International Journal of Refrigeration-revue Internationale Du Froid最新文献_第5页

Study on intermittent drying process of lemon slices employing a closed-loop transcritical CO2 heat pump system

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-31 DOI: 10.1016/j.ijrefrig.2025.01.034

Chunlin Guan, Weidong Wu, Tao Zeng, Yaxiang Hou

To address the decline in energy efficiency during the mid-to-late stages of the drying process in heat pump drying (HPD), this study introduces intermittent drying based on a closed-loop transcritical CO₂ HPD system, and with lemon slices as the research object, experimentally investigates the impact of intermittent ratio in closed-loop heat pump intermittent drying on the wet-basis moisture content (M_t), drying rate, coefficient of performance of the system (COP_sys), specific moisture extraction rate (SMER), specific energy consumption (SEC), mass of drying per unit volume per unit time (MDVT), rehydration ratio, brightness of dried material and vitamin C content. The findings suggest that when the intermittent ratio rises, the average drying rate, average SMER, SEC, MDVT, rehydration ratio, brightness of dried material and vitamin C content all increase, while the average COP_sys remains essentially unchanged. The average drying rate, average SMER, SEC, MDVT, rehydration ratio, brightness of dried material and vitamin C content have maximum values at an optimal intermittent ratio of 4/6. Accordingly, a combined drying process of “continuous drying-intermittent drying-continuous drying” is proposed: when the M_t reaches 70 %, the drying mode should transition from continuous drying to intermittent drying; when the M_t reaches 40 %, the mode should shift back from intermittent drying to continuous drying. The findings provide important references for the industrial drying of lemon.

{"title":"Study on intermittent drying process of lemon slices employing a closed-loop transcritical CO2 heat pump system","authors":"Chunlin Guan, Weidong Wu, Tao Zeng, Yaxiang Hou","doi":"10.1016/j.ijrefrig.2025.01.034","DOIUrl":"10.1016/j.ijrefrig.2025.01.034","url":null,"abstract":"<div><div>To address the decline in energy efficiency during the mid-to-late stages of the drying process in heat pump drying (HPD), this study introduces intermittent drying based on a closed-loop transcritical CO<sub>2</sub> HPD system, and with lemon slices as the research object, experimentally investigates the impact of intermittent ratio in closed-loop heat pump intermittent drying on the wet-basis moisture content (<em>M</em><sub>t</sub>), drying rate, coefficient of performance of the system (<em>COP</em><sub>sys</sub>), specific moisture extraction rate (<em>SMER</em>), specific energy consumption (<em>SEC</em>), mass of drying per unit volume per unit time (<em>MDVT</em>), rehydration ratio, brightness of dried material and vitamin C content. The findings suggest that when the intermittent ratio rises, the average drying rate, average <em>SMER, SEC, MDVT</em>, rehydration ratio, brightness of dried material and vitamin C content all increase, while the average <em>COP</em><sub>sys</sub> remains essentially unchanged. The average drying rate, average <em>SMER, SEC, MDVT</em>, rehydration ratio, brightness of dried material and vitamin C content have maximum values at an optimal intermittent ratio of 4/6. Accordingly, a combined drying process of “continuous drying-intermittent drying-continuous drying” is proposed: when the <em>M</em><sub>t</sub> reaches 70 %, the drying mode should transition from continuous drying to intermittent drying; when the <em>M</em><sub>t</sub> reaches 40 %, the mode should shift back from intermittent drying to continuous drying. The findings provide important references for the industrial drying of lemon.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 147-157"},"PeriodicalIF":3.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143214257","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}

引用次数: 0

Multi-objective optimization of cooling capacity and input power of precooled JT cryocooler working at liquid helium temperature 多目标优化在液氦温度下工作的预冷 JT 低温冷却器的冷却能力和输入功率

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-31 DOI: 10.1016/j.ijrefrig.2025.01.035

Changxu Qiu , Yunwei Shen , Ruize Li , Tongfei Wu , Bo Wang , Qinyu Zhao , Zhihua Gan

