Shengyuan Zhao , Yanxia Li , Fengjiao Yu , Jing Ren , Zhongliang Liu , Zhongyuan Wang
{"title":"Molecular dynamics study of the initial frosting phenomenon on cold surfaces from ordinary-low to cryogenic temperatures","authors":"Shengyuan Zhao , Yanxia Li , Fengjiao Yu , Jing Ren , Zhongliang Liu , Zhongyuan Wang","doi":"10.1016/j.ijrefrig.2025.12.036","DOIUrl":"10.1016/j.ijrefrig.2025.12.036","url":null,"abstract":"<div><div>Frost formation is a prevalent phase transition phenomenon in both natural environments and industrial processes. Current research on frost formation mechanisms and processes has primarily focused on macroscopic scales. This macroscopic focus limits the ability to investigate thoroughly the nanoscale dynamic processes and underlying mechanisms, particularly the systematic evolution characteristics during initial frost formation under ordinary-low and cryogenic conditions. In this study, a physical model for the initial stage of frost formation on cryogenic surfaces was developed using molecular dynamics simulations, enabling nanoscale investigation of early-stage frost formation at low temperatures. The simulation results demonstrate that the frost morphology on copper surfaces varies with substrate temperature, consistent with experimental observations. By employing MATLAB for phase identification of water molecules, we found that the frost crystal structure transitions from dendritic to clustered morphology as the cold surface temperature decreases. This transition results in a non-monotonic variation in frost coverage area: it decreases first, then increases, and subsequently decreases again. Furthermore, the frost formation completion time does not vary monotonically with decreasing cold surface temperature. Within the temperature range of -90 °C to -30 °C, the completion time decreases with temperature reduction; whereas between -130 °C and -90 °C, the formation time increases with further cooling. All these variations are significantly influenced by the evolving frost morphology patterns.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 231-240"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ali M. Ashour , Saif Ali Kadhim , Osama B. Ahmed , Walid Aich , Kaouther Ghachem , Farhan Lafta Rashid , Karrar A. Hammoodi
{"title":"Experimental investigation of a vapor compression refrigeration system integrated with thermoelectric generators for enhanced energy recovery","authors":"Ali M. Ashour , Saif Ali Kadhim , Osama B. Ahmed , Walid Aich , Kaouther Ghachem , Farhan Lafta Rashid , Karrar A. Hammoodi","doi":"10.1016/j.ijrefrig.2025.12.033","DOIUrl":"10.1016/j.ijrefrig.2025.12.033","url":null,"abstract":"<div><div>Energy efficiency and waste heat recovery have become crucial challenges in refrigeration technology, especially with the increasing demand for sustainable and environmentally friendly cooling systems. In this paper, a hybrid thermoelectric generator system and vapor compression refrigeration, operated with R600a refrigerant, are analyzed with respect to utilizing waste heat sources as a means of generating electric power and enhancing the system’s efficacy. The experimental setup consists of a conventional vapor compression refrigeration cycle combined with thermoelectric generator modules between an aluminum cooling block. The experimental setup includes varying cooling water rates, ranging from 0.5 to 3.0 L/min, and condenser temperatures of 35 °C, 40 °C, and 45 °C to examine the influence of operating conditions on both thermal and electrical performance. The findings reveal that increasing water flow dramatically enhances cold-side heat transfer, resulting in a 40 °C temperature difference across the TEG, measured at a 45 °C condenser temperature, compared to 22.5 °C. Therefore, the electrical power output fluctuates from 0.05 W to 1.05 W, and the TEG efficiency reaches up to 2.2%, which is comparable to the best commercially available bismuth-telluride modules. The compressor pressure ratio and discharge temperature are reduced by 10% and 5 °C, respectively, which increases the system’s COP improvement to 7.9% and approximately 8% of total energy recovery. These findings confirm the thermodynamic benefit of TEG integration functioning as a desuperheating system for simultaneous cooling, power generation, and energy recovery.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 15-29"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yicheng Zhu , Ceyi Wang , Zhewen Xiong , Aiguo Wei , Juan Huang , Fei Wang , Junming Li , Haishan Cao
