Buffering PV Output During Cloud Transients with Energy Storage

Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis provides a detailed analysis with appropriate Matlab codes to put onto the grid during the day time a constant amount of power on one hand and on the other, shift the less valuable off-peak electricity to the on-peak time, i.e. between 1pm to 7pm, where the electricity price is much better. In this study, a range of base constant power levels were assumed including 15kW, 20kW, 21kW, 22kW, 23kW, 24kW and 25kW. The hypothesis based on an iterative solution was that the capacity of the battery was increased by steps of 5 while the base supply was decreased by the same step size until satisfactorily results were achieved. Hence, it turned out with the chosen battery capacity of 54kWh coupled to the data from the Amonix CPV 7700 unit for Las Vegas for a 3-month period, it was found that 20kW was the largest constant load the system can supply uninterruptedly to the utility company. Simulated results are presented to show the feasibility of the proposed scheme

Graduate Students and Their Publishing Future

What is OA? The need (Desire) to publish OA Behind a subscription Advantages of OA Disadvantages of OA Conclusion Reference

Designing, Building and Testing a Solar Thermoelectric Generation, STEG, for Energy Delivery to Remote Residential Areas in Developing Regions

New alternatives and inventive renewable energy techniques which encompass both generation and power management solutions are fundamental for meeting remote residential energy supply and demand today, especially if the grid is quasi-inexistent. Solar thermoelectric generators can be a cost-effective alternative to photovoltaics for a remote residential household power supply. A complete solar thermoelectric energy harvesting system is presented for energy delivery to remote residential areas in developing regions. To this end, the entire system was built, modeled, and then validated with LTspice simulator software via thermal-to-electrical analogy schemes. Valuable data in conjunction with two novel LTspice circuits were obtained, showing the achievability of analyzing transient heat transfer with the Spice simulator. Hence, the proposed study begins with a comprehensive method of extracting thermal parameters that appear in thermoelectric modules. A step-by-step procedure was developed and followed to succinctly extract parameters, such as the Seebeck coefficient, electrical conductivity, thermal resistance, and thermal conductivity needed to model the system. Data extracted from datasheet, material properties, and geometries were successfully utilized to compute the thermal capacities and resistances necessary to perform the analogy. In addition, temperature variations of the intrinsic internal parameters were accounted for in this process for accuracy purposes. The steps that it takes to simulate any thermo-electrical system with the LTspice simulator are thoroughly explained in this work. As a consequence, an improved Spice model for a thermoelectric generator is proposed. Experimental results were compiled in the form of a lookup table and then fed into the Spice simulator using the piecewise linear (PWL) command in order to validate the model. Experimental results show that a temperature differential of 13.43°C was achievable whereas the simulation indicates a temperature gap of 9.86°C, with the higher error being associated with the hot side. Also, since the analytical method of transient heat transfer analysis is cumbersome, an LTspice model of a real-world solar thermoelectric generation system was investigated. All the physical parameters were converted into their electrical equivalences through the thermal-to-electrical analogy. Real site direct normal insolation was fed into the Spice model via PWL in order to capture the true system’s thermal behavior. Interestingly, two distinct analogies result from this study: 1) an RC analogy and 2) another analogy similar to an N-type doped semiconductor material’s carrier density dependence with temperature. The RC analogy is derived in order to demonstrate how thermoelectric generation systems respond to square wave-like solar radiation. This analogy is utilized to measure temperature variations on the cold side of the Spice model; it shows 80% accuracy. The N-type analogy is intended to help analyze the actual performance of a LTC3105 converter. However a few of the problems to be solved remain at the practical level. Despite the unusual operation of the thermoelectric modules with the solar radiation, the measurements and simulation were in good agreement, thus validating the new thermal modeling strategy

Solar energy powered decentralized smart-grid for sustainable energy supply in low-income countries: analysis considering climate change influences in Togo

A smart and decentralized electrical system, powered by grid-connected renewable energy (RE) with a reliable storage system, has the potential to change the future socio-economic dynamics. Climate change may, however, affect the potential of RE and its related technologies. This study investigated the impact of climate change on photovoltaic cells’ temperature response and energy potential under two CO2 emission scenarios, RCP2.6 and 8.5, for the near future (2024–2040) and mid-century (2041–2065) in Togo. An integrated Regional Climate Model version 4 (RegCM4) from the CORDEX-CORE initiative datasets has been used as input. The latter platform recorded various weather variables, such as solar irradiance, air temperature, wind speed and direction, and relative humidity. Results showed that PV cells’ temperature would likely rise over all five regions in the country and may trigger a decline in the PV potential under RCP2.6 and 8.5. However, the magnitude of the induced change, caused by the changing climate, depended on two major factors: (1) the PV technology and (2) geographical position. Results also revealed that these dissimilarities were more pronounced under RCP8.5 with the amorphous technology. It was further found that, nationally, the average cell temperature would have risen by 1 °C and 1.82 °C under RCP2.6 and 8.5, in that order, during the 2024–2065 period for a-Si technology. Finally, the PV potential would likely decrease, on average, by 0.23% for RCP2.6 and 0.4% for RCP8.5 for a-Si technology

