International Journal of Refrigeration-revue Internationale Du Froid最新文献

{"title":"Improving thermal energy efficiency in a Norwegian dairy utilising integrated CO2 refrigeration systems: performance data and energy efficiency improvement possibilities","authors":"Lukas KÖSTER ,&nbsp;Jan BENGSCH ,&nbsp;Kristina Norne WIDELL","doi":"10.1016/j.ijrefrig.2025.10.001","DOIUrl":"10.1016/j.ijrefrig.2025.10.001","url":null,"abstract":"<div><div>Dairies are considered very energy intensive due to the high demand for thermal energy at different temperature levels. This study investigates the thermal energy demand of the largest organic dairy in central Norway, which utilises a fully integrated CO₂ refrigeration system to cover their cooling and hot water demand and an electric steam boiler for pasteurisation, sterilisation and cleaning in place (CIP). The specific energy flows of 2024 were analysed monthly and thermal demand profiles created. The specific energy consumptions were found to be between 27.5 Wh/l to 43.0 Wh/l for cooling and 34.3 Wh/l and 48.4 Wh/l for hot water heating. The electric steam boiler accounted for 36.4% of the plant’s electricity consumption in 2024. Therewith, the study aims to present real world data of the (thermal) energy consumption of a dairy and thereby lay ground for further system developments, which are conceptualised in this paper.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 564-571"},"PeriodicalIF":3.8,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266765","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":"Off-design modeling of gas turbines integrated with reverse Brayton refrigeration cycle for inlet air cooling","authors":"Navid Sharifi","doi":"10.1016/j.ijrefrig.2025.09.032","DOIUrl":"10.1016/j.ijrefrig.2025.09.032","url":null,"abstract":"<div><div>This study develops and validates an off-design simulation framework for a gas turbine integrated with a reverse Brayton refrigeration cycle (RBC) for inlet air cooling. Compressed air is extracted from intermediate compressor stages and cooled before expansion to pre-cool the gas turbine inlet air stream, with the model accounting for off-design compressor performance, ambient conditions, humidity, and latent heat effects. Validation against published data shows close agreement in compressor relative power output and relative heat output across varying extraction ratios. Results demonstrate that integrating the RBC with the gas turbine power cycle significantly enhances performance characteristics under warm and humid conditions. Cooling capacity consistently increases with ambient temperature, rising by over 50% at high humidity levels compared with low-temperature conditions. Efficiency improvements also grow with temperature, with the divergence between cooled and uncooled cycles reaching up to 30% under hot and humid conditions. Optimal extraction pressure ratios (π_ext ≈ 3) and tuned extraction ratios (ER ≈ 0.25 to 0.5) provide sufficient cooling while balancing compressor work, resulting in reduced specific fuel consumption. Net power output similarly benefits from RBC integration, with relative gains increasing with ambient temperature and humidity, reaching improvements exceeding 40% under extreme climate conditions. These trends highlight that the combined effects of high temperature and humidity amplify cooling demands, making inlet air cooling increasingly advantageous. Overall, the study confirms that careful adjustment of extraction parameters enables substantial gains in cooling capacity, cycle efficiency, and net power output, providing a validated framework for optimizing RBC-gas turbine integration in challenging ambient environments.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 548-563"},"PeriodicalIF":3.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266767","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":"Effect of the discharge valve thickness and lift on the performance of the oil-free linear compressor in R134a refrigeration system","authors":"Jiale Ma ,&nbsp;Xi Chen ,&nbsp;Qun Wang","doi":"10.1016/j.ijrefrig.2025.09.031","DOIUrl":"10.1016/j.ijrefrig.2025.09.031","url":null,"abstract":"<div><div>As the core component of the linear compressor, the discharge valve has a significant impact on its reliability and efficiency. Therefore, studying the influence of the key parameters of discharge valve on the linear compressor is indispensable for improving the compressor efficiency and refrigeration performance. A test system based on the laboratory's independently developed linear compressor for small refrigeration equipment was established to investigate the effects of the discharge valve thickness and lift on the volumetric efficiency, cooling capacity, and COP of the linear compressor. The transient pressure in the compression chamber was measured, and a piston stroke calculation model based on analyzing the compression chamber pressure was constructed. The dynamic characteristics of the discharge valve were analyzed using fluid-structure interaction, and its key parameters were optimized. The experimental and simulation results indicated that the volumetric efficiency and refrigeration performance with the discharge valve thickness of 0.1 mm, 0.2 mm and the discharge valve lift of 0.6 mm are the prime. This research provides valuable guidance for the optimal design of the small refrigeration linear compressor.