Modeling and Analysis of Effect of Various Tank Geometries and Relief Pressure on Liquid Hydrogen (LH2) Boil-Off Losses

This research investigates the effect of various storage tank geometries and relief pressure on boil-off losses for liquid hydrogen (LH2). The effect of storage volume of LH2 in the tanks for the various geometries is analyzed as well. The model takes into consideration the heat transfer between the liquid and vapor phases, integrates actual heat transfer mechanisms, and employs variety equations of state to estimate evaporative losses. For this, a software package BoilFAST has been used to investigate the boil-off losses. The model was validated against experimental data available in open literature from NASA. Results showed that the effect of relief pressure on the evaporation of LH2 is very high. The LH2 volume is reduced by 34% in the case of cuboid shape and 22% the for spherical shape of the tank from relief pressure of 111 to 10 kPa. However, the effect of the filled volume of LH2 in the storage tank on the evaporation of LH2 is minimal as the volume is reduced only by less than 5% for all tank shapes. Overall, for various tank geometries, spherical shape showed minimum evaporation losses compared to other tank geometries.The work presented in this publication was made possible by grant QUPD - CENG - 23/24 - 537 from the Qatar University. The findings herein reflect the work, and are solely the responsibility, of the authors.Scopu

CFD simulation of modified solar still for effective condensation and evaporation: energy and exergy analysis

Water scarcity is a global challenge, underscoring the importance of efficient water resource management. Solar stills offer a cost-effective method to convert brackish water into potable water but face productivity limitations. This study aims to enhance solar still productivity through modifications using different fin materials and water depth. Computational Fluid Dynamics (CFD) simulations were employed to evaluate thermal performance across four scenarios: copper and aluminum fins at water depths of 20 mm and 40 mm. Key parameters including temperature distributions, friction volume, and fluid velocity were analyzed for each configuration (MSS-I to MSS-IV). Energy and exergy efficiencies were also assessed. MSS-III, utilizing copper fins at a 20 mm depth, demonstrated the highest daily productivity (8.33 liters) compared to MSS-IV (8.02 liters), MSS-I (7.81 liters), and MSS-II (6.71 liters). Energy efficiencies were highest for MSS-III (60.10%), followed by MSS-IV (57.41%), MSS-I (55.22%), and MSS-II (52.18%). MSS-III also exhibited the highest exergy efficiency (21.50%), with MSS-I (17.15%), MSS-IV (16.43%), and MSS-II (14.12%) following. The study underscores significant improvements in thermal and energy efficiency achieved through specific design modifications of solar stills. MSS-III’s higher performance, attributed to the use of copper fins and optimized depth, highlights the critical role of material selection and structural design in enhancing solar still productivity. These findings have important implications for sustainable water resource management, emphasizing the potential of optimized solar still designs to address water scarcity challenges

A comprehensive review of solar thermal desalination technologies for freshwater production

This review is inspired by the increasing shortage of fresh water in areas of the world, and is written in response to the expanding demand for sustainable technologies due to the prevailing crisis of depleting natural water resources. It focuses on comprehending different solar energy-based technologies. Since the increasing population has resulted in the rising demand for freshwater, desalination installation volume is rapidly increasing globally. Conventional ways of desalination technologies involve the use of fossil fuels to extract thermal energy which imparts adverse impacts on the environment. To lessen the carbon footprint left by energy-intensive desalination processes, the emphasis has shifted to using renewable energy sources to drive desalination systems. The growing interest in combining solar energy with desalination with an emphasis on increasing energy efficiency has been sparked by the rapid advancements in solar energy technology, particularly solar thermal. This review paper aims to reflect various developments in solar thermal desalination technologies and presents prospects of solar energy-based desalination techniques. This paper reviews direct and indirect desalination techniques coupled with solar energy, and goes on to explain recent trends in technologies. This review also summarizes the emerging trends in the field of solar thermal desalination technologies. The use of nanoparticles and photo-thermal materials for localized heating in solar desalination systems has decreased energy consumption and enhanced the efficiency of the system. Solar power combined with emerging processes like membrane distillation (MD) has also a recent resurgence

Energy, exergy and economic analysis of liquid flat-plate solar collector using green covalent functionalized graphene nanoplatelets

