado maduro y en la política de inyección a la red marcada por la actual normativa brasileña. Se han verificado los potenciales de ahorro económico que los sistemas activos fotovoltaicos podrían aportar, y asimismo se calculan diversos indicadores de rentabilidad financiera. En suma, esta investigación ha permitido extraer conclusiones que contribuyen al avance de la investigación y entender las condiciones que propician la viabilidad de la aplicación de componentes fotovoltaicas en las envolventes de edificios en Brasil, y hasta un cierto punto en otros países en latitudes equivalentes. ABSTRACT The hypothesis that inspired this thesis sustains that integration of photovoltaic components in the opaque envelope and shading elements of office buildings placed at low-latitude countries, using the specific case of Brazil, could increase its energy efficiency. This is possible because those components block a significant part of the incident solar irradiation, reducing its heating effect on the building and transforming its energy into electricity in such a way that the extra investments needed can be paid back in acceptable periods given the electricity bill savings they produce. In order to check this hypothesis, the main goal was to analyze the thermal and electrical performance of photovoltaic components integrated into roofs, opaque façades and window shadings. The first step is an introduction and discussion of the state of the art in the studied subjects, as well as the chosen methodology (which is theoretical), based on calculations and simulations. Starting from an office building located in Brazil, four case studies and their parameters are defined, and then analyzed, for seven cities located between latitudes -1.4° and -30°, with an approximate distance of 5° separating each one. Results of more than 500 simulations are presented and discussed for the following concepts: - Solar resource, from the perspective of irradiation availability on different surfaces for the integration of photovoltaic systems in buildings located at low latitudes; - Shading analysis, in order to determine the vertical shading angles (VSA) for protection of the glazed surfaces on office buildings; - Thermal energy balance, to identify the screening effect caused by photovoltaic components on roofs, opaque façades and window shadings on the cooling loads, and hence electricity demands; - Electric energy balance, comparing thermal energy balance with the energy potentially generated using the active skin of the buildings; - Economic analysis, based on a mature-market scenario and the current net metering rules established by the Brazilian government, to identify the potential savings these photovoltaic systems could deliver, as well as several indicators related to the return on the investment. In short, this research has led to conclusions that contribute to the further development of knowledge in this area and understanding of the conditions that favor the application of photovoltaic components in the envelope of office buildings in Brazil and, to a certain extent, in other countries at similar latitudes

Electrochromic Glazing and Evaluation of Visual and Non-Visual Effects of Daylight: Simulation Studies for Brasilia – Brazil

The employment of electrochromic glazing can be a solution to balance circadian lighting and avoid glare. This can be achieved by controlling daylight entering the room and may be useful within the context of highly glazed facades in buildings in hot climates. Nevertheless, the use of this technology is rarely discussed in this context. In this regard, the aim of this study is to investigate the electrochromic glazing for the lighting conditions, including visual and non-visual effects within the luminous context of Brasilia, Brazil. The method consisted of computer simulations of a representative highly glazed non-residential room with the comparison of electrochromic glazing and conventional clear glass. Climate Studio was used to evaluate the visual effects of light for the entire year, and ALFA for the evaluation of melanopic daylight illuminance, vertical illuminance, and melanopic daylight efficacy ratio (mel-DER) in four days, including two solstices and two equinoxes encompassing the beginning of the four seasons. Results for the electrochromic glazing showed a better balance between a minimum threshold of 250 lux of mel-EDI without exceeding 1,500 lux of vertical illuminance in comparison with the clear glass. This was achieved in 33.33% of the hours for the north, against 27.78% of the hours for the east, 29.17% for the west, and 24.72% for the south. For the clear glass, this balance was achieved in only 9.17% of the hours for north, 10.28% for east, 12.22% for west, and 15% for south. Regarding the spectrum, higher results of melanopic daylight efficacy ratio were observed for the clear glass over the four simulated days. The main conclusion was that the electrochromic glazing was capable of providing a better balance between visual and non-visual requirements and can be a suitable solution for highly glazed facades in Brasilia. Nevertheless, particularly for the north orientation, the supply of circadian lighting can be jeopardized when the electrochromic glazing remained at the dark state

An integrated design process in practice : a nearly zero energy building at the University of Brasília - Brazil

This study aims to present the design experience of LabZERO|UnB, an NZEB building awarded in a public call, that will be built on the University of Brasília campus. The method consisted of defining the design team and the Integrated Design Process (IDP), establishing assumptions and design guidelines, schematic design, initial computer simulations, design development, new simulations, and final calculations for the synthesis of energy performance. As a result, IDP proved to be efficient and underlined the possibility of translating research experiences into practice. The barriers and potentialities related to the coordination of a multidisciplinary team stand out, likewise the organization, planning, and achievement of goals. In the design concept of the 200m2 building, the basic assumption was the adequacy of the architecture to favor the use of passive resources, respecting the local climate, classified as high-altitude tropical climate. Moreover, bioclimatic strategies were used, such as the North/South orientation of main façades, narrow floor plan, limited windowwall ratio, and adequate construction materials, to optimize energy consumption. As a result, the distributed generation of electricity was estimated at 58.29 kWh/m2. a year and the final electricity demand was 34.29 kWh/m2. year. Hence, this process indicates the real possibility of reaching the zero energy balance

An Integrated Design Process in Practice: A Nearly Zero Energy Building at the University of Brasília - Brazil

This study aims to present the design experience of LabZERO|UnB, an NZEB building awarded in a public call, that will be built on the University of Brasília campus. The method consisted of defining the design team and the Integrated Design Process (IDP), establishing assumptions and design guidelines, schematic design, initial computer simulations, design development, new simulations, and final calculations for the synthesis of energy performance. As a result, IDP proved to be efficient and underlined the possibility of translating research experiences into practice. The barriers and potentialities related to the coordination of a multidisciplinary team stand out, likewise the organization, planning, and achievement of goals. In the design concept of the 200m2 building, the basic assumption was the adequacy of the architecture to favor the use of passive resources, respecting the local climate, classified as high-altitude tropical climate. Moreover, bioclimatic strategies were used, such as the North/South orientation of main façades, narrow floor plan, limited window-wall ratio, and adequate construction materials, to optimize energy consumption. As a result, the distributed generation of electricity was estimated at 58.29 kWh/m2. a year and the final electricity demand was 34.29 kWh/m2. year. Hence, this process indicates the real possibility of reaching the zero energy balance