Gabino Almonacid - Academia.edu (original) (raw)
Papers by Gabino Almonacid
The main purpose of the present study is presenting the FIVE Project (Fotovoltaico Integrado en V... more The main purpose of the present study is presenting the FIVE Project (Fotovoltaico Integrado en Vehículos de Emergencias) which focuses on the integration of a PV system on a health emergency vehicle (1) (2) (3). This new idea extends the use of photovoltaic technology into the improvement of the performance of this type of vehicles where the high electric consumption
Journal of Solar Energy Engineering, 2012
Frequently changing regulation codes, photovoltaic (PV) technology progress and variations in eco... more Frequently changing regulation codes, photovoltaic (PV) technology progress and variations in economic parameters that determine a specific economic scenario make a prospective owner of photovoltaic grid-connected systems (PVGCS) on buildings require information concerning the profitability of their investment on these systems. Hence, an analysis of the main economic factors of PVGCS on buildings addressed to ascertain their influence on the latter profitability is demanded and welcome. Consequently, a sensitivity analysis of some profitability indices such as the net internal rate of return, the net present value, and the discounted payback time has been carried out. This sensitivity analysis is aimed at demonstrating the influence on these indices of possible changes in the factors that are involved in their estimation. Two scenarios have been considered that closely resemble two top PV geographical areas: Germany and Spain. The results obtained here provide clear evidence that fa...
El Girasol, a two axis tracking PV system of 9.6 kWp, connected to the grid at Jaén University ca... more El Girasol, a two axis tracking PV system of 9.6 kWp, connected to the grid at Jaén University campus has reach a yield of 2,140 kWh/kWp·year. It is one of the highest productivity reported up to now in PV Systems. It is presented in this paper the description of the system and the working analysis along its first year operation. Related to the system behaviour, we would like to highlight the following performances: global efficiency of 11.1 %; performance ratio of 78.2%, a yield increase compared with a fixed and ideally faced one of 49% and high operation reliability and minimal maintenance needs.
Los ultimos datos del crecimiento del sector fotovoltaico situan a Espana como el mercado mas din... more Los ultimos datos del crecimiento del sector fotovoltaico situan a Espana como el mercado mas dinamico a nivel mundial, con tasas de crecimiento por encima incluso del mercado germano. Durante los pasados anos el crecimiento anual del sector fotovoltaico conectado a la red en nuestro pais ha sido de 252% en 2006 y 227% en 2007 [1][2]. Este formidable incremento se ha sustentado en gran parte en las ayudas estatales a la produccion, asi como en una flexible politica crediticia. Los ingresos estimados por la produccion electrica del sistema fotovoltaico, son en el mejor aval para hacer frente al pago de los creditos contraidos por el propietario. Llevar a cabo controles de calidad es aconsejable para conocer en profundidad el estado del sistema fotovoltaico, verificando su correcta operacion en la actualidad y proporcionando una base solida para asegurar su produccion en el futuro. En el presente articulo presentamos un protocolo detallado de actuacion a la hora de acometer dichos con...
Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000
This project consists in the installation of four photovoltaic subgenerators connected to the low... more This project consists in the installation of four photovoltaic subgenerators connected to the low voltage grid at Jaen University Campus (Spain), with a total power of 200 kWp. The Univer Project is developed under the Thermie Programme of the EU, with a budget of about 1.8 M euros. The main objective is the integration of a medium scale PV plant using different architectural solutions. This project presents two innovative aspects: on the one hand, the development of the technology necessary to implement medium-high scale PV plants in crowded places, mainly focused on safety and protection systems; on the other, the development and analysis of different architectural solutions to integrate PV generators using constructive structures easily replicable.
2013 Spanish Conference on Electron Devices, 2013
Knowledge of solar cell operating temperature is critical to evaluate the energy performance of a... more Knowledge of solar cell operating temperature is critical to evaluate the energy performance of a HCPV module. However, the measurement of the cell temperature in HCPV modules is a very complex task due to the special features of these types of modules, so it is useful to find indirect methods to calculate this. DNI, cell temperature and I-V curves have been measured for one year in the Centre of Advanced Studies in Energy and Environment of the University of Jaen located in the south of Spain. Thanks to these measurements, cell temperature can be determinate as a function of Voc with a mean relative error of -0.38 %.
