Jose Luis Moreno Tapias · Universidad Industrial de Santander · 2016
En el presente trabajo de aplicación se llevó a cabo un análisis exergético al proceso de recuperación de etano a partir de gas natural desarrollado en la planta turboexpander, con el objetivo de establecer la eficiencia exergética actual e identificar etapas con oportunidades de aprovechamiento de calor residual, que permitan a futuro mediante la implementación de alguna técnica de integración energética la disminución de costos asociados a servicios y aumento en el margen de ganancia. El proceso productivo fue dividido en ocho etapas para facilitar la posterior elaboración de la simulación de toda la unidad a través del software PRO II, obteniéndose de esta manera los flujos de masa, molar y las propiedades físicas y termodinámicas de cada una de las corrientes de proceso. Los cálculos de las exergías físicas, químicas, de calor y trabajo propios del análisis exergético fueron realizadas teniendo en cuenta dos escenarios: En el primero de ellos sólo se tuvo en cuenta el etano como producto valioso obteniéndose como resultados que la etapa con mayores irreversibilidades fue la deetanización con 306,47 kJ/kg y la de menor la compresión secundaria con sólo 15,71 kJ/kg; Así también la de mayor eficiencia exergética fue la compresión secundaria con 99,31%, la de menor eficiencia la deetanización con 11,15% y la global sólo 7,50%. En el segundo escenario se tuvo en cuenta el etano y el metano como productos valiosos obteniéndose como resultados que la irreversibilidades de las etapas de compresión secundaria y deetanización se mantienen con 15,71 kJ/kg y 306,47 kJ/kg respectivamente; Así también las eficiencias exergéticas de la compresión secundaria y deetanización se mantienen con valores de 99,31% y 11,15% respectivamente, pero la eficiencia de la sección de demetanización pasa de un 12,23% a 73,69% y la global cambia de un valor de 7,50% a uno de 89,30%.
Cited by 0Open access
Sorin, M., Brodyansky, V., Paris, Jean · PolyPublie (École Polytechnique de Montréal) · 1994
Cited by 7
Yongjian Gu · Proceeding of 4th Thermal and Fluids Engineering Conference · 2019
Cited by 0
Muhammad Alam Zaib Khan (16877184), Abdul Wahab (607551), Fawad Ali (2154529) et al. · Figshare · 2023
<div><p>Deployment of solar photovoltaic panels are significantly rising to tackle adverse effects of climate change however, factors affecting output need to be categorized in addition to latitude angle and space. It is important to consider the atmospheric impact which can drastically change output power of solar panels. This study covers dust accumulation of soil, sand and ash at variable weights to foresee its effects on panel power output. Mixtures of these particles at multiple constituents were also analyzed. Experimental results indicated that clean panel gives maximum power output of 21.37W and exergy efficiency of 7.96% whereas ash accumulation showed worst results of 2.88W power output and 1.07% exergy efficiency at 700W/m2 and 50g dust accumulation. Other parameters like energy destruction, exergy losses and sustainability index were also analyzed. Trends have been illustrated in graphs along with the change in solar intensity and dust accumulations.</p></div>
Cited by 0Open access
W. van Gool, Herman ter Horst · Elsevier eBooks · 1982
Cited by 2
Muhammad Alam Zaib Khan (16877184), Abdul Wahab (607551), Fawad Ali (2154529) et al. · Figshare · 2023
<div><p>Deployment of solar photovoltaic panels are significantly rising to tackle adverse effects of climate change however, factors affecting output need to be categorized in addition to latitude angle and space. It is important to consider the atmospheric impact which can drastically change output power of solar panels. This study covers dust accumulation of soil, sand and ash at variable weights to foresee its effects on panel power output. Mixtures of these particles at multiple constituents were also analyzed. Experimental results indicated that clean panel gives maximum power output of 21.37W and exergy efficiency of 7.96% whereas ash accumulation showed worst results of 2.88W power output and 1.07% exergy efficiency at 700W/m2 and 50g dust accumulation. Other parameters like energy destruction, exergy losses and sustainability index were also analyzed. Trends have been illustrated in graphs along with the change in solar intensity and dust accumulations.</p></div>
Cited by 0Open access
Johannes Brötz, Christian Schänzle, Peter F. Pelz · International Journal of Turbomachinery Propulsion and Power · 2023
The efficiency definition allows us to compare two machines with each other. In general, the efficiency is defined as the ratio of usable power to the required power. This raises the question: what is the usable power? Most engineers discuss efficiency on the basis of the energy balance, i.e., the first law of thermodynamics. In this paper, we derive the exegetic efficiency taking the second law of thermodynamics into account. Exergy analysis takes into account work and heat and is able to model reality very accurately. On this basis, a comparison between the isentropic and exergetic efficiencies is given. A high-pressure radial fan is used as an example, and the differences are discussed. Therefore, measurements of a non-adiabatic fan are evaluated, and the role of the heat flux in the environment is discussed. The investigations show that a relevant difference between the isentropic and exergetic efficiencies becomes apparent in the partial-load range with high-pressure build-up. The thermal energy contained in the flow belongs proportionally to the exergy, i.e., the working capacity of the gas relative to its environment. For a standard such as ISO 5801 “Fans—Performance testing using standardized airways”, the efficiency must not only be physically correct, it must also be simple and practical. Against this background, the outlook of this paper discusses when and which efficiency definition is appropriate and best suited for a standard.
