International Journal of Exergy (18 papers in press)

Regular Issues

• Impact of support pillars geometry on thermal insulation performance of vacuum glazing: CFD research and exergy analysis  
  by Pinar Mert Cuce, Erdem Cuce, Harun Sen 
  Abstract: Vacuum glazing technology is based on evacuating the gas between the double glass and aims to prevent heat losses by eliminating convection effects. This study evaluates the effect of thermal conductivity and column design on the window heat transfer coefficient with a 2D CFD study, taking 200
  Keywords: vacuum glazing; heat transfer coefficient; support pillar design; thermal resistance; exergy analysis.
  DOI: 10.1504/IJEX.2024.10063157
   
  
• Occupancy and occupant number detection for energy saving in smart buildings via machine learning techniques  
  by Zeynep Turgut, Gökçe Akgün 
  Abstract: In this study, various machine learning techniques are applied for occupancy detection to provide occupancy-based energy savings in smart buildings. Occupancy detection can be achieved using environmental data obtained via various environmental sensors placed in smart environments. This study focuses on energy saving in smart buildings with occupancy detection, and avoiding unnecessary sensor use by determining which features are more effective in detecting occupancy by utilising a sample dataset. Sensor information considered as features and tested using various machine learning algorithms. In this context, both occupancy detection and occupant number detection classification are realised, and an exergy analysis is presented.
  Keywords: occupancy detection; internet of things; IoT; machine learning; energy saving; smart buildings.
  DOI: 10.1504/IJEX.2024.10063797
   
  
• Evaluation of Exergy Destructions of Different Refrigerants in a Vaccine Cooling System with Artificial Intelligence  
  by Elif Altıntaş Kahriman, Alişan Gönül, Ali Köse, C.E.M. Parmaksızoğlu 
  Abstract: Nowadays, low-temperature storage and distribution of many vaccines are as important as their production. In this study, the performance of a storage device operating in a vapour compression refrigeration cycle designed to provide low-temperature cooling between 201 K and 275 K using R134a, R1234yf, R502, and R717 fluids is evaluated by both thermodynamic and artificial neural network (ANN) methods. Levenberg-Marquardt, Bayesian regularisation, and scaled conjugate gradient algorithms are compared with thermodynamical calculations to predict the energy efficiency and exergy destruction of the cooling system. All the considered artificial intelligence algorithms are found to accurately predict the expected outputs with R2 values greater than 0.9.
  Keywords: low temperature cooling; artificial intelligence; exergy analysis; vaccine storage unit; artificial neural network; ANN.
  DOI: 10.1504/IJEX.2024.10063963
   
  
• Assessment of Conventional and Enhanced Exergy Analysis of the Natural Gas Liquefaction Plant  
  by Arif Karabuga, Zafer Utlu 
  Abstract: The liquefaction method has become increasingly important in the natural gas trade as a result of both the cost and application difficulties associated with pipe transfer. In this study, enhanced exergy analysis of the cryogenic method used in the liquefaction of natural gas is discussed. When each component is examined, the highest exergy destruction was obtained in the turbine as 1,164 kW. The exergy efficiency of the overall system was calculated as 52.52%. In this study, the most significant consequence of exergy destruction ?n the turbine was discovered to be caused by unavoidable exergy destruction.
  Keywords: liquefied natural gas; LNG; enhanced exergy analysis; liquefaction system; cryogenic.
  DOI: 10.1504/IJEX.2024.10064052
   
  
• Assessment of entropy-based approach for environmental impact of cooling process in clinker production  
  by Mehmet Sogut 
  Abstract: Cement clinker production is an energy-intensive process that results in significant environmental pollution. This study analyses the environmental effects and exergy performance of the cooling process in dry-type cement production using an entropy-based approach. The processs useful exergy efficiency was found to be 17.4%, while the waste-induced exergy was 51.1%. The useful exergy EPI value was 0.685, with a development rate of 65.87% and an energy efficiency rate of 56.52%. The process has an energy efficiency rate of 27.18%. Based on the results, measures to improve environmental sustainability by reducing entropy production in the cooling process were recommended.
  Keywords: Cement Cooling process Exergy Entropy Environmental performance.
  DOI: 10.1504/IJEX.2024.10064257
   