The precooled JT cryocooler has become the mainstream mechanical refrigeration technology at liquid helium temperature with the advantages of low vibration, high reliability and high efficiency. The efficient matching of the precooler, JT compressor and JT side cryocooler is the key to improving the cooling capacity and reducing input power. Input power and cooling capacity of JT cryocooler are key parameters related to thermodynamics and economic performance that deserve equal attention in most industrial and research applications. In this study, a thermodynamic model of the precooled JT cryocooler working at liquid helium temperature incorporating the heat exchangers, the JT compressor and the precooler is developed. Characteristics of cooling capacity, input power and efficiency of JT cryocooler under different working conditions are analyzed. A multi-objective optimization method is employed to holistically optimize both input power and cooling capacity. The Pareto frontier consisting of a series of non-dominated solutions is obtained. The linear programming technology of multidimensional analysis preference (LINMAP) method is utilized to choose the final optimal solution from the Pareto frontier. The multi-objective optimization results of input power and cooling capacity of the cryocooler are 10,991.3 W and 7.60 W, respectively.

{"title":"Multi-objective optimization of cooling capacity and input power of precooled JT cryocooler working at liquid helium temperature","authors":"Changxu Qiu , Yunwei Shen , Ruize Li , Tongfei Wu , Bo Wang , Qinyu Zhao , Zhihua Gan","doi":"10.1016/j.ijrefrig.2025.01.035","DOIUrl":"10.1016/j.ijrefrig.2025.01.035","url":null,"abstract":"<div><div>The precooled JT cryocooler has become the mainstream mechanical refrigeration technology at liquid helium temperature with the advantages of low vibration, high reliability and high efficiency. The efficient matching of the precooler, JT compressor and JT side cryocooler is the key to improving the cooling capacity and reducing input power. Input power and cooling capacity of JT cryocooler are key parameters related to thermodynamics and economic performance that deserve equal attention in most industrial and research applications. In this study, a thermodynamic model of the precooled JT cryocooler working at liquid helium temperature incorporating the heat exchangers, the JT compressor and the precooler is developed. Characteristics of cooling capacity, input power and efficiency of JT cryocooler under different working conditions are analyzed. A multi-objective optimization method is employed to holistically optimize both input power and cooling capacity. The Pareto frontier consisting of a series of non-dominated solutions is obtained. The linear programming technology of multidimensional analysis preference (LINMAP) method is utilized to choose the final optimal solution from the Pareto frontier. The multi-objective optimization results of input power and cooling capacity of the cryocooler are 10,991.3 W and 7.60 W, respectively.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 18-28"},"PeriodicalIF":3.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394993","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}

引用次数: 0

Two-phase flow characteristics and leakage in the shaft seal of steam screw expanders

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-31 DOI: 10.1016/j.ijrefrig.2025.01.028

Yafen Tian , Zebin Wang , Zhixiang Liu , Ziqi Jiang , Zhaorui Zhao , Hua Zhang

Twin-screw expander is an efficient technology for steam pipeline pressure recovery applications. It operates at lower pressures than turbines and exhibits good performance with droplets. Leakage through the suction end face directly reduces the expander's volumetric efficiency, highlighting the significance of research on shaft seals. This study confirms that the Wet Steam Model is more accurate than the Ideal and Real Gas Models in reflecting the phase change phenomena and flow characteristics of steam after throttling. The effects of four key operating parameters were further investigated on the leakage and flow characteristics of the shaft seal, including suction pressure, superheat degree, rotating speed and liquid mass fraction. The results indicate that, within the specified pressure range, droplet condensation occurs after the final throttling when the superheat ranges from 0 to 30 K. Furthermore, leakage decreases by 1.5 % to 1.7 % with every increment of 10 K in superheat. Higher rotating speeds alter the steam flow path due to wall drag, thereby reducing leakage. An optimal liquid mass fraction of 0.1 was found for two-phase operating conditions, resulting in a 3.6 % reduction in leakage and a 20 K decrease in outlet temperature.