Cited by 3Open access
Nguyễn Văn Hoàng · International Journal of Science and Research Archive · 2024
This study presents a detailed analysis of the exergy losses, exergy efficiency, and cooling coefficient of performance (COP) for the refrigerant R22 in refrigeration systems. Exergy analysis, which considers both the quantity and quality of energy, is used to identify and quantify the irreversibilities within the system. The objective of this analysis is to provide insights into the areas of inefficiency and potential improvements for enhanced energy performance. Results indicate that the exergy losses in R22 systems are primarily associated with the compressor and expansion valve, highlighting these components as key targets for efficiency improvements. The exergy efficiency was found to vary significantly with operating conditions, suggesting that system performance could be optimized through appropriate design and control strategies. Additionally, the cooling COP of R22 was evaluated, demonstrating its effectiveness in converting input energy into cooling capacity under various conditions. This analysis contributes to the broader understanding of R22's thermodynamic performance and offers a foundation for developing more sustainable and efficient refrigeration technologies.
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Muhammad Alam Zaib Khan (16877184), Abdul Wahab (607551), Kamran Khan (669876) et al. · Figshare · 2023
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Sorin, M., Bonhivers, J.-C., Paris, Jean · PolyPublie (École Polytechnique de Montréal) · 1997
Cited by 0
Jaramaz, Lana, Banjac, Miloš · 2017
The solar energy is an inexhaustible source of energy and offers many environmental advantages compared to conventional energy sources. This paper deals with exergy efficiency of solar systems. The exergy is the measure of the maximum useful work which can be achieved by a system having to interact with an environment which is at a constant pressure and temperature. The exergetic analysis or analysis by the Second Law of Thermodynamics, has proven to be a powerful tool for thermodynamic analysis of power systems. In other words, it can be widely used in the assessment and evaluation of processes and the performances of energy systems. Although today many technically and economically successful solar systems are in operation, there is no widely accepted basis for comparison of achieved performances of a solar system with one that runs under different conditions. For this reason, this paper has focused on developing simple methods for assessing and comparing the exergetic efficiencies of the solar systems. There are several ways of using solar energy, and this work is focused on the collectors of solar energy used in solar water heaters, solar cookers, as well as photovoltaic and hybrid solar collectors.