  
• Using advanced exergy analysis to select an optimal working fluid pair in an absorption refrigeration cycle  
  by Hamid-Reza Bahrami, Peyman Rafie 
  Abstract: This study has been done to compare LiNO3-NH3, LiBr-H2O and LiCl-H2O for using in absorption chillers using advanced exergy analysis (AEA) where LiCl-H2O showed the highest COP and ECOP, and has in turn the lowest unavoidable exergy destruction. AEA results indicate that only 26% of the total exergy destruction in the cycle is preventable. The desorber has the highest exergy destruction with only 88% of it being unavoidable. The solution heat exchanger and the absorber could be improved as over 50% of their exergy destructions are avoidable. The research highlights how AEA provides insights into exergy destruction sources and potential improvements in absorption chiller systems.
  Keywords: advanced exergy analysis; absorption chiller; second law of thermodynamics; coefficient of performance; exergy coefficient of performance; heat transfer.
  DOI: 10.1504/IJEX.2024.10064259
   
  
• Energy and Exergy Analyses of a Submerged Arc Furnace used for Ferrochrome Production  
  by Sinan Kapan, Nevin Celik, Unal Camdali, Ali Taskiran 
  Abstract: In this study submerged arc furnace (SAF) of an important ferrochrome production facility in Elazig-Turkey is discussed. The 1st and 2nd laws of thermodynamics are applied to the SAF in which smelting processes of chrome ore are carried out. It has been concluded that, the energy efficiency of the SAF in the facility is 50.69% and the exergy efficiency is 46.49%. The energy losses are nearly 5.85% of the total energy entering into the control volume, and the exergy losses is 20.39% of the total exergy input. The results show that there are some areas to improve the energy and exergy efficiencies. The energy efficiency is 50.69%. The exergy efficiency is 46.49%. Lost energy is 182.85 GJ. Lost exergy is 831.16 GJ.
  Keywords: energy and exergy analysis; high carbone ferrochrome; submerged arc furnace; SAF.
  DOI: 10.1504/IJEX.2024.10064355
   
  
• Exergy analysis of an innovative power generation and refrigeration system  
  by M. Omprakash, Shankar Ganesh Narayanan 
  Abstract: This study looks at the performance of a system that combines an organic Rankine cycle (ORC) and an ejector refrigeration cycle (ERC) using energy, conventional, and advanced exergy techniques to find ways to make it better and to see how the different parts of the system work together. The fluids selected for investigation are R245fa and R236ea as working fluids because they are widely known for dealing with waste heat from internal combustion engines. When the temperature is 150
  Keywords: power generation; organic Rankine cycle; ORC; working fluid; ejector refrigeration cycle; ERC; cogeneration.
  DOI: 10.1504/IJEX.2024.10064412
   
  
• Solar Radiation Estimation Modelling through the Maximum Entropy Principle  
  by Atteeq Razzak, Zoobia Khalid, Shafiq Urrehman, Muhammad Mustaqeem Zahid, Muhammad Adeel 
  Abstract: Pakistan has great potential for gathering solar energy due to its geographical position. In this paper, we have estimated three types of radiation, global solar radiation, bean solar radiation, and diffused solar radiation, through the maximum entropy principle for eight cities of Pakistan which are geographically apart at least 500 km; this principle maximises the entropy function based on some constraints. The maximum entropy principal distribution results generate the best curve representing these radiations. There are three plots for each city corresponding to three radiations for each city; the plot shows that the fitted curves are excellent and give the best knowledge about the radiations.
  Keywords: solar radiations; entropy; maximum entropy principle; ASHRAE model.
  DOI: 10.1504/IJEX.2024.10064414
   
  
• Exergy analysis and optimisation of two CO2-booster refrigeration systems  
  by Yosra Ben Salem, Ahmed Bellagi 
  Abstract: The objective of this study is energetic and exergetic analysis, optimisation and comparison of two trans-critical CO2-booster refrigeration systems for simultaneous heating and cooling applications: A unit with flash gas bypass (Config1) and a system with an auxiliary parallel compressor (Config2). The units are designed to produce cold at two temperatures levels, -10
  Keywords: CO2-Booster refrigeration; Flash-gas by-pass; Parallel compression; Exergy analysis; RSM methodology; Optimization.
  DOI: 10.1504/IJEX.2024.10064415
   
