Volume 3 Issue 1 (2024): In Progress

Article

Effects of Temperature and Solar Irradiation Variations on The Performances of Photovoltaic Pumping Systems

Climate and solar radiation levels are two major environmental elements that affect the operation of photovoltaic (PV) pumping systems. Rising temperatures cause a decrease in PV modules' electrical efficiency because of the fall of fill factor and open-circuit voltage. They may also cause a decrease in motor efficiency because of the growing winding resistance losses. Besides, the increased photocurrent and power production of the PV array are caused by higher levels of solar irradiation, which makes the pump run at higher speeds or flow rates. To quantify these impacts and forecast system performance, precise modeling techniques and control laws are used such as MPPT, PWM and U/F in this paper. This paper presents solar performances and responses such as the flow of the pumped water, the PV power outputs, motor voltages, currents, speed and finally converter controls. However, although MPPT and PWM control laws improve the energy efficiency of the overall system, the simulation results show that the performance of the PV pumping system degrades when the temperature increases and the solar flux decreases, which will affect the autonomy of the PV system.

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Article

Topological Vulnerability Analysis of the Mexican Power Grid Using Complex Network Theory

This study presents a pioneering analysis of the network properties within the Mexican power grid (MXPG). The study included the 400 kV and 230 kV grids. Both grids were analysed independently and as a single combined grid. Based on complex network theory, several topological metrics were calculated, and the vulnerability of the power grid to random failures and intentional attacks was investigated. The MXPG displays several features of small-world networks, namely, a large clustering coefficient and a small average shortest path length. The degree distribution reveals exponential behaviour. Additionally, it was found that the power grid is more vulnerable to targeted attacks on nodes with a high degree than to random failures. In general terms, this study illuminates the intricate structure of the Mexican power grid, shedding light on its structural vulnerabilities, crucial for informing future strategies aimed at enhancing its robustness against potential disruptions.

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Article

Optimization of Matrix Components for Improved Catalytic Activities of Cellulase Immobilized on Biochar-Chitosan Beads

Bioethanol is a renewable energy that is gaining popularity globally. It’s biochemical production requires the use of enzyme, especially cellulase. Cellulase is an enzyme that catalyzes the degradation of cellulose and related polysaccharides which finds applications in food, textiles, detergents, biofuels etc. However, the worldwide use of cellulase is limited by its relatively high production costs and low biological activity. This study was design to locally produce biochar-chitosan beads at optimized conditions to immobilize cellulase for improved thermal and storage stability as well as ensure reusability of the enzyme so as to improve biological activity and avoid the continuous production of free cellulase thereby reducing the production cost. Biochar was produced by pyrolyzing sugarcane bagasse in a local airtight chamber for 1 hour. Beads were formed from different ratios of biochar and chitosan in varying concentrations of calcium chloride solution as generated by design expert software version 13. The beads were dried in an oven at 50 0C for 24 hours and functionalized in 25% glutaraldehyde (GDA). The beads were loaded with enzyme (10.06 µmole/min/mL) at room temperature (27 ± 3 oC). Enzyme activity, thermal stability, storage stability and reusability tests were carried out according to standard procedures. The half-life and activation energy were also evaluated. The result showed that the optimum activity of the loaded enzyme (2.63 µmole/min/mL) was obtained when 2.46 g of porous biochar was mixed with 2.48 g chitosan in 5 % Calcium chloride aqueous solution. The immobilized enzyme was able to maintain thermal stability between 30 oC and 70 oC while the activity for free enzyme started declining after 50 oC. Also, the activation energy for immobilized cellulase enzyme (23.17 KJ/mol) was lower than the activation energy (55.146 KJ/mol) for free cellulase. The half-life, when stored at ambient Temperature (27 ± 3 oC), for free enzyme was 0.4 days while the half-life for immobilized enzyme was 3.59 days. Therefore, cellulase immobilized on support locally produced at optimal conditions had improved catalytic properties when compared to the free enzyme. Hence, more indigenous materials and practices may be employed for a cost effective and cheaper industrial processes.

