Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2025.01.021
Shrikant Kol, Manoj Arya
{"title":"Withdrawal notice to: “Improving Liquid Desiccant Dehumidifiers through Square Baffle Plate Design and Nanofluid Innovation” [International Journal of Refrigeration 170 (2025) 398]","authors":"Shrikant Kol, Manoj Arya","doi":"10.1016/j.ijrefrig.2025.01.021","DOIUrl":"10.1016/j.ijrefrig.2025.01.021","url":null,"abstract":"","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Page 510"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099164","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.11.032
Junyoung Kim , Mingjie Zhu , Jinwoo Oh , James E. Braun , Eckhard A. Groll , Davide Ziviani
The chemical looping heat pump (CLHP) is a promising electrochemical heat pump technology due to high system efficiency, scalability, and use of low-to-zero Global Warming Potential (GWP) fluids. However, similar to other emerging HVAC&R technologies, there is a lack of direct comparison and discussion of economics between CLHPs and conventional vapor compression (VC) heat pumps. In this work, a generalized modeling framework to estimate the levelized cost of energy (LCOE) for space conditioning applications is used to assess the early-stage economic feasibility of CLHP. The LCOE consists of two components: levelized operating expenditures and levelized capital expenditures. These clarify the influence of key factors such as annual cooling and heating delivered and price of electricity. The simulations show that the LCOE of CLHP could be less than that of VC in the case of unit utilization of 30,000 kWh yr−1, operating current density of 0.4 A cm−2, and 30% performance improvements. This is despite the projected capital cost of CLHP is nearly 1.6 times higher than that of VC system.
{"title":"Techno-economic analysis of chemical looping heat pumps based on the levelized cost of energy","authors":"Junyoung Kim , Mingjie Zhu , Jinwoo Oh , James E. Braun , Eckhard A. Groll , Davide Ziviani","doi":"10.1016/j.ijrefrig.2024.11.032","DOIUrl":"10.1016/j.ijrefrig.2024.11.032","url":null,"abstract":"<div><div>The chemical looping heat pump (CLHP) is a promising electrochemical heat pump technology due to high system efficiency, scalability, and use of low-to-zero Global Warming Potential (GWP) fluids. However, similar to other emerging HVAC&R technologies, there is a lack of direct comparison and discussion of economics between CLHPs and conventional vapor compression (VC) heat pumps. In this work, a generalized modeling framework to estimate the levelized cost of energy (LCOE) for space conditioning applications is used to assess the early-stage economic feasibility of CLHP. The LCOE consists of two components: levelized operating expenditures and levelized capital expenditures. These clarify the influence of key factors such as annual cooling and heating delivered and price of electricity. The simulations show that the LCOE of CLHP could be less than that of VC in the case of unit utilization of <span><math><mo>></mo></math></span>30,000 kWh<span><math><msub><mrow></mrow><mrow><mtext>t</mtext></mrow></msub></math></span> yr<sup>−1</sup>, operating current density of <span><math><mo>></mo></math></span>0.4 A cm<sup>−2</sup>, and 30% performance improvements. This is despite the projected capital cost of CLHP is nearly 1.6 times higher than that of VC system.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 273-286"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099181","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.12.019
Haocheng Gong , Chuang Pan , Yuande Dai
As a new alternative working fluid of heat pump, HFO-1233 has excellent environmental performance and theoretical cycle characteristics. However, the differences in physicochemical properties between its isomers can affect the interfacial evaporation characteristics, which is of great significance for further screening of the working fluid. In this paper, the evaporation behavior of liquid films of R1233zd(E), R1233zd(Z) and R1233xf on Cu surface at 335 K was simulated by molecular dynamics method. The results show that among the three working fluids, R1233xf has the smallest Kapitza thermal resistance at the vapor-liquid interface, which is only 0.38 × 10−7 m2⋅K⋅W−1. Moreover, the surface tension and liquid interaction energy of R1233xf are the smallest, and the self-diffusion coefficient is the largest, which will accelerate the escape of R1233xf at the vapor-liquid interface. The resulting evaporation rate and heat flux are R1233xf > R1233zd(E) > R1233zd(Z). At steady state, the evaporation rate of R1233xf reaches 1240 kg⋅m−2⋅s−1, which is 1.38 times that of R1233zd(Z). Finally, the solid-liquid interaction strength of the three working fluids in the solid-like layer was studied by the solid-liquid interaction model, and it was found that R1233xf still had the smallest solid-liquid interaction force. The results explain the interfacial phase change mechanism of working fluids from the molecular-scale, providing insights for the selection of working fluids and the design of heat exchangers in high-temperature heat pumps.
