Introducción a la I+D+I a través de concursos de ideas: emprendimiento e Innovación en la formación de los ingeniero

Ponencia presentada en: VI Jornadas de Innovación Docente de la UBU, Burgos, 23 y 24 de febrero de 2012, organizadas por el Instituto de Formación e Innovación Educativa-IFIE de la Universidad de Burgo

A Numerical Simulation of an Experimental Melting Process of a Phase-Change Material without Convective Flows

The melting process of lauric acid in a square container heated from the top surface was numerically studied from an experimental case. Knowledge of this process is of special interest for computationally efficient modeling systems, such as PCM-enhanced photovoltaic panels in horizontal positions or energy storage using PCM embedded on flat surfaces. In these systems, the geometric arrangement of the PCM hinders the fluid-phase movements through natural convection, which slows the melting process and can cause overheating in the fluid phase. Using Ansys Fluent Software, three different approaches and two simulation methods, enthalpy-porosity and effective heat capacity, were developed for the numerical study. The results were compared with experimental measurements in a successful evaluation of the accuracy of computational fluid dynamics simulations. It could be observed that the effective heat capacity method presented significant advantages over the enthalpy-porosity method, since similar accuracy results were obtained, and a lower computational cost was required.The authors gratefully acknowledge the financial support provided by the Regional Government of Castilla y León under the “Support Program for Recognized Research Groups of Public Universities of Castilla y León” (BU021G19) and the Spanish Ministry of Science & Innovation under the R+D+i state program “Challenges Research Projects” (Ref. RTI2018-098900-B-I00)

Review of the legislative framework for the remuneration of photovoltaic production in Spain: a case study

Spain is among the European countries with the greatest photovoltaic potential. During the first decade of the 2000s, Spain was a European leader in installed photovoltaic power and job creation in the renewable energy sector, strongly influenced by a very favorable regulatory framework and public subsidies at a time of economic growth. That situation would be completely reversed with the regulatory changes introduced in 2012 to combat the tari deficit and the instability in the electricity supply system, problems accentuated by the economic crisis. The main objective of this study is to present an exhaustive review of the legislative changes that have a ected photovoltaic energy in Spain. Using real data on electricity production and the remuneration of a typical photovoltaic plant, we show that there was a very significant fall in the economic returns that investors had come to expect, within a system that prioritized, first and foremost, the initial investment rather than the levels of electricity production. The changes to the legislative framework a ecting a typical 100 kWp photovoltaic (PV) facility that entered into service before 2007 provoked a significant decrease of 8.7% in expected revenues, calculated from real data of production and income. These economic losses can be even higher, with a drop in revenue of almost 25% if the entire period of the installation’s useful life is analyzed. Public support for renewable energy is important for its introduction into the electricity market, but so is regulatory stability that o ers investment security and predictability for maintaining investment and development in the renewable energy sectorRegional Government of Castilla y León under the “Support Program for Recognized Research Groups of Public Universities of Castilla y León” (ORDEN EDU/667/2019) and the Spanish Ministry of Science, Innovation, and Universities under the I + D + i state program “Challenges Research Projects” (Ref. RTI2018-098900-B-I00

Real energy payback time and carbon footprint of a GCPVS

Grid connected PV systems, or GCPVS, produce clean and renewable energy through the photovoltaic e ect in the operation stage of the power plant. However, this is the penultimate stage of the facilities before its dismantlement. Before starting generating electricity with zero CO2 emissions, a negative energy balance exists mainly because of the embodied energy costs of the PV components manufacturing, transport and late dismantlement. First, a review of existing studies about energy life cycle assessment (LCA) and Carbon Footprint of PV systems has been carried out in this paper. Then, a new method to evaluate the Real Energy Payback Time (REPBT), which includes power looses due to PV panels degradation is proposed and di erences with traditional Energy Payback Time are analysed. Finally, a typical PV grid connected plant (100 kW nominal power) located in Northern Spain is studied in these sustainability terms. This facility has been firstly completely modelled, including PV modules, inverters, structures and wiring. It has been also considerated the energy involved in the replacement of those components with shorter lifespan. The PV panels degradation has been analysed through the comparison of normalised flash test reports on a significant sample of the installed modules before and 5 years after installation. Results show that real PV degradation a ect significantly to the Energy Payback Time of the installation increasing slightly a 4:2% more the EPBT value for the case study. However, along a lifespan of 30 years, the GCPVS under analysis will return only 5:6 times the inverted energy on components manufacturing, transport and installation, rather than the expected 9:1 times with the classical estimation

