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

{"title":"Enhanced heat transfer and flow dynamics in liquid helium-free MRI cooling devices: A physical-based modeling approach","authors":"Changhao Luo ,&nbsp;Zhiqiang Long ,&nbsp;Yi Deng ,&nbsp;Guanhua Liu ,&nbsp;Meng Lin","doi":"10.1016/j.ijrefrig.2025.06.037","DOIUrl":"10.1016/j.ijrefrig.2025.06.037","url":null,"abstract":"<div><div>Cryocooler contact cooling methods partially mitigate the challenges of liquid helium use in medical Magnetic Resonance Imaging (MRI), where resource constraints and costs are critical. However, these systems still face challenges, including mechanical vibrations, limited cooling capacity, prolonged pre-cooling times, and thermal overload originating from copper leads. This study presents a liquid helium-free MRI cooling device that maintains a temperature of 4 K through natural convection in a helium circuit. A three-dimensional multi-physical model was developed to investigate cool-down times for both single and double pipe configurations and to quantitatively assess their thermal performance. The cooling process was optimized by varying pipe diameters and the integration of copper foam inserts. Increasing porosity and particle diameter significantly reduced cool-down time. The single pipe device achieved a 25 % reduction in cool-down time (from 40 h to 30 h), while the double pipe configuration showed a 72.5 % decrease (from 40 h to 11 h). As the pipe diameter increased from 5 mm to 45 mm, performance markedly improved. The double pipe device’s cool-down time dropped from 38.1 h to 11.3 h (70.1 % improvement), and the single pipe device reduced from 395.7 h to 13 h (96.7 % reduction). To further enhance heat transfer and minimize vortex formation, baffles were introduced, resulting in a significant improvement in the cooling efficiency of the 40 mm diameter single pipe device. Increasing the bottom baffle length (<em>D</em>₂) led to 60 mm reduced the cool-down time by 28.7 % matching the performance of double pipe configurations. This optimized design and the developed models provide a framework for advancing sustainable, cost-effective liquid helium-free MRI systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 243-255"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631530","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":"Cooling degree hour-based optimization of air-side free and partial free cooling strategies for mediterranean buildings: A case study","authors":"Mustafa Ertürk ,&nbsp;Ali Keçebaş","doi":"10.1016/j.ijrefrig.2025.06.033","DOIUrl":"10.1016/j.ijrefrig.2025.06.033","url":null,"abstract":"<div><div>This study presents an advanced assessment of air-based free and partial free cooling strategies to optimize energy efficiency in Mediterranean buildings, specifically in Muğla, Turkey. Utilizing cooling degree hours, free cooling degree hours, and partial free cooling degree hours, the study extends conventional models by incorporating varied comfort thresholds and outdoor climatic variations. The results reveal that a higher free cooling threshold (28 °C) maximizes energy savings, reaching up to 18 % during transitional seasons, whereas a lower threshold (22 °C) leads to increased reliance on mechanical cooling. The findings emphasize that free cooling is most effective during nighttime and transitional months, while mechanical cooling remains necessary during peak summer, with cooling degree hours peaking at 461 °C·h. An optimal partial free cooling range of 23 °C to 24 °C is identified for further efficiency improvements. This research fills a knowledge gap by offering a rigorous methodology tailored to Mediterranean climates and provides actionable insights for sustainable cooling strategies. Future studies could integrate real-time weather data and humidity effects to refine predictive models for enhanced energy efficiency.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 227-242"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144623391","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 evaluation of natural CO2-based mixtures with hydrocarbons R290 and R1270 in a transcritical refrigeration plant","authors":"R. Larrondo-Sancho,&nbsp;D. Sánchez,&nbsp;R. Cabello","doi":"10.1016/j.ijrefrig.2025.06.034","DOIUrl":"10.1016/j.ijrefrig.2025.06.034","url":null,"abstract":"<div><div>In light of the low performance of the basic CO₂ transcritical refrigeration cycle, this study explores several CO₂-hydrocarbon blends to enhance the Coefficient of Performance (COP) and, consequently, minimise the cycle's electrical power consumption. Based on a single-stage cycle with IHX four blends of carbon dioxide/propylene (CO₂/R1270) and carbon dioxide/propane (CO₂/R290) (96/4 %_mass and 94/6 %_mass each) were tested at identical operating conditions rejecting heat to three temperature levels (20, 27, and 34 °C) with similar cooling demanding conditions (0 °C). Test results revealed COP improvements at transcritical conditions up to 9.7 % using a 4 %_mass of R1270 and up to 4.7 % with a 6 %_mass of R290. Furthermore, by adding 4 %_mass of R1270, the resulting mixture increases the cooling capacity from 2.3 to 5.8 % regardless of the heat rejection temperature. Finally, the compressor power consumption showed a significant reduction from 1.2 to 7.4 % compared to pure CO₂, mainly due to improved compressor efficiencies by mixtures. The results demonstrate the convenience of using CO₂ – hydrocarbon mixtures as drop-ins to replace pure CO₂ in existing transcritical plants.