Energy yield determination of concentrator solar cells using laboratory measurements

The annual energy conversion efficiency is calculated for a four junction inverted metamorphic solar cell that has been completely characterized in the laboratory at room temperature using measurements fit to a comprehensive optoelectronic model of the multijunction solar cells. A simple model of the temperature dependence is used redict the performance of the solar cell under varying temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are ighlighted.

Evaluation of the Magnetic Field Generated by the Inverter of an Electric Vehicle

In hybrid and electric vehicles, passengers sit very close to an electric system of significant power, which means that they may be subjected to high electromagnetic fields. The hazards of long-term exposure to these fields must be taken into account when designing electric vehicles and their components. Among all the electric devices present in the power train, the electronic converter is the most difficult to analyze, given that it works with different frequencies. In this paper, a methodology to evaluate the magnetic field created by a power electronics converter is proposed. After a brief overview of the recommendations of electromagnetic fields exposure, the magnetic field produced by an inverter is analyzed using finite element techniques. The results obtained are compared to laboratory measurements, taken from a real inverter, in order to validate the model. Finally, results are used to draw some conclusions regarding vehicle design criteria and magnetic shielding efficiency.

La influencia en el aislamiento acústicoa ruido aéreo de los aireadores en las ventanas compactas

En la actualidad, el crecimiento de la población urbana, el incremento de la demanda energética junto al desarrollo tecnológico impulsado en los últimos veinte años han originado un estudio y replanteamiento de los sistemas constructivos empleados. Como consecuencia se han establecido nuevos marcos normativos, marcando nuevos objetivos de confort y de demanda energética. En España, el Código Técnico de la Edificación (aprobado en el Real Decreto 314/2006 de 17 de Marzo) es el marco normativo que establece las exigencias que se deben cumplir al proyectar construir, usar, mantener y conservar los edificios, incluidas sus instalaciones, con el fin de asegurar la calidad, seguridad y salud del usuario, respetando en todo momento su entorno. Para asegurar el cumplimiento de las exigencias del Código Técnico de la Edificación (CTE), se han elaborado diferentes Documentos Básicos (DB). Entre ellos están los documentos básicos DB HR-Protección frente al ruido y el DB HS-Salubridad. En el DB HS 3 Calidad del aire interior, se establecen las condiciones que deben de adoptarse para que los recintos de los edificios se puedan ventilar adecuadamente, eliminando los contaminantes que se produzcan de forma habitual durante un uso normal de los edificios, de forma que se aporte un caudal suficiente de aire exterior y se garantice la extracción y expulsión del aire viciado por los contaminantes. En el apartado 3.1, Condiciones generales de los sistemas de ventilación, se indica que las viviendas deben disponer de un sistema general de ventilación donde el aire debe circular desde los locales secos a los húmedos. Para ello los comedores, los dormitorios y las salas de estar deben de disponer de aberturas de admisión, pudiéndose resolver esta cuestión técnica con diversas soluciones. El DB HR Protección frente al ruido del CTE, establece unos valores del aislamiento acústico a ruido aéreo, entre un recinto protegido y el exterior, en función del uso del edificio y del nivel sonoro continuo equivalente día, Ld de la zona donde se ubique el edificio. El hacer compatibles el cumplimiento de las exigencias de los dos Documentos Básicos anteriormente citados, origina algunas dificultades en los proyectos de edificación actuales. Los proyectistas tienen que recurrir en la mayoría de los casos a nuevos sistemas constructivos o duplicaciones de soluciones existentes, evitando la manipulación de los elementos de regulación de entrada de aire en las viviendas. El objetivo fundamental de la Tesis presentada es el estudio de los efectos que producen la colocación de sistemas de aireación permanente en el aislamiento acústico a ruido aéreo de las ventanas compactas. Se comprueba la influencia de cada uno de los componentes de la ventana compacta: perfiles, unidades de vidrio, sistema de apertura, cajón de persiana, persiana, aireadores, etc. en el aislamiento a ruido aéreo del sistema completo. Los ensayos acústicos se han realizado mediante dos métodos: conforme a la norma UNE-EN ISO 10140-2:2011 Medición en laboratorio del aislamiento acústico al ruido aéreo de los elementos de construcción y mediante intensimetría acústica acorde a la norma UNE-EN ISO 15186-1:2004 Medición del aislamiento acústico en los edificios y de los elementos de construcción utilizando intensidad sonora. Los resultados obtenidos podrán ser de gran utilidad para todos los profesionales que intervienen en el proceso edificatorio: arquitectos, ingenieros, instaladores, promotores, fabricantes de productos, etc., tanto en la obra nueva como en la rehabilitación. En un futuro, podrían incorporarse a los Catálogos y Documentos de Aplicación del CTE, así como a los nuevos programas informáticos de diseño y aislamiento acústico. Con el conocimiento adquirido y su aplicación, se contribuirá a la mejora de la calidad de una edificación más sostenible y eficiente. Se incrementará la productividad y la competitividad de los fabricantes de materiales y sistemas constructivos, aumentando el grado de satisfacción del usuario final con el consiguiente aumento de la calidad de vida de los ciudadanos. También se ampliará el conocimiento técnico de este tipo de sistemas y la compatibilidad entre las distintas exigencias marcadas por la normativa. ABSTRACT At present, the urban population growth, the increase of energy demand and the technological development in the last twenty years have led to a rethinking of the used building systems. As a result, new regulatory frameworks have been established, setting new goals of comfort and energy demand. In Spain, the Building Code, Código Técnico de la Edificación (CTE) (RD 314/2006 of March 17th) is the regulatory framework that establishes the requirements to be met by projecting, building, using, maintaining and preserving buildings, including its facilities in order to ensure the quality, safety and health of the user, always respecting the environment. To ensure compliance with the requirements of the CTE, different technical requirements Documentos básicos (DB) have been developed. Among them, are the DB-HR-Protection against noise and DB-HS-Health. In the DB-HS- part3, Indoor Air Quality, are set the conditions needed to be taken into consideration so that the building enclosures can be adequately ventilated, eliminating pollutants that occur regularly during normal use of the buildings, so that a sufficient airflow of outdoor is supplied and a removal and extraction of stale air pollutants is guaranteed. In section 3.1, General Terms of ventilation systems, is indicated that dwellings must have a general ventilation system where air can circulate from dry to wet enclosures. For this, dining rooms, bedrooms and living rooms should have air intake, being able to resolve this technical issue with various solutions. The DB-HR Protection against noise, provides sound insulation values of airborne sound transmission between a protected room and the outside, depending on the use of the building and the equivalent continuous sound level day, Ld, in the area where the building is located. Satisfying the requirements of the two requirements mentioned above causes some difficulties in current building project. Designers have to rely in most cases, to new construction elements or duplicate existing solutions, avoiding the manipulation of the air intakes elements. The main objective of this Thesis is the study of the effects of permanent intakes systems in the acoustic insulation against airborne noise transmission in compact windows. The influence of each of the components of the compact window is determined: frames, glass units, opening systems, shutter box, trickle vents, etc. in the airborne sound insulation of the entire system. The acoustic survey were performed using two methods: UNE-EN ISO 10140-2: 2011 Laboratory measurements of sound insulation of building elements and UNE-EN ISO 15186-1:2004 Measurement of sound insulation in buildings and of building elements using sound intensity. The obtained results may be useful for all professionals involved in the building process: architects, engineers, installers, developers, manufacturers, etc. in the new construction developments and in rehabilitation. In the future, it could be added to building catalogues and applications of the Spanish Building Code, as well as to the new design and sound insulation software. With the acquired knowledge and its application, there will be a contribution to improve the quality of a more sustainable and efficient construction. Productivity and competitiveness of manufacturers of building materials and components will improve, increasing the degree of satisfaction of the final user with a consequent increase in the quality of life of citizens. Technical knowledge of such systems and compatibility between the various requirements set by the legislation will also expand.

Passenger Exposure to Magnetic Fields due to the Batteries of an Electric Vehicle

In electric vehicles, passengers sit very close to an electric system of significant power. The high currents achieved in these vehicles mean that the passengers could be exposed to significant magnetic fields. One of the electric devices present in the power train are the batteries. In this paper, a methodology to evaluate the magnetic field created by these batteries is presented. First, the magnetic field generated by a single battery is analyzed using finite elements simulations. Results are compared to laboratory measurements, taken from a real battery, in order to validate the model. After this, the magnetic field created by a complete battery pack is estimated and results are discussed.