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Article

Techno-Economic Analysis of Heat-Assisted Hydrogen Production from Nuclear Power

To play a full role in decarbonisation, hydrogen must be produced economically at scale; the role of nuclear power is interesting to national governments as it is capable of supplying both low-carbon electricity and high-quality heat. Depending on the hydrogen production technology choice, a plant may require electricity and/or heat input. This techno-economic evaluation considers not only the costs of the hydrogen plant itself but also the costs of the power supply it requires. This paper calculates cost estimates for HTSE (High Temperature Steam Electrolysis) coupled with nuclear heat and electricity, and a thermochemical SI (Sulphur Iodine) cycle coupled with nuclear heat, based on the predictions of technical process models. These estimates are then compared to estimates made elsewhere for the costs of using wind with low temperature liquid water electrolysis, and steam methane reformation with carbon capture. This analysis led to the identification of the conditions under which nuclear-heat-coupled hydrogen production would be competitively priced. Estimates for nuclear-coupled LCOH2 (levelised cost of hydrogen) in 2050 range from 2.14 to 1.24 £/kg for HTSE, and from 2.88 to 0.89 £/kg for the SI cycle. There is still a great deal of uncertainty around the efficiency of SI and how it may improve over time, and this limits the accuracy to which the LCOH2 can be predicted.

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Article

Modelling System Generation: Towards the New Model in Albania and SEE Countries

The electricity utility industry is undergoing rapid and irreversible changes resulting from volatile fuel costs, transmission access, less predictable load growth and a more complex regulatory environment. Due to the rising importance of renewable (and variable) energy sources, power systems are now more vulnerable to uncertainties and intermittent in supply. Hydropower plays an important role in the energy mix and power market, helping in providing base and peak load power as well as being the ‘fuel’ (water) not subject to fluctuations in the market; these paving the way toward a clean energy by 2030 and net-zero emissions by 2050 as part of de-carbonization agenda. All production and conversion processes in the energy sector require Water for nearly including fuel extraction and processing (fossil and nuclear fuels as well as biofuels) and electricity generation (thermoelectric, hydropower, and renewable technologies). This paper’s objective is to analyze cross-border trade in SEE through economic electricity exchange, while also exploring reasons for promoting Hydroelectricity. This is achieved through the following objectives: first, an overview is made of the available energy and economic data in the region; second, a model is developed for regional least cost expansion planning when allowing for cross-border trade. These aim to assess electricity supply and demand in the region with the purpose of making a comparative analysis regarding energy resource endowments.

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Review

Review of Community Solar in the United States of America

Community solar is a concept where a large number of entities (consumers, businesses, charitable foundations, investors, etc.) can participate with or without having 100% ownership of the solar hardware. The objective of this paper is to provide an in-depth review of community solar. Although we have kept the global picture in mind, the United States has been our focus. The authors have provided details of the overall role of photovoltaics and battery-based power networks in global electrical power generation. Based on published reviews and research papers, the authors have analyzed the operation of community solar, ownership models and business models used in community solar projects. Based on the published results, the authors found that community solar might grow exponentially. However, due to ultra-small scale power level, this concept has not played a significant role as compared to residential, commercial, industrial and utility-scale use of solar photovoltaics. For the growth of community solar, the authors have proposed a new concept where new constructions can provide large-scale use of community solar projects. The proposed concept is off-grid and can be implemented without the introduction of any new public policy. In conclusion, the proposed concept can play a major role in providing green electrical power for new loads that also include the charging of electrical vehicles.

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Article

Thermal Conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ

CaSrFe0.75Co0.75Mn0.5O6-δ, an oxygen-deficient perovskite, had been reported for its better electrocatalytic properties of oxygen evolution reaction. It is essential to investigate different properties such as the thermal conductivity of such efficient functional materials. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, the authors present an investigation of the thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe0.75Co0.75Mn0.5O6-δ was found to be 0.724 W/m/K at 25 °C, exhibiting a notable thermal insulation property i.e., low thermal conductivity.

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Article

Direct Absorption Solar Collector: An Experimental Investigation of Al2O3-H2O Nanofluid over the Flat Plate at Different Tilt Angles, and Mass-Flow Rates

The escalating demand for solar thermal energy, coupled with the current inefficiencies in existing systems, underscores the critical need for innovative advancements in thermal storage solar collectors. The efficiency of solar collectors relies not solely on design effectiveness but also on the thermophysical properties, such as heat capacity and thermal conductivity, inherent in the working fluid. This study investigates a novel solar collector with a gross area of 0.36 m2, operating on the principle of direct absorption. Experimental investigations were done at various tilt angles (15°, 20°, and 30°) with respect to the horizontal, considering different flow rates and nanofluid settlement within the base fluids. The use of Al2O3 nanoparticles into the base fluid as water, exhibits significant positive effects on the thermophysical properties of the nanofluids, with a volume concentration of 0.003%. The efficiency of the solar collector was calculated across three mass flow rates (0.5, 1, and 1.33 L/min) at each tilt angle. Notably, the study reveals that the efficiency peaks at a 15° tilt due to an optimal flow configuration for maximum energy harvest across all three mass flow rates. Increasing the mass flow rate yields efficiency increments for all tilt angles (15°, 20°, and 30°), with 1 L/min emerging as the optimal mass-flow rate in most cases. This research not only addresses the immediate need for improved solar thermal technologies but also aligns with global sustainability goals, contributing to the IEA Net Zero Emissions initiative and supporting UN Sustainable Development Goals 7, 9, and 11. The paper also includes a critical literature review on the use of nanofluids in solar thermal collectors to improve thermo-physical properties and enhance solar efficiency. Additionally, the key findings regarding the influence and tilt angle on solar efficiency are discussed.