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 215-226"},"PeriodicalIF":3.5,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611760","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":"Design and analysis of LNG cold energy utilization system combining hydrogen liquefaction and power output","authors":"Xu Zheng,&nbsp;Yan Li,&nbsp;Ji Zhang,&nbsp;Han Yuan,&nbsp;Ning Mei","doi":"10.1016/j.ijrefrig.2025.06.032","DOIUrl":"10.1016/j.ijrefrig.2025.06.032","url":null,"abstract":"<div><div>The integration of hydrogen liquefaction with power output represents a forward-looking approach in the context of liquefied natural gas (LNG) gasification processes. This study proposes a system that incorporates a double cascade organic Rankine cycle (ORC) and an enhanced deep-cooling liquefaction cycle to optimize cold energy utilization and efficiency during the hydrogen cryogenic cooling stage. Additionally, the optimization process employs both the particle swarm optimization algorithm (PSO) and the non-dominated sorting genetic algorithm (NSGA-II). The findings indicate that NSGA-II outperforms PSO, achieving an exergy efficiency of 61.01 %, a net ORC output power of 1584 kW, and a specific energy consumption of 6.67 kWh/kg_H2. Economic and exergy analyses undertaken to evaluate and contrast the conventional system with the proposed one. The results demonstrate a cost savings of 8.2 % in the improved system, accompanied by a decrease in the helium mass flow rate from 18.51 kg/s to 12.65 kg/s. This study aims to offer theoretical support for refrigeration cycles in the hydrogen liquefaction stage and LNG gasification processes.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 37-50"},"PeriodicalIF":3.5,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144550008","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":"Research on fault diagnosis strategy for air conditioning system based on MSMF-PD model","authors":"Yongxing Song ,&nbsp;Yanjie Zhao ,&nbsp;Qiang Liu ,&nbsp;Tonghe Zhang ,&nbsp;Zhichen Song ,&nbsp;Linhua Zhang","doi":"10.1016/j.ijrefrig.2025.06.024","DOIUrl":"10.1016/j.ijrefrig.2025.06.024","url":null,"abstract":"<div><div>The energy consumption of the air conditioning system accounts for approximately 30 % of the total energy consumption of a building. Its fault diagnosis is of great significance for energy conservation and emission reduction. This study proposes a fault diagnosis method for air conditioning systems based on the multi-source modulation signal feature fusion and Probability distribution (MSMF-PD) model. This method adopts the DPCA signal demodulation technology to extract the vibration modulation signal characteristics of the scroll compressor in the horizontal, vertical and axial directions. It enhances the fault feature characterization ability through multi-source feature fusion technology and realizes fault classification in combination with the Bayesian probability distribution model. The experiment verified four typical faults: condenser fan failure, refrigerant leakage, excessive refrigerant and main shaft wear. The results show that multi-source feature fusion significantly improves the fault identification ability. When the input frequency band is set to 150 Hz, the model accuracy rate reaches 98.75 %. Compared with the DC, FSCB and FSCC models, the diagnostic accuracy of the MSMF-PD model has increased by 28 %, 8 % and 23 % respectively, demonstrating excellent diagnostic performance and robustness, and providing an effective technical solution for the fault diagnosis of air conditioning systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 145-159"},"PeriodicalIF":3.5,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570938","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 on dehumidification and heating performance of CO₂ heat pump system for electric vehicles at low ambient temperatures (5 °C and 15 °C)","authors":"Kang Li ,&nbsp;Mingfei Tan ,&nbsp;Soheil Mohtaram ,&nbsp;Ni Liu ,&nbsp;Hua Zhang ,&nbsp;Zhuohan Lu ,&nbsp;Jinjun Yan ,&nbsp;Qize He ,&nbsp;Chao Li","doi":"10.1016/j.ijrefrig.2025.06.029","DOIUrl":"10.1016/j.ijrefrig.2025.06.029","url":null,"abstract":"<div><div>Efficient thermal management in electric vehicles (EVs) is critical for maintaining passenger comfort, particularly under cold and humid environmental conditions. Carbon dioxide (CO₂), as a natural, environmentally friendly, and thermodynamically