Methodology for estimating building integrated photovoltaics electricity production under shadowing conditions and case study

Building integrated photovoltaic (BIPV) systems are a relevant application of photovoltaics. In countries belonging to the International Energy Agency countries, 24% of total installed PV power corresponds to BIPV systems. Electricity losses caused by shadows over the PV generator have a significant impact on the performance of BIPV systems, being the major source of electricity losses. This paper presents a methodology to estimate electricity produced by BIPV systems which incorporates a model for shading losses. The proposed methodology has been validated on a one year study with real data from two similar PV systems placed on the south façade of a building belonging to the Technical University of Madrid. This study has covered all weather conditions: clear, partially overcast and fully overcast sky. Results of this study are shown at different time scales, resulting that the errors committed by the best performing model are below 1% and 3% in annual and daily electricity estimation. The use of models which account for the reduced performance at low irradiance levels also improves the estimation of generated electricity

Edificios fotovoltaicos conectados a la red eléctrica: caracterización y análisis

Los sistemas fotovoltaicos conectados a la red eléctrica, y en particular los llamados "Edificios Fotovoltaicos Conectados a la Red" (EFCR), constituyen la aplicación de la energía solar fotovoltaica que mayor expansión ha experimentando en los últimos años, y en un número cada vez mayor de países. Semejante situación constrasta, no obstante, con la ausencia de métodos de caracterización y análisis que faciliten una buena práctica de la ingeniería de los sistemas fotovoltaicos. Tal es el bjetivo de la presente tesis doctoral, en concreto el desarrollo de la ingeniería asociada al diseño, caracterización y análisis de EFCR. El trabajo realizado en esta línea se presenta estructurado en cuatro capítulos, más uno de conclusiones finales, con los que se pretende analizar los EFCR en sus distintas facetas complementarias. El primer capítulo realiza una presentación general de los EFCR, en la que se describen sus bloques funcionales, sus características más importantes, y se revisa el estado del arte de estos sistemas a nivel mundial. El capítulo 2 aborda el estudio de los EFCR desde una perspectiva energética, a la vez que presenta un método de modelado propio que combina análisis teórico y trabajo experimental, para predecir la energía útil anual generada por un EFCR. El método propuesto presenta la ventaja añadida de proporcionar las pérdidas del sistema con respecto de un sistema óptimo, estableciendo así una distinción entre lo que es tecnológicamente esperable, dadas las características del sistema, y las pérdidas debidas a las condiciones de operación reales, fallos, etc. El capítulo se completa con un ejemplo de aplicación práctica del método desarrollado, realizada en un EFCR real, el constituido por la sede del Instituto de Energía Solar. El capítulo 3 analiza los EFCR desde el punto de vista del grado de abastecimiento del consumo del edificio que puede ser proporcionado por el sistema fotovoltaico. Se propone un procedimiento de modelado basado en el balance energético característico de estos sistemas, que sólo precisa del conocimiento de determinadas características del sistema fotovoltaico, así como sencillos parámetros de consumo del edificio. El modelo, validado con datos reales de consumo pertenecientes a EFCR y viviendas convencionales de Alemania y España, es además susceptible de utilización como herramienta de planificación energética, en la medida que permite estimar el efecto sinérgico derivado de la existencia de numerosos EFCR conectados a una misma línea de la red eléctrica. El capítulo 4 realiza una valoración de los EFCR desde dos perspectivas: la clásica económico-financiera, combinando los métodos propuestos en capítulos anteriores con herramientas de la Teoría de Análisis de inversiones, y aquélla que considera el impacto que supone el EFCR en su entorno económico, social y medioambiental. A continuación se revisa la experiencia de tres países especialmente involucrados en la promoción de los EFCR —Estados Unidos, Alemania y Holanda—, cuya enseñanza juzgamos de enorme valía y aprovechamiento. El capítulo finaliza con un análisis del potencial que presentan los EFCR en España, seguido de diversas consideraciones relativas a un posible plan nacional de fomento de los EFCR. Por último, el capítulo 5 recoge las conclusiones más importantes del trabajo realizado y propone una serie de líneas de investigación futuras que consideramos relevantes para el futuro de los EFCR

