• Energy Research

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.

Solar PV has a disadvantage over its many advantages that its electrical efficiency falls due to rise in surface/operating temperature of solar PV cells. Therefore, it is necessary to find a way to mitigate the efficiency loss due to rise in temperature as well as to increase life span of solar photovoltaics by lowering its cell temperature. In this research, the impact of mist cooling on output of PV panel is observed through experimental setup installed at rooftop of Postgraduate Department, Mehran University of Engineering and Technology, Jamshoro, Pakistan. The rear surface of PV module is cooled with designed mist nozzle assembly. The performance of modified mist cooled PV module is than compared with reference PV module. Experimental investigation is performed several days in different weather conditions with natural circulation and with forced circulations by using submerged pump. The maximum efficiency gains of 7% and average gain of 3.72% is observed with natural circulation, and maximum gain of 9.2% and average gain 1.72% are observed with forced circulated mist. The overall impact of proposed mist cooled system is positive on performance of PV panels. This work was supported by the Qatar University. The work presented in this publication was made possible from QUPD-CENG-23-24-537 project funded by Qatar University Office of VP for Research support and Mehran University of Engineering and Technology, Jamshoro, Pakistan. The findings herein reflect the work, and are solely the responsibility, of the authors. Open Access funding provided by the Qatar National Library. Scopus

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.

