Energy performance evaluation of a photovoltaic window

A photovoltaic window specially built by a manufacturer has been studied. An amorphous silicon photovoltaic module encapsulated between two transparent glass sheets, an air chamber and a second double glass sheet with an air chamber forms the photovoltaic window. Everything is framed in a PVC structure. The effective dimensions of the a-Si photovoltaic module are 0.57x1.17 m2, equivalent to a standard measurement of 0.60x1.20 m2. To know the electrical characteristics of PV window in standard test conditions, a test in accordance with IEC standard 61646 it has carried out. A peak power of 50.74 Wp was obtained. Measurements of energy production in real sunlight were carried out. The window was placed vertically facing south on a test bench. Measurements of the energy produced by the photovoltaic window were made in several sunny days of August and September 2016 from sunrise to sunset. On average, the irradiance received on the plane of the photovoltaic window was 4114 Wh/m2 and the energy produced 71.2 Wh each day. These results match those obtained using the Malaga radiation databases. For one square meter of the window studied, 79.868 kWh/m2/year are obtained, when an overall efficiency of 0.8 is considered. Integrating this PV window in a building in Malaga (Spain), an annual electric production of 345030 kWh is obtained when a glazing surface of 4320 m2 is considered. This energy is enough to meet the annual electricity needs of the 68 household of the building.Universidad de Málaga. Campus de Excelencia Internacional Andalucia Tech. This work is partially derived from the contract nº 8.06/5.31.4644 Libre Evolución de Energía S.L

Exergy analysis of a solar photovoltaic module

PV energy is the direct conversion of solar radiation into electricity. In this paper, an analysis of the influence of parameters such as global irradiance or temperature in the performance of a PV installation has been carried out. A PV module was installed in a building at the University of Málaga, and these parameters were experimentally determined for different days and different conditions of irradiance and temperature. Moreover, IV curves were obtained under these conditions to know the open-circuit voltage and the short-circuit current of the module. With this information, and using the first law of thermodynamics, an energy analysis was performed to determine the energy efficiency of the installation. Similarly, using the second law of thermodynamics, an exergy analysis is used to obtain the exergy efficiency. The results show that the energy efficiency varies between 10% and 12% and the exergy efficiency between 14% and 17%. It was concluded that the exergy analysis is more suitable for studying the performance, and that only electric exergy must be considered as useful exergy. This exergy efficiency can be improved if heat is removed from the PV module surface, and an optimal temperature is reached.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Las energías renovables

El desarrollo sostenible se concibe para mejorar la calidad de vida del ser humano sin que ello suponga peligro para el bienestar de actuales y futuras generaciones. Un objetivo que pone de relieve la estrecha relación entre el suministro de fuentes llimpias como el viento, el sol y el mar y su consumo eficiente

2022-8 Slutsky Matrix Symmetry: A New Behavioral Condition

The Slutsky matrix function encodes all the information about local variations in demand with respect to small (Slutsky) compensated price changes. When the demand function is the result of utility maximization the Slutsky matrix is symmetric. However, symmetry does not imply rationality. Here, we provide a necessary and sufficient condition for Slutsky symmetry. The new condition requires symmetric attention to compensated price-paths

Moldeamiento de la comprensión y profundización de un concepto

La matemática tradicional se ha enfocado en enseñar números, formulas y procesos mecánicos, los mismos que no tienen necesariamente una relación con los problemas del diario vivir de las personas; es por eso que este estudio se fundamenta en relacionar problemas reales o situaciones cotidianas, que permitan al estudiante generar un conocimiento propio a partir de una experiencia de la vida real. El propósito de la aplicación de este modelamiento matemático busca generar un concepto propio o interpretación de la relación del fenómeno natural con el fenómeno matemático mediante la proporcionalidad mayor a 1 y menor a 1

Generación de hidrógeno a partir de energia solar para su uso en vehículos con célula de combustible

Tradicionalmente se ha considerado a los combustibles fósiles como fuente de energía barata y abundante. Sin embargo, la disminución de las reservas y el aumento de la demanda mundial de energía, además de la contaminación que producen, hacen insostenible el modelo energético basado en este tipo de combustibles. Por ello se hace necesario un nuevo modelo basado en el empleo de fuentes de energía renovable. El principal inconveniente de las energías renovables es el desfase entre producción y demanda, por lo que muchas veces es necesario acumular la energía producida para tenerla disponible en el momento en el que se demanda. Hasta ahora, la forma más extendida de acumular energía en instalaciones de energía renovable es mediante el empleo de baterías. Sin embargo, el problema de la acumulación de grandes cantidades de energía puede superarse mediante la tecnología del hidrógeno. El hidrógeno no es una fuente de energía sino un vector energético puesto que no existen yacimientos. Por lo tanto hay que obtenerlo a partir de otras sustancias. La manera más sencilla y limpia de extraer hidrógeno es del agua mediante la electrolisis, empleando energías renovables para generar la energía eléctrica necesaria. En este proceso no se generan emisiones contaminantes. En este trabajo se ha diseñado una estación de repostaje de vehículos de pila de combustible en un campo de golf. La estación emplea energía solar fotovoltaica para generar el hidrógeno necesario mediante electrolizadores. El hidrógeno se almacena en estado gaseoso en depósitos a presión y se comprime empleando también energía solar fotovoltaica. Se ha calculado que para satisfacer la demanda anual de hidrógeno hacen falta 117 módulos alimentando a 6 electrolizadores. El modelo de módulo fotovoltaico escogido es el SUNTECH STP320S. El electrolizador es el ACTA EL1000, que produce 1 Nm3/h de hidrógeno a 30 bar consumiendo 4,78 kW. El modelo de inversor de red escogido es el Sunny Tripower 15000 TL HE del fabricante SMA. Debido a que la demanda de hidrógeno no coincide con su producción, es necesario acumular el hidrógeno producido. El hidrógeno que se debe tener disponible requiere un volumen para los depósitos de baja presión de 118 m3 y 12,2 m3 para los de alta presión A partir de la demanda energética y la generación de hidrógeno, se ha obtenido, con un programa desarrollado en MatLab, la curva de la cantidad de hidrógeno que se debe tener acumulada cada día del año. Los resultados muestran que el sistema de generación diseñado cubre la demanda anual de hidrógeno para el funcionamiento de las células de combustible de los vehículos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