Renewable and Sustainable Energy Reviews, 2011
Photovoltaic devices are in a mature technological stage with a long and wide field experience; b... more Photovoltaic devices are in a mature technological stage with a long and wide field experience; but if this source of energy wants to compete against other renewable energy sources or even to get into the traditional energy generation system, it is necessary a novel scientific progress in the behavior of these photovoltaic systems. In this challenge is where High Concentrator Photovoltaic technology can have a main role, as it has proved, in the last researches published, to have the potential to achieve high levels of energy conversion performance. In this paper, it is described a brief summary of the CPV state of the art, as well as it is forecast some efficiencies values up to 2015, where a CPV module could reach 40% of efficiency, while the global CPV system could achieve approximately a 32%.
Concentrator photovoltaic CPV modules under real conditions from different manufactures have been... more Concentrator photovoltaic CPV modules under real conditions from different manufactures have been measured in a new research centre at Jaen, Spain. Influence in maximum power point Pmax of irradiance levels, air temperature and air mass were under study for six months. Pmax shows a good linear behavior for irradiance levels from 400 to 1000 w/m2 and air temperature could be considered negligible in first approximation for temperatures between 20 and 40 ºC. A maximum in Pmax at AM1.5d was found, beyond this point, system losses power per AM unit.
Solar Energy Materials and Solar Cells, 2012
Abstract Grid-connected photovoltaic systems show energy losses due to angular, spectral and low ... more Abstract Grid-connected photovoltaic systems show energy losses due to angular, spectral and low irradiance effects. It would be desirable to know the amount of these losses in real systems. Nowadays, we can find in literature several models, which estimate these losses. However, they are not easy to implement. In this paper, a new method that allows the calculation of angular, spectral and low irradiance losses as a whole is presented. It uses an artificial neural network model in combination with the Osterwald model. Both models are integrated in a single structure. The method is an easy-to-use tool, which only receives two inputs: the global irradiance on the plane of the generator and the cell temperature. At present, the method allows the calculation of the mentioned losses as a whole for systems located at Southern Spain.
Advances in Electrical and Computer Engineering, 2014
The detection of irregularities such as a fraudulent branch line or a fault in short-length low v... more The detection of irregularities such as a fraudulent branch line or a fault in short-length low voltage (LV) lines is of great interest for electricity supply companies as well as for o ...
The integration of grid-connected PV systems into buildings or public areas is one of the most us... more The integration of grid-connected PV systems into buildings or public areas is one of the most usual applications of the photovoltaic solar energy in developed countries. The University of Jaén (Spain) is a pioneering public organism in the field of grid-connected PV systems, as it proves the milestones developed by its IDEA research group in the last decades. Recently, the University has proposed an ambitious project, the so-called UNIVERSOL project, where the necessary tasks will be carried out in order to evaluate the "photovoltaic potential" of the Campus of the University. This project is the previous step to convert this Campus in a big public area which combines the PV electricity generation with the common uses of a university place, in other words, to create a mixed space where the generation of knowledge can be combined with the electricity generation
This paper aims to describe the total load curve for large electricity grids, by analyzing power ... more This paper aims to describe the total load curve for large electricity grids, by analyzing power demand curves, and particularly the representative daily load curve, on large grids. To such end, data from eight large power grids of different sizes (England-Wales, Peninsular Spain, Texas, Belgium, Baden-Wuttemberg, the island of Tenerife, the island of Lanzarote and the island of El Hierro) have been analyzed
The recent research and field experiences in CPV systems have proved that this technology has pre... more The recent research and field experiences in CPV systems have proved that this technology has present and potential advantages when compared with other sources of energy. Despite of that, if this technology wants to initiate its learning curve with the increment of the production and the consequent price reduction, it is necessary an institutional support that allows this technology to compete against other sources of energy through the creation of a favourable and attractive economic environment for potential investors to get interested in this new technology. Nowadays, Spain is a world CPV referent. The research developed by some of its organism and the industrial experience obtained in the past years through the installation of thousands of MW, is a guarantee of its scientific and industrial potential. The intention of this report is to justify the reasons to set aside a power cap of 10 MW in the Spanish PV regulatory framework dedicated exclusively to CPV systems, and the increment of the feed-in tariff in 10.2 c€/kWh over the present tariff and to reduce progressively this support in a 13% annual until it reaches the flat PV tariff.