  
• Energetic and Exergetic Performance Analysis of a Double Pass Asymmetric CPC Photovoltaic/Thermal Solar Collector Suitable for Building Facade  
  by W.A.N. N.U.R. Adilah W.A.N. Roshdan, Hasila Jarimi, Adnan Ibrahim 
  Abstract: An asymmetric compound parabolic concentrator (CPC) photovoltaic/thermal (ACPC-PV/T) solar collector with a double-pass air channel has the potential to enhance PVT performance for facade applications. Through outdoor experiments, we compared the ACPC-PVT with the symmetric CPC PV/T and conventional flat-type PV/T. The analysis shows ACPC PV/T exhibits superior energetic efficiency by 3.95% and 10.79% compared to symmetric CPC PV/T and conventional flat-type PV/T, respectively. Exergy analysis strengthens these findings, with overall exergy efficiency higher by 3.79% and 20.07%, respectively. Economic evaluation reveals a favourable 6.84-year payback for ACPC PV/T, the lowest among the three.
  Keywords: PV/thermal; asymmetric; compound parabolic concentrator; CPC; energy; exergy.
  DOI: 10.1504/IJEX.2024.10064416
   
  
• Exergy-economic Analysis and Optimisation of Sulfuric Acid Production from Sulphur Based on Aspen Plus  
  by Li Li, Hongchen Mu, Feng Wang, Minmin Ma, Yuncheng Shen, Shenghui Gao, Yafei Tian, Ye Huang, Le Wu 
  Abstract: Energy recovery is important for sulphuric acid productions due to high exothermal effects of oxidation reactions and acid adsorption. Aspen Plus and exergy analysis of a sulphuric acid process was carried out based on actual operating data to reduce the energy consumption and enhance the exergy performance. After optimisation, the exergy loss was decreased from 15,139.73 kW to 8,917.86 kW by adding two pumps and one heat exchanger. The economic analysis showed that the steam revenue was also raised with 18.34% growth. The exergy performance and the product revenue were optimised by the proposed Aspen simulation and exergy analysis.
  Keywords: sulphuric acid production; exergy analysis; Aspen simulation; economic analysis.
  DOI: 10.1504/IJEX.2024.10064419
   
  
• Energy and exergy analyses of a hydrogen added wet-ethanol fuelled HCCI engine-based cogeneration of power and refrigeration  
  by Tawfiq Abdul-Aziz Al-Mughanam, Abdul Khaliq 
  Abstract: This study aimed to propose and investigate a novel system that combines organic Rankine cycle and ejector refrigeration cycle with hydrogen production and on-site utilisation in HCCI engine. Energy and exergy analyses shown that using R134a as working fluid and elevation of pressure ratio by 40% results in enhancement of cogeneration efficiency by 4.63%. Promoting vapour generator pressure (P_VG) decreases the cooling capacity by more than 2% for R134a systems, while this decrease becomes 1.9% for R600a. Increasing evaporator pressure (P_evap) greatly improves performance and cooling capacity. Exergy destruction in HCCI engine dropped from 90.09% to 89% with 20% hydrogen.
  Keywords: HCCI engine; organic Rankine cycle; ORC; ejector refrigeration cycle; ERC; electrolyser; exergy; hydrogen; wet-ethanol.
  DOI: 10.1504/IJEX.2024.10063899
   
  
• Exergoenvironmental assessment of a solar still modified with the evacuated tube heat pipe using paraffin wax  
  by Benjamin Franklin Selvanayagam, Kumaresan Govindasamy, Rajagopal Rangaraj, Dominic Antonisamy 
  Abstract: This manuscript proposes a hybrid approach for enhancing a solar still (SS) modified with an evacuated-tube heat-pipe utilising paraffin wax (PW). The system combines the Osprey optimisation algorithm (OOA) and quantum neural network (QNN). The OOA increases water temperature and lowers glass cover temperature, while QNN predicts daily distillate productivity and forecasts water and glass temperatures. The major objective of the proposed approach is to improve solar still efficiency and reduce costs. By then the proposed approach is executed in MATLAB/Simulink, and contrasted with existing techniques. The proposed approach results in a cost of 140 USD notably lower than current techniques.
  Keywords: heat pipe; phase change material; PCM; paraffin wax; temperature; optimisation; thermal energy storage; liquid fractions; fresh water.
  DOI: 10.1504/IJEX.2024.10063794
   
