International Journal of Refrigeration-revue Internationale Du Froid最新文献

{"title":"A component-level analysis of brazed-type capillary tube-suction line heat exchangers","authors":"Fernando Testoni Knabben,&nbsp;Joel Boeng","doi":"10.1016/j.ijrefrig.2025.06.007","DOIUrl":"10.1016/j.ijrefrig.2025.06.007","url":null,"abstract":"<div><div>Despite the important role played by capillary tube-suction line heat exchangers in the performance of small refrigerators, they are still sized through trial-and-error procedures. In this context, the present work aims, for the first time, to comprehensively analyze the impact of geometric parameters often overlooked in the design of brazed-type heat exchangers, such as the adiabatic entrance and heat exchange lengths, as well as the width and height of the welded region. To this end, a mathematical model was developed and the walls of both tubes were discretized in a 3D mesh so that the heat transfer could be calculated over a wide range of conditions without the need of an effectiveness correlation. The model was validated within ±10 % error bands for the mass flow rate against 54 points found in the literature for R600a. Moreover, to extend the applicability of the analysis, the simulations were performed considering not only sub-cooled but also two-phase conditions at the capillary tube inlet. For instance, for sub-cooled inlets, the mass flow rate always increases for larger heat exchanger lengths if flashing occurs outside the entrance region. For two-phase inlets, the trends are opposite and the mass flow rate tends to decrease as the heat exchanger length increases. It was also seen that the width of the brazed region and the suction line inner diameter have a minor impact on the mass flow rate. Finally, the heat exchanger effectiveness was found to be nearly insensitive to the adiabatic entrance length.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 181-194"},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307902","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":"Comprehensive analysis of dynamic behavior and lubrication performance in a two-cylinder rotary compressor featuring hinge-joined vane and roller","authors":"Dongjun Kim ,&nbsp;Siraj Azam ,&nbsp;Sangha Lee ,&nbsp;Sang-Shin Park","doi":"10.1016/j.ijrefrig.2025.06.005","DOIUrl":"10.1016/j.ijrefrig.2025.06.005","url":null,"abstract":"<div><div>This study presents the novel comprehensive dynamic and lubrication analysis of a two-cylinder rotary compressor incorporating a hinge-joined vane and roller mechanism. A novel contribution lies in the development of complete equilibrium equations for all major components (crankshaft, roller, and vane) explicitly capturing eccentricity and tilting effects. By integrating multibody dynamics simulations with FEM-based solutions of Reynolds equations across sixteen lubrication interfaces, the study reveals critical tribo-dynamic behaviors previously unaddressed. Key findings include minimum oil film thicknesses of 1.56 µm on the roller's bottom surface and 1.0 µm on the vane’s left surface, indicating a transition toward mixed lubrication regimes. The analysis also uncovers significant moment asymmetry at the hinge joints, where the upper joint experiences 10× higher moments than the lower, resulting in enhanced structural tilting and localized lubrication failure risks. Pressure peaks exceeding 14 MPa were observed in the roller's inner surface, confirming it as the dominant friction loss contributor. These results demonstrate the necessity of accounting for coupled eccentricity, tilting, and interfacial interactions in lubrication modeling. The proposed framework provides essential guidance for optimizing hinge-joined rotary compressor designs and improving efficiency, structural integrity, and operational reliability under high-load refrigeration conditions.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 124-140"},"PeriodicalIF":3.5,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255307","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":"Comparative analysis of HFO-CO₂ cascade vs CO₂ transcritical refrigeration systems in two supermarkets. Part II: Evaluation of heat recovery and integration of heat pumps based on field measurements","authors":"Shabnam Javanshir ,&nbsp;Paolo Toninelli ,&nbsp;Anna Stoppato ,&nbsp;Samer Sawalha","doi":"10.1016/j.ijrefrig.2025.06.003","DOIUrl":"10.1016/j.ijrefrig.2025.06.003","url":null,"abstract":"<div><div>This study examines heat recovery from refrigeration systems and the operational benefits of integrating heat recovery in two medium-sized supermarkets in northern Italy based on field measurements. A supermarket operates with a R1234ze/CO₂ cascade system, which is integrated with heat pumps, and the other is a CO₂ transcritical system. The system description, along with the processes of data collection and validation, is discussed in detail in part Ⅰ of the article. Both systems are equipped with heat recovery and began operating in 2023. The