International Journal of Exergy (13 papers in press)

Regular Issues

• Performance Analysis of a Domestic Refrigerator Using R134a/CeO2 Nano-Enhanced Refrigerants: Energy, Exergy, and Economic Perspectives  
  by K. Arumuganainar, D. Palaniswamy, K. Viswanath, R. J. Eya Raj 
  Abstract: Household energy consumption is rising, with refrigerators being major contributors due to compressor load. This study explores enhancing refrigerator performance using ceria (CeO?) nanoparticle-enhanced refrigerants. Four blends R0 (R134a), R1, R2, and R3 (with 0.05%, 0.10%, and 0.15% CeO2 by volume) were tested. Results showed R3 improved cooling capacity by 7.8% (58.4 W) and COP by 14.5% (2.93) compared to R0. The exergy defect decreased by 5.5%, and exergy efficiency improved by 8.7% (23.92%). Economic analysis revealed operational costs dominate total cost. These findings highlight CeO2 additives potential in improving refrigeration efficiency, energy use, and sustainability.
  Keywords: Vapour compression; Refrigeration; R134a refrigerant; Nanoparticles; Exergy analysis; Economic analysis.
  DOI: 10.1504/IJEX.2025.10073021
   
  
• Exergy-Based Parametric Analysis of Induced Draft Cooling Towers in Ammonia and Urea Production Units  
  by Dino Dewantara, Ambo Intang, Muhammad D. Bustan, Sri Haryati, Ismail Ismail, Fatur Assyidiq 
  Abstract: In the era of big data, efficient semantic parsing of multi-modal data is crucial for intelligent service systems. However, existing image semantic understanding methods face issues such as cross-modal semantic gaps and insufficient modelling of long-range dependencies. To address these challenges, this paper proposes a novel hybrid network architecture that combines convolutional neural networks, recursive auto-encoders, and a dual-layer long short-term memory (LSTM) network guided by information gain. The proposed model achieves a highest semantic description score of 0.168 and improves both type agnostic accuracy and type aware accuracy to 0.932 and 0.901, respectively outperforming three baseline methods. Compared to the original model, it increases accuracy by 0.016 and 0.010. This architecture effectively bridges cross-modal gaps and enhances feature selection and long-term dependency modelling. The model demonstrates strong potential for deployment in cloud services, semantic web platforms, and virtualised infrastructures to support fault detection, resource optimisation, and intelligent quality management.
  Keywords: Exergy analysis; cooling tower performance; ammonia and urea production; entropy generation; exergy destruction.
  DOI: 10.1504/IJEX.2025.10073179
   
  
• Effect of Using Ejector on Energetic and Exergetic Performance of Refrigeration Systems  
  by Erdem Ersay?n, Leyla Ozgener 
  Abstract: The urgent need to decarbonize thermal systems has renewed focus on heat-driven refrigeration. Ejector refrigeration systems (ERCs) convert low-grade solar or waste heat into cooling using eco-friendly refrigerants. This paper critically reviews ejector design principles, refrigerant selection, and modeling approaches. A bibliometric analysis maps the transition from basic to integrated systems. While basic ERCs achieve COPs near 0.35, integration as expansion devices improves COP to 0.6, and hybrid systems exceed 0.75. Exergy efficiencies up to 35% are reported in advanced configurations. Findings highlight performance trends, research gaps, and future directions for ejectors in sustainable energy applications.
  Keywords: Ejector fundamentals; ejector refrigeration cycle; ejector applications; ejector studies; technology comparision.
  DOI: 10.1504/IJEX.2025.10073902
   
  
• Exergy-Based Performance Optimisation of Combined Gas-Steam Power Plant using Hybrid Approach  
  by Umesh Kumar, Manoj Kumar Pal 
  Abstract: Improving energy efficiency and cutting losses in combined gas-steam power plants depends on their optimization. A hybrid method of Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) is used in this study to boost the performance of plants. Such a model, based on both the first and second laws of thermodynamics, simulates the main parts of a power plant, like compressors, turbines, combustion chambers, and condensers. The (Air-to-Fuel Ratio) AFR, Gas-to-Steam Ratio (GSR), pressure ratio, Turbine Inlet Temperature (TIT), and effectiveness of heat recovery are all improved. Compared to single optimization techniques, the results show a 23.49% rise in thermal efficiency and a 23.61% drop in exergy destruction, proving that the system works better.
  Keywords: combined gas-steam power plants; Thermodynamic Modeling; Genetic Algorithm (GA); Particle Swarm Optimization (PSO); Hybrid Optimization; Thermal Efficiency.
  DOI: 10.1504/IJEX.2025.10074041
   
