Exergy Analysis Research Articles

Exergy analysis and novel topological optimization of fin structures in latent heat thermal energy storage system: Experimental study

Exergy analysis and novel topological optimization of fin structures in latent heat thermal energy storage system: Experimental study

Exergy and energy analysis of pyrolysis of pretreated single-use waste plastics

Exergy and energy analysis of pyrolysis of pretreated single-use waste plastics

Energy, exergy and enviro-economic analysis of a hybrid energy plant utilizing biogas and solar technologies in the Almaty region, Republic of Kazakhstan

Energy, exergy and enviro-economic analysis of a hybrid energy plant utilizing biogas and solar technologies in the Almaty region, Republic of Kazakhstan

Simulation, and comparative energy, exergy, economic, and environmental analyses of utilizing different solvents for post-combustion CO2 capture from flue gases

Simulation, and comparative energy, exergy, economic, and environmental analyses of utilizing different solvents for post-combustion CO2 capture from flue gases

Exergy and electrochemical impedance spectroscopy analysis of proton exchange membrane fuel cell at wide working conditions

Exergy and electrochemical impedance spectroscopy analysis of proton exchange membrane fuel cell at wide working conditions

Proposing wavy-shaped legs for performance improvement of thermoelectric generators: energy, exergy, environmental, and mechanical analysis using a CFD-trained machine learning method

Proposing wavy-shaped legs for performance improvement of thermoelectric generators: energy, exergy, environmental, and mechanical analysis using a CFD-trained machine learning method

Energy, exergy and economic analysis of a heat pump heating system extracting static water phase change latent heat

Energy, exergy and economic analysis of a heat pump heating system extracting static water phase change latent heat

Energy, exergy, sustainability, and economic analysis of a waste heat recovery for a heavy fuel oil-based power plant using Kalina cycle integrated with Rankine cycle

Energy, exergy, sustainability, and economic analysis of a waste heat recovery for a heavy fuel oil-based power plant using Kalina cycle integrated with Rankine cycle

Energy and exergy analysis of a biomass-CO2 transcritical brayton cycle

Energy and exergy analysis of a biomass-CO2 transcritical brayton cycle

Conventional and advanced exergy analysis of a dual-evaporator transcritical CO2 refrigeration system enhanced with ejectors

Conventional and advanced exergy analysis of a dual-evaporator transcritical CO2 refrigeration system enhanced with ejectors

Energy and exergy analysis for VCRS of a water dispenser

Energy and exergy analysis for VCRS of a water dispenser

Exergy analysis for solid oxide fuel cell integrated hybrid desiccant cooling system

Exergy analysis for solid oxide fuel cell integrated hybrid desiccant cooling system

Energy and exergy analysis of a reversed circular flow jet impingement bifacial PVT collector: CFD simulation and experimental study

Energy and exergy analysis of a reversed circular flow jet impingement bifacial PVT collector: CFD simulation and experimental study

Exergy Analysis of Oxy-Biogas Combustion with Different Rates of the CO2 Content

This work presents the exergetic evaluations of the oxy-biogas combustion process in an adiabatic furnace for the cases of biogas involving different carbon dioxide (CO2) concentrations. A three-dimensional steady-state computational fluid dynamics model was developed for combustion simulation. The model was first verified with the data of oxy-natural gas and showed good agreement with the data. Thus, simulation studies were performed for the oxy-biogas combustion with different CO2 concentrations of biogas fuel, from 10 vol% to 40 vol% with a 10% increment, at a constant input power capacity. The results show that the sum of specific thermo-mechanical and chemical exergy of combustion products has a decreasing trend with increasing CO2 content in biogas. However, the exergy flow rates of the combustion products increased with the increase in CO2 due to the increasing mass flow rates. Increasing the CO2 level in biogas led to an increase in the chemical exergy fraction of the combustion products. Thus, the exergy loss fractions resulting from incomplete combustion varied increasingly from 5.8 % to 13.8 % in the range from 10 % CO2 to 40 % CO2 contents of biogas.