floating condensation model was developed in MATLAB, utilizing REFPROP to calculate the coefficient of performance (COP) of heat recovery. Furthermore, the COP of heat pumps and the COP of each stage in floating condensation mode are calculated. Results show R1234ze/CO₂ cascade system integrated with a heat pump and air conditioning fully meets the cooling and heating demands of the supermarket's sales area, by using 12 % more annual electricity compared to the floating condensation mode. The continuous heat recovery in the R1234ze/CO₂ cascade system leads to a higher amount of heat recovery compared to the CO₂ transcritical system. The heat recovery of the CO₂ transcritical system is not used as a main source to cover the heat demand. In this system, due to lower heat demand, heat recovery most often occurs in subcritical mode, and it does not fully utilise its heat recovery potential. Only 39 % of the total heat recovered occurs in transcritical mode, with the remaining heat rejected to the air. COP of heat recovery of this system is higher than the cascade system; however, the values in both systems for ambient temperature lower than 4 °C are comparable. Furthermore, the results show that in floating condensation mode, the COP of the CO₂ transcritical system in the MT and LT stages is higher than the cascade system at temperatures below 16 °C and 9 °C, respectively, this trend reverses at temperatures above these values. The global COP of the cascade system consistently remains higher than that of the CO₂ system.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 156-167"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263744","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":"Accurate estimation of the methane hydrate equilibrium in brines based on advanced modeling tools","authors":"Liwei Xin,&nbsp;Xiaoling Shi,&nbsp;Shoukang Hou,&nbsp;Chunmao Zhang","doi":"10.1016/j.ijrefrig.2025.05.028","DOIUrl":"10.1016/j.ijrefrig.2025.05.028","url":null,"abstract":"<div><div>Knowledge of hydrate equilibrium conditions is of significant importance for processes associated with seawater purification, energy storage, and gas separation. Therefore, it is vital to design reliable models for determining such conditions. This investigation aimed to construct robust machine learning algorithms for assessing the equilibrium state of methane hydrates within aqueous salt solutions. A substantial dataset, comprising 1051 individual data points, was compiled from available literature. This dataset contained methane hydrate equilibrium across 26 distinct brines. Data-driven modeling was executed via the application of Support Vector Machine (SVM) and Decision Tree (DT) methodologies. Various graphical and statistical tools were employed to evaluate the validity of the models. It was found that both SVM and DT models exhibit strong capabilities, achieving mean absolute percentage errors (MAPEs) of 0.36 % and 0.48 %, and relative root mean square errors (RRMSEs) of 0.89 % and 0.83 %, respectively, in the testing stage. The intelligent models also adeptly captured the relationships between hydrate equilibrium and operational parameters. A sensitivity analysis ultimately elucidated the relative importance of the factors influencing the hydrate equilibrium phenomenon.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 195-206"},"PeriodicalIF":3.5,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307903","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 study of a retrofitted scroll compressor for operation with two-phase refrigerant flows","authors":"Nicolas Leclercq ,&nbsp;Benedikt G. Bederna ,&nbsp;Vincent Lemort","doi":"10.1016/j.ijrefrig.2025.05.013","DOIUrl":"10.1016/j.ijrefrig.2025.05.013","url":null,"abstract":"<div><div>The present paper introduces an experimental investigation of a scroll compressor working with two-phase refrigerant flows, in the frame of a novel thermodynamic cycle making use of two-phase compressions/expansions called REGEN-BY-2.</div><div>The design of the test bench dedicated to two-phase compression will first be explained. The objective of this test bench is to assess the performances of the compressor working with a two-phase refrigerant-oil mixture under varying conditions such as inlet pressures, inlet vapor qualities, oil circulation ratios, pressure ratios and speeds. Three experimental campaigns have been conducted, the first two are dedicated to compare different oils, while the third does not use any oil, thereby experimenting a pure-refrigerant two-phase compression. The methodology to obtain the compressor inlet vapor quality is detailed, and the related assumptions developed. The performance indicators, i.e., isentropic and volumetric efficiencies, are defined for a two-phase oil-refrigerant mixture. A total of 253 operating points (with and without oil) have been used to generate 3D maps, showing the evolution of the efficiencies for varying pressure ratios and inlet qualities. The results shows a decrease of efficiency at low vapor qualities, especially at high pressure ratios, where under-compression is amplified. Finally, the results of the pure-refrigerant compression are analyzed, showing decent isentropic efficiencies, with a minimum of 50% at a vapor quality of 0.35 and an optimal pressure ratio of 2.7.