{"title":"Condenser-side thermal resistance in heat pump water heaters: Experimental investigation and quantitative decomposition","authors":"Yicheng Zhu , Ceyi Wang , Zhewen Xiong , Aiguo Wei , Juan Huang , Fei Wang , Junming Li , Haishan Cao","doi":"10.1016/j.ijrefrig.2026.01.010","DOIUrl":"10.1016/j.ijrefrig.2026.01.010","url":null,"abstract":"<div><div>Comprehensive analysis of the condenser-side thermal resistance in heat pump water heaters (HPWHs) offers valuable insights for improving system efficiency and reducing energy consumption. This study presents both experimental investigations on a prototype HPWH and a numerical analysis based on a thermal resistance network model. In the model, the total thermal resistance is decomposed into three components for separate calculation and analysis, namely the refrigerant-side condensation resistance, the thermal conduction resistance of the microchannels and the thermally conductive silicone grease as thermal interface materials, and the combined resistance of cylinder wall conduction and water-side convection. A quantitative analysis of each component was conducted, and the calculated total thermal resistance deviated by only 4.9 % from experimental measurements, demonstrating the accuracy of the proposed model. The results showed that the combined resistance of cylinder wall conduction and water-side convection contributed more than 60 % of the total resistance. Therefore, reducing the combined resistance should be a primary focus to enhance overall HPWH performance. This study establishes a quantitative basis for the optimization and design of next-generation, high-efficiency HPWH systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 315-325"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental and simulation analysis of the explosive behavior and free radical spectroscopic characteristics of R1233zd(E)/R290 mixed gas","authors":"Baolin Guo , Lanfang Zheng , Xiaobin Li","doi":"10.1016/j.ijrefrig.2026.01.013","DOIUrl":"10.1016/j.ijrefrig.2026.01.013","url":null,"abstract":"<div><div>To explore the combustion safety characteristics of environmentally friendly mixed refrigerants, this study systematically investigates the impact and mechanism of R1233zd(E) on the explosion behavior of R290 through a combination of experiments, spectral analysis, and density functional theory calculations. The results indicate that R1233zd(E) has a significant dual effect on the combustion process of R290: when the volume fraction ratio of R1233zd(E)/R290 is ≤ 0.2, it exhibits a slight promoting effect, with the pressure peak and maximum pressure rise rate increasing by 1.86% and 17.16%, respectively, the flame propagation speed increasing by 0.418 m/s, and the CH* peak time advancing by 8.33%. However, when the volume fraction exceeds 1.1, a significant inhibiting effect is observed. At a volume fraction of 1.6, the pressure peak and maximum pressure rise rate decrease by 56.08% and 82.97%, respectively, the time to reach the explosion pressure peak is extended by 155.54%, the flame propagation speed is only 17% of that of pure R290, and the peak times of OH* and H<sub>2</sub>O* are delayed by 446.15%. Furthermore, as the concentration of R1233zd(E) increases, the intensity peak times of key reactive radicals/molecules CH*, OH*, H<sub>2</sub>O* and O<sub>2</sub>* exhibit exponential growth, and when the volume fraction is ≤ 1.1, the transition process from CO to CO₂ is delayed. Simultaneously, theoretical calculations and flame-retardant radical spectra indicate that R1233zd(E) preferentially cleaves the C<img>Cl bond to generate chlorine radicals, which effectively capture reactive radicals, becoming the dominant factor in blocking chain reactions.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 306-314"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Na Liu, Hao Ji, Yeyi Liu, Run Li, Dezheng Sun, Qian Zhao, Jianxiang Guo
{"title":"Experimental investigation on adiabatic two-phase frictional pressure drop of R290, R600a, and their mixtures in a horizontal minichannel","authors":"Na Liu, Hao Ji, Yeyi Liu, Run Li, Dezheng Sun, Qian Zhao, Jianxiang Guo","doi":"10.1016/j.ijrefrig.2026.01.022","DOIUrl":"10.1016/j.ijrefrig.2026.01.022","url":null,"abstract":"<div><div>To support the application of eco-friendly refrigerants, this study reports the adiabatic two-phase frictional pressure drop of R290, R600a, and their mixtures (mass fractions 70/30, 50/50, 30/70) in a 1.54 mm horizontal minichannel. Experiments were conducted under specific operating conditions: mass fluxes of 200-400 kg/(m<sup>2</sup>·s), saturation temperatures of 22-26°C, and vapor quality ranging from 0 to 1.0. Key influencing factors were systematically analyzed, and results were compared with