Energy and exergy analysis of a photocatalytic Trombe wall based on visible-light photocatalytic purification

Energy and exergy analysis of a photocatalytic Trombe wall based on visible-light photocatalytic purification

Conventional and advanced exergy analysis of a novel SOFC-MGT hybrid power system coupled with external solar methane hydrogen production process

Conventional and advanced exergy analysis of a novel SOFC-MGT hybrid power system coupled with external solar methane hydrogen production process

Exergy Analysis of a Biogas Plant for Municipal Solid Waste Treatment and Energy Cogeneration

The amount of municipal solid waste (MSW) produced has increased with population growth and consumption patterns. Currently, most waste goes to dumps, although the Brazilian law requires the final destination to be landfills. The latter does not consider the energy lost by these solutions and the carbon footprint that better destinations could avoid. However, not treating the waste correctly aggravates land availability problems, especially in large cities such as São Paulo. Anaerobic digestion is an alternative to traditional waste management, and in addition to treating residues, it generates energy and recovers the nutrients present in MSW. Thermodynamic analyses are still scarce in the literature despite being a known process. This study performed an exergy analysis of an existing biogas plant at the Institute of Energy and Environment of the University of São Paulo with a processing capacity of 20 tons of MSW per day composed of three reactors (430 m3 each) and one internal combustion engine (ICE) of 75 kW. The plant uses MSW as the substrate for anaerobic digestion and generates electrical energy, biogas, and fertilizer for agriculture (digestate). Additionally, the plant operates in cogeneration, as the anaerobic digestion reactor uses the heat produced to generate electrical energy. The results showed that the exergy present in the substrate is 67,320 MJ/day. The products’ exergy flows and the processes’ efficiencies show that the exergy flow of the biogas (44,488 MJ/day) is significantly higher than the exergy flow of the digestate (1455 MJ/day). When considering the cogeneration process, the exergy flow was similar for heat and electric energy as the final products, with 10,987 MJ/day for electric energy and 5215 MJ/day for electric energy. The exergy efficiency of the digestion process was 68.25%, while that of cogeneration (digestate, heat and electric energy) was 26.23%. These results can help identify inefficiencies and optimize processes in an anaerobic digestion plant. Furthermore, thermodynamic analyses of anaerobic digestion found in the literature are mostly based on theoretical models. Thus, this study fills a gap regarding exergy analysis of actual biogas plants.

Performance Analysis of Solar-Integrated Vapour Compression Air Conditioning System for Multi-Story Residential Buildings in Hot Climates: Energy, Exergy, Economic, and Environmental Insights

Decarbonisation in hot climates demands innovative cooling solutions that minimise environmental impact through renewable energy integration and advanced system optimisation. This study investigates the energetic and economic feasibility of a thermo-mechanical vapour compression (TMVC) cooling system that integrates a conventional vapour compression cycle with an ejector and a thermally driven second-stage compressor powered by solar-heated water from evacuated flat-plate collectors. The system is designed to reduce mechanical compressor work and enhance cooling performance in hot climates. A comprehensive 4E (energy, exergy, economic, and environmental) analysis is conducted for a multi-story residential building in Baghdad, Iraq, with a total floor area of approximately 8000 m2 and a peak cooling demand of 521.75 kW. Numerical simulations were conducted to evaluate various configurations of solar collector areas, thermal storage tank volumes, and collector mass flow rate, aiming to identify the most energy-efficient combinations. These optimal configurations were then assessed from economic and environmental perspectives. Among them, the system featuring a 600 m2 collector area and a 34 m3 storage tank was selected as the optimal case based on its superior electricity savings and energy performance. Specifically, this configuration achieved a 28.28% improvement in the coefficient of performance, a 22.05% reduction in energy consumption, and an average of 15.3 h of daily solar-assisted operation compared to a baseline vapour compression system. These findings highlight the potential of the TMVC system to significantly reduce energy usage and environmental impact, thereby supporting the deployment of sustainable cooling technologies in hot climate regions.