{"title":"Molecular dynamics study of the evaporation of R1233zd(E) and its isomers on Cu surface","authors":"Haocheng Gong , Chuang Pan , Yuande Dai","doi":"10.1016/j.ijrefrig.2024.12.019","DOIUrl":"10.1016/j.ijrefrig.2024.12.019","url":null,"abstract":"<div><div>As a new alternative working fluid of heat pump, HFO-1233 has excellent environmental performance and theoretical cycle characteristics. However, the differences in physicochemical properties between its isomers can affect the interfacial evaporation characteristics, which is of great significance for further screening of the working fluid. In this paper, the evaporation behavior of liquid films of R1233zd(E), R1233zd(Z) and R1233xf on Cu surface at 335 K was simulated by molecular dynamics method. The results show that among the three working fluids, R1233xf has the smallest Kapitza thermal resistance at the vapor-liquid interface, which is only 0.38 × 10<sup>−7</sup> m<sup>2</sup>⋅K⋅W<sup>−1</sup>. Moreover, the surface tension and liquid interaction energy of R1233xf are the smallest, and the self-diffusion coefficient is the largest, which will accelerate the escape of R1233xf at the vapor-liquid interface. The resulting evaporation rate and heat flux are R1233xf > R1233zd(E) > R1233zd(Z). At steady state, the evaporation rate of R1233xf reaches 1240 kg⋅m<sup>−2</sup>⋅s<sup>−1</sup>, which is 1.38 times that of R1233zd(Z). Finally, the solid-liquid interaction strength of the three working fluids in the solid-like layer was studied by the solid-liquid interaction model, and it was found that R1233xf still had the smallest solid-liquid interaction force. The results explain the interfacial phase change mechanism of working fluids from the molecular-scale, providing insights for the selection of working fluids and the design of heat exchangers in high-temperature heat pumps.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 500-509"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099760","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.11.001
Shrikant Kol, Manoj Arya
This article has been withdrawn: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal).
Please note that this notice had been updated in January 2025, as follows:
This article has been withdrawn at the request of the editor and publisher.
The publisher regrets that an error occurred which led to the premature publication of this paper. This error bears no reflection on the article or its authors. The publisher apologizes to the authors and the readers for this unfortunate error.
{"title":"WITHDRAWN: Improving liquid desiccant dehumidifiers through square baffle plate design and nanofluid innovation","authors":"Shrikant Kol, Manoj Arya","doi":"10.1016/j.ijrefrig.2024.11.001","DOIUrl":"10.1016/j.ijrefrig.2024.11.001","url":null,"abstract":"<div><div>This article has been withdrawn: please see Elsevier Policy on Article Withdrawal (<span><span>https://www.elsevier.com/about/policies/article-withdrawal</span><svg><path></path></svg></span>).</div><div>Please note that this notice had been updated in January 2025, as follows:</div><div>This article has been withdrawn at the request of the editor and publisher.</div><div>The publisher regrets that an error occurred which led to the premature publication of this paper. This error bears no reflection on the article or its authors. The publisher apologizes to the authors and the readers for this unfortunate error.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Page 398"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099759","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.12.009
Shrikant Kol, Manoj Arya
Enhancing the performance of the liquid desiccant dehumidifier (LDDs) is pivotal, with mass transfer playing a significant role. Compared to the previous method, using a baffles plate improved liquid desiccant dehumidification performance. The study utilized an aqueous solution containing nanocarbon tubes (NCTs) in LiCl/H2O as the desiccant, cascading over baffles plate with a square profile. The performance of this system was determined using numerical methods. The concentrations of NCTs ranged from 0.03 % to 0.05 % by weight. Furthermore, this paper investigates the impact of nanoparticles and parameters, including flow rates, solution concentration, humidity, solution temperature, etc. on the analysis through Computational Fluid Dynamics (CFD) simulation. The study shows a 29 % increase in moisture removal and humidity change, along with a 15.57 % improvement in film thickness. These findings are underpinned by the principle of a reduced in contact angle from 57° to 29°, resulting in reduced partial pressure of water vapor from the solution, thereby enhancing the mass transfer mechanism. Consequently, the utilization of baffles plate demonstrates a significant improvement in the moisture removal performance of the LDDs.