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 426-436"},"PeriodicalIF":3.8,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217339","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":"Optimization of heat transfer mechanisms in elastocaloric cooling systems","authors":"Het Mevada ,&nbsp;Yunho Hwang ,&nbsp;Ichiro Takeuchi","doi":"10.1016/j.ijrefrig.2025.09.022","DOIUrl":"10.1016/j.ijrefrig.2025.09.022","url":null,"abstract":"<div><div>Elastocaloric cooling has swiftly emerged as a promising cutting-edge solid-state cooling technology, offering environmentally friendly and efficient alternatives to conventional cooling systems. To enhance the performance of the elastocaloric cooling system, the primary strategy involves increasing the operational frequency and specific heat transfer area. This study investigates the heat transfer mechanisms within the elastocaloric regenerator, focusing on the time scales associated with different heat transfer modes, namely conduction and convection. A novel non-dimensional design variable, thermal utilization ratio (<em>Z*</em>), is introduced to evaluate the performance of elastocaloric systems. Using a numerical model, the cooling capacity and temperature lift of a tubular NiTi elastocaloric cooling system were optimized with respect to <em>Z*</em>. Additionally, the effect of the optimized <em>Z*</em> parameter for the elastocaloric system was studied by simulating different materials and geometries. This analysis provided a relation between the optimum value of <em>Z*</em> for different elastocaloric materials and geometries, providing critical insight into the selection of design parameters for maximizing the performance of elastocaloric cooling systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 407-415"},"PeriodicalIF":3.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217245","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":"A procedure for rating the seasonal coefficient of performance of heat pump dishwashers using a minimum dataset","authors":"Leonardo Kerbes ,&nbsp;Alexsandro S. Silveira ,&nbsp;Adriano F. Ronzoni ,&nbsp;Christian J.L. Hermes","doi":"10.1016/j.ijrefrig.2025.09.030","DOIUrl":"10.1016/j.ijrefrig.2025.09.030","url":null,"abstract":"<div><div>The present work is aimed at mapping the thermodynamic performance of a dishwasher operating in the so-called ‘Ecomode’, where the heating is provided exclusively by a heat pump, in accordance with the requirements of the IEC 60436 standard. Tests were carried out in a climate chamber that allows strict control of the surrounding air temperature. In addition, an auxiliary rig was built to control the dishwasher water supply temperature. Initially, a test matrix was proposed for screening the appliance performance in a broad envelope of operating conditions for a given washing load. Later, the test matrix was reduced to get the most out of the standardized tests with a minimum set of data. To this end, a simplified mathematical approach was put forward to reduce the experimental data to come out with key system parameters, such as the thermal conductance and capacitance of the washing cabinet, and the seasonal heat pump coefficient of performance (<em>SCOP</em>), which cannot be easily obtained by means of direct measurements.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 485-493"},"PeriodicalIF":3.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217254","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":"Frost-EffNet: A deep learning model for frost detection in refrigeration systems","authors":"Mussawir Ul Mehmood ,&nbsp;Hammad Ur Rahman ,&nbsp;Demet Baldan Desdemir ,&nbsp;Ismail Lazoglu","doi":"10.1016/j.ijrefrig.2025.09.029","DOIUrl":"10.1016/j.ijrefrig.2025.09.029","url":null,"abstract":"<div><div>Frost accumulation on the heat exchange units in refrigeration systems significantly impairs performance by restricting airflow, leading to increased power consumption. Despite its impact, the accurate and timely detection of frost buildup remains a challenging task, hindering the efficient initiation and control of defrost mechanisms. This study introduces Frost-EffNet, an innovative model to predict frost accumulation on refrigeration unit evaporator coils. Frost-EffNet is a modified version of the EfficientNet architecture. The model was validated using five distinct EfficientNet variants, with performance evaluated on a dataset of evaporator coil images. Comparative analysis was conducted by varying key hyperparameters to identify the optimal configuration for the best-performing model. Additionally, Grad-CAM (Gradient-weighted Class Activation Mapping) analysis was employed to highlight the areas of the evaporator coil that the model focused on for frost estimation, providing valuable insights into the model’s decision-making process. The proposed Frost-EffNet model demonstrated high predictive accuracy, achieving 92.47 % accuracy on the test dataset, with a mean absolute error (MAE) of 0.11 mm. A comparative performance analysis revealed that Frost-EffNet outperforms other convolutional neural network (CNN) models in terms of accuracy, while also being computationally more efficient.