{"title":"Two-phase flow characteristics and leakage in the shaft seal of steam screw expanders","authors":"Yafen Tian , Zebin Wang , Zhixiang Liu , Ziqi Jiang , Zhaorui Zhao , Hua Zhang","doi":"10.1016/j.ijrefrig.2025.01.028","DOIUrl":"10.1016/j.ijrefrig.2025.01.028","url":null,"abstract":"<div><div>Twin-screw expander is an efficient technology for steam pipeline pressure recovery applications. It operates at lower pressures than turbines and exhibits good performance with droplets. Leakage through the suction end face directly reduces the expander's volumetric efficiency, highlighting the significance of research on shaft seals. This study confirms that the Wet Steam Model is more accurate than the Ideal and Real Gas Models in reflecting the phase change phenomena and flow characteristics of steam after throttling. The effects of four key operating parameters were further investigated on the leakage and flow characteristics of the shaft seal, including suction pressure, superheat degree, rotating speed and liquid mass fraction. The results indicate that, within the specified pressure range, droplet condensation occurs after the final throttling when the superheat ranges from 0 to 30 K. Furthermore, leakage decreases by 1.5 % to 1.7 % with every increment of 10 K in superheat. Higher rotating speeds alter the steam flow path due to wall drag, thereby reducing leakage. An optimal liquid mass fraction of 0.1 was found for two-phase operating conditions, resulting in a 3.6 % reduction in leakage and a 20 K decrease in outlet temperature.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 214-227"},"PeriodicalIF":3.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372711","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}

引用次数: 0

Advanced exergy analysis on an ejector using zeotropic mixture in a refrigeration system

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-30 DOI: 10.1016/j.ijrefrig.2025.01.031

Zhengshu Dai , Xiaoluo Chen , Xuejun Zhang , Hua Zhang , Kashif Nawaz

Ejector performance plays a vital role in overall cycle efficiency of an ejector refrigeration cycle. This work focuses on reducing irreversibility within the ejector by conducting both advanced and conventional exergy analysis of the ejector using R600a/R290, evaluating exergy destruction and the possibility for performance enhancement in each component of the ejector. Effects of primary flow pressure, secondary flow pressure, mass fraction, mixing chamber diameter, nozzle throat diameter and the ejector efficiency on exergy destruction in each component were discussed, and improvement potential of each component was provided. Results show that the exergy destruction of mixing chamber is the main contributor. The improvement potential from large to small recommended by avoidable endogenous exergy destruction analysis are nozzle (48.3 %), suction chamber (45.1 %), diffuser (34.8 %), and mixing chamber (21.7 %). In addition, the total exergy destruction in the ejector increases from 924 W to 1109 W as the low-boiling-point mass fraction varies from 0.1 to 0.9, but the improvement priority will not change. Moreover, the diameters of nozzle throat and mixing chamber affect ejector performance greatly, and the ejector exergy destruction is more sensitive to the changes in nozzle throat diameter. With every 0.1 mm increment in both diameters, the maximum increment of total exergy destruction reaches 1.4 % and 9.2 % with mixing chamber diameter and nozzle throat diameter, respectively. Ejector efficiency has great impact on ejector performance, as ejector efficiency changes from 0.80 to 0.90, the exergy efficiency of the ejector increases from 4 % to 19 %.