A new procedure have been developed to assists the Technical Due Diligent (TDD) assessment proces... more A new procedure have been developed to assists the Technical Due Diligent (TDD) assessment process. This methodology uses the combined judgments of individual reviewer and the project manager to apply a weighting to the risk assessments carried out as part of the review. With all of this and with the theoretical background of the CIEMAT (the Spanish National Center for Energetic, Environmental and Technology Research), the University of Jaén and the University Carlos III of Madrid we have created a new tool, easy implemented on a spreadsheet, to do reliable energy production estimations in order to assist the completion of the TDD assessments.
3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of, 2003
This paper describes and analyzes general conclusions about how the design of a photovoltaic inst... more This paper describes and analyzes general conclusions about how the design of a photovoltaic installation can affect the maintenance and evaluation tasks when using just classic parameters. Due to the sole use of classic parameters, it is more difficult to make an effective monitoring of the installation actual operation and suitable maintenance tasks. This situation worsens when the grid-connected PV system is a medium power system, a high power system or has a centralized inverter. These conclusions are the result from the experience lived during the design, implementation, evaluation and maintenance of a 200-kWp photovoltaic plant integrated at the Jaen university campus. We include some solutions to be considered during the design in order to make the measurements, monitoring and maintenance tasks easier.
An optimistic industrial and commercial growth of CPV systems will be successfully possible with ... more An optimistic industrial and commercial growth of CPV systems will be successfully possible with the creation of standardization norms that regulate not only the design and manufacturing stages, but the energy and power rating too, apart from other requirements discussed for traditional flat-PV. The research group IDEA, from the University of Jaen, has made a preliminary CPV technology study, where it was detected the lack of CPV standardization norms. The IEC 62108 norm, which is an evolution of the IEEE 1513 standard, is the first international standard developed exclusively for CPV technology, and it is a compendium of accelerated aging tests that identify long-term reliability problems in the CPV modules or assemblies, reducing the risk of failure, which means to guarantee the durability and reliability of the CPV systems Nowadays certification companies are encountering some problems when applying the test sequence described in the standard mentioned above and they also have detected some critical points in the norm, especially in the excessive duration and the strict requirements of some of the test.
The main purpose of the present study is presenting the FIVE Project (Fotovoltaico Integrado en V... more The main purpose of the present study is presenting the FIVE Project (Fotovoltaico Integrado en Vehículos de Emergencias) which focuses on the integration of a PV system on a health emergency vehicle (1) (2) (3). This new idea extends the use of photovoltaic technology into the improvement of the performance of this type of vehicles where the high electric consumption
Journal of Solar Energy Engineering, 2012
Frequently changing regulation codes, photovoltaic (PV) technology progress and variations in eco... more Frequently changing regulation codes, photovoltaic (PV) technology progress and variations in economic parameters that determine a specific economic scenario make a prospective owner of photovoltaic grid-connected systems (PVGCS) on buildings require information concerning the profitability of their investment on these systems. Hence, an analysis of the main economic factors of PVGCS on buildings addressed to ascertain their influence on the latter profitability is demanded and welcome. Consequently, a sensitivity analysis of some profitability indices such as the net internal rate of return, the net present value, and the discounted payback time has been carried out. This sensitivity analysis is aimed at demonstrating the influence on these indices of possible changes in the factors that are involved in their estimation. Two scenarios have been considered that closely resemble two top PV geographical areas: Germany and Spain. The results obtained here provide clear evidence that fa...
El Girasol, a two axis tracking PV system of 9.6 kWp, connected to the grid at Jaén University ca... more El Girasol, a two axis tracking PV system of 9.6 kWp, connected to the grid at Jaén University campus has reach a yield of 2,140 kWh/kWp·year. It is one of the highest productivity reported up to now in PV Systems. It is presented in this paper the description of the system and the working analysis along its first year operation. Related to the system behaviour, we would like to highlight the following performances: global efficiency of 11.1 %; performance ratio of 78.2%, a yield increase compared with a fixed and ideally faced one of 49% and high operation reliability and minimal maintenance needs.
