International Journal of Refrigeration-revue Internationale Du Froid最新文献_第4页

Detailed study of a condensation-driven dilution refrigerator reaching below 50 mK

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-14 DOI: 10.1016/j.ijrefrig.2025.02.016

Weijun Cheng , Zhiheng Li , Yanan Wang , Wei Dai

{"title":"Detailed study of a condensation-driven dilution refrigerator reaching below 50 mK","authors":"Weijun Cheng , Zhiheng Li , Yanan Wang , Wei Dai","doi":"10.1016/j.ijrefrig.2025.02.016","DOIUrl":"10.1016/j.ijrefrig.2025.02.016","url":null,"abstract":"<div><div>The condensation-driven dilution refrigerator employs a condensation pump to accomplish the circulation of <sup>3</sup>He, offering advantages such as compactness, lightweight, and low cost. In our previous work, we constructed a prototype with a lowest temperature of around 60 mK, yet the system performance needs further improvement. In this paper, we present our latest advances. By adding a step heat exchanger made from sintered silver powder and reducing heat leakage in the system, a lowest temperature of 45 mK, a maximum cooling power of 8.4 μW @100 mK, and a corresponding thermodynamic degree of perfection of 11.28 % is achieved in the experiments. A comprehensive numerical model of the condensation-driven dilution refrigerator has been developed. The results of experiments and simulations are compared and analyzed, revealing the influence of key parameters on the system performance. Firstly, the efficiency is significantly related to the temperature of the mixing chamber, still, and condensation pump. The entropy generation analysis is conducted, and it is found that the contribution of the still to the total entropy production always remains predominant. Secondly, to circulate the <sup>3</sup>He, the vapor pressure above the still should be greater than the saturated vapor pressure corresponding to the condensation pump temperature. This imposes a requirement on both the still and condensation pump temperatures to activate the dilution cycle with a certain mixing chamber temperature. Finally, the comparison between the experiments and simulations indicates a maximum cooling power exists at a certain high still temperature as the other conditions are kept the same. With the help of the simulation, the internal dynamic and thermodynamic characteristics during operation have been clarified, which can guide further optimizations.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 201-211"},"PeriodicalIF":3.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487556","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

Thermodynamic and environment analysis of a modified transcritical CO2 refrigeration cycle integrated with ejector and subcooler

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-13 DOI: 10.1016/j.ijrefrig.2025.02.012

Lingeng Zou , Ye Liu , Jianlin Yu

{"title":"Thermodynamic and environment analysis of a modified transcritical CO2 refrigeration cycle integrated with ejector and subcooler","authors":"Lingeng Zou , Ye Liu , Jianlin Yu","doi":"10.1016/j.ijrefrig.2025.02.012","DOIUrl":"10.1016/j.ijrefrig.2025.02.012","url":null,"abstract":"<div><div>The traditional transcritical CO<sub>2</sub> two-stage compression refrigeration cycle (TTRC) has a great advantage in supermarket refrigeration applications. Currently, however, the performance of the TTRC still has the potential to be improved. In this paper, an ejector-enhanced transcritical two-stage compression CO<sub>2</sub> cycle is presented for supermarket refrigeration application. Based on the basic TTRC with a subcooler, a flash tank, an ejector and are introduced. On the one hand, part of the expansion work can be recovered by the ejector. Moreover, the subcooler is employed to increase the subcooling degree of refrigerant entering the expansion valve, which could increase the evaporator's cooling capacity. The cycle performances of the cycles are theoretically studied by energy, exergy and carbon footprint evaluation. Meanwhile, the intermediate pressures of the two cycles are also optimized. Under optimum intermediate pressure, the energy analyses show that the coefficient of performance is improved by 9.6–11.0% and the volume cooling capacity is enhanced by 14.5%-18.4% with the modified cycle. Moreover, the exergy analysis indicates that the expansion valves account for 27.1% of the exergy destruction of the basic cycle, while it is just 7.51% for the modified cycle. The carbon footprint analysis shows that the modified system with CO<sub>2</sub> refrigerant could reduce carbon emissions by 17.95% compared to the conventional refrigerant R404A. It shows the feasibility of using CO<sub>2</sub> to replace R404A refrigerant in commercial supermarket refrigeration, and has significant eco-friendly benefits.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 123-138"},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445710","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