  
• An exergy-based efficiency analysis framework for industrial pneumatic systems  
  by Zecheng Zhao, Zhiwen Wang, Hu Wang, Rupp Carriveau, David S-K. Ting, Wei Xiong 
  Abstract: Pneumatic systems are widely used in industrial production. It is valuable to conduct detailed analyses on pneumatic systems in the interest of improving their energy performance. In this study, an exergy-based efficiency analysis framework is proposed for industrial pneumatic systems. The product exergy, fuel exergy, and exergy efficiency of various pneumatic components are clearly defined. The exergy sensors and exergy analysis toolbox are developed in the software AMESim. Finally, both simulation and experiment of a typical pneumatic system are conducted and compared to validate the feasibility of the proposed exergy-based efficiency analysis framework.
  Keywords: pneumatic; exergy; energy saving; exergy efficiency; compressed air.
  DOI: 10.1504/IJEX.2024.10063645
   
  
• Energy and exergy analysis of hydrogen production from seawater using waste heat recovery system on a model ship  
  by Meryem Gizem Sürer, Hüseyin Turan Arat 
  Abstract: Marine transportation has been the subject of many studies on the green environment. Contributing to these studies, a system that uses electricity obtained from the waste heat of a diesel engine to obtain hydrogen has been designed. Concept ship design, energy and exergy analysis was applied. In the results evaluation of the exergy destruction, the components having the highest exergy destruction in the Rankine system were the turbine with 97%, and the system producing hydrogen from seawater was the electrolyser with 54%. As a result, the system of using seawater in hydrogen production seems feasible and can be used as a storage option.
  Keywords: waste heat recovery; seawater; hydrogen; Rankine cycle; exergy.
  DOI: 10.1504/IJEX.2024.10064021
   
  
• Experimental analysis of photovoltaic/thermal system under composite climate in terms of exergy efficiency  
  by Sinan Caliskan, Ismail Burak Soydan, Sertac Samed Seyitoglu, Furkan Guler 
  Abstract: In this study, we examined data from a photovoltaic thermal (PV/T) module designed with a simple structure in comparison to data from a reference photovoltaic module. The highest thermal efficiency was determined as 74.15%, the highest electrical efficiency was determined as 13.41% for reference PV module and 14.36% for PV/T module at 1.25 l/min flow rate. Thanks to the cooling system, the module surface temperature was reduced and the electrical efficiency was increased by 7.11% at 1.25 l/min flow rate. Furthermore, the maximum exergy efficiency of the PVT panel was calculated to be 16.71%.
  Keywords: photovoltaic thermal module; performance analysis; exergy efficiency.
  DOI: 10.1504/IJEX.2024.10063959
   
  
• Exergy analysis and exergetic sustainability index of package boiler  
  by Serigianto Serigianto, Muhammad Djoni Bustan, Sri Haryati 
  Abstract: Energy utilisation in the fertiliser industry can be improved by conserving energy. One way to achieve this is by modifying the operating conditions of the package boiler. Research shows that 94.3% of the total exergy destruction of the package boiler is obtained from the evaporator component with a value of 2.7 × 10⁸ kJ/hour. The modification of evaporator operating conditions involves lowering the inlet temperature of boiler feed water (BFW) by ΔT (196°C-116°C). This decrease in BFW temperature increases the latent heat required and reduces the convection heat carried by the flue gas to produce superheated steam. The optimum temperature of BFW is 161°C which results in a reduction in exergy destruction of 6.2 × 10⁶ kJ/hour and produces a difference in loss costs based on actual data (196°C) of Rp 1,370,354,743/hour. The exergetic sustainability index (ESI) obtained was 0.918.
  Keywords: exergy analysis; exergy destruction; exergoeconomic analysis; package boiler.
  DOI: 10.1504/IJEX.2024.10064326