Workflow Design and Operational Analysis of a Coal‐Based Multi‐Energy Combined Supply System for Electricity, Heating, Cooling, and Gas

ABSTRACTThe combined cooling, heating, and power (CCHP) system, as a typical representative of novel distributed energy systems, demonstrates significant advantages in the cascade utilization of energy and the control of transmission and distribution losses. However, the inherent reliance of traditional CCHP systems on natural gas as fuel structurally conflicts with China's energy endowment, characterized by abundant coal and scarce natural gas, severely limiting their large‐scale application. To adapt to this energy consumption profile and fully leverage the strengths of CCHP systems, this study establishes a coal‐fueled electricity‐gas‐heating‐cooling polygeneration system based on physical and mathematical models within the Aspen Plus 9.0 commercial simulation platform. The reliability of the proposed model is validated through comparisons with data from relevant literature. To identify the optimal operating parameters, the effects of coal‐water slurry concentration and oxygen‐to‐coal ratio on key gasification indicators (e.g., gasifier temperature, syngas composition, syngas calorific value, and cold gas efficiency) and system output loads (e.g., electricity, heating, cooling, and municipal gas) are systematically investigated. Finally, a comprehensive simulation of the entire system is conducted, with energy and exergy analyses performed on major functional units. The results indicate that coal‐water slurry concentration and oxygen‐to‐coal ratio significantly influence gasifier temperature, syngas composition, calorific value, and cold gas efficiency. The system achieves optimal performance at an oxygen‐to‐coal ratio of 1.05 and a coal‐water slurry concentration of 65%. Under design conditions, the system attains a comprehensive energy efficiency of 66.18% and an exergy efficiency of 34.43%. This study provides an innovative solution to address technological bottlenecks in China's energy transition, not only enhancing the efficiency of clean coal utilization but also offering a new technical pathway for coal‐fired power transformation under the “dual carbon” goals (carbon peaking and carbon neutrality).

Experimental Study for Energy Balance and Exergy Analysis of a Single-Cylinder, Spark-Ignition, Air-Cooled Engine

<div>In a time when small and micro energy sources are becoming increasingly important due to current environmental challenges, the efficient recovery of low-grade waste heat has emerged as a key strategy to enhance overall energy sustainability. Although extensive research has been conducted on energy and exergy distributions in large-scale internal combustion engines, experimental studies focusing on small, air-cooled gasoline engines remain limited, particularly regarding the quantification of their recoverable energy potential. Addressing this gap, this work analyzes and quantifies the global energy distribution and exergy availability in a single-cylinder, spark-ignition, air-cooled Robin EY15 engine operating at rotational speeds between 1500 and 4600 min<sup>−1</sup>, and throttle valve openings from one-quarter to full. The defined control volume includes the engine and the load system. The mass flows analyzed are fuel flow (standard gasoline), intake air, exhaust gas (assumed as air) and cooling air, while the energy flows are net power and miscellaneous heat losses. It is found that the maximum net and exergy efficiencies of the engine are 14.1% and 13%, respectively, at 2500 min<sup>−1</sup> and full open throttle. The major energy dissipation ways are the cooling air 24.3%–73.6% and miscellaneous losses 9%–61% (percentage related to total energy flow provided by the fuel). Based on exergy analysis, between 6%–9.7% and 22%–29.7%, respectively, of that energy flows are transformable into mechanical work; however, the exhaust gases has the higher potential, between 22.7% and 34.7%. The rate of exergy destroyed ranges between 69.6% and 89.7%, meaning that the maximum achievable efficiency would range from 10.3% up to 30.5% throughout the tested engine speed–load conditions. These findings provide useful insights into the low-grade heat recovery potential of small-scale combustion engines and contribute new experimental data to the field of micro energy systems.</div>