efficient refrigerant, offers a promising alternative to conventional hydrofluorocarbon (HFC) refrigerants in vehicle heat pump systems. This study presents a dual-mode CO₂-based heat pump system specifically designed for EV applications, enabling flexible operation for both dehumidification and heating functions. Mode A utilizes an additional outdoor heat exchanger (ODHX) for refrigerant subcooling, enhancing dehumidification. Mode B eliminates ODHX, concentrating heat release in the gas cooler for superior heating output. A series of experimental investigations were conducted to assess system performance across a range of ambient temperatures and compressor speeds. Key performance metrics—including moisture extraction rate (MER), heating capacity, coefficient of performance (COP), and specific moisture extraction rate (SMER)—were evaluated under various operating conditions for both functional modes. The results reveal that at an ambient temperature of 5 °C, Mode B demonstrates superior heating performance, achieving 26.3–27.9 % higher heating capacity and a 26.3–27.6 % improvement in COP compared to Mode A, indicating its suitability for cold climate operation. Conversely, Mode A outperforms Mode B in mild-humid conditions (e.g., 15 °C), delivering 25.4–28.6 % higher MER and 26.3–29.2 % greater SMER, making it more effective for moisture control.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 170-179"},"PeriodicalIF":3.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588323","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 design of an ejector-supported cycle using krypton for cooling of particle detector accelerators","authors":"Luca Contiero ,&nbsp;Krzysztof Banasiak ,&nbsp;Bart Verlaat ,&nbsp;Armin Hafner ,&nbsp;Sven Försterling ,&nbsp;Yosr Allouche","doi":"10.1016/j.ijrefrig.2025.06.030","DOIUrl":"10.1016/j.ijrefrig.2025.06.030","url":null,"abstract":"<div><div>According to the High-Luminosity plan (HL-LHC) the Large Hadron Collider will be upgraded to further extend physics discoveries (2033–2034). The increase of the luminosity is followed by an increase of the radiation damage on the silicon sensors used to detect those particles, which they must be preserved from the thermal runaway after which the sensors reach electrical breakdown. The future upgrade will require to the cooling system temperature levels ranging from -60 to -80 °C, currently unattainable by the CO₂ cooling technology (2PACL). From a previous study the noble gas krypton was selected for the thermal management of future detectors as working medium. To meet the requirements of the new generation of particle accelerators, a new ejector-supported cooling system was proposed.</div><div>In this work, thermal design of the innovative ejector cycle was carried out starting from the detector. The semi-passive detector loop was first designed to ensure optimal working conditions of the detector. Liquid krypton is supplied to the detector by the ejector, maintaining a constant pressure lift independently of the operating temperature, with a flow variation not exceeding 4.3 % of the design value. The boundary conditions expressed by pressure, density and flow rates will serve as inputs for the design of the adjustable geometry ejector. To verify the thermal stability along the detectors, development of a control strategy to handle setpoint changes and sudden change in the cooling power is also addressed. The off-design case with fluctuating heat loads shows an offset in the evaporating temperature below 0.3 K.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 160-169"},"PeriodicalIF":3.5,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579619","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":"Effect of permanent magnetic fields on freezing characteristics of agar gel and potato","authors":"In-U Jeong ,&nbsp;Chang Joo Lee ,&nbsp;Jin Hong Mok ,&nbsp;Taiyoung Kang","doi":"10.1016/j.ijrefrig.2025.06.027","DOIUrl":"10.1016/j.ijrefrig.2025.06.027","url":null,"abstract":"<div><div>The application of magnetic field in food freezing has shown potential to improve freezing characteristics and product quality; however, findings remain inconsistent across studies. This study investigated the effects of a permanent magnetic field (PMF) with different magnetic flux densities on the freezing behavior of agar gel and potato samples. Three PMF treatments at 5.8, 14.7, and 25.0 mT were produced by ferrite magnets, and their field strength and distribution were predicted through numerical simulations. In agar gel samples, the degree of supercooling slightly increased with higher PMF strength; however, this effect was limited to the specific freezing condition (0.04 °C min⁻¹ at -20 °C) and no noticeable microstructural changes were observed. Moreover, PMF treatments did not affect the freezing behavior of potato samples and their quality attributes. These findings indicate the limited contribution of PMF treatment for improving freezing performance in food systems under the tested conditions.