Net Energy Balance and Smart Grids in Spain: Integration with PV Systems

En este documento se presentan las principales configuraciones y reglamentos técnicos en España sobre Net Energy Balance Systems y Smart Grids. Esta falta de instalaciones es bastante interesante para los futuros desarrollos de fuentes de energía verde, especialmente fotovoltaicas. Los principales beneficios son la reducción de las pérdidas de energía en el sistema de distribución, la optimización de los recursos energéticos y un mejor seguimiento de la oferta de energía y la demanda de energía. Las redes inteligentes y los sistemas de equilibrio energético neto son las últimas tendencias en generación y distribución de energía eléctrica. Sus beneficios están ampliamente demostrados y contribuyen a reducir las emisiones de CO2 a la atmósfera y aumentar las tasas de eficiencia. La falta de apoyo público a la generación de energía fotovoltaica hace obligatorio buscar nuevos puntos de vista. Sin piensos en las políticas arancelarias, las enormes plantas fotovoltaicas no son atractivas hoy en día. Debemos centrarnos en los sistemas pequeños implementados en Smart Grids y apoyados con estrategias de Net Energy Balance. Esta es otra manera de apoyar la generación de energía verde y tiene grandes beneficios para los usuarios domésticos

Performance Indicators for Sun-Tracking Systems: A Case Study in Spain

pp. 292-302Current PV cells technology takes advantage mainly from beam radiation. In this context the sun-trackers are such devices for efficiency improvement. On the other hand, projected shadows between devices make mandatory to increase the distances between mounting systems. Thus, the land’s capacity for mounting PV panels can be dramatically decreased. This fact conducts us to wonder where the optimum efficient point is. First, in this paper different types of sun-tracking systems are classified according to the movement they perform (cinematic classification). Further, three real PV installations-fixed, horizontal-axis tracking and dual-axis mount tracking—located in the same geographical area in Spain (they are approximately under the same weather conditions) are analyzed. These installations have been studied in order to establish which one is the most efficient and affordable—Specific Energy Production (SEP) and Performance Ratio (PR) analysis. PVGIS solar radiation estimate tool has been used for comparing the theoretical radiation potential on each plant. The land requirements have been considered in the analysis of the Ground Cover Ratio (GCR) and the Surface Performance Ratio (SPR). Moreover, comparing three main financial indicators let us carry out a financial study: Payback Time (PBT), Net Present Value (NPV) and Internal Rate of Return (IRR). In the case study, final annual energetic results demonstrate that the dual-axis plant shows a relevant SEP advantage, but if we take into account the land occupied for this sort of devices we find much more profitable the horizontal-axis sun-tracking system, with a SPR value 4.24% higher than the fixed system we have studied. Its PBT is also a 22% lower than the dual-axis tracking installationS

Sun‐trackers profitability analysis in Spain

pp.1010-1022El objetivo principal de este estudio es analizar el rendimiento de los dispositivos de seguimiento solar en comparación con los sistemas de placaplana fija utilizando datos de un software de predicción de irradiación ampliamente utilizado (PVGIS). Analizamos los parámetros típicos comosuma diaria y mensual de irradiación global (HdandHm) o la producción media diaria y mensual estimada de electricidad (EhandEm) y también sus costos asociados y requisitos de tierra (generalmente descritos por la relación de cobertura del suelo,GCR ). Se observó que la influencia de estos dos últimos parámetros es bastante importante para el cálculo del tiempo de amortización de toda la instalación. Como resultado final, se concluye que aunque el rastreador de doble eje permite el máximo rendimiento energético, un 38% más alto que un sistema fijo en promedio, si tenemos en cuenta el valor GCR y calculamos la relación de rendimiento super-cara, la más eficiente configuración es el rastreador solar de eje horizontalS