fluorinated refrigerants (R32, R1234ze(E), their mixtures) and existing predictive correlations. The results indicate that the frictional pressure drop is significantly influenced by mass flux, vapor quality, and R600a mass fraction. An increase in these parameters leads to a substantial rise in pressure drop, attributed to intensified gas-liquid interfacial shear stress and the thermophysical properties of R600a (low liquid-vapor density and high liquid viscosity). Within the narrow investigated temperature span (22-26°C), saturation temperature has a negligible impact, as the variation in reduced pressure is insufficient to cause significant shifts in thermophysical properties. While R290/R600a mixtures exhibit higher pressure drop than fluorinated refrigerants, they offer superior environmental performance (zero ozone depletion potential, ultra-low global warming potential). The Tran et al. correlation shows the highest predictive accuracy, with a mean absolute relative deviation of 10.75%, mean relative deviation of 6.15%, and 92.06% of data within ±30% deviation. This work enriches the pressure drop database for hydrocarbon mixtures in minichannels. It provides a reliable design tool and lays a foundation for optimizing compact heat exchangers using eco-friendly mixed refrigerants, especially in environmentally sensitive scenarios.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 431-443"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance assessment and parametric optimum selection of the hybrid system consisting of a direct ethanol fuel cell and three-heat-reservoir cycle","authors":"Xiuqin Zhang , Jian Lin , Xiaohang Chen","doi":"10.1016/j.ijrefrig.2026.01.014","DOIUrl":"10.1016/j.ijrefrig.2026.01.014","url":null,"abstract":"<div><div>A direct ethanol fuel cell is the device to directly convert the chemical energy of the ethanol and oxygen into the electricity and heat. To improve the electrical power density and increase the energy conversion efficiency as much as possible, a three-heat-reservoir refrigeration cycle is coupled to the direct ethanol fuel cell, so that the waste heat of the fuel cell can be effectively utilized. The performances of the direct ethanol fuel cell and hybrid system are systemically assessed and compared.</div><div>The whole performance of the hybrid system is optimized. The maximum power densities of the hybrid system can attain, respectively, 0.20, 0.21, and 0.22 (Js<sup>-1</sup>cm<sup>-2</sup>), which are 1.41, 1.71, and 2.10 times those of the fuel cell, when the temperatures of the fuel cell are 328.15, 338.15, and 348.15 (K). The partial current densities, voltage output, and flow density of waste heat of the fuel cell, and coefficient of performance and cooling rate of the three-heat-reservoir cycle are determined at a given molar concentration of the inlet ethanol at the optimum power density, and consequently, the optimum selection criterion of the molar concentration of the inlet ethanol is obtained.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 391-401"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adaptive neural network temperature control for thermoelectric refrigeration systems using online self-learning mechanism","authors":"Chaoqi Wei, Jiapeng Liu, Dongxiao Liu","doi":"10.1016/j.ijrefrig.2026.01.015","DOIUrl":"10.1016/j.ijrefrig.2026.01.015","url":null,"abstract":"<div><div>This article presents a new adaptive neural network control method designed for thermoelectric refrigeration systems. This approach leverages the capabilities of neural networks to address the uncertain nonlinear dynamics within the system. A self-learning mechanism is developed to enable the online training of the neural network’s weights, as well as the center points and widths of the basis functions, resulting in improved control performance. Additionally, an adaptive law based on a projection algorithm is introduced to prevent potential parameter drift and singularities of the basis functions. The stability of the closed-loop system is analyzed using Lyapunov stability theory. To demonstrate the effectiveness of this proposed method, both simulation and experimental results are presented. Compared with traditional neural network control method, our control method reduces the maximum error by 29.4% and the set time by 39.3% in the experiment.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 379-390"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kevin Wimmer, Jan Kummer, Michael Lang, Raimund Almbauer