{"title":"Improving liquid desiccant dehumidifiers through square baffle plate design and nanofluid innovation","authors":"Shrikant Kol, Manoj Arya","doi":"10.1016/j.ijrefrig.2024.12.009","DOIUrl":"10.1016/j.ijrefrig.2024.12.009","url":null,"abstract":"<div><div>Enhancing the performance of the liquid desiccant dehumidifier (LDDs) is pivotal, with mass transfer playing a significant role. Compared to the previous method, using a baffles plate improved liquid desiccant dehumidification performance. The study utilized an aqueous solution containing nanocarbon tubes (NCTs) in LiCl/H2O as the desiccant, cascading over baffles plate with a square profile. The performance of this system was determined using numerical methods. The concentrations of NCTs ranged from 0.03 % to 0.05 % by weight. Furthermore, this paper investigates the impact of nanoparticles and parameters, including flow rates, solution concentration, humidity, solution temperature, etc. on the analysis through Computational Fluid Dynamics (CFD) simulation. The study shows a 29 % increase in moisture removal and humidity change, along with a 15.57 % improvement in film thickness. These findings are underpinned by the principle of a reduced in contact angle from 57° to 29°, resulting in reduced partial pressure of water vapor from the solution, thereby enhancing the mass transfer mechanism. Consequently, the utilization of baffles plate demonstrates a significant improvement in the moisture removal performance of the LDDs.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 440-452"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099765","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.12.012
Weiyan Lu , Yuhe Shang , Yanbo Liu , Dong Li
Droplet condensation significantly impacts the heat transfer efficiency of equipment and can lead to frost formation, further exacerbating performance issues. Here, we propose a novel method for removing condensed droplets from tube surfaces using ultrasonic vibration, identifying three key processes: droplet aggregation, liquid film atomization, and liquid film shrinkage, which collectively facilitate droplet removal from the tube surface. Our analysis explores the effects of varying ultrasonic power and vibration modes on the atomization of condensation droplets. The results indicate that at a low ultrasonic power, extended vibration time improves atomization, while at higher power, periodic vibration yields superior results. Higher ultrasonic power results in a smaller axial average diameter of the droplets remaining on the tube surface. These finding provide valuable insights for enhancing heat transfer efficiency and mitigating frost formation in relevant applications.