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 219-231"},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307905","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":"Enhanced energy efficiency in dual-evaporator refrigerators: experimental insights into parallel cooling cycle optimization","authors":"Mohammad Nazemi Babadi ,&nbsp;Hossein SadoughiPour ,&nbsp;Omid Nematollahi ,&nbsp;Dong Kim ,&nbsp;Eunseop Yeom","doi":"10.1016/j.ijrefrig.2025.06.001","DOIUrl":"10.1016/j.ijrefrig.2025.06.001","url":null,"abstract":"<div><div>This study systematically investigates the optimization of the cooling cycle for a bottom-mounted freezer (BMF) refrigerator equipped with dual evaporators dedicated to fridge and freezer compartments. Unlike prior research focused on theoretical models or generalized designs, this work emphasizes a comprehensive, step-by-step experimental approach. The optimization involved transitioning the cooling cycle from a serial evaporator configuration to a parallel configuration, facilitated by a 3-way valve enabling independent refrigerant flow control to each evaporator. The transition addressed critical technical challenges, including refrigerant starvation in the fridge evaporator, through iterative modifications to algorithms and hardware. The performance was rigorously evaluated according to the IEC 62552 standard, measuring key metrics such as energy efficiency, energy consumption, energy class, and temperature distribution. The findings reveal a 7.2 % improvement in energy efficiency alongside enhanced cooling performance, achieved through innovative design and operational adjustments. Notable outcomes include a reduction in compressor frequency, enhanced defrosting efficiency, and improved refrigerant flow management. The research highlights the importance of experimental validation and iterative testing for optimizing complex refrigeration systems, addressing both energy savings and environmental sustainability.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 111-123"},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229602","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":"Thermal-hydraulic performance evaluation of a novel cellular heat sink architected with hierarchical triply periodic minimal surface lattices","authors":"Hong Xu ,&nbsp;Yuan Zhang ,&nbsp;Yuheng Mei ,&nbsp;Boyang Lv ,&nbsp;Xiaohu Liu","doi":"10.1016/j.ijrefrig.2025.06.004","DOIUrl":"10.1016/j.ijrefrig.2025.06.004","url":null,"abstract":"<div><div>Efficient heat dissipation is critical in the design of cooling systems to ensure device operation within the required temperature range. With the continued development of high-heat-generating devices such as microelectronic chips and power batteries, the exploration of novel heat dissipation structures is imperative. Triple periodic minimal surfaces (TPMS) have shown potential for efficient heat management. In this study, bioinspired hierarchical design principles are introduced to fabricate a novel solid-sheet hybrid two-order hierarchical structure, where first-order lattices (sheet TPMS cells) are arranged based on the topological structure of second-order lattices (solid TPMS cells). Detailed three-dimensional numerical simulations are performed to investigate the flow characteristics and overall heat transfer performance of these hierarchical structures. The well-established Diamond structure, known for its superior performance, serves as a benchmark for comparison. Our results show a 20.3 % to 95.8 % improvement in the overall thermal performance of the hierarchical structure compared to the benchmark. The proposed hybrid structure also allows for increased wall thickness while maintaining the same porosity, which significantly reduces the resolution load on 3D printers. Furthermore, it is observed that the flow characteristics of the hierarchical structure are mainly influenced by the type of first-order lattice, while the heat transfer performance is significantly affected by the type of second-order lattice.