Dynamic synergy optimization (DSO): An integrated approach of metaheuristic algorithms and PID control for real-time stability enhancement in refrigeration systems

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-13 DOI: 10.1016/j.ijrefrig.2025.02.015

Jieyu Li, Xingxiang Xie, Leyang Dai, Lijie Xu

{"title":"Dynamic synergy optimization (DSO): An integrated approach of metaheuristic algorithms and PID control for real-time stability enhancement in refrigeration systems","authors":"Jieyu Li, Xingxiang Xie, Leyang Dai, Lijie Xu","doi":"10.1016/j.ijrefrig.2025.02.015","DOIUrl":"10.1016/j.ijrefrig.2025.02.015","url":null,"abstract":"<div><div>With increasing global energy demand, improving the efficiency of refrigeration systems and reducing their environmental impact is crucial, especially since refrigeration often accounts for a significant portion of energy consumption. Traditional Proportional-Integral-Derivative (PID) control methods struggle with the complex, nonlinear nature of refrigeration systems, resulting in slow response times and limited optimization capabilities. While metaheuristic algorithms can perform global searches, they often lack the real-time fine-tuning necessary for optimal dynamic control. This study introduces Dynamic Synergy Optimization (DSO), a novel framework that integrates metaheuristic algorithms with PID control. Unlike conventional methods that only turn PID parameters using metaheuristics, DSO combines the global optimization power of metaheuristics with the real-time adjustment capabilities of PID, providing effective global search and local refinement. The PID controller ensures quick adaptation and system stability. Experimental results show that the Harris Hawks Optimization algorithm integrated with PID control outperforms standard PID control with a 63.3 % reduction in response time, a 69.2 % decrease in stabilization time, and a 19.65 % enhancement in energy efficiency. The DSO strategy significantly enhances the dynamic response and stability of refrigeration systems, reduces hysteresis, and accelerates the attainment of steady-state operation.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 100-110"},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438189","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

Research of CO2 high temperature heat pump for industrial steam generation with data center heat source

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-13 DOI: 10.1016/j.ijrefrig.2025.02.014

Junbin Chen, Cong Guo , Chunyu Feng, Xiao Qu, Sicong Tan, Yuyan Jiang

{"title":"Research of CO2 high temperature heat pump for industrial steam generation with data center heat source","authors":"Junbin Chen, Cong Guo , Chunyu Feng, Xiao Qu, Sicong Tan, Yuyan Jiang","doi":"10.1016/j.ijrefrig.2025.02.014","DOIUrl":"10.1016/j.ijrefrig.2025.02.014","url":null,"abstract":"<div><div>The solution of integrating large-scale high-temperature heat pump (HTHP) with data center not only reduces carbon emissions but also enhances energy efficiency, aligning with dual-carbon goals. However, pressure ratios and environmentally friendly refrigerants limit the conventional HTHPs. Therefore, this paper proposes an improved transcritical CO<sub>2</sub> HTHP steam system (CO<sub>2</sub>-NC) with dual-pressure gas coolers and expander. Detailed thermodynamic analysis, exergy analysis, and economic analysis are conducted to evaluate the cycle performance. Compared to the conventional CO<sub>2</sub> cycle, the COP of CO<sub>2</sub>-NC is improved by 32.7 %, and the pressure ratio is reduced by 13.22 %, with a 110 °C saturated steam supply. With the superior thermal matching performance of dual-pressure gas coolers, the irreversible loss of gas coolers in CO<sub>2</sub>-NC is diminished by 75.89 %. The total pressure ratio of CO<sub>2</sub>-NC is less than 1/4 of that in the conventional cycles with HFC/HFO refrigerants, providing an advantage in large-scale HTHPs with centrifugal compressors. Exergy analysis highlights that the expander in the CO<sub>2</sub>-NC decreases irreversible losses in the expansion process by 81.27 %. CO<sub>2</sub>-NC with the least variation in COP and pressure ratio shows excellent adaptability to data center heat sources, and CO<sub>2</sub>-NC exhibits the least variation with changes in saturated steam temperature. Furthermore, the optimum compressor discharge pressure for CO<sub>2</sub> HTHPs is analyzed. Economic analysis highlights the advantages of CO<sub>2</sub>-NC in operation and refrigerant costs with the constraints of high initial capital costs. This study emphasizes the potential of combining transcritical CO<sub>2</sub> HTHP to fulfill data center cooling and industrial heating needs.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 185-200"},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464623","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 assessment of two-phase nozzle performance for low-GWP refrigerants