{"title":"Enhancing condensation droplets removal on tube through periodic ultrasonic vibration","authors":"Weiyan Lu , Yuhe Shang , Yanbo Liu , Dong Li","doi":"10.1016/j.ijrefrig.2024.12.012","DOIUrl":"10.1016/j.ijrefrig.2024.12.012","url":null,"abstract":"<div><div>Droplet condensation significantly impacts the heat transfer efficiency of equipment and can lead to frost formation, further exacerbating performance issues. Here, we propose a novel method for removing condensed droplets from tube surfaces using ultrasonic vibration, identifying three key processes: droplet aggregation, liquid film atomization, and liquid film shrinkage, which collectively facilitate droplet removal from the tube surface. Our analysis explores the effects of varying ultrasonic power and vibration modes on the atomization of condensation droplets. The results indicate that at a low ultrasonic power, extended vibration time improves atomization, while at higher power, periodic vibration yields superior results. Higher ultrasonic power results in a smaller axial average diameter of the droplets remaining on the tube surface. These finding provide valuable insights for enhancing heat transfer efficiency and mitigating frost formation in relevant applications.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 412-422"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099768","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.12.005
Sangmin Ji , Sejun Park , Youngkyun Seo , Minsoo Choi , Jinkwang Lee
This study stems from the burgeoning interest in ammonia (NH3) as a green energy source, particularly for maritime applications where conventional refrigeration cycles pose both environmental and economic challenges, specifically focusing on an 88,000 m3 class Very Large Ammonia Carrier (VLAC). Two distinct refrigeration cycle concepts were evaluated for the re-liquefaction system. The optimization technique used in the study was a hybrid method that combined the SQP and BOX algorithms to optimize the system. Key process variables were set to the final compression and expansion pressures of the refrigeration cycle, which were optimized to minimize the specific energy consumption (SEC) of the systems. An economic analysis was conducted to assess the costs associated with the equipment used in both systems. The first optimized re-liquefaction system employs a vapor-compression refrigeration cycle using NH3 as the refrigerant. The thermodynamic analysis indicated energy consumption, SEC, and exergy efficiency of 112.44 kW, 0.1898 kWh/kg, and 38.31 %, respectively. The second system utilizing the Linde–Hampson refrigeration cycle demonstrated energy consumption, SEC, and exergy efficiency of 102.35 kW, 0.1728 kWh/kg, and 43.03 %, respectively. Exergy destruction within these systems was predominantly observed in the heat exchangers, accounting for 43.00 % and 51.80 % of the total exergy destruction, respectively. Economic analysis revealed that the life cycle cost (LCC) and sensitivity analysis of the re-liquefaction system using the Linde-Hampson refrigeration cycle are approximately 2.0 million USD lower than the system using the vapor compression refrigeration cycle. In conclusion, the Linde-Hampson re-liquefaction system is energy efficient and economical.
{"title":"Design and thermodynamic evaluation of onboard NH3 BOG re-liquefaction systems for ocean-going NH3 Carriers","authors":"Sangmin Ji , Sejun Park , Youngkyun Seo , Minsoo Choi , Jinkwang Lee","doi":"10.1016/j.ijrefrig.2024.12.005","DOIUrl":"10.1016/j.ijrefrig.2024.12.005","url":null,"abstract":"<div><div>This study stems from the burgeoning interest in ammonia (NH<sub>3</sub>) as a green energy source, particularly for maritime applications where conventional refrigeration cycles pose both environmental and economic challenges, specifically focusing on an 88,000 m<sup>3</sup> class Very Large Ammonia Carrier (VLAC). Two distinct refrigeration cycle concepts were evaluated for the re-liquefaction system. The optimization technique used in the study was a hybrid method that combined the SQP and BOX algorithms to optimize the system. Key process variables were set to the final compression and expansion pressures of the refrigeration cycle, which were optimized to minimize the specific energy consumption (SEC) of the systems. An economic analysis was conducted to assess the costs associated with the equipment used in both systems. The first optimized re-liquefaction system employs a vapor-compression refrigeration cycle using NH<sub>3</sub> as the refrigerant. The thermodynamic analysis indicated energy consumption, SEC, and exergy efficiency of 112.44 kW, 0.1898 kWh/kg, and 38.31 %, respectively. The second system utilizing the Linde–Hampson refrigeration cycle demonstrated energy consumption, SEC, and exergy efficiency of 102.35 kW, 0.1728 kWh/kg, and 43.03 %, respectively. Exergy destruction within these systems was predominantly observed in the heat exchangers, accounting for 43.00 % and 51.80 % of the total exergy destruction, respectively. Economic analysis revealed that the life cycle cost (LCC) and sensitivity analysis of the re-liquefaction system using the Linde-Hampson refrigeration cycle are approximately 2.0 million USD lower than the system using the vapor compression refrigeration cycle. In conclusion, the Linde-Hampson re-liquefaction system is energy efficient and economical.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 399-411"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099769","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.10.010
Alpaslan Alkan , Mehmet Akif Koç