{"title":"Advanced exergy analysis on an ejector using zeotropic mixture in a refrigeration system","authors":"Zhengshu Dai , Xiaoluo Chen , Xuejun Zhang , Hua Zhang , Kashif Nawaz","doi":"10.1016/j.ijrefrig.2025.01.031","DOIUrl":"10.1016/j.ijrefrig.2025.01.031","url":null,"abstract":"<div><div>Ejector performance plays a vital role in overall cycle efficiency of an ejector refrigeration cycle. This work focuses on reducing irreversibility within the ejector by conducting both advanced and conventional exergy analysis of the ejector using R600a/R290, evaluating exergy destruction and the possibility for performance enhancement in each component of the ejector. Effects of primary flow pressure, secondary flow pressure, mass fraction, mixing chamber diameter, nozzle throat diameter and the ejector efficiency on exergy destruction in each component were discussed, and improvement potential of each component was provided. Results show that the exergy destruction of mixing chamber is the main contributor. The improvement potential from large to small recommended by avoidable endogenous exergy destruction analysis are nozzle (48.3 %), suction chamber (45.1 %), diffuser (34.8 %), and mixing chamber (21.7 %). In addition, the total exergy destruction in the ejector increases from 924 W to 1109 W as the low-boiling-point mass fraction varies from 0.1 to 0.9, but the improvement priority will not change. Moreover, the diameters of nozzle throat and mixing chamber affect ejector performance greatly, and the ejector exergy destruction is more sensitive to the changes in nozzle throat diameter. With every 0.1 mm increment in both diameters, the maximum increment of total exergy destruction reaches 1.4 % and 9.2 % with mixing chamber diameter and nozzle throat diameter, respectively. Ejector efficiency has great impact on ejector performance, as ejector efficiency changes from 0.80 to 0.90, the exergy efficiency of the ejector increases from 4 % to 19 %.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 266-283"},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387157","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}

引用次数: 0

New phase separation phenomena in refrigeration plants working with CO2-based mixtures. Experimental approach

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-30 DOI: 10.1016/j.ijrefrig.2025.01.032

M. Martínez-Ángeles , F. Petruzziello , L. Nebot-Andrés , C. Aprea , A. Maiorino , R. Llopis

Use of CO₂-based mixtures results in COP improvements for simple cycle layouts, however, mixtures working in the parallel compression cycle where fractionation process takes place have not been deeply explored yet. This work provides an experimental analysis of phase separator inner behavior using pure CO₂ and three CO₂-based mixtures with R600a and R290 as additives. With pure CO₂ we identify and define a process of internal evaporation in the phase separator, which occurs with both pure CO₂ and mixtures, leading to subcooling in the liquid phase and an increased vapor mass flow rate. Circulating compositions for the mixtures were calculated using a model which does not rely on REFPROP v.10.0 fractionation rules and significant deviations compared to it have been observed. These deviations are caused by three simultaneous phenomena in the phase separator: fractionation, internal evaporation, and partial density-layering. The latter two phenomena effects are contrary to that of fractionation, causing significant changes in the circulating compositions. With a self-developed model, internal evaporation mass flow rate, composition and capacity are then calculated. All results show consistency across all phase separator conditions and complete the explanation for the deviations between measured and REFPROP-predicted compositions. Consequently, the real behavior of the phase separator is described as well as its implications.

{"title":"New phase separation phenomena in refrigeration plants working with CO2-based mixtures. Experimental approach","authors":"M. Martínez-Ángeles , F. Petruzziello , L. Nebot-Andrés , C. Aprea , A. Maiorino , R. Llopis","doi":"10.1016/j.ijrefrig.2025.01.032","DOIUrl":"10.1016/j.ijrefrig.2025.01.032","url":null,"abstract":"<div><div>Use of CO<sub>2</sub>-based mixtures results in COP improvements for simple cycle layouts, however, mixtures working in the parallel compression cycle where fractionation process takes place have not been deeply explored yet. This work provides an experimental analysis of phase separator inner behavior using pure CO<sub>2</sub> and three CO<sub>2</sub>-based mixtures with R600a and R290 as additives. With pure CO<sub>2</sub> we identify and define a process of internal evaporation in the phase separator, which occurs with both pure CO<sub>2</sub> and mixtures, leading to subcooling in the liquid phase and an increased vapor mass flow rate. Circulating compositions for the mixtures were calculated using a model which does not rely on REFPROP v.10.0 fractionation rules and significant deviations compared to it have been observed. These deviations are caused by three simultaneous phenomena in the phase separator: fractionation, internal evaporation, and partial density-layering. The latter two phenomena effects are contrary to that of fractionation, causing significant changes in the circulating compositions. With a self-developed model, internal evaporation mass flow rate, composition and capacity are then calculated. All results show consistency across all phase separator conditions and complete the explanation for the deviations between measured and REFPROP-predicted compositions. Consequently, the real behavior of the phase separator is described as well as its implications.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 75-86"},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175230","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}