El CCS (Captura y Almacenamiento de Carbono) es una de las soluciones significativas para reducir las emisiones de CO2 de las plantas de generación de electricidad con combustibles fósiles y minimizar el efecto del calentamiento global. El análisis económico de la tecnología de CAC es, por lo tanto, esencial para la evaluación de viabilidad hacia la reducción de CO2. En este documento, se ha estimado el LCOE (Coste Nivelado de la Generación de Electricidad) con y sin tecnología CCS para las centrales eléctricas basadas en combustibles fósiles de Pakistán y también se ha comparado con el LCOE calculado de las centrales eléctricas basadas en WE (Energía Eólica) de Pakistán. Los resultados de este estudio sugieren que los costos de generación de electricidad de las plantas de energía de combustibles fósiles aumentan más del 44% con la tecnología CCS en comparación con sin la tecnología CCS. También se encuentra que los costos de generación son un 10% más altos cuando se considera la penalización de eficiencia debido a la instalación de la tecnología CCS. Además, los costes evitados de CO2 de la planta de gas natural son un 40 y un 10% más altos que los de las plantas locales de carbón y de carbón importado, respectivamente. Como tal, se encuentra que el costo de generación de electricidad de 5.09 Rs/kWh de las plantas WE es competitivo incluso cuando las plantas basadas en combustibles fósiles no cuentan con tecnología CCS, con el costo más bajo de 5.9 Rs./kWh de la planta CCNG (Combined Cycle Natural Gas). Con base en el análisis de los resultados de este estudio y el desarrollo futuro anticipado de tecnologías WE eficientes y baratas, se concluye que la generación de electricidad basada en WE sería la opción más apropiada para la reducción de CO2 para Pakistán. Le captage et le stockage du carbone (CSC) est l'une des solutions importantes pour réduire les émissions de CO2 des centrales électriques à combustibles fossiles et minimiser l'effet du réchauffement climatique. L'analyse économique de la technologie CSC est donc essentielle pour l'évaluation de la faisabilité de la réduction des émissions de CO2. Dans cet article, le LCOE (coût nivelé de la production d'électricité) a été estimé avec et sans la technologie CCS pour les centrales électriques à combustibles fossiles du Pakistan et également comparé aux LCOE calculés des centrales électriques basées sur l'énergie éolienne du Pakistan. Les résultats de cette étude suggèrent que les coûts de production d'électricité des centrales à combustibles fossiles augmentent de plus de 44 % avec la technologie CSC par rapport à la technologie sans CSC. Les coûts de production sont également de 10% plus élevés lorsque l'on considère la pénalité d'efficacité due à l'installation de la technologie CCS. En outre, les coûts évités en CO2 des centrales au gaz naturel sont respectivement 40 et 10 % plus élevés que ceux des centrales au charbon locales et des centrales au charbon importées. En tant que tel, le coût de production d'électricité de 5,09 Rs/kWh à partir d'installations WE s'avère compétitif même lorsque les installations à base de combustibles fossiles ne sont pas équipées de la technologie CCS, avec le coût le plus bas de 5,9 Rs/kWh de l'installation CCNG (Combined Cycle Natural Gas). Sur la base de l'analyse des résultats de cette étude et du développement futur anticipé de technologies WE efficaces et bon marché, il est conclu que la production d'électricité basée sur WE serait l'option la plus appropriée pour la réduction du CO2 au Pakistan. The CCS (Carbon Capture and Storage) is one of the significant solutions to reduce CO2 emissions from fossil fuelled electricity generation plants and minimize the effect of global warming. Economic analysis of CCS technology is, therefore, essential for the feasibility appraisal towards CO2 reduction. In this paper LCOE (Levelized Cost of Electricity Generation) has been estimated with and without CCS technology for fossil fuel based power plants of Pakistan and also further compared with computed LCOE of WE (Wind Energy) based power plants of the Pakistan. The results of this study suggest that the electricity generation costs of the fossil fuel power plants increase more than 44% with CCS technology as compared to without CCS technology. The generation costs are also found to be 10% further on higher side when considering efficiency penalty owing to installation of CCS technology. In addition, the CO2 avoided costs from natural gas plant are found to be 40 and 10% higher than the local coal and imported coal plants respectively. As such, the electricity generation cost of 5.09 Rs/kWh from WE plants is found to be competitive even when fossil fuel based plants are without CCS technology, with lowest cost of 5.9 Rs./kWh of CCNG (Combined Cycle Natural Gas) plant. Based on analysis of results of this study and anticipated future development of efficient and cheap WE technologies, it is concluded that WE based electricity generation would be most appropriate option for CO2 reduction for Pakistan. يعد احتجاز الكربون وتخزينه (CCS) أحد الحلول المهمة للحد من انبعاثات ثاني أكسيد الكربون من محطات توليد الكهرباء التي تعمل بالوقود الأحفوري وتقليل تأثير الاحترار العالمي. وبالتالي، فإن التحليل الاقتصادي لتكنولوجيا احتجاز ثاني أكسيد الكربون وتخزينه ضروري لتقييم الجدوى نحو خفض ثاني أكسيد الكربون. في هذه الورقة، تم تقدير LCOE (التكلفة المستوية لتوليد الكهرباء) مع وبدون تقنية CCS لمحطات الطاقة القائمة على الوقود الأحفوري في باكستان وأيضًا مقارنة مع LCOE المحسوبة لمحطات الطاقة القائمة على WE (طاقة الرياح) في باكستان. تشير نتائج هذه الدراسة إلى أن تكاليف توليد الكهرباء لمحطات توليد الطاقة بالوقود الأحفوري تزيد بأكثر من 44 ٪ مع تقنية احتجاز ثاني أكسيد الكربون وتخزينه مقارنة بدون تقنية احتجاز ثاني أكسيد الكربون وتخزينه. كما تبين أن تكاليف التوليد تزيد بنسبة 10 ٪ على الجانب الأعلى عند النظر في عقوبة الكفاءة بسبب تركيب تقنية احتجاز ثاني أكسيد الكربون وتخزينه. بالإضافة إلى ذلك، وجد أن التكاليف التي تم تجنبها من ثاني أكسيد الكربون من محطة الغاز الطبيعي أعلى بنسبة 40 و 10 ٪ من محطات الفحم المحلية ومحطات الفحم المستوردة على التوالي. على هذا النحو، تم العثور على تكلفة توليد الكهرباء البالغة 5.09 روبية/كيلوواط ساعة من محطات WE لتكون قادرة على المنافسة حتى عندما تكون المحطات القائمة على الوقود الأحفوري بدون تقنية CCS، بأقل تكلفة تبلغ 5.9 روبية/كيلوواط ساعة من محطة CCNG (دورة الغاز الطبيعي المركبة). استنادًا إلى تحليل نتائج هذه الدراسة والتطوير المستقبلي المتوقع لتقنيات WE الفعالة والرخيصة، تم استنتاج أن توليد الكهرباء على أساس WE سيكون الخيار الأنسب لخفض ثاني أكسيد الكربون في باكستان.

In this study, the economic and environmental impacts of insulation material are determined for different sizes of heating, ventilation and air conditioning (HVAC) duct. The optimum insulation thickness (OIT), energy-saving (ES) and payback period (PP) for HVAC duct are estimated using Life cycle cost (LCC) analysis. The analysis considers coal, natural gas (NG), liquefied petroleum gas (LPG), fuel oil (FO), bagasse, rice husk (RH) and geothermal as an energy source and the fiberglass as an insulation material. The results indicate the OIT and PP for an HVAC duct increase with the size of the duct while ES decreases. The maximum value of OIT, ES and minimum value of PP for different sizes and energy sources are determined as 48.27 mm in size A (300 mm) and NG, 84.91% in size E (500 mm) and LPG, and 0.2035 years in size A and NG, respectively. Additionally, the environmental analysis results indicate emission of CO2, CO and SO2 decreases with insulation thickness. The maximum value of CO2 and CO emission is determined for size E and NG i.e. 81.8% and SO2 emission for size E and FO i.e. 76.66%, respectively.

