International Journal of Refrigeration-revue Internationale Du Froid最新文献_第8页

1D models of an active magnetic regeneration cycle for cryogenic applications 低温应用中主动磁再生循环的一维模型

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-20 DOI: 10.1016/j.ijrefrig.2024.08.011

{"title":"1D models of an active magnetic regeneration cycle for cryogenic applications","authors":"","doi":"10.1016/j.ijrefrig.2024.08.011","DOIUrl":"10.1016/j.ijrefrig.2024.08.011","url":null,"abstract":"<div><p>In investigation of an active magnetic regenerator (AMR) cycle operating at room temperatures, 1D models have been extensively used to accurately computing its performance metrics. However, extending these models to simulate an AMR cycle at cryogenic temperatures introduces inherent complexities and challenges. The broad temperature span and low operating temperatures required for cryogenic applications, such as hydrogen liquefaction, lead to significant density variations of the working fluid within the AMR that cannot be overlooked. In this work, two 1D AMR models assuming a compressible working fluid operating at cryogenic temperatures are demonstrated which address the large density variations and the numerical stiffness of the equations. The models exhibit good agreement with experimental and 2D numerical results of an AMR configuration designed for hydrogen liquefaction. A comparative study is conducted between the developed models and an incompressible AMR model at cryogenic temperatures shows that the incompressible model predicts cooling powers that are higher by a factor of up to 10 at high values of utilization, highlighting the error of assuming an incompressible fluid on estimating the performance metrics.</p></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142039620","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

Simplifying bidisperse pore diffusion model for adsorbent felt 简化吸附剂毡的双分散孔隙扩散模型

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-20 DOI: 10.1016/j.ijrefrig.2024.08.009

引用次数: 0

Simulation study of a novel phase change cooling garment for electricians in a high-temperature environment 高温环境下电工用新型相变冷却服装的模拟研究

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-19 DOI: 10.1016/j.ijrefrig.2024.08.013

{"title":"Simulation study of a novel phase change cooling garment for electricians in a high-temperature environment","authors":"","doi":"10.1016/j.ijrefrig.2024.08.013","DOIUrl":"10.1016/j.ijrefrig.2024.08.013","url":null,"abstract":"<div><p>To mitigate the effects of heat stress on electricians during outdoor activities such as inspection, circuit repair, and daily maintenance in high-temperature environments, a novel design for a portable, efficient, and ergonomic phase change cooling garment is presented. First, the optimal phase change material is selected considering economic and environmental factors. Then, based on the heat balance equation of the human body and Fourier's law, the required phase change material mass and the optimal thickness of the retarded heat-absorbing layer are obtained and verified by numerical simulations and experiments. The results indicate that in a high-temperature environment of 38 °C for 2 h, electricians require 2.39 kg of phase change material. To meet the protective duration requirements of electricians' daily tasks, the optimal thickness of the phase change material is 8 mm, and the optimal thickness of the slow-release heat absorption layer is 3 mm. The results of this study have significant implications for the safety and protection of electricians in high-temperature environments. It aims to provide theoretical guidance for the design and innovation of personal cooling garments for electricians.</p></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239277","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

Relative cooling power modeling of RE2TM2Y ternary intermetallic rare-earth-based magnetocaloric compounds for magnetic refrigeration application using extreme learning machine and hybrid intelligent method 利用极端学习机和混合智能方法为 RE2TM2Y 三元金属间稀土基磁致化合物建立磁制冷应用的相对制冷功率模型

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-15 DOI: 10.1016/j.ijrefrig.2024.08.010

{"title":"Relative cooling power modeling of RE2TM2Y ternary intermetallic rare-earth-based magnetocaloric compounds for magnetic refrigeration application using extreme learning machine and hybrid intelligent method","authors":"","doi":"10.1016/j.ijrefrig.2024.08.010","DOIUrl":"10.1016/j.ijrefrig.2024.08.010","url":null,"abstract":"<div><div>Ternary intermetallic rare-earth-based magnetocaloric compounds (RE<sub>2</sub>TM<sub>2</sub>Y, where RE = Gd, Tb, Dy, Ho, Er, Tm, TM= Ni, Cu, Co and <em>Y</em> = Sn, In, Cd, Ga, Al) have attracted attention lately as magnetic refrigerants in addressing major concerns of the conventional system of refrigeration. Assessment of the amount of heat transferred between cold and hot reservoirs at varying applied magnetic fields through relative cooling power (RCP) determination is costly and experimentally intensive which calls for predictive computational techniques with characteristic precision. In this contribution, intelligent-based predictive models are developed through sine activation function-based extreme learning machine (SELM) and genetically optimized support vector regression (GSVR) with Gaussian (GU) and polynomial (PY) kernel functions for data mapping and transformation using applied magnetic field and ionic radii of the constituent elements as descriptors. The GU-GSVR model exhibits superior performance compared to both the PY-GSVR and SELM models when validated using a testing set of ternary intermetallic rare-earth-based magnetocaloric compounds with improvement of 10.55% and 2.28%, respectively using correlation coefficient (CC) as assessment parameter. During model validation, the developed GU-GSVR also showcases enhanced performance across additional performance metrics, including root mean square error (RMSE) and mean absolute error (MAE). The impact of externally applied magnetic field on the RCP of different ternary intermetallic rare-earth-based magnetocaloric compounds was examined by utilizing the developed GU-GSVR model. The characteristic precision and accuracy of the developed computational intelligent models would enable adequate as well as comprehensive investigation of ternary intermetallic rare-earth-based magnetocaloric compounds for a clean system of refrigeration.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264526","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 validation of RE170 / R600 (Dimethyl Ether / Butane) mixture as a superior refrigerant compared to R600a (Isobutane) 实验验证 RE170/R600（二甲醚/丁烷）混合物是一种优于 R600a（异丁烷）的制冷剂

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-14 DOI: 10.1016/j.ijrefrig.2024.08.008

{"title":"Experimental validation of RE170 / R600 (Dimethyl Ether / Butane) mixture as a superior refrigerant compared to R600a (Isobutane)","authors":"","doi":"10.1016/j.ijrefrig.2024.08.008","DOIUrl":"10.1016/j.ijrefrig.2024.08.008","url":null,"abstract":"<div><div>Isobutane (R600a) is the most used refrigerant for low-capacity refrigeration systems, as it combines excellent environmental properties and offers good energy performance. A real possibility to increase the efficiency of these systems is using new refrigerant mixtures offering energy improvements (being compatible with existing systems). This work, from an experimental perspective, proposes mixtures of dimethyl ether and butane (RE170/R600) as potential drop-in refrigerants of R600a systems. For a given operating condition, the energy performance of RE170/R600 mixtures with maximum proportion of 27.5 % of RE170 has been tested using a water-to-water single-stage compression cycle, measuring COP increments from 10.1 to 17.6 % in relation to R600a. Then, the blend RE170/R600 (15/85 %), considered as the potential drop-in fluid of R600a, has been tested in a wide range of operating conditions, concluding that it offers the same cooling capacity than R600a but with COP increments from 12.6 % to 17.6 %.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0140700724002822/pdfft?md5=c1ce2ba429bbb5bc2f29e787ee6ef494&pid=1-s2.0-S0140700724002822-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312538","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}

引用次数: 0

A high efficiency rooftop air conditioning system using multi-speed compressors 使用多速压缩机的高效屋顶空调系统

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-12 DOI: 10.1016/j.ijrefrig.2024.07.024

{"title":"A high efficiency rooftop air conditioning system using multi-speed compressors","authors":"","doi":"10.1016/j.ijrefrig.2024.07.024","DOIUrl":"10.1016/j.ijrefrig.2024.07.024","url":null,"abstract":"<div><p>This study delineates a meticulous exploration of technologies to enhance the energy efficiency of rooftop air conditioning units, employing the DOE/ORNL heat pump design model for comprehensive engineering design and optimization. A baseline rooftop air conditioning unit, featuring a 13 ton (45.7 kW) cooling capacity and a 17.9 integrated energy efficiency ratio, served as the point of departure for substantive efficiency enhancements. Key modifications included the consolidation of two refrigerant circuits into one, integrating three parallel 2-stage (dual-speed) compressors, fan replacements with high-efficiency substitutes. Notably, a lower global warming potential refrigerant, R452B, was evaluated as a substitute for R-410A, demonstrating better performance in the lab prototype. The achieved measured integrated energy efficiency ratio of 21.4 in the lab prototype surpassed the baseline integrated energy efficiency ratio. Comparative evaluations between R410A and R452B indicated heightened efficiency with the latter, showcasing a lab-demonstrated integrated energy efficiency ratio of 22.4 at the rated capacity of 13.8 ton (48.5 kW) and 23.9 integrated energy efficiency ratio at the rated capacity of 10 ton (35.2 kW). This research underscores the successful development of a rigorous, energy efficient rooftop air conditioning unit prototype with noteworthy environmental and economic implications.</p></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985115","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

Overview of a newly-installed high-temperature heat pump demonstrator coupled with high-temperature mine thermal energy storage 新安装的高温热泵示范装置与高温矿井热能储存装置概览

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-08 DOI: 10.1016/j.ijrefrig.2024.08.002

{"title":"Overview of a newly-installed high-temperature heat pump demonstrator coupled with high-temperature mine thermal energy storage","authors":"","doi":"10.1016/j.ijrefrig.2024.08.002","DOIUrl":"10.1016/j.ijrefrig.2024.08.002","url":null,"abstract":"<div><p>The research aims to prove that renewable energy sources in the heating sector can enable the energy transition towards European and German CO<sub>2</sub> reduction targets.</p><p>To do so, at the premises of the Fraunhofer IEG Institute in Bochum a demonstrator for high-temperature heat pumps (HTHPs), coupled with seasonal high-temperature mine thermal energy storage (MTES), was developed.</p><p>The goal is achieved by demonstrating the feasibility of the technology by connecting mine water present in a small flooded coal colliery (MTES) to solar parabolic trough collectors (SPTCs) and also to a HTHP system that serves the local district heating (DH) grid of Bochum south.</p><p>The MTES, with an estimated water volume of approximately 20000 m<sup>3</sup> is employed as seasonal storage for a 500 kW HTHP system that can reach a supply temperature of 120°C, as needed by the existing DH grid when the ambient temperature is lower or equal to -10°C.</p><p>During the summer operation, the heat is injected into the MTES from the SPTCs to obtain a mine water temperature of 60°C; and in the winter operation, the heat is extracted through the HTHP until the mine water reaches the unheated temperature of 12°C at the end of the heating season.</p><p>A literature review of the main components of the plant, the description of the installed system parts and performed tests are reported, along with the results of the successfully executed tests.</p></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0140700724002706/pdfft?md5=8bd13f34fa4a473178ad7788989d99e8&pid=1-s2.0-S0140700724002706-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142128729","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}

引用次数: 0

Investigation on the flow characteristics through different discharge port in scroll compressor for electric vehicles 电动汽车涡旋式压缩机不同排气口的流动特性研究

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-06 DOI: 10.1016/j.ijrefrig.2024.08.003

{"title":"Investigation on the flow characteristics through different discharge port in scroll compressor for electric vehicles","authors":"","doi":"10.1016/j.ijrefrig.2024.08.003","DOIUrl":"10.1016/j.ijrefrig.2024.08.003","url":null,"abstract":"<div><div>Scroll compressor with short scroll profile length shows great potential in electric vehicles for its compact structure and better reliability, while shorter scroll profile results in less compression time and under-compression in most cases. To investigate the influence of discharge port structure on compressor performance, a three-dimensional transient model of scroll compressor for electric vehicle is established. The theoretical and experimental results exhibit good consistency within a deviation of 9.5 %. With this validated model, the effects of discharge port size and shape on compressor performance are studied respectively. When the circular discharge port diameter increases from 5.2 mm to 9.0 mm, the power consumption and discharge temperature can be reduced respectively by 5.82 % and 5.29 %. The discharge mass flow rate can be promoted by 1.09 %. The discharge pressure fluctuation and imbalance between the upside and downside chambers enhanced obviously. To further improve the discharge flow characteristics, different discharge port shapes were employed including waist-shaped, arc-shaped and composite-shaped port. Compared with 5.2 mm circular port, the power consumption with composite-shaped port reduces by 5.81 % and mass flow grows by 1.26 %. Results indicated changes in discharge port structure parameters have greater influence on power consumption rather than mass flow rate.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264659","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 water vapor sorption performance of metal organic frameworks and their application potential for indoor air dehumidification 金属有机框架的水蒸气吸附性能实验研究及其在室内空气除湿中的应用潜力

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-06 DOI: 10.1016/j.ijrefrig.2024.08.007

引用次数: 0

Comparative analysis of entropy generation in smooth and micro-fin tubes using R513A refrigerant: A parametric study 使用 R513A 制冷剂的光滑管和微翅管中熵产生的比较分析：参数研究

IF 3.5 2区工程技术

International Journal of Refrigeration-revue Internationale Du Froid Pub Date : 2024-08-06 DOI: 10.1016/j.ijrefrig.2024.08.004

{"title":"Comparative analysis of entropy generation in smooth and micro-fin tubes using R513A refrigerant: A parametric study","authors":"","doi":"10.1016/j.ijrefrig.2024.08.004","DOIUrl":"10.1016/j.ijrefrig.2024.08.004","url":null,"abstract":"<div><div>Currently, although significant advancements have been made in understanding heat transfer coefficients and pressure decreases in different tube shapes, there is still a noticeable lack of detailed studies on the generation of entropy under flow boiling conditions. In this work, the entropy generation in micro-fin tubes (MFT1 and MFT2) and smooth tubes (ST1 and ST2) in flow boiling conditions experimentally investigated with refrigerant R513A. Research focused on evaluating influence of different input parameters on entropy generation, specifically contribution of heat transfer coefficient (HTC) and total pressure drop (TPD) on entropy generation for all testing tubes. As at a heat flux of 6 kW·<em>m</em><sup>−</sup>² and a saturation temperature of 12 °C, MFT1 shows HTC contributions to entropy generation ranging from 0.032 to 0.156 W·<em>K</em><sup>−1</sup>, while MFT2 ranges from 0.03 to 0.14 W·<em>K</em><sup>−1</sup>. TPD contributions for both MFT1 and MFT2 range from 0.001 to 0.04 W·<em>K</em><sup>−1</sup>. Hence, MFT2 shows better results than MFT1 as low entropy generation required for a good heat exchanger. Among input parameters, heat flux displays the highest sensitivity, indicating its significant influence on total entropy generation variations, while vapor quality, mass flux, and saturation temperature also demonstrate notable sensitivity. This research helps us design systems that transfer heat more effectively while using less energy. Understanding these factors can lead to more efficient heat exchangers and other thermal systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264529","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