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 1-8"},"PeriodicalIF":3.5,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144516891","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":"Numerical simulation and experimental validation of dynamic liquid-return characteristics of refrigerant-lubricating oil mixtures in accumulator of room air-conditioner","authors":"Ziteng Yan ,&nbsp;Feilong Zhan ,&nbsp;Guoliang Ding ,&nbsp;Jiansheng Liao ,&nbsp;Liyu Zheng","doi":"10.1016/j.ijrefrig.2025.06.026","DOIUrl":"10.1016/j.ijrefrig.2025.06.026","url":null,"abstract":"<div><div>Room air-conditioners adopt accumulators to supply vapor refrigerant and liquid refrigerant-lubricating oil mixture to the compressors, and the excessive or insufficient liquid mixture returning to the compressor may respectively lead to liquid slugging or oil starvation, resulting in compressor damage. Optimization design of the accumulator based on accurate simulation is an effective way to appropriately regulate the liquid return rate. The purpose of this paper is to develop a model for accumulator simulation and to validate it by experiments. In the model, the mass and energy conservation equations for both vapor phase and liquid phase within the accumulator cavity are established to reflect the flow processes in two phases; the equations for calculating the refrigerant dissolution and desorption rates are formulated to describe the flow process of vapor-liquid interphase; the pressure balance equations based on flow path divisions are formulated to reflect the flow processes in the inlet and outlet pipes. An experimental rig is built to measure liquid return rate, oil return rate and height of liquid level of the accumulator, and the validation results show that the mean absolute deviations between predicted and experimental data of those three parameters are 6.3 %, 8.7 % and 4.6 %, respectively. By using the model, the structural parameters of the oil bleed hole for a room air conditioner accumulator with a rated cooling capacity of 3.5 kW were optimized, and the optimization results indicate the reasonable ranges for the diameter and the height of oil bleed hole are 0.65–0.92 mm and 15–30 mm, respectively.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 88-104"},"PeriodicalIF":3.5,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557680","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 transfer model of spray evaporation on tube bundles for refrigerant and lubricant mixtures","authors":"Lorenzo Cremaschi ,&nbsp;Jerin Robins Ebanesar ,&nbsp;Joshua Rothe","doi":"10.1016/j.ijrefrig.2025.06.025","DOIUrl":"10.1016/j.ijrefrig.2025.06.025","url":null,"abstract":"<div><div>Spray-type evaporators are often used in large chillers for building air conditioning and industrial refrigeration. Spray-type evaporators reduce the refrigerant charge while maintaining high energy efficiency. Studies in the literature focused on heat transfer models for spray evaporation. However, the insights gleaned from single-tube heat transfer experiments cannot be directly applied to tube bundles. In addition, models in the literature overlook the inevitable presence of lubricant in the system.</div><div>This paper introduces an innovative semi-empirical heat transfer model that predicts the heat transfer coefficients (HTCs) of the tubes within the bundle while factoring in the lubricant. The model, which was also experimentally validated for R1234ze(E)/oil and R134a/POE mixtures, accounted for the type of bundle configuration (square vs. triangular) and type of tube surface enhancements (boiling vs condensing).</div><div>Utilizing a novel segmented tube bundle approach, the model considered the spatial distribution of lubricating oil to predict the decrease in the tube HTC due to their vertical placement in the bundle. The local film flow rates decreased for the lower tubes of the bundle, especially at high heat fluxes. When considering the HTC from single tube experiments, approximately 50% of the HTC degradation was attributed to the bundle effect, and the remaining 50% was due to the lubricant. The lubricant affected boiling-like tubes negatively, while sometimes increasing the HTC of condensing-like tubes used in the bundle. Foaming and film breakdown when oil was present affected the bottom tubes of the bundles the most, especially if the feed ratio was less than 2. At a concentration of 1%, the lubricant decreased the HTC by 30% or more if the heat flux was above 15 kW/m². The new model enables engineers to forecast the performance of spray-based tube bundle evaporators based on tube geometry, bundle configuration, refrigerant conditions, and the specific refrigerant-lubricant pair in use.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"178 ","pages":"Pages 23-36"},"PeriodicalIF":3.5,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523625","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}