Evaluation of the antimicrobial susceptibility testing process in clinical microbiology laboratories at Niamey, Niger

Background: Risk assessment is the means of identifying and evaluating potential errors or problems that may occur in testing process. The aim of this study was to perform risk assessment of antimicrobial susceptibility testing (AST) process in clinical microbiology laboratories of Niamey, Niger Republic.Methodology: We conducted a descriptive cross-sectional study from October 1 to December 31, 2019, to evaluate AST performance in seven clinical microbiology laboratories at Niamey, the capital city of Niger republic. The evaluation focused on the determination of the criticality index (CI) of each critical point (frequency of occurrence of anomalies, severity of the process anomaly, and detectability of the anomaly during the process) in the AST process and the performance of the AST through an observation sheet using two reference strains; Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213.Results: The criticality index (CI) was greater than 6 for most of the critical points related to material, medium, equipment, method and labour for the AST process in all the laboratories. A range of 18-100% errors on the inhibition zone diameters of the reference strains were observed. Major and/or minor categorization (Sensitive S, Intermediate I and Resistance R) discrepancies were found at all the laboratories for either one or both reference strains. The antibiotics most affected by the S/I/R discrepancies were trimethoprim (100%), vancomycin (100%), amoxicillin (80%) and amoxicillin + clavulanic acid (70%).Conclusion: This study showed a deficiency in the control of critical control points that impacts the performance of the AST reported by the laboratories in Niger. Corrective actions are needed to improve the performance of AST in clinical microbiology laboratories in Niger.   French title: Evaluation du processus de réalisation de l’antibiogramme dans les laboratoires d’analyses de biologie médicale de la ville de Niamey, Niger Contexte: L'évaluation des risques est le moyen d'identifier et d'évaluer les erreurs ou les problèmes potentiels qui peuvent survenir dans le processus de test. L'objectif de cette étude était de réaliser une évaluation des risques du processus d'antibiogramme (ABG) dans les laboratoires de microbiologie clinique de Niamey, en République du Niger.Méthodologie: Nous avons mené une étude transversale descriptive du 1er octobre au 31 décembre 2019 pour évaluer la performance des ABG dans sept laboratoires de microbiologie clinique à Niamey, capitale de la république du Niger. L'évaluation a porté sur la détermination de l'indice de criticité (IC) de chaque point critique (fréquence d'apparition des anomalies, gravité de l'anomalie du processus et détectabilité de l'anomalie au cours du processus) dans le processus et la performance des AGB à travers une fiche d'observation en utilisant deux souches de référence; Escherichia coli ATCC 25922 et Staphylococcus aureus ATCC 29213.Résultats: L'indice de criticité était supérieur à 6 pour la plupart des points critiques liés au matériel, au milieu, à l'équipement, à la méthode et à la main-d'oeuvre pour le processus AST dans tous les laboratoires. Une fourchette d'erreurs de 18 à 100% sur les diamètres des zones d'inhibition des souches de référence a été observée. Des écarts de catégorisation majeurs et/ou mineurs (Sensible: S, Intermédiaire: I et Résistance: R) ont été constatés dans tous les laboratoires pour l'une ou les deux souches de référence. Les  antibiotiques les plus touchés par les écarts S/I/R étaient la triméthoprime (100%), la vancomycine (100%), l'amoxicilline (80%) et l'amoxicilline + acide clavulanique (70%).Conclusion: Cette étude a montré une déficience dans le contrôle des points de contrôle critiques qui a un impact sur la performance de l'antibiogramme rapportée par les laboratoires au Niger. Des actions correctives sont nécessaires pour améliorer la performance des ABG dans les laboratoires de microbiologie clinique au Niger

Exploring the dynamics of stakeholders’ perspectives towards planning low-carbon energy transitions: a case of the Nigerian power sector

This study uses a multi-stakeholder analysis approach to consolidate lowcarbon energy planning and facilitate energy transition (ET). To do this, we assess factors that influence ET strategies in the Nigerian power sector. Here we employ both quantitative and qualitative data obtained via well-structured, and concise questionnaires and semi-structured interviews. While our study brings to light a sustainable approach to achieving a low-carbon future, it identified technology, motivation and finance as variables that are significant in accelerating the country’s transition to clean energy. It revealed that prioritising low-interest rate and tax holiday for investors’ of solar energy and consistence expansion in energy efficiency (EE) is pertinent to achieving a sustainable lowcarbon future in Nigeria. We conclude that robust policy frameworks that prioritise investment in solar energy and EE through incentivising energy management solutions with appropriate financial tools and fostering active verbal support through advocacy are essential to ET in Nigeria

Improved SPICE Modeling and Analysis of a Thermoelectric Module," submitted for publication in MWSCAS