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 416-425"},"PeriodicalIF":3.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217338","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 R744-hydrocarbon blends in a two-stage refrigeration cycle for transport applications","authors":"William Ferretto,&nbsp;Chiara D’Ignazi,&nbsp;Igor Matteo Carraretto,&nbsp;Luca Molinaroli","doi":"10.1016/j.ijrefrig.2025.09.024","DOIUrl":"10.1016/j.ijrefrig.2025.09.024","url":null,"abstract":"<div><div>The increasing environmental concerns and regulations are forcing the HVAC&amp;R sector to shift towards low-GWP refrigerants. Hence, research is actively exploring sustainable alternatives to traditional HFC-based systems. This study provides a numerical drop-in analysis of CO₂ (R744) - hydrocarbon blends in a two-stage vapor compression cycle designed for a mid-sized refrigerated truck. By simulating blends of R744 with small amounts (up to 10 %) of R290, R600a, R1270, and RE170 under various ambient conditions, this research identifies the options that could match or enhance the performance with respect to pure R744. Seasonal simulations, accounting for typical thermal loads in two Italian cities, i.e., Milan and Palermo, reveal that R744 blends with R290 and R1270 achieve comparable or improved seasonal COP (SCOP), especially in colder climates where the system performance benefits from temperature glide. The optimal blend, 92 % R744 and 8 % R290, provides SCOP increases of 2.96 % in Milan and 2.13 % in Palermo, while blends with R600a or RE170 show reduced efficiency. These findings suggest the R744 - R290 and R744 - R1270 blends as a promising low-GWP option for refrigerated transport.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 535-547"},"PeriodicalIF":3.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266768","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 analysis of direct-expansion solar-assisted heat pump system","authors":"Bin Yang,&nbsp;Xu Zhang,&nbsp;Shuoshuang Liu,&nbsp;Xiaohui Yu,&nbsp;Zhonglian Guo","doi":"10.1016/j.ijrefrig.2025.09.027","DOIUrl":"10.1016/j.ijrefrig.2025.09.027","url":null,"abstract":"<div><div>Direct-expansion solar-assisted heat pump (DX-SAHP) system has proven to be an effective energy-saving application. At present, the majority of research on the heat transfer characteristics of the DX-SAHP system concentrates on steady-state conditions. In steady-state research, the temperature and pressure parameters of the system remain constant over time. However, the operational state of the system under actual application conditions is influenced by numerous factors. The current paper employs the moving boundary model to construct dynamic models of the condenser and collector-evaporator based on thermodynamic principles, whilst establishing steady-state models for the compressor and expansion valve to investigate the system's dynamic response characteristics. This model simulates sudden temperature changes and the compressor's speed to assess its performance in real-world scenarios. Under step increases in ambient temperature of 5 K, 10 K, and 15 K, the evaporating pressure rose significantly by 3.63 %, 6.56 %, and 10.93 %, respectively, indicating a strong sensitivity to environmental changes.The 30 % step increase in compressor speed resulted in a 1.60 % rise in condensing pressure but a 7.79 % decrease in evaporating pressure. These responses were accompanied by considerable variations in zone lengths and wall temperatures; the condenser’s two-phase zone expanded by up to 4.10 % with ambient change, while the evaporator’s two-phase zone consistently shortened by 0.097 % across compressor speed changes. These quantified insights underscore the critical influence of dynamic perturbations on system behavior, highlighting the need for advanced control strategies to optimize DX-SAHP performance under realistic operating conditions.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 453-466"},"PeriodicalIF":3.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217336","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 assessment of aluminum slitted finned tube heat exchangers with small tube diameters","authors":"Fang Wang ,&nbsp;JiCheng Li ,&nbsp;ChaoWen Deng ,&nbsp;XianFei Liu ,&nbsp;Jun Zhang ,&nbsp;Ye Tian ,&nbsp;Hong Liu ,&nbsp;Senqing Zhuo ,&nbsp;Wei Guo","doi":"10.1016/j.ijrefrig.2025.09.026","DOIUrl":"10.1016/j.ijrefrig.2025.09.026","url":null,"abstract":"<div><div>This paper investigates the effects of different geometric parameters for the fin structure of an aluminum slitted finned tube heat exchanger on the heat transfer and resistance characteristics on the air side of the heat exchanger. Aluminum offers good ductility, electrical conductivity, and thermal conductivity at low economic cost, and the slitted fin structure is effective in improving the overall heat transfer performance of the heat exchanger. This study presents a numerical investigation of the effects of important structural parameters (including the base tube outer diameter <span><math><msub><mi>d</mi><mi>o</mi></msub></math></span>, the fin thickness <span><math><msub><mi>δ</mi><mi>f</mi></msub></math></span>, the slit height <span><math><msub><mi>S</mi><mi>h</mi></msub></math></span>, the slit width <span><math><msub><mi>S</mi><mi>w</mi></msub></math></span>, and the slit length <span><math><msub><mi>S</mi><mi>L</mi></msub></math></span>) in the aluminum slitted finned tube heat exchanger’s fin structure on its air-side heat transfer and flow resistance characteristics. Recommended parameter combinations were identified and the experimental data were fitted to derive a simplified mathematical model to represent the complex dataset. The results show that <span><math><msub><mi>S</mi><mi>h</mi></msub></math></span> has the most significant effect on the overall heat transfer performance of the slitted finned tube heat exchanger, while the effects of <span><math><msub><mi>S</mi><mi>L</mi></msub></math></span> and <span><math><msub><mi>S</mi><mi>w</mi></msub></math></span> are less obvious and are basically negligible. The favorable parameters combinations were obtained after improvement as follows: <span><math><msub><mi>d</mi><mi>o</mi></msub></math></span>=5.6 mm, <span><math><msub><mi>δ</mi><mi>f</mi></msub></math></span>=0.115 mm, <span><math><msub><mi>S</mi><mi>h</mi></msub></math></span>=0.6 mm, <span><math><msub><mi>S</mi><mi>w</mi></msub></math></span>=1.1 mm, <span><math><msub><mi>S</mi><mrow><mi>L</mi><mn>1</mn></mrow></msub></math></span>=9.0 mm, and <span><math><msub><mi>S</mi><mrow><mi>L</mi><mn>2</mn></mrow></msub></math></span>=6.6 mm. The results of this study will be highly significant in guiding improvement of the structure and the performance of aluminum slitted finned tube heat exchangers with small tube diameters.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 437-452"},"PeriodicalIF":3.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217337","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":"Critical analysis of the design of atmospheric water generators based on vapour compression refrigeration cycle: A numerical study","authors":"Aitor Cendoya ,&nbsp;Daniel Sacasas ,&nbsp;Matias Pezo ,&nbsp;Cristian Cuevas ,&nbsp;Enrique Wagemann","doi":"10.1016/j.ijrefrig.2025.09.025","DOIUrl":"10.1016/j.ijrefrig.2025.09.025","url":null,"abstract":"<div><div>Water scarcity is a problem affecting millions of people in the world, which is amplified by climate change, pollution and population growth. To address this problem, an Atmospheric Water Harvesting system is evaluated, introducing a novel critical analysis using five refrigerants typically used by manufacturers and broadens the current spectrum of ambient conditions. The system is mathematically modelled by integrating semi-empirical models of every component. Each semi-empirical model is individually validated, with errors ranging from 2.5% to 6%. The system is evaluated through a) a parametric analysis and b) an annual analysis using climate conditions of seven cities and five refrigerants. From the parametric analysis it is concluded that the trend of the main indicators is similar for the five refrigerants. The best operating conditions are located at ambient temperatures lower than 25 °C with relative humidities within 40% and 80%. The results are highly influenced by the control system. Cities, such as Beijing and Kabul, having low temperatures during winter, present almost 5000 non-operating hours. In terms of water collection, Sao Paulo presents the highest values, ranging from 3.58 L h⁻¹ for R1234yf to 4.54 L h⁻¹ for R407C. For the SEC, the best performance is also obtained in Sao Paulo, with R407C having the best SEC of 0.34 kWh L⁻¹ and refrigerants R134a and R1234yf having the worst SEC of 0.43 kWh L⁻¹. According to the limitations found for this technology, it is recommended to consider a system with an adaptive control and to combine it with sorption systems.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"180 ","pages":"Pages 467-484"},"PeriodicalIF":3.8,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217252","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}