Aplicación web para a xestión da formación bonificada nas empresas

[Resumo] A formación continua das persoas, unha vez comezan a desenvolver a súa vida laboral, é un proceso moi importante para seguir aumentando as súas capacidades e aptitudes. Dita formación supón un custo para as empresas que queiran formar ós seus traballadores, pero existe a FUNDAE que bonifica a aquelas empresas que realizan estas accións, á cal hai que comunicarlle toda a información que precisa mediante uns formularios que presenta na súa páxina web ou por medio de entidades externas, provocando neste último caso unha perda do control do proceso co seu consecuente custo. Para axudar a facilitar esta comunicación, crearase unha aplicación web que permita rexistrar usuarios asociados a empresas e posibilitar que estes empreguen a aplicación para que lles sexa máis doado solicitar axudas para a formación dos seus traballadores, podendo rexistrar nesta aplicación información sobre os centros de formación, os formadores, as accións formativas e os grupos formativos. A aplicación tamén permitirá que os seus usuarios poidan xerar ficheiros XML para comunicar a información das súas formacións á plataforma da FUNDAE que concede as axudas.[Abstract] Continuous training of people, when they have already started their working life, is a very important process to continue increasing their own capabilities and skills. This training represents a cost for companies that want to train their workers, but there is the FUNDAE that rewards those companies that carry out these actions. It’s necessary to communicate to the FUNDAE all the information that it requests through the forms on its website or by external entities, causing in this case a loss of process control and an additional cost. To help make this happen, a web application will be created that allows to register companies as users and that enables these users to use the application to make it easier for them to request financial aid for the training of their employees. This appliacation also also allows information about the training centers, the trainers, the formative actions and the formative groups. The application will also allow users to generate XML files to communicate their training informaton to the FUNDAE platform, the granting authority aid.Traballo fin de grao. Enxeñaría Informática. Curso 2020/202

A Semi-Distributed Electric Demand-Side Management System with PV Generation for Self-Consumption Enhancement

This paper presents the operation of an Electrical Demand-Side Management (EDSM) system in a real solar house. The use of EDSM is one of the most important action lines to improve the grid electrical efficiency. The combination between the EDSM and the PV generation performs a new control level in the local electric behavior and allows new energy possibilities. The solar house used as test-bed for the EDSM system owns a PV generator, a lead-acid battery storage system and a grid connection. The electrical appliances are controllable from an embedded computer. The EDSM is implemented by a control system which schedules the tasks commanded by the user. By using the control system, we define the house energy policy and improve the energy behavior with regard to a selected energy criterion, self-consumption. The EDSM system favors self-consumption with regard to a standard user behavior and reduces the energy load from the grid

Luminous and solar characterization of PV modules for building integration

The optical characterization of different PV modules for integration in buildings (BIPV) is presented in this paper. The investigated PV modules are laminated glasses (PV laminates) suitable for integration in façades and windows. They are made of different PV cell technologies and some of them present a certain transparency degree, making possible to combine daylighting properties with solar control and electrical generation. The approach is based on spectral UV/vis/NIR reflectance and transmittance measurements of the different considered samples, both at normal incidence and as a function of the angle of incidence when it is possible. The European standard protocols are used to determine the luminous and the solar characteristics of each sample, enabling the optical assessment of these PV modules as building elements. The results indicate the good properties of PV laminates in terms of daylighting and solar control capabilities allowing a feasible efficient integration in building façades and windows. The obtained characteristic parameters can be used to simulate the influence in the energy balance of a building of different types of PV modules integrated in façade or window elements. © 2015 Elsevier B.V. All rights reserved

Optical characterisation of semi-transparent PV modules for building integration

A complete characterisation of PV modules for building integration is needed in order to know their influence on the building’s global energy balance. Specifically, certain characteristic parameters should be obtained for each different PV module suitable for building integrated photovoltaics (BIPV), some by direct or indirect measurements at the laboratory, and others by monitoring the element performance mounted in real operating conditions. In the case of transparent building envelopes it is particularly important to perform an optical and thermal characterization of the PV modules that would be integrated in them. This paper addresses the optical characterization of some commercial thin-film PV modules having different degrees of transparency, suitable for building integration in façades. The approach is based on the measurement of the spectral UV/Vis/NIR reflectance and transmittance of the different considered samples, both at normal incidence and as a function of the angle of incidence. With the obtained results, the total and zoned UV, visible and NIR transmission and reflection values are calculated, enabling the correct characterization of the PV modules integrated in façades and the subsequent evaluation of their impact over the electrical, thermal and lighting performance in a building