Los ultimos datos del crecimiento del sector fotovoltaico situan a Espana como el mercado mas din... more Los ultimos datos del crecimiento del sector fotovoltaico situan a Espana como el mercado mas dinamico a nivel mundial, con tasas de crecimiento por encima incluso del mercado germano. Durante los pasados anos el crecimiento anual del sector fotovoltaico conectado a la red en nuestro pais ha sido de 252% en 2006 y 227% en 2007 [1][2]. Este formidable incremento se ha sustentado en gran parte en las ayudas estatales a la produccion, asi como en una flexible politica crediticia. Los ingresos estimados por la produccion electrica del sistema fotovoltaico, son en el mejor aval para hacer frente al pago de los creditos contraidos por el propietario. Llevar a cabo controles de calidad es aconsejable para conocer en profundidad el estado del sistema fotovoltaico, verificando su correcta operacion en la actualidad y proporcionando una base solida para asegurar su produccion en el futuro. En el presente articulo presentamos un protocolo detallado de actuacion a la hora de acometer dichos con...
Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000
This project consists in the installation of four photovoltaic subgenerators connected to the low... more This project consists in the installation of four photovoltaic subgenerators connected to the low voltage grid at Jaen University Campus (Spain), with a total power of 200 kWp. The Univer Project is developed under the Thermie Programme of the EU, with a budget of about 1.8 M euros. The main objective is the integration of a medium scale PV plant using different architectural solutions. This project presents two innovative aspects: on the one hand, the development of the technology necessary to implement medium-high scale PV plants in crowded places, mainly focused on safety and protection systems; on the other, the development and analysis of different architectural solutions to integrate PV generators using constructive structures easily replicable.
2013 Spanish Conference on Electron Devices, 2013
Knowledge of solar cell operating temperature is critical to evaluate the energy performance of a... more Knowledge of solar cell operating temperature is critical to evaluate the energy performance of a HCPV module. However, the measurement of the cell temperature in HCPV modules is a very complex task due to the special features of these types of modules, so it is useful to find indirect methods to calculate this. DNI, cell temperature and I-V curves have been measured for one year in the Centre of Advanced Studies in Energy and Environment of the University of Jaen located in the south of Spain. Thanks to these measurements, cell temperature can be determinate as a function of Voc with a mean relative error of -0.38 %.
Renewable and Sustainable Energy Reviews, 2011
Photovoltaic devices are in a mature technological stage with a long and wide field experience; b... more Photovoltaic devices are in a mature technological stage with a long and wide field experience; but if this source of energy wants to compete against other renewable energy sources or even to get into the traditional energy generation system, it is necessary a novel scientific progress in the behavior of these photovoltaic systems. In this challenge is where High Concentrator Photovoltaic technology can have a main role, as it has proved, in the last researches published, to have the potential to achieve high levels of energy conversion performance. In this paper, it is described a brief summary of the CPV state of the art, as well as it is forecast some efficiencies values up to 2015, where a CPV module could reach 40% of efficiency, while the global CPV system could achieve approximately a 32%.
Concentrator photovoltaic CPV modules under real conditions from different manufactures have been... more Concentrator photovoltaic CPV modules under real conditions from different manufactures have been measured in a new research centre at Jaen, Spain. Influence in maximum power point Pmax of irradiance levels, air temperature and air mass were under study for six months. Pmax shows a good linear behavior for irradiance levels from 400 to 1000 w/m2 and air temperature could be considered negligible in first approximation for temperatures between 20 and 40 ºC. A maximum in Pmax at AM1.5d was found, beyond this point, system losses power per AM unit.
Solar Energy Materials and Solar Cells, 2012
Abstract Grid-connected photovoltaic systems show energy losses due to angular, spectral and low ... more Abstract Grid-connected photovoltaic systems show energy losses due to angular, spectral and low irradiance effects. It would be desirable to know the amount of these losses in real systems. Nowadays, we can find in literature several models, which estimate these losses. However, they are not easy to implement. In this paper, a new method that allows the calculation of angular, spectral and low irradiance losses as a whole is presented. It uses an artificial neural network model in combination with the Osterwald model. Both models are integrated in a single structure. The method is an easy-to-use tool, which only receives two inputs: the global irradiance on the plane of the generator and the cell temperature. At present, the method allows the calculation of the mentioned losses as a whole for systems located at Southern Spain.
Advances in Electrical and Computer Engineering, 2014
The detection of irregularities such as a fraudulent branch line or a fault in short-length low v... more The detection of irregularities such as a fraudulent branch line or a fault in short-length low voltage (LV) lines is of great interest for electricity supply companies as well as for o ...