  
• Financial Inclusion as a Catalyst for Reducing Social Entropy: Application of Thermodynamics  
  by Sabana Parveen, Souvik Dey 
  Abstract: This scientific research uses thermodynamic laws to model the relationship between Financial and Social inclusion in 113 nations (20052022). Unlike other models, it regards FII as economic energy, SII as the ordered state, and capital-labour ratio as economic temperature. Using two-stage PCA, we constructed the composite index of SII and FII then employed the neo-classical theory of Cobb-Douglas function and logit model to test three thermodynamic hypotheses. Results indicate that FII significantly boosts SII, particularly in middle-and low-income countries with rising returns to scale, and reduces SII variation (entropy), implying more stability. The Boltzmann-type pattern of high inclusion, tempered by FII and structural balance, provides new perceptions into equality, efficiency, and convergence.
  Keywords: Financial Inclusion; Social Inclusion; Thermodynamic Laws; Capital; Labor.
  DOI: 10.1504/IJEX.2026.10074164
   
  
• Energy and Exergy Analysis of Solar Stills by using Single and Hybrid Nanofluid and Experimentally Determined Climatic Conditions  
  by Fatih Selimefendigil, Fethi Ahmet Çakmak, Hakan Fehmi Oztop 
  Abstract: In this study, the performance improvement of solar stills using different nanofluids was investigated analytically. Addition of CNTs to water (case 1), addition of Cu-Al2O3 nanoparticles (case 2) and addition of Al2O3-MWCNT-Graphene nanoparticles (case 3) were considered. By using binary nanofluid, 26.67% more water was obtained compared to the traditional distiller. Similarly, a 24.41% energy efficiency and 33.32% increase in exergy efficiency was achieved. Outcomes is useful for selection of appropriate hybrid nanoparticles in nano-enhanced solar stills as hybrid nanofluids in energy systems is considered due to the cost, stability and synergistic impacts of individual nanoparticles on the overall performance.
  Keywords: energy efficiency; nanofluid; nanoparticle; solar still; heat transfer.
  DOI: 10.1504/IJEX.2026.10074230
   
  
• Recuperative Solar Organic Rankine Cycle a Comparative Parametric Analysis based on Energy and Exergy Approaches  
  by Nalluri Samuel, Dr Adusumilli Srinath, Venu M, Sharma Noble, T. Anup 
  Abstract: Thermodynamic analysis of 1 MW r-SORC with toluene (ORC fluid), therminol VP-1 (HTF) is conducted and heat source temperature (THTF,in), turbine operating parameters (pevp, T5) are optimized for exergetic efficiency maximization. This improved ?Sys,I and ?Sys,II by 17.87%, 179.91% respectively against study [1].Variation of ?OWF, ?HTF and ?Sys,I, ?Sys,II with respect to THTF,in are evaluated. Benefits accrued by operating r-SORC at exergy analysis based optimal conditions are: Improved performance of r-ORC i.e. ?r-ORC,I, ?r-ORC,II by 34.90%, 5.92% and the system i.e. ?r-Sys,I, ?r-Sys,II by 35.16%, 6.51% respectively, as against Nr-SORC[2]. ?HTF decreased by 0.79% and ?OWF increased by 0.05%.
  Keywords: energy; exergy; solar energy; recuperative organic Rankine cycle; thermal energy storage; stable power output; optimization.
  DOI: 10.1504/IJEX.2026.10074279
   
  
• Heat Pump Heating System Based on Waste Heat Recovery from Electrical Equipment: Energy, Exergy, Economic, and Environmental Analysis  
  by Qikun Yuan, Yuxiong Zhang, Feng Shi, ShuChang Pan 
  Abstract: Cold-region substations typically utilize electric heating systems that are energy-intensive and inefficient, resulting in significant energy waste. This study presents a heat pump system using transformer oil waste heat to replace inefficient substation electric heating. Analysing energy, exergy, economic, and environmental performance with real data, it shows coefficient of performance (COP) 1.44-2.86, annual net profits (ANP) $121,300-$178,600, payback periods (PBP) 2.6-2.1 years, and yearly reductions of 75.47t CO?, 4.57t SO?, 2.26t NO?. It meets heating needs even at transformer no-load.
  Keywords: Transformer waste heat; Heat pump; Energy analysis; Exergy analysis; Economic analysis; Environmental analysis.
  DOI: 10.1504/IJEX.2025.10074475
   