The conventional method of synthesizing carbon-based nanofluids produces harmful products that are highly toxic and hazardous. The present investigation deals with the effects of using eco-friendly, non-corrosive, covalent functionalized Graphene Nanoplatelets with gallic acid (GGNPs) as heat transfer fluid on energetic and exergetic performance of a Liquid flat-plate solar collector (LFPSC). Long-term dispersible stable GGNP nanofluids with base fluid distilled water are prepared with different weight concentrations of 0.025%, 0.05% & 0.1%. For varying concentrations, fluid flow rates of 0.8, 1.2, and 1.5 L/min, heat flux intensities of 600, 800, and 1000 W/m(2), and inlet temperature ranging from 303 to 323 K are considered for the conduction of experiments. Improvement in energy and exergetic efficiency was achieved using GGNP nanofluids. Thermal efficiency surges with increment in flow rate and heat flux intensities, meanwhile it decreases for increment in inlet temperature. The maximum enhancement in LFPSC efficiency is 24.09% for 0.1 wt% GGNPs and flow rate of 1.5 L/min than distilled water. Analysis of exergetic performance revealed that exergy efficiency reduces with a rise in mass flow rate meanwhile enhanced with an increase in nanofluid concentration. Exergy efficiency was maximum for 0.1% GGNP concentration and flow rate of 0.8 L/min. The maximum increase in friction factor values is approximately 1.5, 2.6 and 7.9% for 0.025, 0.05 and 0.1% GGNP nanofluids than distilled water. Relative pumping power slightly increases with the increment of GGNP concentration but is quite close to that of the base fluid. Performance index greater than one is obtained with higher values achieved at an increase in GGNP weight concentration. Economic consideration of GGNP nanofluids in LFPSC showcased a maximum reduction of 26.41% in the size of collector area using 0.1% GGNP nanofluid instead of distilled water. The payback period for LFPSC using GGNPs was 5.615% lesser than that of using water

Optimal Multi-Objective Placement and Sizing of Distributed Generation in Distribution System: A Comprehensive Review

For over a decade, distributed generations (DGs) have sufficiently convinced the researchers that they are the economic and environment-friendly solution that can be integrated with the centralized generations. The optimal planning of distributed generations requires the appropriate location and sizing and their corresponding control with various power network types to obtain the best of the technical, economical, commercial, and regulatory objectives. Most of these objectives are conflicting in nature and require multi-objective solutions. Therefore, this paper brings a comprehensive literature review and a critical analysis of the state of the art of the optimal multi-objective planning of DG installation in the power network with different objective functions and their constraints. The paper considers the adoption of optimization techniques for distributed generation planning in radial distribution systems from different power system performance viewpoints; it considers the use of different DG types, distribution models, DG variables, and mathematical formulations; and it considers the participation of different countries in the stated DG placement and sizing problem. Moreover, the summary of the literature review and critical analysis of this article helps the researchers and engineers to explore the research gap and to find the future recommendations for the robust optimal planning of the DGs working with various objectives and algorithms. The paper considers the adoption of uncertainties on the load and generation side, the introduction of DGs with energy storage backups, and the testing of DG placement and sizing on large and complex distribution networks

Simulation Study on the Effect of Cover Tilt Angle of SolarStill on its Productivity

Survival hinges on access to water, serving as both the foundation for human existence and its continuous sustenance. Developing nations grapple with the significant challenge of ensuring clean drinking water availability. One solution is the utilization of solar stills, which harness solar energy for desalination to produce potable water, all without relying on high-energy sources. Solar stills remain a viable choice for providing safe drinking water to remote regions lacking reliable energy access. In this research, a comprehensive multi-phase 3D Computational Fluid Dynamics (CFD) model was employed to investigate single-slope solar still with glass cover angles of 200 and 250This model accurately depicts temperature variations within the solar still during different phases of operation. The simulation results presented herein reveal that the efficiency is notably superior in solar stills equipped with copper plates, achieving an output of 1.24 when inclined at 200 compared to other inclinations.  It becomes evident that the tilt angle of the cover has a substantial impact on the output.  Additionally, the most suitable water depth for a 200 angle is found to be 18mm. This cost-effective innovation is designed to provide rural populations with an efficient method to transform brackish water into potable drinking water

Aspects of artificial intelligence in future electric vehicle technology for sustainable environmental impact

Global energy trends are experiencing a profound transformation, and the future of transportation will boost sustainable development by controlling energy production and consumption while limiting vehicle emissions. Hence, Electric Vehicles (EVs) can substantially influence energy consumption trends by addressing potential environmental hazards. In the coming decades, Artificial Intelligence (AI) based systems will play a crucial role in future EVs' overall energy management systems. Advanced electric vehicle technology and intelligent modules will lead the automotive powertrain architecture. Numerous barriers, such as government support in certain regions, user compatibility, vehicle limitation, battery technology, and charging infrastructure, limit electric vehicle expansion. Therefore, the current state and emerging trends in this area are a matter of concern for increasing the expansion of electric vehicles. This study presents the existing charging technologies and compatible standards that may assist in its adaptability. It also examines the applications of artificial intelligence in electric vehicle development to render a collectively smarter package for EVs. The current level of development, in accordance with the paper's purpose, is to deduce the adaptability of EVs to certain obstacles. Hence, the categorization of methodologies and standards may be investigated and improved by scholars at a later time

Thermal Modeling and Performance Investigation of Proton Exchange Membrane (PEM) Fuel Cell

Abstract This research paper presents analysis of heat generation problem in Proton Exchange Membrane (PEM) fuel cell using COMSOL Multiphysics software. PEM fuel cells are widely recognized for their high electrical power output and environmental sustainability. However, in a PEM fuel cell around 50 to 60 % of energy generated from chemical reactions is dissipated as heat energy. To address this issue PEM fuel cell stack model is designed and thermal modeling is carried out to evaluate its performance. Based on thermal modeling of surface temperature distribution of cell it is found that the cathode side of PEM fuel cell is warmer and generates more heat as compared to other parts due to the exothermic reactions,slow reaction rate,joule heating effect and material properties.Moreover, it is also found that there is uniform temperature distribution across the cell due to rapid heat conduction from cathode side to the surface of the cell.The results of this study show that due to more heat generation on cathode side temperature will tend to increase.This increasing temperature enhancesthe average cell current density but as the average cell current density increases it reduces the average cell voltage thus declining the efficiency of PEM fuel cell. Hence ,there should be an optimal temperature range between 60 to 80°C for the better performance of a PEM fuel cell. Findings of this study can serve as a valuable resource for understanding heat generation process in PEM fuel cell for the development of efficient and reliable fuel cell technology in future

Advancements of Biochar-Based Catalyst for Improved Production of Biodiesel: A Comprehensive Review

Despite being a limited and scarce resource, the necessity and exploitation of fossil fuels are unstoppable in serving human demands. In order to supply energy demand without causing environmental damage, it is crucial to utilize a variety of renewable feedstock resources. Biochar, made up mostly of carbon, oxygen, and hydrogen, is the product of the thermochemical processes of pyrolysis, hydrothermal carbonization, torrefaction, and hydrothermal liquefaction. Biochar, once activated, has the potential to act as a catalyst in a variety of energy generation processes, including transesterification and fermentation. Transesterification is the process that is used to produce biodiesel from a variety of oils, both edible and non-edible, as well as animal fats in the presence of either a homogeneous or a heterogeneous catalyst. When selecting a catalyst, the amount of free fatty acid (FFA) content in the oil is considered. Homogeneous catalysts are superior to heterogeneous catalysts because they are unaffected by the concentration of free fatty acids in the oil. Homogeneous catalysts are extremely hazardous, as they are poisonous, combustible, and corrosive. In addition, the production of soaps as a byproduct and a large volume of wastewater from the use of homogeneous catalysts necessitates additional pretreatment procedures and costs for adequate disposal. This article examines the biochar-based fuel-generation catalyst in detail. At first, a wide variety of thermochemical methods were provided for manufacturing biochar and its production. Biochar’s chemical nature was analyzed, and the case for using it as a catalyst in the production of biofuels was also scrutinized. An explanation of how the biochar catalyst can improve fuel synthesis is provided for readers. Biodiesel’s transesterification and esterification processes, biomass hydrolysis, and biohydrogen generation with the help of a biochar catalyst are all reviewed in detail