Cited by 0
Maryam Rabiu Aliyu (19207391), Huzaifa Umar (19207394), Michael Adedeji (19672333) et al. · Figshare · 2025
<div> This study investigates the potential of water and ethylene glycol-based ternary nanofluids, enhanced with both chemically and green synthesized Fe-Cu-Fe<sub>2</sub>O<sub>3</sub> nanoparticles, to improve the performance of a heating, ventilation and air conditioning (HVAC) system. It also compares the effectiveness of the two synthesis methods, addressing the current research gap in the practical application of green-synthesized nanofluids in HVAC systems. Two sets of nanoparticles were synthesized using chemical and eco-friendly methods and dispersed in a base fluid of water and ethylene glycol (EG) at varying concentrations of 0%, 50%, and 75% EG with various nanoparticle mixture ratios. The prepared ternary nanofluids were used to evaluate the thermal performance of the heater in an air-handling unit (AHU). Experimental data on the thermophysical properties of the nanofluid at the different mixture ratios were incorporated into a numerical model simulating the AHU operating in a Mediterranean climate. Results show that the nanofluids significantly enhance system performance, with the 1Fe: 2Cu: 1Fe<sub>2</sub>O<sub>3</sub> nanoparticle mixture ratio offering the best balance between efficiency and operational stability. The heat transfer rates were improved by up to 20% in summer and 15% in winter compared to the base fluid. In addition, the mixture ratio achieved optimal exergy efficiency, peaking at 98% during winter operation and 96% during summer. Comparative analysis also shows that the ternary nanofluids containing the chemical-synthesized nanoparticles (CSNTNF) perform only slightly better than the nanofluids containing the green-synthesized nanoparticles (GSNTNF). This suggests that GSNTNF is a suitable replacement for the CSNTNF, considering the environmental benefits. </div>
Cited by 0Open access
Володимир Нікульшин, Chuansong Wu, V. Nikulshina · Exergy An International Journal · 2002
Cited by 27
Çamdalı, Ünal, Tunç, Murat · DergiPark (Istanbul University) · 2016
Cited by 0
Seyed Hamed Pour Rahmati Khalejan, Vedat Keskin · Tehnicki vjesnik - Technical Gazette · 2022
In this study, the effects of dynamic shading caused by an incorrectly positioned transformer building in a Photovoltaic array were investigated regarding the exergy efficiency and thermal exergy for a year. Experimental and theoretical results show that the thermal exergy is affected by the surface temperature of solar panels depending on their shading ratio. In addition, as the shading ratio increases, the electrical exergy and power conversion efficiency decrease. It is also seen that the thermal exergy and exergy efficiency of the PV power system is negatively affected by the increasing solar cell temperature. The average shading ratio of 3.11% during a year causes an increase of about 23.32% of the thermal exergy, and loss in power conversion efficiency of about 4.88% and loss in exergy efficiency of about 13.72% over a year. Overall, it can be concluded that the long-term shading will significantly adversely affect the PV array performance in terms of electrical exergy and thermal exergy.
Cited by 4Open access
Muhammad Alam Zaib Khan (16877184), Abdul Wahab (607551), Fawad Ali (2154529) et al. · Figshare · 2023
Cited by 0Open access
A. Kerim Kar · Applied Energy · 1985
Cited by 22
Guangduo Liu, Jinliang Xu, Shuyun Cao · IOP Conference Series Earth and Environmental Science · 2019
Organic Rankine cycle (ORC) which recovers waste heat in the temperature range of 80°C-140°C was investigated. Exergy efficiencies of various components and ORC system were paid great attention. The working fluids of R245fa and R600a are used. It is found that, for saturated ORCs, the expander inlet temperature has the optimum value, so the system exergy efficiency is maximum. With the increase of heat source temperature, the optimal inlet temperature of the expander is also increased. And also for saturated ORCs, the exergy efficiencies of evaporator and expander are highest efficiency, when evaporator exergy efficiency is increased with increase of heat source temperatures, the expander exergy efficiency is unchanged. The condenser decreased exergy efficiencies by increasing the heat source temperatures.
Cited by 1Open access
Mostafa Mohammadnejad, Mahdi Ghazvini, F.S. Javadi et al. · The University of Malaya Research Repository (University of Malaya) · 2011
Friction is an effective factor in the reduction of the exergy efficiency in engines. In this study, the effects of using nanolubricants on friction reduction, thereby increasing the engine exergy efficiency, have been investigated. First, studies done on exergy, engine lubrication and friction reduction with nanolubricants have been reviewed. Based on these studies the mathematical formula for estimating the exergy efficiency of an engine that uses nanolubrication was derived. Finally, it has been found that adding CuO nanoparticles to SF oil has the greatest effect on the exergy efficiency improvement and the maximum amount of this improvement is 4.6.
Cited by 19
Robert U. Ayres · Edward Elgar Publishing eBooks · 2002
Cited by 10