  
• Variation characteristics of personnel exergy transfer under different environmental conditions  
  by Guoshan Wu, Heqing Liu, Yiming Huang, You Bo, Shiqiang Chen 
  Abstract: In this paper, the exergy method is combined with the prediction heat strain model to establish a worker exergy model and study whether exergy transfer can express the thermal comfort of workers. The results show the exergy transfer changes in a 'single peak' curve with the temperature increase. Exergy transfer reflects the influence of temperature, humidity, wind speed, and labour intensity. A method was proposed to judge workers' thermal comfort based on the difference between the current exergy transfer and the maximum exergy transfer. This provides a new idea for studying workplace thermal comfort and ventilation cooling.
  Keywords: exergy analysis; exergy transfer; worker; thermal environment.
  DOI: 10.1504/IJEX.2025.10072675
   
  
• Exergoeconomic optimisation of a geothermal-enhanced cooling and power generation system: a multi-objective approach  
  by Ali Esmaeili, Shoaib Khanmohammadi, Hossein Tamim, Ali Abbasi 
  Abstract: This study examines a multi-generation geothermal power plant, comparing a basic cycle and an advanced cycle. The basic cycle generates electricity only, while the advanced cycle simultaneously produces electricity, cooling, and hydrogen. Despite a reduction in energy and exergy efficiency, the advanced cycle offers benefits like hydrogen production and improved cooling capacity. It delivers 106.7 kW of net electricity and 21.36 kW of cooling load. Exergy destruction and parametric analyses were performed to assess system performance and efficiencies. Multi-criteria optimisation was used to identify the optimal operational conditions of the proposed system.
  Keywords: geothermal; upgraded; refrigeration; parametric study; multi-objective optimisation.
  DOI: 10.1504/IJEX.2025.10072919
   
  
• Exergy analysis of flat plate collector integrated with thermoelectric cooler: a novel approach to enhance thermal and electrical efficiency  
  by Sunil Kumar, Gopal Nath Tiwari, Madhu Sudan 
  Abstract: An analytical expression for the characteristic equation of flat plate collector integrated with a thermoelectric cooler (TEC) under forced flow condition has been developed in this communication. The output parameters of a single unit collector are marginally affected by mass flow rates greater than 0.02 kg/s. The findings show that as the mass flow rate increases, the outlet temperatures decrease, and the output energy increases. The temperature, energy and exergy efficiency are significantly impacted by low mass flow rate (below 0.01 kg/s), and packing factor. It was discovered that the FPC-TEC unit's overall exergy efficiency was significantly greater than its thermal exergy efficiency.
  Keywords: flat plate collector; FPC; thermoelectric cooler; TEC; exergy efficiency; mass flow rate.
  DOI: 10.1504/IJEX.2025.10073183
   
  
• Thermodynamic analysis of a heat pump polygeneration system  
  by Vajeer Baba Shaik, Tangellapalli Srinivas, Rajeev Kukreja 
  Abstract: To accomplish the drinking water, air cooling/heating, and hot water requirements for small-scale and domestic industries, a solar-powered heat pump polygeneration system is incorporated with the least floor area. It operates by extracting heat from a low-temperature source for heating or cooling. Key variables include airflow rate, temperature, and humidity. Using simulation tool, at 75% humidity and 40°C, the GOR and COP become 2.3 and 1.85. Additionally, the plant has an ECF of 2.2 and its cycle's ECF is 2.9. Furthermore, at 25°C and 75% humidity, the cycle and plant ECF were found to be 3.8 and 2.37, respectively.
  Keywords: solar energy; heat pump; thermal pollution; desalination; polygeneration.
  DOI: 10.1504/IJEX.2025.10072837
   
  
• Energy and exergy efficiency optimisation for solar-integrated hydrogen fuel stations with synergy of electrocatalysis and chemical reactions  
  by Yan Tao, Anqi Wu, Xiaoshuang Hu 
  Abstract: A hybrid model combining is proposed for accurate direct normal irradiance (DNI) forecasting. The model significantly outperforms SARIMAX and GRU benchmarks, with an average R² of 0.975. Enhanced DNI prediction enables optimised operation of a photovoltaic-powered hydrogen refuelling station, aligning solar input with hydrogen production needs. A techno-economic analysis confirms system feasibility, achieving a levelised cost of hydrogen of 3.20/kg and a net present cost of $2.14 million. Exergy analysis shows the rising irreversibility (10 kW-35 kW) with PV array size (3,000 m²-6,000 m²), revealing key energy-efficiency tradeoffs for optimal system design.
  Keywords: hydrogen fuel station; solar energy integration; DNI forecasting; energy and entropy efficiency; exergy analysis; techno-economic optimisation.
  DOI: 10.1504/IJEX.2025.10072890