Examinando por Autor "Vivar, Marta"
Mostrando 1 - 9 de 9
- Resultados por página
- Opciones de ordenación
Ítem An experimental comparison between commercial hybrid PV-T and simple PV systems intended for BIPV(Elsevier, 2018) Fuentes-Conde, Manuel; Vivar, Marta; de la Casa, Juan; Aguilera-Tejero, JorgeThe idea of combining both thermal and photovoltaic collectors in hybrid photovoltaic-thermal (PV-T) modules actually shows a great potential for integration on facades and rooftops of buildings, mainly because of the reduced available space and the benefits of the on-site electricity and thermal generation. The objective of this work is to compare the real performance (experimental data obtained under real sun during a year) of a commercial hybrid PV-T system vs. a simple PV system using microinverters, assessing the suitability of one-unit hybrid PV-T systems vs. two separated units – PV systems + Thermal systems – for building integration. The combined efficiency over the span of a full day could reach values up to 80%, but this apparent high value needs to be analysed in detail. From the experimental results, it can be observed that both systems, PV and PV-T, have a good electrical performance. But the PV-T system output does not benefit from the lower module temperatures that it should achieve from the active cooling in its back, presenting the same performance as the simple PV system. Regarding the microinverters configuration performance, it has been very positive working with high efficiencies above 96%, justifying its use in this type of applications. In conclusion, the commercial PV-T system has not performed as expected, showing problems with the integration of the active cooling in the back of the PV modules. At this moment, and despite the potential of PV-T systems for BIPV due to space limitations, commercial PV-T systems are still far from PV and Thermal systems using separately.Ítem Analysing the reciprocity law for UV-LEDs in water disinfection of Escherichia coli, Enterococcus faecalis and Clostridium perfringens(MDPI, 2023) Kamel, Ahmed; Palacios, Ana; Fuentes, Manuel; Vivar, MartaThe aim of this study is to verify the reciprocity law in the wastewater disinfection process using UV light. The optical power UV-LEDs used were 1.6 mW and 50 mW, and the wavelengths were 265 nm and 275 nm. E. coli, Enterococcus faecalis, and Clostridium perfringens were the three microorganisms analysed in the study. The results showed lower inactivation rates around 0.063–0.065 cm2/mJ for 265 nm and 0.047–0.049 cm2/mJ for 275 nm for the Clostridium perfringens compared with the other two bacteria. For E. coli and Enterococcus faecalis, the inactivation rate was almost identical; 0.28 and 0.21 cm2/mJ, respectively, using 265 nm wavelength. There was a slightly better inactivation performance using the medium-power 275 nm UV-LEDs of 0.39 cm2/mJ and 0.29 cm2/mJ for E. coli and Enterococcus faecalis, respectively, and 0.33 cm2/mJ and 0.26 cm2/mJ using the low-power 275 nm UV-LEDs. The analysed data justify the reciprocity law for UV-LEDs disinfection using 265 nm and 275 nm UV-LEDs with two optical powers of 1.6 mW and 50 mW.Ítem Enhancing photovoltaic efficiency through evaporative cooling and a solar still(Elsevier, 2023) Srithar, K; Akash, K; Nambi, R; Vivar, Marta; Saravanan, RajagopalThe efficiency of photovoltaic panels decreases with the increase in panel temperature while converting light into electricity. The issue of temperature rise and the associated decrease in efficiency has been widely analysed by active and passive cooling methods. In those processes, normally water is used as a cooling medium, and it results in water loss along with power loss due to circulating or compensating for the lost water. The current study aims to address both efficiency as well as water loss by combining an evaporative cooling technique with a solar still. A Photovoltaic panel with rear-side evaporative cooling is attempted by using a jute sack dipped in water at both ends. As a result of capillary action, the water from a solar still rises through the sack and cools the panel’s rear side. Solar still operation is ensured by an extended portion of glass. During desalination, the evaporated vapour from the solar still condenses on the back cover of the glass surface and is collected in a collection trough. As a result, the output power increased by 5.6 % and the electrical efficiency increased by 14.51 % and the surface temperature are reduced by 8°C. After seven hours of sunshine, the proposed PV panels and solar still system produced approximately 550 ml of water.