Pakistan has been facing energy crises for more than a decade as a result of its reliance on imported fossil fuels, circular debt, political instability, and absurd energy policies. However, the country has abundant renewable energy resources which, if harnessed, may help to effectively cope with ever-increasing energy demand. This review study investigates the country’s economic and energy situations, energy crises, and energy sector performance. A critical analysis of studies conducted on Pakistan’s energy planning since its independence in 1947 is, and policies announced to date are assessed. This review reveals that the economic situation of the country has remained severely stressed, and energy sector performance has been compromised over the years for various underlying reasons. The energy policy narrative in the early decades of the post-independence period focused on water resource management, whereas energy concerns were only realized in the late 1960s as demand grew. The first-ever energy and power planning study in Pakistan was conducted in 1967, and since then, various studies have been conducted to support the medium-term development plans of the government. These planning studies inspired further development, and in 1994, the first-ever electricity-focused power policy was announced by the government in response to industrial growth and subsequent electricity demand. However, this and subsequent policies were fossil-fuel-centric until 2006, when the government announced the first-ever renewable energy policy. This 2006 policy focused on increasing renewable energy penetration in the overall energy mix by setting specific targets. However, these targets have rarely been accomplished as a result of a lack of an effective planning paradigm, as most of studies have been conducted without sound demand forecasting and without considering renewable energy’s potential to meet growing demand. As such, planning efforts based on proven methodologies/modeling tools and the undertaking of demand forecasts and renewable energy assessments are inevitable for countries such as Pakistan. Therefore, we suggest that sectoral energy demand forecasting, estimation of renewable energy potential with end use, and modeling of optimal penetration of renewable energy using energy modeling tools will be helpful to develop sustainable energy policies in Pakistan to eradicate the energy crisis.

Solid fuel combustion in a chamber does not necessarily occur at a constant rate and may show fluctuations due to variables such as varying burning rates, chamber pressure, and residual combustion. These variables can cause the fuel to burn disproportionately. The acoustic environment of obstacle vortex-driven flow due to transient combustion with pressure oscillations in a solid fuel chamber is numerically investigated in the present study. Solid fuel combustion is considered transient, and flow characteristics of the present problem are governed by large eddies shed from an obstacle. Since unsteady Reynolds-averaged Navier-Stokes (URANS) simulations are not appropriate to compute the present flow phenomenon, therefore, a detached eddy simulation (DES) is performed to precisely predict the flow behavior. Simulation of steady-state combustion is carried out to validate the numerical results with available experimental data from the literature. The simulation of transient combustion shows that if the combustion frequency is close to the chamber’s modal frequency of the chamber, its amplitude increases greatly and creates an acute acoustic environment. This will result in fuel savings. The amplitude of pressure oscillation up to 18% and 5% of mean pressure are evident at the first and second mode of forced oscillation frequencies respectively. Interestingly, it is also found that pressure oscillation always occurs at inlet mass flux disturbance frequency and not between the disturbance and natural frequency of the chamber. As a result, it is evident that the combustion process or chamber configuration could be modified to ensure that both frequencies are far away enough to interact and create both a harsh acoustic environment and sufficient fuel to burn disproportionately.

In this paper, exergy analysis of a 210 MW SPP (Steam Power Plant) is performed. Firstly, the plant is modeled and validated, followed by a parametric study to show the effects of various operating parameters on the performance parameters. The net power output, energy efficiency, and exergy efficiency are taken as the performance parameters, while the condenser pressure, main steam pressure, bled steam pressures, main steam temperature, and reheat steam temperature isnominated as the operating parameters. Moreover, multiple polynomial regression models are developed to correlate each performance parameter with the operating parameters. The performance is then optimizedby using Direct-searchmethod. According to the results, the net power output, energy efficiency, and exergy efficiency are calculated as 186.5 MW, 31.37 and 30.41%, respectively under normal operating conditions as a base case. The condenser is a major contributor towards the energy loss, followed by the boiler, whereas the highest irreversibilities occur in the boiler and turbine. According to the parametric study, variation in the operating parameters greatly influences the performance parameters. The regression models have appeared to be a good estimator of the performance parameters. The optimum net power output, energy efficiency and exergy efficiency are obtained as 227.6 MW, 37.4 and 36.4, respectively, which have been calculated along with optimal values of selected operating parameters.