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Article

Francis Type Turbine Runner Design and Comparison with Model Test Results

Cavitation wear and hydraulic efficiency decrease in hydroelectric power plants have frequently been the subject of various research and studies. A hydroelectric power plant built on the Kızılırmak River in Türkiye started operating in 1960 and has not been subjected to any large-scale rehabilitation work other than general maintenance until today. The power plant has 4 Francis-type turbines, each with a power of 32 MW. Due to cavitation wear of turbine runners over the years, performance loss, vibration, and noise problems have arisen. Moreover, the maximum turbine hydraulic efficiency, which was 92% in 1960, the year the power plant was commissioned, decreased to 87.9% according to the efficiency measurements carried out at the power plant in 2020. In this study, Computational Fluid Dynamics (CFD) analyses were accomplished with Reynolds averaged Navier Stokes (RANS) calculations for the redesign of the Francis-type turbine runner and finally checked by a model test according to IEC 60193. It was observed that the model test and CFD results were close to each other, especially at the best efficiency point. The maximum turbine hydraulic efficiency, which was calculated as 94.95% as a result of CFD analysis at the nominal head, was calculated as 95.19% by the model test. The x-blade shape created in the redesigned turbine runner blades ensured homogeneous pressure distribution and increased the hydraulic efficiency significantly.

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Article

Proposing an Approach for the Diffusion of Building Integrated Photovoltaics (BIPVs)—A Case Study

Consistent probing into building integrity has led to the exploration of clean energy options such as building integrated photovoltaic (BIPV). BIPV has proven to be aesthetically pleasing, architecturally feasible, and capable of making buildings energy producers instead of mere energy consumers. Despite the enormous benefits of BIPV, its adoption and diffusion have been relatively sluggish and remain far below expectations, especially in developing countries like Ghana. This empirical study aims to assess the impact of advertising on BIPV awareness in Ghana. It also highlights the aesthetic preferences of various respondents. The study uses online surveys to gather quantitative data from 412 respondents across all 16 regions of the country. An initial study conducted on the awareness of BIPV in Ghana indicated a low rate of awareness. Therefore, a sensitisation poster and architectural visualization (AV) were adopted to boost awareness across all 16 regions of the country. Awareness of BIPV increased from 18% to 79.5% after the introduction of the sensitisation poster. Also, 88.8% of the respondents preferred BIPV to Building Applied Photovoltaic (BAPV) mainly because of aesthetics (beauty) and the cost benefits. The respondents indicated that aesthetics is paramount when choosing solar panels for their homes. This study therefore recommends high investment in awareness creation, development of specific design guidelines for BIPV applications and establishment of demo projects in developing countries. The findings of this study contribute to the existing literature on BIPV adoption and may be useful for BIPV manufacturers, marketers, government, and other stakeholders as it provides evidence on the often-neglected approach to BIPV diffusion.

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Article

Optimizing Thermal Management: An Evaluation of Embedded Aluminum-Ammonia Heat Pipes Honeycomb Sandwich Panel as a Heat Sink for Satellite Use

This study presents an innovative approach to enhancing thermal management in satellite applications by utilizing an embedded aluminum-ammonia heat pipes honeycomb sandwich panel (HPA-PNL) as a high-performance heat sink. The study focuses on developing and evaluating this advanced heat sink technology, addressing the challenges associated with assessing its performance and suitability for satellite use. The research explores the selection of materials and testing methodologies, highlighting the significance of overcoming existing limitations in the absence of standardized testing methods. The results of the thermal conductivity in Z-directions (KZ) indicated that the areas on top of the heat pipes show higher thermal conductivity than those on top of the honeycomb core. Also, the effect of background heat sources and different kinds of thermal interface material (TIM) on HPA-PNL performance is insignificant. The heat dissipation through the heat pipe is substantial, emphasizing the effective ability to dissipate heat for an HPA-PNL with many heat sources acting simultaneously. The outcomes of this study reveal promising testing methods for evaluating the KZ of the HPA-PNL, proposing the potential of the embedded aluminum-ammonia heat pipes honeycomb sandwich panel as a highly effective and efficient heat sink for satellite systems, thus contributing to the advancement of satellite technology.

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