‘State-of-the-art’ of building integrated photovoltaic products

During the last decades, the photovoltaic (PV) modules and their associated architectural materials are increasingly being incorporated into the construction of the building envelope such as façade, roof and skylights in the urban centers. This paper analyzes the-state-of-the-art of the PV elements and construction materials which are advertised as BIPV-products at the most important companies in the world. For this purpose 136 companies and 445 PV elements have been investigated and analyzed from a technical and architectural point of view. Also, the study has been divided into two main groups according to industry which producing the product: BIPV-Modules, which comes from the PV modules manufacturers and consist of standard PV-modules with some variations in its aesthetic features, support or dimensions; and PV-Constructions Elements, which consist of conventional constructive elements with architectural features intentionally manufactured for photovoltaic integration. In advance for conclusions, the solar tile is the most common PV-constructions element, the Si-crystalline is the most widely used PV technology, and the BIPV-urban furniture is the fastest growing market experienced in recent years. However, it is clear the absences of innovative elements which meet at the same time both the constructive purpose as the quality standards of PV technology

Effects of large-scale PV self-consumption on the aggregated consumption

Self-consumption is modifying the classical structure of the electrical grids worldwide. This energy supply method allows a distributed energy generation and the possibility of involving citizens in the electrical grid. Many countries have defined or are defining rules regarding self-consumption because of the evidence of its unstoppable growth. From the technical point of view, there are numerous associated advantages to the self-consumption, nevertheless it represents a new challenge in the management and design of the electrical grids. In general, the main generation technology for self-consumption is the PV energy. The PV generators are installed in a facility and their generation can be considered as a reduction on the local consumption or even negative consumption. Therefore, high penetration of PV self-consumption will modify the aggregated consumption shape of the electrical grid. The electrical grid should be able to respond to this new shape by adapting generation, controlling consumption or using storage systems. In this paper, we analyze the effects of high penetration of PV self-consumption on the aggregated consumption of the Spanish electrical grid. For this analysis we use historical solar resource data from different cities of Spain and historical data of the aggregated consumption of the country. The results show that PV self-consumption can smooth the aggregated consumption shape, mainly during summer periods. On the other hand, the PV self-consumption can increase the variability of the aggregated consumption shape for high penetration levels

Integral energy performance characterization of semi-transparent photovoltaic elements for building integration under real operation conditions

In this paper, a methodology for the integral energy performance characterization (thermal, daylighting and electrical behavior) of semi-transparent photovoltaic modules (STPV) under real operation conditions is presented. An outdoor testing facility to analyze simultaneously thermal, luminous and electrical performance of the devices has been designed, constructed and validated. The system, composed of three independent measurement subsystems, has been operated in Madrid with four prototypes of a-Si STPV modules, each one corresponding to a specific degree of transparency. The extensive experimental campaign, continued for a whole year rotating the modules under test, has validated the reliability of the testing facility under varying environmental conditions. The thermal analyses show that both the solar protection and insulating properties of the laminated prototypes are lower than those achieved by a reference glazing whose characteristics are in accordance with the Spanish Technical Building Code. Daylighting analysis shows that STPV elements have an important lighting energy saving potential that could be exploited through their integration with strategies focused to reduce illuminance values in sunny conditions. Finally, the electrical tests show that the degree of transparency is not the most determining factor that affects the conversion efficiency

Design, development and construction of an outdoor testing facility for semi-transparent photovoltaic modules

Building-integrated Photovoltaics (BIPV) is one of the most promising technologies enabling buildings to generate on-site part of their electricity needs while performing architectural functionalities. A clear example of BIPV products consists of semi-transparent photovoltaic modules (STPV), designed to replace the conventional glazing solutions in building façades. Accordingly, the active building envelope is required to perform multiple requirements such as provide solar shading to avoid overheating, supply solar gains and thermal insulation to reduce heat loads and improve daylight utilization. To date, various studies into STPV systems have focused on their energy performance based on existing simulation programs, or on the modelling, normally validated by limited experimental data, of the STPV modules thermal behaviour. Taking into account that very limited experimental research has been conducted on the energy performance of STPV elements and that the characterization in real operation conditions is necessary to promote an energetically efficient integration of this technology in the building envelope, an outdoor testing facility has been designed, developed and built at the Solar Energy Institute of the Technical University of Madrid. In this work, the methodology used in the definition of the testing facility, its capability and limitations are presented and discussed