Abstract-An improved SPICE model for a thermoelectric generator (TEG) is presented. Temperature variations of the intrinsic internal parameters are included in the proposed model. For accuracy in the proposed model, the internal parasitic components effects and the temperature dependence of the parameters that occur in any thermoelectric module (TEM) were taken into account. Experimental results were compiled in the form of a lookup table and then fed into the SPICE simulator using a piecewise linear (PWL) model in order to validate the model. Experimental results showed that a differential temperature of 13.43C was achievable whereas the SPICE model indicated a temperature gap of 9.86C with the higher error being associated with the hot side. Overall, both experimental and simulated results were in a good agreement. Index Terms-thermoelectric generator (TEG), thermoelectric cooler (TEC), Thermo-electrical equivalence, SPICE model, renewable energy, internal parameters

Concise Thermal to Electrical Parameters Extraction of Thermoelectric Generator for Spice Modeling

Abstract-This paper presents a comprehensive method of extracting thermal to electrical parameters that appear in a thermoelectric module (TEM). A step-by-step procedure was developed and followed to succinctly extract the parameters needed to model the TEM. These parameters include the Seebeck coefficient, electrical conductivity, thermal resistance, and thermal conductivity from a datasheet. Data extracted from the manufacturer datasheet, material properties, and geometries were successfully utilized to compute the thermal capacities and resistances necessary to perform the thermal to electrical conversion steps required for simulation accuracy. In addition, temperature variations of the intrinsic internal parameters were accounted for in this process. The aforementioned extracted parameters are compatible with the LTspice circuit simulator and other related software. The steps that it takes to simulate any thermo-electrical system with the LTspice simulator are not only found to be of two kinds, but are also thoroughly explained in this paper

Energy efficiency potential and policy program in urban residential sector: a case study of Lomé: Potentiel d'efficacite energetique et programme politique dans le secteur residentiel urbain : une etude de cas de Lome

An assessment of energy efficiency potential with a subsequent policy program was proposed. The scope of the study was the residential lighting, refrigeration, cooling, and ventilation in Lomé, the capital city of Togo. This research sought to assess inefficient installed light fixtures along with household appliances and to estimate ways to save energy by utilizing both brand new and more efficient electrical devices. A survey was conducted not only to assess the appliances, but also to identify their status as “brand new” or “used” items. The results were analyzed with the Statistical Package for Social Science (SPSS) software and the 2016 spreadsheet. In addition, a real-time monitoring experiment was conducted on used and brand-new televisions (TVs) and refrigerator-freezers. The potential of energy efficiency was evaluated under two policy scenarios: 1) New Policies and 2) Sensitivity Analysis. Results revealed predominantly less efficient appliances in Lomé’s housing sector. Results also showed that by opting for only new and efficient appliances, Togo would save a huge amount of energy over the next two decades or so.RESUME Une évaluation du potentiel d'efficacité énergétique avec un programme politique subséquente a été proposée. L'étude a porté sur l'éclairage résidentiel, la réfrigération, le refroidissement et la ventilation à Lomé, la capitale du Togo. Cette recherche visait à évaluer les luminaires installés inefficaces avec les appareils électroménagers et à estimer les moyens d'économiser l'énergie en utilisant des appareils électriques neufs et plus efficaces. Une enquête a été menée non seulement pour évaluer les appareils, mais aussi pour identifier leur statut en tant qu'articles « neufs » ou « d’occasion ». Les résultats ont été analysés avec le logiciel Statistical Package for Social Science (SPSS) et le tableur 2016. De plus, une expérience de surveillance en temps réel a été menée sur des téléviseurs et des réfrigérateurs-congélateurs neufs et d'occasion afin de suivre leur consommation électrique. Le potentiel d'efficacité énergétique a été évalué selon deux scénarios : 1) nouvelles politiques et 2) analyse de sensibilité. Les résultats ont révélé des appareils électroménagers principalement moins efficaces dans le secteur du logement à Lomé. Les résultats ont également montré qu'en optant uniquement pour des appareils nouveaux et efficaces, le Togo économiserait une énorme quantité d'énergie au cours des deux prochaines décennies

Development of typical meteorological year for massive renewable energy deployment in Togo

Renewable energy (RE) penetration assessment and the development typical meteorological year (TMY) for five cities are considered together in this study. Thus, an integrated method is utilised encompassing RE status assessment and the Sandia method to generate the typical meteorological months of TMY. TMY and long-term data (LT) are then compared as well as a PV system of 3kWc output using TMY and LT under statistical errors. Until 2020 only 11.27% out of 360.02 MW capacity in power demand was RE (hydro and solar). LT and TMY are close for all the towns with a better closeness for Sokode. The latter predicts PV system performance within 2% of the LT in all the sites. More investment has to be put in RE sector because of its potential: 5.27 kWh/m2/day of mean solar radiation, 1238.21 mm of average annual precipitation and 7 m/s of mean wind speed at 50 m above the ground