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-12 DOI: 10.1016/j.ijrefrig.2025.02.008

Paweł Jakończuk, Kamil Śmierciew, Adam Dudar, Jerzy Gagan, Dariusz Butrymowicz

{"title":"Experimental assessment of two-phase nozzle performance for low-GWP refrigerants","authors":"Paweł Jakończuk, Kamil Śmierciew, Adam Dudar, Jerzy Gagan, Dariusz Butrymowicz","doi":"10.1016/j.ijrefrig.2025.02.008","DOIUrl":"10.1016/j.ijrefrig.2025.02.008","url":null,"abstract":"<div><div>The performance of two-phase ejectors critically depends on the efficiency of motive nozzles, which govern the critical mass flow rate and overall system operation. However, accurately predicting nozzle performance under two-phase flow conditions remains challenging due to the complex interplay of thermodynamic and flow dynamics. This study addresses this issue by evaluating the performance coefficient of motive nozzles for three refrigerants: CO<sub>2</sub>, R600a, and R1234ze(E). Beyond ejector applications, understanding two-phase flow dynamics is essential for optimizing other key components, such as control valves and safety valves, which operate under similar conditions. Experiments conducted on a versatile test bench revealed significant differences in nozzle performance among the refrigerants. The performance coefficient ranged from 0.85 to 1.35 for CO<sub>2</sub>, 0.90 to 1.15 for R600a, and 0.92 to 1.22 for R1234ze(E). The Henry-Fauske model, used to predict critical mass flow, demonstrated an average deviation of 30 % for CO<sub>2</sub>, while deviations were much lower for R600a (9 %) and R1234ze(E) (4 %). The results highlight the sensitivity of the performance coefficient to the refrigerant thermodynamic properties, with CO<sub>2</sub> exhibiting the most complex flow behavior due to its lower critical temperature and higher compressibility. This study provides quantitative insights into the performance of motive nozzles under two-phase flow and validates the applicability of simplified models for predicting critical flow rates. The findings contribute to optimizing ejector and valve design, emphasizing the need for further validation with additional refrigerants to enhance model universality.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"173 ","pages":"Pages 111-122"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445764","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

Sensor fault detection, diagnosis, and data reconstruction strategy for chiller based on an improved tree-based pipeline optimization tool framework

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-12 DOI: 10.1016/j.ijrefrig.2025.02.013

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}

引用次数: 0

Flow distribution characteristics of gravity- and pump-driven CO2 two-phase thermosyphon loops with three evaporators

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-12 DOI: 10.1016/j.ijrefrig.2025.02.011

Zhen Tong , Peng Wang , Zekun Han , Wencheng Wang

{"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}

引用次数: 0

A sustainable cooling solution for machining: Internally cooled toolholder enhanced by nanorefrigerants and electrohydrodynamic effect

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-12 DOI: 10.1016/j.ijrefrig.2025.02.010

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}

引用次数: 0

Theoretical and experimental analysis of heat storage material integration in household refrigerators

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-11 DOI: 10.1016/j.ijrefrig.2025.02.007

Joel Boeng , Joaquim Manoel Gonçalves

{"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}

引用次数: 0

Numerical and experimental evaluation of the thermal and dynamic performance of a phase change material in an indirect solar dryer

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2025-02-10 DOI: 10.1016/j.ijrefrig.2025.02.006

Dounia CHAATOUF, Mourad SALHI, Abir Bria, Benyounes RAILLANI, Samir AMRAQUI, Ahmed MEZRHAB

{"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}

引用次数: 0