{"title":"Corrigendum to “Thermodynamic analysis of the refrigeration cycle of a domestic freezer with an electronic expansion valve” [International Journal of Refrigeration 181 (2026) 413–428]","authors":"Kevin Wimmer, Jan Kummer, Michael Lang, Raimund Almbauer","doi":"10.1016/j.ijrefrig.2026.01.019","DOIUrl":"10.1016/j.ijrefrig.2026.01.019","url":null,"abstract":"","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Page 455"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Heat-driven thermoacoustic cooling technologies: A comprehensive review and future prospects for hot climate applications","authors":"Irna Farikhah, Ammar M. Bahman","doi":"10.1016/j.ijrefrig.2025.12.030","DOIUrl":"10.1016/j.ijrefrig.2025.12.030","url":null,"abstract":"<div><div>The escalating demand for cooling in hot climate regions, driven by rising global temperatures and rapid urbanization, underscores the urgent need for sustainable and efficient refrigeration technologies. Conventional vapor-compression systems, reliant on electricity and high-global-warming-potential refrigerants, are ill-suited for off-grid and high-ambient-temperature environments. Heat-driven thermoacoustic cooler (HDTCs) present a promising alternative, leveraging thermal energy from solar, waste, or combustion heat to generate acoustic waves that produce a refrigeration effect without moving parts or harmful refrigerants. This review provides a comprehensive analysis of recent advancements in HDTC technology, with a specific emphasis on their potential for hot-climate applications. It synthesizes progress in system design—from standing-wave to advanced multi-stage traveling-wave configurations—scaling, and the optimization of stack materials and geometries. The paper further explores technological applications across cryogenics, LNG, industry, buildings, and transportation, with a dedicated focus on hot-climate technologies such as off-grid cooling, desalination, and solar integration. Despite significant achievements, including coefficients of performance (COP) exceeding 3.0 in simulations and experimental exergy efficiencies up to 21%, a persistent gap remains between theoretical predictions and practical performance. Key challenges such as acoustic losses, phase mismatch, and material limitations are discussed, alongside future research directions aimed at enhancing efficiency, scalability, and reliability. The review concludes that HDTCs are poised for practical deployment and can become a cornerstone for sustainable, grid-resilient cooling in hot-climate regions, pending further research to bridge the performance gap and optimize real-world operation.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 153-187"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Edgardo J. Tabilo , Roberto Lemus-Mondaca , Juan I. Jaime , Nelson O. Moraga
{"title":"Conjugate heat transfer model of non-Newtonian fruit pulp freezing by turbulent convective air flow in a refrigeration cabinet","authors":"Edgardo J. Tabilo , Roberto Lemus-Mondaca , Juan I. Jaime , Nelson O. Moraga","doi":"10.1016/j.ijrefrig.2026.01.018","DOIUrl":"10.1016/j.ijrefrig.2026.01.018","url":null,"abstract":"<div><div>This study develops a three-dimensional conjugate numerical model to predict the unsteady solidification of blueberry pulp in a container cooled by buoyancy-driven turbulent natural convection within a domestic freezer. The finite volume method, combined with the SIMPLERnP algorithm, simultaneously solves airflow turbulence, heat conduction, natural convection within the pulp, and the liquid-to-solid phase change. Results demonstrate that reducing food thickness and optimizing placement enhance heat transfer, shorten freezing time, and lower energy consumption. Specifically, thinner samples (aspect ratio 0.125) achieved a 200% increase in heat flux compared to the baseline, while dividing the food into two batches placed at the corners increased heat flux by 223%, reducing freezing time by nearly half. The average drip loss decreased from ∼17% in thicker samples to ∼15% in thinner ones, and the pectin content increased from 0.90 to 0.99 g/kg, indicating improved texture and quality. The model also captured differences in airflow, predicting counter-rotating vortices and boundary-layer thinning, which reinforced convection and accelerated cooling. It accurately reproduces freezing curves, isotherms, velocity fields, and Nusselt numbers, confirming its reliability. Overall, the model underscores the significant impact of food geometry and placement in the freezer on performance, offering a robust tool to optimize energy efficiency and product quality in frozen fruit pulps.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 350-363"},"PeriodicalIF":3.8,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}