This study used experimental data to illustrate the accuracy of artificial neural network modelling for vehicle heat pump systems. The system had a four-way valve, thermostatic expansion valves, and a fixed-capacity compressor. The system used R1234yf refrigerant instead of R134a in automotive air conditioning systems. The system was evaluated using varying compressor speeds, indoor unit intake air flow rates, interior and outdoor unit inlet air flow temperatures, and relative humidity. The experimental system was tested 72 times using different control and data-collecting technologies to determine steady-state performance and how artificial intelligence may enhance it. The projected performance parameter of the automotive heat pump system employing R1234yf refrigerant was assessed using an artificial neural network model. Six scenarios were examined: compressor discharge temperature, indoor unit output airflow temperature, refrigerant mass flow rate, compressor power, heating capacity, and performance coefficient. Data was divided into training (269 patterns, 68.27 %) and testing sets (125 patterns, 31.73 %) to ensure accurate model development and performance assessment across different experimental configurations. This approach guarantees robust data handling and reliable artificial neural network predictions. The training and testing of the artificial neural network model of the automobile heat pump system with R1234yf was evaluated. In the best case, training R² was 0.99817, MSE 0.0012, and MEP 0.005. High prediction accuracy and robust linear associations were observed with R² = 0.99969, MSE = 0.0008, and MEP = 0.003. Future vehicle heat pump research using alternative refrigerants will benefit from this study's shortened experimental techniques and system performance estimates.
{"title":"Predicting the energetic performance of an automobile heat pump utilising a fixed capacity compressor and R1234yf using ANN modelling","authors":"Alpaslan Alkan , Mehmet Akif Koç","doi":"10.1016/j.ijrefrig.2024.10.010","DOIUrl":"10.1016/j.ijrefrig.2024.10.010","url":null,"abstract":"<div><div>This study used experimental data to illustrate the accuracy of artificial neural network modelling for vehicle heat pump systems. The system had a four-way valve, thermostatic expansion valves, and a fixed-capacity compressor. The system used R1234yf refrigerant instead of R134a in automotive air conditioning systems. The system was evaluated using varying compressor speeds, indoor unit intake air flow rates, interior and outdoor unit inlet air flow temperatures, and relative humidity. The experimental system was tested 72 times using different control and data-collecting technologies to determine steady-state performance and how artificial intelligence may enhance it. The projected performance parameter of the automotive heat pump system employing R1234yf refrigerant was assessed using an artificial neural network model. Six scenarios were examined: compressor discharge temperature, indoor unit output airflow temperature, refrigerant mass flow rate, compressor power, heating capacity, and performance coefficient. Data was divided into training (269 patterns, 68.27 %) and testing sets (125 patterns, 31.73 %) to ensure accurate model development and performance assessment across different experimental configurations. This approach guarantees robust data handling and reliable artificial neural network predictions. The training and testing of the artificial neural network model of the automobile heat pump system with R1234yf was evaluated. In the best case, training R² was 0.99817, MSE 0.0012, and MEP 0.005. High prediction accuracy and robust linear associations were observed with R² = 0.99969, MSE = 0.0008, and MEP = 0.003. Future vehicle heat pump research using alternative refrigerants will benefit from this study's shortened experimental techniques and system performance estimates.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 363-384"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099162","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.11.015
Wenting Wu , Xiaoyu Cui , Wang Yin , Hejun Hui , Zhenhua Jiang , Yinong Wu , Shaoshuai Liu
Stirling-type pulse tube cryocoolers (SPTCs) working at temperatures below 8 K represent advantages in very long wave infrared detection, terahertz detection, etc. It is essential for SPTCs to obtain reasonable distribution of impedance to achieve good cooling performance. However, adjusting the distribution of impedance to an optimal value is hard as temperature decreases. It is critical for muti-stage SPTCs working at temperatures below 8 K to arrange appropriate phase shifter at each stage. This paper introduces a gas-coupled pulse tube cold finger with active piston and cold inertance tube as phase shifters for 8 K applications. The cold finger consists of pulse tube 1 (PT1) which works at liquid hydrogen temperatures and pulse tube 2 (PT2) which operates at liquid helium temperatures. Active piston is the phase shifter of PT1. It could adjust the impedance to any value theoretically under different operating conditions. The phase shifter of PT2 is cold inertance tube and gas reservoir. Cold inertance tube and gas reservoir has simple structure which makes it suitable for space applications. The impact of frequency and operating parameters of active piston on no-load temperature is investigated by experiments. A lowest no-load temperature of 5.16 K is achieved in experiments. The effect of temperature distribution of cold finger on cooling capacity at 8 K is also researched. A cooling capacity of 74 mW at 8 K can be obtained with the electric input power of 177.5 W and a pre-cooling capacity of 9.1 W/70 K.