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 378-392"},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481656","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":"Study on the oil supply characteristics of R290 rotary compressors under high-speed conditions","authors":"Jie Lin ,&nbsp;Ran Zhang ,&nbsp;Che Wang ,&nbsp;Jianhua Wu ,&nbsp;Liangyou Zhu","doi":"10.1016/j.ijrefrig.2025.06.002","DOIUrl":"10.1016/j.ijrefrig.2025.06.002","url":null,"abstract":"<div><div>To minimize the charge of flammable refrigerants in air conditioning systems, there is an increasing trend towards the miniaturization and high-speed operation of rotary compressors. However, the oil supply behavior of rotary compressors under high-speed conditions remains unclear. This study conducts a numerical investigation into the oil supply characteristics of high back-pressure R290 rotary compressors at elevated rotational speeds. A comprehensive simulation model of the oil supply system was developed, integrating both stationary and rotating regions and employing the volume of fluid (VOF) method. Experimental validation confirmed a deviation of less than 4 % between the simulated and measured results. The study systematically examines the effects of factors such as rotational speed, refrigerant type, and gas hole direction on the oil supply performance under high-speed conditions. Results revealed that with increasing rotational speed, the oil supply through the spiral groove increased linearly, and the oil film in the central hole of the crankshaft became thinner. Additionally, compressors using R290 exhibited a lower oil supply rate compared with those utilizing R134a, primarily due to the lower gas density of R290. Crankshafts featuring radial gas holes demonstrated superior oil supply efficiency compared with those with axial outlets. This study offers valuable theoretical insights for optimizing oil supply systems in high-speed rotary compressors, contributing to the advancement of their design and performance.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 254-262"},"PeriodicalIF":3.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312479","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":"Optimization of trans-critical CO2 high-temperature heat pump cycle and study of maximum heating temperature","authors":"Wenqing Li ,&nbsp;Bao Yue ,&nbsp;Hao Zhang ,&nbsp;Chunyuan Zheng ,&nbsp;Peixue Jiang ,&nbsp;Yinhai Zhu","doi":"10.1016/j.ijrefrig.2025.05.023","DOIUrl":"10.1016/j.ijrefrig.2025.05.023","url":null,"abstract":"<div><div>High-temperature heat pump (HTHP) applications can be expanded from building heating to broader industrial heating fields, which is an important direction for developing heat pumps. A detailed study of five trans-critical CO₂ HTHP cycles was conducted: basic cycle, basic cycle with an internal heat exchanger (IHX), ejector cycle, ejector cycle with an IHX, and dual-temperature evaporation ejector cycle. A thermodynamic model and a multi-objective optimization model of each cycle were established, considering the heat transfer pinch temperature difference (PTD) of the heat exchanger and the non-equilibrium phase change phenomenon of the ejector. A cycle optimization method was proposed for the ejector heat pump to solve the phase equilibrium problem. The maximum heating temperature of the trans-critical CO₂ HTHP cycle is limited by the compressor discharge pressure and discharge temperature; the maximum heating temperature is up to 124.0 °C at a 20 °C ambient temperature. When the heating temperature is 85 °C, the COP of each cycle is equal at approximately 4. However, when the heating temperature exceeds 85 °C, the ejector cycle with an IHX demonstrates enhanced performance, attributable to the capability of the IHX to elevate the compressor inlet temperature and reduce the optimal discharge pressure. Conversely, when the heating temperature is &lt;85 °C, the dual-temperature evaporation ejector cycle exhibits superior performance due to higher average evaporation temperature, which increases the COP of the cycle.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 99-110"},"PeriodicalIF":3.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221826","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":"Investigating the effect of cooling tower height on PVT system efficiency with a four-inlet air cooling: energy and exergy analysis","authors":"Mahmoud Bady ,&nbsp;Mohammed El Hadi Attia ,&nbsp;Abdelkrim Khelifa ,&nbsp;Abd Elnaby Kabeel","doi":"10.1016/j.ijrefrig.2025.05.029","DOIUrl":"10.1016/j.ijrefrig.2025.05.029","url":null,"abstract":"<div><div>High operating temperatures reduce photovoltaic (PV) panel efficiency and longevity, yet few studies explore multi-inlet cooling towers for rooftop PV systems. This study investigates the impact of cooling tower height on PV efficiency using a novel four-inlet air cooling system to optimize airflow and heat dissipation. Numerical analyses assessed 1, 20, 40, 60, 80, and 100 cm tower heights, evaluating temperature reduction, electrical output, and energy efficiency. Results show taller towers enhance cooling, with thermal efficiency rising from 25 % to 55 %, electrical efficiency increasing from 8 % to 14 %, and exergy efficiency improving from 3 % to 6 % at 100 cm. These findings highlight cooling tower height as a critical design parameter for optimizing air-cooled PV systems and advancing sustainable solar solutions.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"177 ","pages":"Pages 207-218"},"PeriodicalIF":3.5,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144307904","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}