Ítem Lessons learned from the field analysis of PV installations in the Saharawi refugee camps after 10 years of operation(Elsevier, 2018-10) Fuentes-Conde, Manuel; Vivar, Marta; Hosein, Hasena; Aguilera-Tejero, Jorge; Muñoz-Cerón, EmilioEnergy access at refugee camps is one of the main challenges to address in humanitarian response actions, especially on long-term situations. The lack of access to electricity depends, among other factors, on the local natural resources and available technologies. In this sense, solar photovoltaic is one of the most appropriate technologies, especially now with the decrease of the photovoltaic costs. But long-term performance, reliability and social acceptance must be ensured to facilitate the introduction of the technology and its rapid widespread in these humanitarian context. This work presents the results of a field study conducted at the Saharawi refugee camps, inspecting the photovoltaic systems installed in the health institutions after 10 years of use. Results show how despite the good initial system design and high quality of the PV components, the lack of training on operation and maintenance of the PV installations have led to a dramatic reduction of the lifetime of the systems. Strong training programs on basic photovoltaic concepts and operation and maintenance of systems are required to solve this problem and guarantee the long-term functioning of the installations.Ítem Lessons learned from the field analysis of PV installations in the Saharawi refugee camps after 10 years of operation(Elsevier, 2018) Fuentes-Conde, Manuel; Vivar, Marta; Hosein, Hasena; Aguilera-Tejero, Jorge; Muñoz-Cerón, EmilioEnergy access at refugee camps is one of the main challenges to address in humanitarian response actions, especially on long-term situations. The lack of access to electricity depends, among other factors, on the local natural resources and available technologies. In this sense, solar photovoltaic is one of the most appropriate technologies, especially now with the decrease of the photovoltaic costs. But long-term performance, reliability and social acceptance must be ensured to facilitate the introduction of the technology and its rapid widespread in these humanitarian context. This work presents the results of a field study conducted at the Saharawi refugee camps, inspecting the photovoltaic systems installed in the health institutions after 10 years of use. Results show how despite the good initial system design and high quality of the PV components, the lack of training on operation and maintenance of the PV installations have led to a dramatic reduction of the lifetime of the systems. Strong training programs on basic photovoltaic concepts and operation and maintenance of systems are required to solve this problem and guarantee the long-term functioning of the installations.Ítem Photovoltaic System Adoption in Water Related Technologies – A Review(Elsevier, 2024) Vivar, Marta; Sharon, H; Fuentes, ManuelWater and energy are intimately related, as water is required for energy applications and energy is required for water-based technologies. Two large groups of photovoltaic adoptions have been identified in this review: first, those in which the photovoltaic system is separated from the water technology. In second group, the photovoltaic system is in physical contact with the water technology thereby its performance is affected either in a positive or negative way. The novelty of this review work lies in the classification of photovoltaic system adoption in various water related technologies. Apart from classification, discussions on system configurations, working aspects, performance aspects, economic aspects and scope for further investigations have been presented in detail. Wastewater treatment plants are identified to be the most suitable site for photovoltaic module installation and utilization. Among power sectors, hydro power plants are highly compatible with photovoltaic adoption because it enhances hydro power plant’s operation time and utilization. Floating photovoltaic, submerged photovoltaic, agrivoltaic, aquavoltaic and solar photovoltaic + water disinfection are relatively new, highly attractive and have more scope for further improvements. Agrivoltaic and aquavoltaic increases crop & sea food production, enhances farmers’ income, encourage clean energy transition and rural electrification. Research works in the area of unmanned photovoltaic based water vehicles, photovoltaic salt harvest and various applications of water based photovoltaic/thermal modules have also been discussed. This review will serve as a guidebook for researchers and policy makers to identify and select suitable configuration of photovoltaic–water related technologies for implementation and further investigations.