引用次数: 0

A numerical investigation on refrigeration vapor cycles, operating with carbon-dioxide and a single-stage heat-powered sorption compressor

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-30 DOI: 10.1016/j.ijrefrig.2025.01.033

S. Iraqi, N. Tzabar

In recent decades we witness a surge in electricity consumption rates, thereby, a growing demand for electricity production and transmission. These trends yield escalating emissions, accelerating global warming and other deleterious environmental impacts. Heat powered cycles convert heat to work or to heat pumping and are, therefore, suitable for replacing the common electricity-driven cycles. A common heat source is solar radiation, however, waste heat, especially in industry, is widely available, and at a variety of temperatures. Replacing electricity consumption by available heat sources can significantly reduce the electricity generation demand and the required electricity transmission infrastructure.

Ongoing research on thermally driven sorption compressors is conducted in our research laboratory, aiming for several applications. Within the scope of this research stage, a single-stage sorption compressor for carbon dioxide is numerically investigated, based on a previously developed numerical model. Several sorption cell sizes with different operating conditions are investigated, and the conditions for obtaining maximum coefficient of performance and effectiveness are determined. The research proves the feasibility of harnessing the sorption compressor technology to refrigeration and air-conditioning systems. The presented performances aren't competitive with absorption refrigeration systems, yet; however, the outcomes of this research pave the way for performance improvements and turning the suggested technology to an attractive heat-powered refrigeration and air-conditioning technology.

{"title":"A numerical investigation on refrigeration vapor cycles, operating with carbon-dioxide and a single-stage heat-powered sorption compressor","authors":"S. Iraqi, N. Tzabar","doi":"10.1016/j.ijrefrig.2025.01.033","DOIUrl":"10.1016/j.ijrefrig.2025.01.033","url":null,"abstract":"<div><div>In recent decades we witness a surge in electricity consumption rates, thereby, a growing demand for electricity production and transmission. These trends yield escalating emissions, accelerating global warming and other deleterious environmental impacts. Heat powered cycles convert heat to work or to heat pumping and are, therefore, suitable for replacing the common electricity-driven cycles. A common heat source is solar radiation, however, waste heat, especially in industry, is widely available, and at a variety of temperatures. Replacing electricity consumption by available heat sources can significantly reduce the electricity generation demand and the required electricity transmission infrastructure.</div><div>Ongoing research on thermally driven sorption compressors is conducted in our research laboratory, aiming for several applications. Within the scope of this research stage, a single-stage sorption compressor for carbon dioxide is numerically investigated, based on a previously developed numerical model. Several sorption cell sizes with different operating conditions are investigated, and the conditions for obtaining maximum coefficient of performance and effectiveness are determined. The research proves the feasibility of harnessing the sorption compressor technology to refrigeration and air-conditioning systems. The presented performances aren't competitive with absorption refrigeration systems, yet; however, the outcomes of this research pave the way for performance improvements and turning the suggested technology to an attractive heat-powered refrigeration and air-conditioning technology.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 170-182"},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349281","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}

引用次数: 0

Optimization of a novel magnetic refrigerator based on the demagnetizing effect using a particle swarm-like algorithm

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-30 DOI: 10.1016/j.ijrefrig.2025.01.016

C.R. Fernandes , J.S. Amaral , R. Almeida , J.H. Belo , J.O. Ventura , D.J. Silva

The current state of the art of magnetic refrigerator prototyping relies on changes in magnetic field magnitude for promoting heat transfer processes from cold to hot regions. Although this is the most widespread method, some disadvantages arise, such as requiring massive magnets and complex operation mechanisms to alternate the field intensity. Recently, a new operation approach has been proposed using the demagnetizing effect of polycrystalline and anisotropically shaped magnetocaloric materials, which explores the rotation of the magnetic field rather than changes in its magnitude. In this work, we numerically study the performance of a magnetic refrigerator based on this novel approach using a finite element method, considering the half-plate and half-fluid channel model. After performing 92 simulations with random parameters, the no-load temperature span of the system was optimized using a particle swarm-based algorithm to determine the global best. The initial global best from the simulated results was 5.89 K. A new global best of 7.27 K was obtained after applying the algorithm, which represents an increase of over 20%. For the same volume of magnetocaloric material, the temperature span decreases with the inverse aspect ratio. The maximum temperature span of the remaining inverse aspect ratios was successfully determined. In particular, it was possible to increase the temperature span by 22.91% and 18.28% for the inverse aspect ratios 0.26 and 0.4, respectively. This study highlights the feasibility of a novel kind of magnetic refrigerators based on the demagnetizing field.

{"title":"Optimization of a novel magnetic refrigerator based on the demagnetizing effect using a particle swarm-like algorithm","authors":"C.R. Fernandes , J.S. Amaral , R. Almeida , J.H. Belo , J.O. Ventura , D.J. Silva","doi":"10.1016/j.ijrefrig.2025.01.016","DOIUrl":"10.1016/j.ijrefrig.2025.01.016","url":null,"abstract":"<div><div>The current state of the art of magnetic refrigerator prototyping relies on changes in magnetic field magnitude for promoting heat transfer processes from cold to hot regions. Although this is the most widespread method, some disadvantages arise, such as requiring massive magnets and complex operation mechanisms to alternate the field intensity. Recently, a new operation approach has been proposed using the demagnetizing effect of polycrystalline and anisotropically shaped magnetocaloric materials, which explores the rotation of the magnetic field rather than changes in its magnitude. In this work, we numerically study the performance of a magnetic refrigerator based on this novel approach using a finite element method, considering the half-plate and half-fluid channel model. After performing 92 simulations with random parameters, the no-load temperature span of the system was optimized using a particle swarm-based algorithm to determine the global best. The initial global best from the simulated results was 5.89 K. A new global best of 7.27 K was obtained after applying the algorithm, which represents an increase of over 20%. For the same volume of magnetocaloric material, the temperature span decreases with the inverse aspect ratio. The maximum temperature span of the remaining inverse aspect ratios was successfully determined. In particular, it was possible to increase the temperature span by 22.91% and 18.28% for the inverse aspect ratios 0.26 and 0.4, respectively. This study highlights the feasibility of a novel kind of magnetic refrigerators based on the demagnetizing field.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 134-146"},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143214256","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}

引用次数: 0

Experimental study on the solubility of Propylene (R1270) in PAG, POE and AB lubricants

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-29 DOI: 10.1016/j.ijrefrig.2025.01.027

Qinying Hou , Zhihao Zhang , Yang Zou, Jialiang Hua, Guogeng He

R1270 is considered a suitable alternative to chlorodifluoromethane (R22) and 1,1,1,2-tetrafluoroethane (R134a) due to its environmentally friendly nature and comparable thermophysical properties. In compression refrigeration systems, the used lubricants need to be matched with alternative refrigerants and exhibit appropriate solubility. Therefore, in this study, the solubility of R1270 in three lubricants: polyalkylene glycol (PAG), polyolester (POE), and alkybenzene (AB) was measured using the isochoric saturation method at temperatures ranging from 283.15 to 323.15 K. Henry's constant was calculated to intuitively compare the solubility of R1270 in the three lubricants. The results indicate that R1270 is miscible with PAG46, POE68, and AB100 lubricants across the entire test temperature range, with the highest solubility observed in PAG46, while POE68 and AB100 exhibit similar solubility characteristics. Subsequently, the non-random two-liquid (NRTL) activity coefficient model was applied to correlate the experimental solubility data. The significance of this study is to provide a reference for the selection of suitable lubricants for R1270 in various applications.

{"title":"Experimental study on the solubility of Propylene (R1270) in PAG, POE and AB lubricants","authors":"Qinying Hou , Zhihao Zhang , Yang Zou, Jialiang Hua, Guogeng He","doi":"10.1016/j.ijrefrig.2025.01.027","DOIUrl":"10.1016/j.ijrefrig.2025.01.027","url":null,"abstract":"<div><div>R1270 is considered a suitable alternative to chlorodifluoromethane (R22) and 1,1,1,2-tetrafluoroethane (R134a) due to its environmentally friendly nature and comparable thermophysical properties. In compression refrigeration systems, the used lubricants need to be matched with alternative refrigerants and exhibit appropriate solubility. Therefore, in this study, the solubility of R1270 in three lubricants: polyalkylene glycol (PAG), polyolester (POE), and alkybenzene (AB) was measured using the isochoric saturation method at temperatures ranging from 283.15 to 323.15 K. Henry's constant was calculated to intuitively compare the solubility of R1270 in the three lubricants. The results indicate that R1270 is miscible with PAG46, POE68, and AB100 lubricants across the entire test temperature range, with the highest solubility observed in PAG46, while POE68 and AB100 exhibit similar solubility characteristics. Subsequently, the non-random two-liquid (NRTL) activity coefficient model was applied to correlate the experimental solubility data. The significance of this study is to provide a reference for the selection of suitable lubricants for R1270 in various applications.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 87-93"},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175231","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}

引用次数: 0

Experimental investigation on airside thermal-hydraulic performance of vertical-fin microchannel heat exchangers

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-28 DOI: 10.1016/j.ijrefrig.2025.01.030

Bin Luo , Feng Li , Siyuan Wu , Kewei Shi , Yunxiao Ding , Rijing Zhao , Dong Huang , Wenxing Shi

The vertical-fin microchannel heat exchanger (MHX) demonstrates significant potential as an evaporator for heat pump systems. This study provides an experimental comparison of three typical vertical-fin configurations: MHXs with fin leading (MHX-L), trailing (MHX-T), and both edges extended (MHX-LT). The airside thermal-hydraulic performance is comprehensively evaluated under dry, wet, and frosting operating conditions. The results indicate that, for dry and wet conditions, the MHX-L outperforms the MHX-T. Under frosting conditions, the MHX-T exhibits the poorest performance in frosting and drainage. Consequently, the MHX-L is recommended for practical applications over the MHX-T. The MHX-LT exhibits the highest heat transfer capacity across all conditions due to its larger heat transfer area, albeit with an increased air pressure drop. When assessing the drainage performance in terms of drainage rate and residual ratio, the MHX-L surpasses the MHX-LT. Although the MHX-LT has a higher capacity in the initial cycle than the MHX-L, its inferior drainage performance may lead to a more significant reduction in cyclic capacity.

{"title":"Experimental investigation on airside thermal-hydraulic performance of vertical-fin microchannel heat exchangers","authors":"Bin Luo , Feng Li , Siyuan Wu , Kewei Shi , Yunxiao Ding , Rijing Zhao , Dong Huang , Wenxing Shi","doi":"10.1016/j.ijrefrig.2025.01.030","DOIUrl":"10.1016/j.ijrefrig.2025.01.030","url":null,"abstract":"<div><div>The vertical-fin microchannel heat exchanger (MHX) demonstrates significant potential as an evaporator for heat pump systems. This study provides an experimental comparison of three typical vertical-fin configurations: MHXs with fin leading (MHX-L), trailing (MHX-T), and both edges extended (MHX-LT). The airside thermal-hydraulic performance is comprehensively evaluated under dry, wet, and frosting operating conditions. The results indicate that, for dry and wet conditions, the MHX-L outperforms the MHX-T. Under frosting conditions, the MHX-T exhibits the poorest performance in frosting and drainage. Consequently, the MHX-L is recommended for practical applications over the MHX-T. The MHX-LT exhibits the highest heat transfer capacity across all conditions due to its larger heat transfer area, albeit with an increased air pressure drop. When assessing the drainage performance in terms of drainage rate and residual ratio, the MHX-L surpasses the MHX-LT. Although the MHX-LT has a higher capacity in the initial cycle than the MHX-L, its inferior drainage performance may lead to a more significant reduction in cyclic capacity.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 167-179"},"PeriodicalIF":3.5,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454258","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}