Experimental analysis of a novel PV/T panel with PCM and heat pipes

A new design for the use of photovoltaic and thermal (PV/T) technology with thermal storage is reported in this work. In the new design, a phase change material (PCM) tank is added to the backside of the photovoltaic panel. The advantages of this design are the storage of thermal energy and the efficiency improvement of the photovoltaic (PV) panel as a result of the temperature control of the PV cell during the phase change process. In addition, a perimeter with a black surface surrounds the PV panel to increase the absorption of thermal energy. The thermal energy is then transferred to the backside of the PCM tank by heat pipes. One prototype with lauric acid as PCM was tested under two different operating configurations and resulted in an overall daily efficiency of 50% coulding be improve by controlling the PCM temperature during the day.Regional Government of Castilla y León, Spain (Ref. BU034U16) and the Spanish Ministry of Science, Innovation & Universities under the I+D+i state program “Challenges Research Projects” (Ref. RTI2018-098900-B-I00

Photosynthetic active radiation, solar irradiance and the CIE standard sky classification

Plant growth is directly related to levels of photosynthetic photon flux density, Qp. The improvement of plant-growth models therefore requires accurate estimations of the Qp parameter that is often indirectly calculated on the basis of its relationship with solar irradiation, RS, due to the scarcity of ground measurements of photosynthetic photon flux density. In this experimental campaign in Burgos, Spain, between April 2019 and January 2020, an average value of the Qp/Rs ratio is determined on the basis of measurements at ten-minute intervals. The most influential factor in the Qp/Rs ratio, over and above any daily or seasonal pattern, is the existence of overcast sky conditions. The CIE standard sky classification can be used to establish an unequivocal characterization of the cloudiness conditions of homogeneous skies. In this study, the relation between the CIE standard sky type and Qp/Rs is investigated. Its conclusions were that the Qp/Rs values, the average of which was 1.93 0.15 mol J�����1, presented statistically significant di erences for each CIE standard sky type. The overcast sky types presented the highest values of the ratio, while the clear sky categories presented the lowest and most dispersed values. During the experimental campaign, only two exceptions were noted for covered and partial covered sky-type categories, respectively, sky types 5 and 9. Their values were closer to those of categories classified as clear sky according to the CIE standard. Both categories presented high uniformity in terms of illumination.Spanish Ministry of Science and Innovation, grant number RTI2018-098900-B-I00 and Consejería de Educación, Junta de Castilla y León, grant number BU021G1

New device for the simultaneous measurement of diffuse solar irradiance on several azimuth and tilting angles

A device is proposed for the measurement of diffuse solar irradiance on tilted surfaces pointing-to as well as fixed on the equatorial direction. Most commercial devices are not designed for this purpose. Here, we present a specific design for a system based on a single multi-lobe shadow-ring that allows us to measure diffuse irradiance with several tilted pyranometers – from 60 to 90 degrees from the horizontal plane – and on different azimuth angles. This first prototype allows us to measure in the four cardinal directions. The ring is designed to minimize the covered celestial dome observed by each sensor. Moreover, the complete device needs a very small installation area and its simplicity means it is inexpensive and easy to operate. The measurements have subsequently to be corrected with a geometrical correction factor that takes into account the portion of the sky vault blocked by the shadow-ring. These measurements are essential for estimating solar potential on tilted surfaces – such as building façades – and for improving current anisotropic solar models, among many other applications.Spanish Government (grant ENE2011-27511