Ítem Sistema híbrido fotoquímico-fotovoltaico como tratamiento terciario para la obtención de agua regenerada y la generación simultánea de energía(2024-09-11) Torres-López, Julia; Vivar, Marta; Universidad de Jaén. Departamento de Energías RenovablesLa presente tesis doctoral está basada en un sistema híbrido solar fotoquímico-fotovoltaico, llamado SolWat, utilizado por primera vez para la desinfección de efluentes de aguas residuales urbanas. Este trabajo, por compendio de artículos, reúne cuatro publicaciones científicas que analizan el avance y el potencial de esta tecnología para obtener agua regenerada (proceso de desinfección solar) y generar energía eléctrica (energía solar fotovoltaica) de manera simultánea, utilizando exclusivamente la energía solar. Estas publicaciones analizan la calidad del agua y sus posibles usos como agua regenerada según las normativas RD 1620/2007 (española) y R(UE) 2020/741 (europea), así como el rendimiento fotovoltaico del sistema (en comparación con un módulo fotovoltaico único de referencia). El objetivo a largo plazo iniciado es integrar esta tecnología como tratamiento terciario de depuradoras, para la reutilización del efluente secundario o mejorar su vertido final, generando además electricidad renovable para promover una gestión eficiente y sostenible The present doctoral thesis is based on a photochemical-photovoltaic solar hybrid system, called SolWat, used for the first time for the disinfection of urban wastewater effluents. This work, a compendium of articles, brings together four scientific publications that analyse the progress and potential of this technology to obtain reclaimed water (solar disinfection process) and generate electricity (solar photovoltaic energy) simultaneously, using exclusively solar energy. These publications analyse the quality of the water and its possible uses as reclaimed water according to RD 1620/2007 (Spanish) and R(EU) 2020/741 (European) regulations, as well as the photovoltaic performance of the system (compared to a single reference photovoltaic module). The long term objective initiated is to integrate this technology as tertiary treatment of wastewater treatment plants, for the reuse of secondary effluent or to improve its final discharge, also generating renewable electricity to promote efficient and sustainable managementÍtem Solar disinfection as a direct tertiary treatment of a wastewater plant using a photochemical-photovoltaic hybrid system(Elsevier, 2021) Vivar, Marta; Fuentes, Manuel; Torres, Julia; Rodrigo, María JesúsThis work evaluates the SolWat hybrid system for solar water disinfection and photovoltaic energy generation, for its implementation in tertiary treatment plants, using real wastewater directly from the effluent after its secondary treatment. Solar disinfection of E. coli, Enterococcus faecalis and Clostridium perfringens microorganisms was evaluated over the course of a complete year. Four experiments in batch mode were conducted in autumn, winter, spring and summer, and microbiological and physicochemical parameters were analysed. In addition, the kinetics of solar disinfection during 4 h were analysed, and the dose of lethal ultraviolet radiation for microorganisms established. Results showed that E. coli, Enterococcus faecalis and C. perfringens did not complete total bacterial inactivation after 4 h of treatment in the SolWat system, but that the inactivation levels achieved were sufficient as to allow for the reuse of water for various uses (urban, agricultural, industrial, etc.). Clostridium perfringens continued to be the most resistant bacteria vs. E. coli and Enterococcus faecalis. The total photovoltaic energy production in the hybrid system compared to the reference system was the same, generating both the SolWat module and the reference module identical electrical power due to the compensating effect of module water cooling vs. radiation losses.Ítem The problem of drinking water access: A review of disinfection technologies with an emphasis on solar treatment methods(Elsevier, 2019-03) Pichel, Natalia; Vivar, Marta; Fuentes, ManuelThe lack of access to safe drinking water is one of the biggest challenges facing humanity in the 21st century. Despite the collective global effort that has been made, the drinking water sources of at least 2 billion people are faecally contaminated, resulting in more than half a million diarrhoeal deaths each year, with the majority occurring in developing countries. Technologies for the inactivation of pathogenic microorganisms in water are therefore of great significance for human health and well-being. However, conventional technologies to provide drinking water, although effective, present limitations that impede their global application. These treatment methods often have high energy and chemical demands, which limits their application for the prevention of waterborne diseases in the most vulnerable regions. These shortcomings have led to rapid research and development of advanced alternative technologies. One of these alternative methods is solar disinfection, which is recognised by the World Health Organization as one of the most appropriate methods for producing drinkable water in developing countries. This study reviews conventional technologies that are being applied at medium to large scales to purify water and emerging technologies currently in development. In addition, this paper describes the merits, demerits, and limitations of these technologies. Finally, the review focuses on solar disinfection, including a novel technology recently developed in this field.