The integration of grid-connected PV systems into buildings or public areas is one of the most us... more The integration of grid-connected PV systems into buildings or public areas is one of the most usual applications of the photovoltaic solar energy in developed countries. The University of Jaén (Spain) is a pioneering public organism in the field of grid-connected PV systems, as it proves the milestones developed by its IDEA research group in the last decades. Recently, the University has proposed an ambitious project, the so-called UNIVERSOL project, where the necessary tasks will be carried out in order to evaluate the "photovoltaic potential" of the Campus of the University. This project is the previous step to convert this Campus in a big public area which combines the PV electricity generation with the common uses of a university place, in other words, to create a mixed space where the generation of knowledge can be combined with the electricity generation
This paper aims to describe the total load curve for large electricity grids, by analyzing power ... more This paper aims to describe the total load curve for large electricity grids, by analyzing power demand curves, and particularly the representative daily load curve, on large grids. To such end, data from eight large power grids of different sizes (England-Wales, Peninsular Spain, Texas, Belgium, Baden-Wuttemberg, the island of Tenerife, the island of Lanzarote and the island of El Hierro) have been analyzed
The recent research and field experiences in CPV systems have proved that this technology has pre... more The recent research and field experiences in CPV systems have proved that this technology has present and potential advantages when compared with other sources of energy. Despite of that, if this technology wants to initiate its learning curve with the increment of the production and the consequent price reduction, it is necessary an institutional support that allows this technology to compete against other sources of energy through the creation of a favourable and attractive economic environment for potential investors to get interested in this new technology. Nowadays, Spain is a world CPV referent. The research developed by some of its organism and the industrial experience obtained in the past years through the installation of thousands of MW, is a guarantee of its scientific and industrial potential. The intention of this report is to justify the reasons to set aside a power cap of 10 MW in the Spanish PV regulatory framework dedicated exclusively to CPV systems, and the increment of the feed-in tariff in 10.2 c€/kWh over the present tariff and to reduce progressively this support in a 13% annual until it reaches the flat PV tariff.
A new procedure have been developed to assists the Technical Due Diligent (TDD) assessment proces... more A new procedure have been developed to assists the Technical Due Diligent (TDD) assessment process. This methodology uses the combined judgments of individual reviewer and the project manager to apply a weighting to the risk assessments carried out as part of the review. With all of this and with the theoretical background of the CIEMAT (the Spanish National Center for Energetic, Environmental and Technology Research), the University of Jaén and the University Carlos III of Madrid we have created a new tool, easy implemented on a spreadsheet, to do reliable energy production estimations in order to assist the completion of the TDD assessments.
3rd World Conference onPhotovoltaic Energy Conversion, 2003. Proceedings of, 2003
This paper describes and analyzes general conclusions about how the design of a photovoltaic inst... more This paper describes and analyzes general conclusions about how the design of a photovoltaic installation can affect the maintenance and evaluation tasks when using just classic parameters. Due to the sole use of classic parameters, it is more difficult to make an effective monitoring of the installation actual operation and suitable maintenance tasks. This situation worsens when the grid-connected PV system is a medium power system, a high power system or has a centralized inverter. These conclusions are the result from the experience lived during the design, implementation, evaluation and maintenance of a 200-kWp photovoltaic plant integrated at the Jaen university campus. We include some solutions to be considered during the design in order to make the measurements, monitoring and maintenance tasks easier.
An optimistic industrial and commercial growth of CPV systems will be successfully possible with ... more An optimistic industrial and commercial growth of CPV systems will be successfully possible with the creation of standardization norms that regulate not only the design and manufacturing stages, but the energy and power rating too, apart from other requirements discussed for traditional flat-PV. The research group IDEA, from the University of Jaen, has made a preliminary CPV technology study, where it was detected the lack of CPV standardization norms. The IEC 62108 norm, which is an evolution of the IEEE 1513 standard, is the first international standard developed exclusively for CPV technology, and it is a compendium of accelerated aging tests that identify long-term reliability problems in the CPV modules or assemblies, reducing the risk of failure, which means to guarantee the durability and reliability of the CPV systems Nowadays certification companies are encountering some problems when applying the test sequence described in the standard mentioned above and they also have detected some critical points in the norm, especially in the excessive duration and the strict requirements of some of the test.