2022-9 A Rationalization of the Weak Axiom of Revealed Preference

Samuelson’s (1938) weak (generalized) axiom of revealed preference– WGARP–is a minimal and appealing consistency condition of choice. We offer a rationalization of WGARP in general settings. Our main result is an exact analog of the celebrated Afriat’s theorem, but for WGARP. Its ordinal rationalization is in terms of an asymmetric and locally nonsatiated preference function. Its cardinal rationalization uses a coalitional multi-utility (CMU) maxmin representation with a coherency restriction on the coalition structure. Effectively, the CMU representation aggregates piecemeal preferences within the decision maker (multiple rationales without preference reversals that allow for transitivity violations). Basic consumer theory and welfare analysis are also developed. Extensions to the weak axiom of revealed preference–WARP–and choices obeying the law of demand are included

Factores que determinan la permanencia de las micro y pequeñas empresas: Estudio de caso en Santa Ana Chiautempan, Tlaxcala

La permanencia de las empresas responde a diversos factores internos y externos, así como la combinación entre ellos. En el caso de las micro y pequeñas empresas (Mypes), las causas que ponen en riesgo su permanencia se hacen más evidentes, pues ante los cambios dinámicos del mercado, estas son más vulnerables dada su estructura organizativa y disponibilidad de recursos. Por lo anterior, este artículo tiene como objetivo conocer los principales factores que determinan la permanencia de las Mypes en el municipio de Chiautempan. El análisis se sustenta en un trabajo de campo realizado recientemente y en el cual se abordó una temática similar, cuya base de datos permite detectar aquellos factores que intervienen en mayor grado dentro de la empresa para su permanencia, como son los aspectos financieros y administrativos, las características del personal, uso de tecnología, y factores externos. Todo ello le da un carácter a esta investigación de tipo mixta, explicativa y descriptiva. Del análisis de resultados se pudo concluir que los factores que más ponen en riesgo la permanencia de las empresas son los aspectos financieros, el nivel de capacitación del personal, la eficiencia administrativa, el uso de tecnologías y los factores externos del mercado

Analysis of a PV Window for Building Integrated Photovoltaic (BIPV) Applications

An amorphous silicon photovoltaic module encapsulated between two transparent glass sheets, an air chamber and a second double glass sheet with an air chamber forms the photovoltaic window. Everything is framed in a PVC structure. The effective dimensions of the a-Si photovoltaic module are 0,57 m x 1,17 m, equivalent to a standard measurement of 0,60 m x 1,20 m. To know the electrical characteristics of PV window in standard test conditions, a test in accordance with IEC standard 61646 and 61215 was carried out. A peak power of 50,74 Wp was obtained and a power uncertainty of ± 6,78% was found. The PV window was placed in a test bench installed on the rooftop of the building of the Andalusian Institute of Renewable Energies, at Málaga (36,73 N; 4,55 W). The test bench allows an adjustment of both azimuth and inclination. A pyranometer was used to measure the global irradiance on the window plane, and a temperature sensor measures its temperature. The photovoltaic window was placed in vertical position facing South. A protocol for data collection that allows knowing the instantaneous power generated by the photovoltaic window has been developed. The irradiance received in a sunny day on the plane of the photovoltaic window was 4114 Wh/m2 and the energy produced was 71,2 Wh. These values are consistent with radiation data obtained from databases and the power value obtained from PV window under standard test conditions. The production of electricity, the economic savings, and CO2 emissions avoided will be analyzed if PV semi-transparent windows were used to replace the glazing skylight of the Industrial Engineering School of Malaga. It will result a BIPV system of 122,73 kWp that could produce 198 MWh per year, save € 27738 and avoid the emission into the atmosphere of 76 tons of CO2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Performance of a Photovoltaic Pumping System

In this work, a PV pumping system was installed in a building at the University of Malaga. The system simulates a conventional PV pumping system which in real conditions would supply a small agricultural installation. In the installation under examination it has been find that it is possible to improve the overall efficiency of the system obtaining a similar volume of water with a less photovoltaic modules installed. It can be concluded that the optimal performance allow a lower investment cost. Also a lower surface for the PV generator is a benefit.Pumping water with solar photovoltaic (PV) is an application of particular interest in isolated systems. This technology has proven over the years to be an effective way to supply drinking water to communities, as well as for agricultural use (irrigation) and livestock (troughs). The earlier installations of PV pumping were based on the use of DC motors of medium and low power directly coupled to the PV generator operating centrifugal pumps. Later they have been proposing and using various types of systems based on different combinations of DC motors, AC motors, DC brushless motors, centrifugal pumps, positive displacement pumps, DC/DC converters and DC/AC inverters. They all have the common characteristic of being a result of specific developments to efficiently use in PV pumping systems. In this work a PV pumping system was installed on a building at the University of Malaga. The system simulates a conventional PV pumping system. A set of experiments has been carried out to study the performance of the system. In the installation studied, it has been proved that it is possible to improve the overall efficiency of the system by reducing the photovoltaic power installed to obtain the same volume of water. As a conclusion it may be said that a lower investment and less surface occupied by photovoltaic system is achieved.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec