Pinguo Wu , Yunpeng Hu , Guannan Li , Qi Liu , Chenglong Xiong , Jiahui Deng , Shiao Chen
{"title":"Sensor fault detection, diagnosis, and data reconstruction strategy for chiller based on an improved tree-based pipeline optimization tool framework","authors":"Pinguo Wu , Yunpeng Hu , Guannan Li , Qi Liu , Chenglong Xiong , Jiahui Deng , Shiao Chen","doi":"10.1016/j.ijrefrig.2025.02.013","DOIUrl":"10.1016/j.ijrefrig.2025.02.013","url":null,"abstract":"<div><div>Machine learning is widely applied to fault detection, diagnosis, and data reconstruction for chiller sensors but often requires domain expertise and manual intervention. Tree-based Pipeline Optimization Tool (TPOT), an automated machine learning framework, shows promise in fault detection, diagnosis, and reconstruction by automating model optimization and parameter tuning. Although the TPOT framework includes automated data preprocessing functions, it lacks the ability to automatically handle outliers. Outliers in sensor data can adversely affect the quality of the modeling process. By leveraging TPOT's capability for automated modeling, an ensemble fault diagnosis model can be developed. However, this model is prone to misdiagnosis when the sensor variables exhibit high correlations. Therefore, this study proposes an improved TPOT framework by incorporating a sliding window strategy to enhance TPOT's ability to handle outliers. The ensemble fault diagnosis model based on TPOT incorporates a Euclidean distance strategy, which identifies faulty sensors by quantifying the difference between the input data and the predicted results. Results show that the improved TPOT framework enhances fault detection, diagnosis, and data reconstruction. In the detection of sensor bias, drift, and precision degradation faults, the fault detection rates increased by a mean of 3.11 %, 4.64 %, and 8.62 %, respectively. The diagnostic strategy incorporating Euclidean distance reduced the number of misdiagnoses by one in the diagnosis of nine different sensor faults. In sensor data reconstruction, the RMSE was reduced by a mean of 68.26 %.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"174 ","pages":"Pages 60-75"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578189","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":"Flow distribution characteristics of gravity- and pump-driven CO2 two-phase thermosyphon loops with three evaporators","authors":"Zhen Tong , Peng Wang , Zekun Han , Wencheng Wang","doi":"10.1016/j.ijrefrig.2025.02.011","DOIUrl":"10.1016/j.ijrefrig.2025.02.011","url":null,"abstract":"<div><div>Currently, most two-phase the<em>r</em>mosyphon loop (TPTL) systems used in data centers feature a multi-evaporator design. The flow rate of the working fluid through each evaporator is one of the crucial factors affecting the cooling effect of the TPTL. Therefore, this paper conducts a comparative study on the flow distribution patterns of gravity- and pump-driven multi-evaporator TPTLs. The impacts of flow resistance and load distribution on each branch's flow distribution of working fluid are analyzed. It was found that the flow distributions of both gravity- and pump-driven TPTLs were influenced by load distribution. Under non-uniform load conditions, the flow rate tended to skew towards evaporators with higher loads. Additionally, the flow distribution of the gravity-driven TPTL was highly affected by individual branch flow resistance, which was markedly different from the pump-driven TPTL. Under uniform load conditions, the flow rate of the pump-driven TPTL was generally evenly distributed among the evaporators.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 76-87"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438190","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}
Renan Luis Fragelli , Vicente Luiz Scalon , Luiz Eduardo de Angelo Sanchez
{"title":"A sustainable cooling solution for machining: Internally cooled toolholder enhanced by nanorefrigerants and electrohydrodynamic effect","authors":"Renan Luis Fragelli , Vicente Luiz Scalon , Luiz Eduardo de Angelo Sanchez","doi":"10.1016/j.ijrefrig.2025.02.010","DOIUrl":"10.1016/j.ijrefrig.2025.02.010","url":null,"abstract":"<div><div>Alternatives to cutting fluids have been extensively researched in machining. While they provide lubrication and cooling for tools, they pose health risks, cause environmental damage, and increase manufacturing costs. Considering that many researchers worldwide have been focusing their efforts on new applications for nanofluids, the objective is to evaluate the application of nanorefrigerants alongside the Electrohydrodynamic Effect (EHD) in a similar device to an internally cooled toolholder in order to reduce or eliminate cutting fluids. R141b/Al<sub>2</sub>O<sub>3</sub> nanorefrigerants with three different concentrations were prepared and subsequently characterized. A heating chamber similar to a toolholder was developed to circulate nanofluids, apply the EHD effect, and evaluate its efficacy in reducing cutting tool temperature. The nanorefrigerants remained stable for up to 48 h; their viscosities increased by 44–64%, depending on concentration. The thermal conductivity of the nanorefrigerant with the lowest concentration increased by 44%. The EHD effect showed positive results in all analyzed conditions, with an increase in the heat transfer coefficient (h) of up to 19%. However, higher nanoparticle concentrations resulted in a smaller increase in the h values. Based on the heat transfer coefficient, the internal cooling system proved viable for reducing or eliminating cutting fluids. The combination of nanorefrigerants and EHD Effect can enhance the internal cooling method, extending tool life.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 88-99"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438188","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":"Theoretical and experimental analysis of heat storage material integration in household refrigerators","authors":"Joel Boeng , Joaquim Manoel Gonçalves","doi":"10.1016/j.ijrefrig.2025.02.007","DOIUrl":"10.1016/j.ijrefrig.2025.02.007","url":null,"abstract":"<div><div>In recent years, the application of heat storage materials (HSMs), particularly phase change materials (PCMs), in heat exchangers and/or refrigerated compartments of household refrigerators has increased substantially. This growth has been primarily driven by the implementation of stringent energy efficiency enhancement policies. The present study first provides a theoretical analysis of the impact of integrating HSMs into refrigerated compartments and heat exchangers of a refrigerator. Specifically, it elucidates the mechanism by which an HSM decreases the difference between condensing and evaporating temperatures and examines the behavior of this attenuation as a function of the compressor run-time ratio and the heat transfer coefficients involved. Subsequently, the study experimentally investigates the effects of incorporating HSMs into natural-draft condensers of household refrigerators. Four distinct types of HSMs were attached to a natural-draft wire-and-tube condenser of an <em>A</em>++ European single-compartment refrigerator. The performance of the refrigerator, with and without HSMs, was assessed through standardized energy consumption tests conducted under varying system operating conditions. Energy savings of up to 7.4 % were achieved by attaching 700 g of a copolymer compound to the condenser. The findings reveal that optimal system performance is associated with specific compressor on-time and off-time periods, which are influenced by the condenser size, HSM attachment method, and material thermal capacity. Furthermore, energy savings were observed to be more pronounced at lower compressor run-time ratios and shorter compressor on-time intervals. These observations suggest that the application of HSMs in natural-draft condensers is not recommended for systems equipped with variable-speed compressors.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 153-166"},"PeriodicalIF":3.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454257","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 and experimental evaluation of the thermal and dynamic performance of a phase change material in an indirect solar dryer","authors":"Dounia CHAATOUF, Mourad SALHI, Abir Bria, Benyounes RAILLANI, Samir AMRAQUI, Ahmed MEZRHAB","doi":"10.1016/j.ijrefrig.2025.02.006","DOIUrl":"10.1016/j.ijrefrig.2025.02.006","url":null,"abstract":"<div><div>The use of solar dryers can be limited due to inherent challenges such as the non-uniform final moisture content of the dried product and the non-continuity of the drying process. These drawbacks are mainly due to the uneven distribution of air between the trays and the intermittent availability of solar energy. Consequently, a storage unit is needed to provide heat during cloudy hours or when the sun sets. This study therefore focuses on an indirect solar dryer to identify the best location for a storage unit. Three cases were examined through numerical simulations using ANSYS Fluent, which were validated experimentally: The first case is where the PCM is located under the absorber plate, the second case is where the PCM is located in the plenum, and the third case is where there is no PCM. In order to make this comparison fair, we respected the same amount of PCM in both cases. The results show that the first case outperforms the second in terms of the average temperature inside the drying chamber. However, beyond 8 p.m., the opposite is observed, with the maximum temperature difference from the case without PCM reaching 9 and 8° for the first and second cases respectively. As regards air uniformity, the second case made the air more uniform along the trays compared with the other cases.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"174 ","pages":"Pages 98-110"},"PeriodicalIF":3.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600791","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":"Thermo-economic evaluation of low-GWP CO2-based zeotropic mixtures in space heating heat pumps with and without internal heat exchanger","authors":"Alireza Zendehboudi","doi":"10.1016/j.ijrefrig.2025.01.036","DOIUrl":"10.1016/j.ijrefrig.2025.01.036","url":null,"abstract":"<div><div>Transcritical CO<sub>2</sub> heat pumps are commonly used for tap water heating in buildings; however, their performance is often limited in space heating applications. Low-GWP CO<sub>2</sub>-based mixtures can enhance subcritical operation and reduce irreversibility during transcritical processes. Promoting this technology requires a comprehensive understanding of its thermo-economic performance; yet, there is a lack of relevant studies. This paper develops thermodynamic models using energy, exergy, and exergoeconomic analyses to evaluate the performance of four CO<sub>2</sub>-binary mixtures (CO<sub>2</sub>/R41, CO<sub>2</sub>/R1234yf, CO<sub>2</sub>/R290, and CO<sub>2</sub>/R1270) in space heating heat pumps. These mixtures are compared against pure CO<sub>2</sub> in two cycle configurations: with and without an internal heat exchanger (IHX). The evaluation is conducted in accordance with the EN 14511–2 standard across various heating temperatures. Results indicate that the CO<sub>2</sub>/R41 blend achieves significant COP improvements, exceeding pure CO<sub>2</sub> by up to 17.1% at 30/35 °<span><math><mi>C</mi></math></span> and 8.3% at 47/55 °<span><math><mi>C</mi></math></span>. CO<sub>2</sub>-based mixtures also significantly lower optimal discharge pressures, with reductions ranging from 24.4% for CO<sub>2</sub>/R41 to 52.9% for CO<sub>2</sub>/R1270. The inclusion of an IHX has a notable effect on COP, particularly for CO<sub>2</sub>/R41, where performance improves when the CO<sub>2</sub> mass fraction exceeds 70% at lower temperatures. Exergy analysis demonstrates that the CO<sub>2</sub>/R41 mixture achieves the highest exergy efficiency up to and including a CO<sub>2</sub> mass fraction of 80%, outperforming pure CO<sub>2</sub> by up to 16.3%. Furthermore, CO<sub>2</sub>/R41 exhibits 16.3%–19.8% lower total exergy destruction cost rates compared to pure CO<sub>2</sub>, with significant cost reductions in the throttling valve (25.5%–42.5%). These findings highlight the potential of CO<sub>2</sub>/R41 as a highly effective and economically viable option for space heating heat pumps, offering superior performance and reduced operational costs compared to pure CO<sub>2</sub> and other mixtures.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 1-17"},"PeriodicalIF":3.5,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394994","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}
Xiaofei Wen , Tianyou Zhou , Chao Chen , Hongxing Li , Feng Zhou , Yunde Liu
{"title":"Dual precooling enhanced nitrogen-expanded BOG reliquefaction process for LNG-fueled ships","authors":"Xiaofei Wen , Tianyou Zhou , Chao Chen , Hongxing Li , Feng Zhou , Yunde Liu","doi":"10.1016/j.ijrefrig.2025.02.005","DOIUrl":"10.1016/j.ijrefrig.2025.02.005","url":null,"abstract":"<div><div>By re-liquefying the evaporated gas in the BOG reliquefaction process, operational expenses are minimized, simultaneously advancing environmental sustainability and improving resource usage. Most current reliquefaction processes untilize a single precooling cycle, with limited research on multi-stage precooling configurations. This paper proposes a dual precooling cycle that utilizes propane and BOG itself as precooling agents, and reliquefies BOG using a nitrogen inverse Brayton cycle. The design focuses minimizing specific energy consumption (SEC) through simulation and optimization. Optimization results indicate that the BOG reliquefaction process achieves an SEC of 1.017 kWh/kg<sub>LNG</sub> and an exergy efficiency of 27.29 % respectively. More than 20 % improvement in SEC compared to other single precooling processes. Cost analyses show that the dual precooled BOG liquefaction process is economically sound. Ultimately, through an analysis of the system based on BOG components and temperature variations, the system was able to operate stably.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 284-294"},"PeriodicalIF":3.5,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394762","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 evaluation of low-temperature operated desiccant wheel integrated heat pump drying system for ponyfish (Leiognathus equula) drying","authors":"A. Lakshmi Kanthan Bharathi , S. Kalaiselvam","doi":"10.1016/j.ijrefrig.2025.02.003","DOIUrl":"10.1016/j.ijrefrig.2025.02.003","url":null,"abstract":"<div><div>Low-temperature drying is an effective technique for preserving the quality of heat-sensitive products such as fish. Integrating a desiccant wheel and a heat pump, the dryer can function at low temperatures and humidity levels while consuming less energy. This study evaluates the performance of a desiccant wheel integrated heat pump dryer (DW-HPD) for drying ponyfish (<em>Leiognathus equula</em>) at 40 °C, 45 °C, and 50 °C, emphasizing drying kinetics, dryer efficiency, mathematical models, and quality retention. The optimal drying temperature of 50 °C achieved the highest drying rate of 8.18 % wb/h. Increasing the temperature from 40 °C to 50 °C reduced the drying time from 10.5 to 5.5 h. Effective moisture diffusivity ranged from 8.40 × 10<sup>−10</sup> to 1.87 × 10<sup>−9</sup> m<sup>2</sup>/s, with an activation energy of 59.14 kJ/mol. The maximum specific moisture extraction rate (SMER) and specific energy consumption (SEC) were 2.21 kg/kWh and 9.4 kWh/kg at 50 °C, respectively. Rehydration ratio (RR) and water holding capacity (WHC) ranged from 1.172 to 1.183 and 0.336–0.406 g water/g dry solid. Water activity and texture values were 0.740–0.748 and 0.698–0.656 kg, respectively. The Hunter L* value indicated improved color quality, while sensory scores for overall acceptability at 45 °C and 50 °C ranged from \"like moderately\" to \"like very much,\" confirming the high-quality standards of DW-HPD dried ponyfish.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 55-67"},"PeriodicalIF":3.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420096","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 numerical investigation of suction muffler outlet pipe geometry effect on volumetric efficiency and COP","authors":"Caglar Sahin , Seyhan Uygur Onbasioglu","doi":"10.1016/j.ijrefrig.2025.02.001","DOIUrl":"10.1016/j.ijrefrig.2025.02.001","url":null,"abstract":"<div><div>This study investigates how the design of the muffler outlet pipe and the compressor speed affect the volumetric efficiency and COP using both experimental and numerical methods. Three distinct muffler outlet pipe designs, characterized by varying lengths and diameters, are tested across four different compressor speeds using R600a refrigerant. Experimental measurements include displacement data of the suction valve obtained via strain gauges, while pressure fluctuations in the suction plenum and cylinder volume are recorded using pressure transducers. Additionally, a magnetic encoder is employed to monitor crank angle and cylinder volume. A numerical model is developed using the GT-SUITE™ platform and subsequently validated against the experimental results. After successful validation, the numerical model is used to investigate the impacts of compressor speed and muffler geometry in more depth. The investigation encompasses the analysis of pressure drop, compressor speed, and valve timing in relation to mass flow rate and valve displacement curves. A general linear model is constructed to quantify the contribution of each parameter and the R-sq (adjusted) is 75 %. The model indicates that compressor speed accounts for 75 % of the variation in volumetric efficiency whereas the pipe diameter is the second-largest contributor, accounting for nearly 22 % and the effects of the pipe length is 3 %.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"172 ","pages":"Pages 309-319"},"PeriodicalIF":3.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427922","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}
Hee Eun Kim , Yun-Jeong Choi , Dong Hyun Park , Min Jung Lee , Minji Kim , Sung Jin Park , Ji Young Choi , Mi Ran Kang , Sung Hee Park , Mi-Ai Lee
{"title":"Impact of thawing methods and packaging sizes on the physicochemical and microbial quality of frozen kimchi","authors":"Hee Eun Kim , Yun-Jeong Choi , Dong Hyun Park , Min Jung Lee , Minji Kim , Sung Jin Park , Ji Young Choi , Mi Ran Kang , Sung Hee Park , Mi-Ai Lee","doi":"10.1016/j.ijrefrig.2025.02.002","DOIUrl":"10.1016/j.ijrefrig.2025.02.002","url":null,"abstract":"<div><div>The method used for thawing kimchi is crucial in determining the final quality of products made from frozen kimchi. While many studies have explored various thawing techniques, research specifically focused on the thawing process of frozen kimchi remains limited. This study investigated the effects of natural air (NT), refrigerator (RT), running water (RWT), microwave (MWT), and radio-frequency thawing (RFT) on the texture, moisture content, and biological properties of frozen kimchi. Kimchi was packaged into 100-, 200-, and 300 gram units, revealing significant differences in thawing loss, moisture content, and texture across both package sizes and thawing methods. MWT resulted in the greatest moisture loss (up to 14.36 %) and the most extensive microbial degradation, whereas RT and RFT effectively preserved moisture, texture, and bioactive compounds with minimal quality deterioration. Overall, larger package sizes were associated with increased thawing losses and decreased microbial viability across all thawing methods. These findings highlight the importance of selecting appropriate thawing techniques to maintain the quality of kimchi during frozen storage and distribution.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 68-75"},"PeriodicalIF":3.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}