引用次数: 0

Performance evaluation and discharge pressure discussion of supermarket CO2 refrigeration system integrated with ejector subcooling using solar energy

IF 3.5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Refrigeration-revue Internationale Du Froid

Pub Date : 2025-01-27 DOI: 10.1016/j.ijrefrig.2025.01.022

Deyong Ran, Qichao Yang, Tailan Yin, Liansheng Li, Yuanyang Zhao, Guangbin Liu

To further enhance the applicability of the supermarket CO₂ refrigeration system in warm or hot climates, a supermarket CO₂ refrigeration system integrated with ejector subcooling using solar energy (SCRS-ES) is proposed and the thermodynamic model is established. A parametric analysis has been conducted on the proposed cycle under varying operating conditions, and the impact of operational parameters on its performance has been discussed. The key operation parameter of discharge pressure is compared analyzed in detail. The results indicate that there exists optimal discharge pressure (P_dis,opt) and subcooling degree (T_Sub,opt) that enable the hybrid system to achieve a maximum COP_m, while the system requires a relatively large collector area (A_Col). When the ambient temperature is 30–40 °C and subcooling degree is 10 °C, the system is operated at the optimal discharge pressure corresponding to the supermarket CO₂ refrigeration system (SCRS) (P_opt,SCRS), the COP_m,max is decreased by 8.11–14.98 % compared to that at P_dis,opt, but A_Col is significantly decreased by 63.7–68.75 %. Meanwhile, the performance is still improved by 15.56–20.29 % compared to the SCRS. Therefore, this hybrid system can be operated with optimal discharge pressure of SCRS. The findings of this research may provide the reference for further optimization and application of the hybrid system.

{"title":"Performance evaluation and discharge pressure discussion of supermarket CO2 refrigeration system integrated with ejector subcooling using solar energy","authors":"Deyong Ran, Qichao Yang, Tailan Yin, Liansheng Li, Yuanyang Zhao, Guangbin Liu","doi":"10.1016/j.ijrefrig.2025.01.022","DOIUrl":"10.1016/j.ijrefrig.2025.01.022","url":null,"abstract":"<div><div>To further enhance the applicability of the supermarket CO<sub>2</sub> refrigeration system in warm or hot climates, a supermarket CO<sub>2</sub> refrigeration system integrated with ejector subcooling using solar energy (SCRS-ES) is proposed and the thermodynamic model is established. A parametric analysis has been conducted on the proposed cycle under varying operating conditions, and the impact of operational parameters on its performance has been discussed. The key operation parameter of discharge pressure is compared analyzed in detail. The results indicate that there exists optimal discharge pressure (<em>P</em><sub>dis,opt</sub>) and subcooling degree (<em>T</em><sub>Sub,opt</sub>) that enable the hybrid system to achieve a maximum COP<sub>m</sub>, while the system requires a relatively large collector area (<em>A</em><sub>Col</sub>). When the ambient temperature is 30–40 °C and subcooling degree is 10 °C, the system is operated at the optimal discharge pressure corresponding to the supermarket CO<sub>2</sub> refrigeration system (SCRS) (<em>P</em><sub>opt,SCRS</sub>), the COP<sub>m,max</sub> is decreased by 8.11–14.98 % compared to that at <em>P</em><sub>dis,opt</sub>, but <em>A</em><sub>Col</sub> is significantly decreased by 63.7–68.75 %. Meanwhile, the performance is still improved by 15.56–20.29 % compared to the SCRS. Therefore, this hybrid system can be operated with optimal discharge pressure of SCRS. The findings of this research may provide the reference for further optimization and application of the hybrid system.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 27-40"},"PeriodicalIF":3.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143173424","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}

引用次数: 0