{"title":"Experimental study of a gas-coupled pulse tube cold finger with both active piston and cold inertance tube as phase shifters for 8 K applications","authors":"Wenting Wu , Xiaoyu Cui , Wang Yin , Hejun Hui , Zhenhua Jiang , Yinong Wu , Shaoshuai Liu","doi":"10.1016/j.ijrefrig.2024.11.015","DOIUrl":"10.1016/j.ijrefrig.2024.11.015","url":null,"abstract":"<div><div>Stirling-type pulse tube cryocoolers (SPTCs) working at temperatures below 8 K represent advantages in very long wave infrared detection, terahertz detection, etc. It is essential for SPTCs to obtain reasonable distribution of impedance to achieve good cooling performance. However, adjusting the distribution of impedance to an optimal value is hard as temperature decreases. It is critical for muti-stage SPTCs working at temperatures below 8 K to arrange appropriate phase shifter at each stage. This paper introduces a gas-coupled pulse tube cold finger with active piston and cold inertance tube as phase shifters for 8 K applications. The cold finger consists of pulse tube 1 (PT1) which works at liquid hydrogen temperatures and pulse tube 2 (PT2) which operates at liquid helium temperatures. Active piston is the phase shifter of PT1. It could adjust the impedance to any value theoretically under different operating conditions. The phase shifter of PT2 is cold inertance tube and gas reservoir. Cold inertance tube and gas reservoir has simple structure which makes it suitable for space applications. The impact of frequency and operating parameters of active piston on no-load temperature is investigated by experiments. A lowest no-load temperature of 5.16 K is achieved in experiments. The effect of temperature distribution of cold finger on cooling capacity at 8 K is also researched. A cooling capacity of 74 mW at 8 K can be obtained with the electric input power of 177.5 W and a pre-cooling capacity of 9.1 W/70 K.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"170 ","pages":"Pages 249-254"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099218","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}
Pub Date : 2025-02-01DOI: 10.1016/j.ijrefrig.2024.12.004
Xiaosheng Zheng , Ji Zhang , Martin Ryhl Kærn , Stephan Kabelac , Fredrik Haglind
This paper experimentally analyzes the non-equilibrium boiling of R1234yf and R1234ze(E) utilizing quasi-local measurements in a plate heat exchanger. The corresponding mechanisms of the targeted processes were identified, and the influence of crucial parameters on the heat transfer performance was explored. Guidelines with respect to the selection of heat transfer correlations for the boiling heat transfer with inlet subcooling are provided. A database containing 270 quasi-local experimental data points was established and used to evaluate the predictive performance of the previous heat transfer models. In addition, new prediction methods are proposed for the subcooled boiling, saturated two-phase, superheating, and preheating regions, respectively. The local measurements are collected at various boiling pressures (0.9 MPa to 1.3 MPa), refrigerant mass fluxes (9 kg∙m-2∙s-1 to 15.6 kg∙m-2∙s-1), inlet subcooling degrees (8.1 K to 31 K), and heat fluxes (0.4 kW∙m-2 to 44.1 kW∙m-2). The results suggest that during high mass flux and moderate inlet subcooling and conditions, more than 23 % of the evaporator's heat transfer area constitutes subcooled boiling. The new prediction methods provide fair predictability, with a deviation of 15 % for the subcooled boiling correlation, 18 % for the two-phase correlation, 16 % for the superheating correlation, and 18 % for the preheating correlation, respectively. The accuracies of the new models are improved by more than 6 %-points compared to the existing prediction methods.
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