Solar and lighting transmission in complex fenestration systems with perforated solar protection systems

Santiago de Chile is a city with a semi-arid climate, with prolonged periods of high temperature and solar radiation. In recent years, in this city, office buildings have been built with high window to wall ratio (WWR) facades. 65% of the office buildings built in the period 2005-2014 have a WWR higher than 60%. Only 5% of these buildings showed an efficient glazed façade solar protection device. One of these systems corresponds to an exterior textile solar protection. This type of systems, together with the perforated screens, could be effective solutions for the solar protection of glazed facades, reducing the cooling energy consumption of buildings, without risking the visual comfort of the occupants. The objective of this research is to evaluate the solar transmission and lighting of seven perforated solar protection systems. Three of these systems correspond to external textile solar protections, and the remaining four are perforated metallic screens. The evaluation was carried out by applying an experimental protocol in two different calorimeters that simulate an office space. In one of the calorimeters, the solar protection systems are installed while the other is used as a reference without any solar protection system. Measurements were made with illuminance sensors and pyranometers. The horizontal illuminance sensors from Konica Minolta (T10) were installed outdoor and at different points inside the calorimeters. Near the facade, vertical indoor and outdoor pyrometers were installed (Kipp Zonnen, CMP11 and Sp Lite 2). The measurements on the north facade are made in summer on clear days. The measurements showed a reduction in solar transmission of 82.1% (metallic screen, 40% drilling) to 94.7% (cloth, 3% drilling) and from 70.8% to 95.4% in the transmission of lighting respectively

Numerical thermal model of a double-glazed window filled with phase change materials

Phase change materials (PCMs) glazing systems might be able to improve the building energy performance because of controlling solar heat gains and peak heating and cooling loads. EnergyPlus, a state-of-the-art energy simulation tool, allows simulating the heat transfer through opaque elements that incorporate PCMs. However, EnergyPlus does not allow this for transparent elements with PCMs. As consequence, the main objective of this research is to develop a numerical thermal model of double glazing windows with PCM in the cavity to be coupled with EnergyPlus in the future. To develop the numerical heat transfer model, the sensible and latent heat of the PCM is numerically modelled in MATLAB. This model is used to evaluate the impact of PCM on the inner surface temperature of the window and the Predicted Mean Vote (PMV) in Santiago of Chile. The PCM RT25HC of Rubitherm® shows the better performance because it keeps the internal surface temperature of the window near of the comfort range for more time and the Predicted Mean Vote (PMV) below 1.0

La “metropolización” en colombia: una aproximación crítica a su institucionalidad. resumen

Los colombianos crecimos con la idea de que el nuestro es un país de regiones. Sin embargo, esta caracterización hoy resulta inexacta. De hecho, espacialmente hablando, somos fundamentalmente un país de grandes ciudades. También de regiones y de pequeños municipios rurales (Bustamante, 2010).Como sugiere lo anterior, son muchos los fenómenos territoriales que nos caracterizan. Algunos de ellos serían: la explosiva aglomeración urbana; la persistente diversidad regional; los grandes desequilibrios, las desigualdades y la fuerte divergencia interterritorial; la población y las actividades económicas concentradas en la mitad del territorio; la desarticulación y la débil integración de las diferentes partes del espacio nacional

Multi-Lagrangians, Hereditary Operators and Lax Pairs for the Korteweg-de Vries Positive and Negative Hierarchies

We present an approach to the construction of action principles for differential equations, and apply it to field theory in order to construct systematically, for integrable equations which are based on a Nijenhuis (or hereditary) operator, a ladder of action principles which is complementary to the well-known multi-Hamiltonian formulation. We work out results for the Korteweg-de Vries (KdV) equation, which is a member of the positive hierarchy related to a hereditary operator. Three negative hierarchies of (negative) evolution equations are defined naturally from the hereditary operator as well, in the context of field theory. The Euler-Lagrange equations arising from the action principles are equivalent to the original evolution equation + deformations, which are obtained in terms of the positive and negative evolution vectors. We recognize the Liouville, Sinh-Gordon, Hunter-Zheng and Camassa-Holm equations as negative equations. The ladder for KdV is directly mappable to a ladder for any of these negative equations and other positive equations (e.g., the Harry-Dym and a special case of the Krichever-Novikov equations): a new nonlocal action principle for the deformed system Sinh-Gordon + spatial translation vector is presented. Several nonequivalent, nonlocal time-reparametrization invariant action principles for KdV are constructed. Hamiltonian and Symplectic operators are obtained in factorized form. Alternative Lax pairs for all negative flows are constructed, using the flows and the hereditary operator as only input. From this result we prove that all positive and negative equations in the hierarchies share the same sets of local and nonlocal constants of the motion for KdV, which are explicitly obtained using the local and nonlocal action principles for KdV.Comment: Final version, accepted in JMP; RevTeX, 31 page

Evaluación comparativa de impacto ambiental aplicando la matriz de Conesa-Fernández, el método de Leopold y método de Batelle, en el proyecto de mejoramiento del servicio de transitabilidad de un sector del eje de integración vial norte, en los distritos de Yura y Cerro Colorado - Arequipa

En esta investigación se hace una evaluación de impacto ambiental para un proyecto vial que tiene un área de influencia entre los distritos de Yura y Cerro Colorado del departamento de Arequipa. Primero se hace una identificación de las actividades que se realizan por el proyecto en las diferentes etapas del mismo. Los métodos que se utilizan para evaluar los impactos ambientales de estas actividades son el método de impacto ambiental de Conesa Fernández (1997), la matriz de Leopold y la matriz de Batelle, esto con el propósito de comparar los resultados de los tres métodos y discernir en el mejor método de evaluación. Los resultados del método Conesa-Fernández fueron que existen 198 impactos negativos de grado leve y moderado y 129 impactos positivos leves y moderados que en su mayoría afectan al medio económico. Con el método de la matriz de Leopold se consigue una puntuación total positiva de 1284, lo que significa que el proyecto trae más impactos positivos que negativos. Con la matriz de Batelle, se concluye que existen 9 señales de riesgo en parámetros ambientales con el proyecto en la zona afectada. Después de hallados los resultados de la evaluación ambiental se comparan los métodos utilizando el método de criterio analítico completo, resultando como mejor método la matriz de Conesa-Fernández. Para finalizar la investigación se proponen 6 programas de gestión ambiental como parte de un plan de manejo ambiental general que se plantea realizar en cinco meses durante la construcción del proyecto vial y se establece un presupuesto de S/520,111.81