Applied Thermal Engineering最新文献

{"title":"Performance analysis of a novel marine engine waste heat recovery system for combined power and cooling generation","authors":"Abdulmalik Alkotami ,&nbsp;H.F. Elattar ,&nbsp;A. Fouda","doi":"10.1016/j.applthermaleng.2025.128604","DOIUrl":"10.1016/j.applthermaleng.2025.128604","url":null,"abstract":"<div><div>The maritime industry’s pursuit of energy efficiency and emission reduction requires advanced waste heat recovery (WHR) systems. Shipping accounts for about 3 % of global greenhouse gas emissions, and marine engines release more than 50 % of fuel energy as exhaust heat. Although many studies have examined the Organic Rankine Cycle (ORC) and CO₂ cycles separately, integrated systems that combine power generation with cooling are still underdeveloped. This paper introduces a new combined power and cooling generation (CPCG) system that integrates multiple ORCs to use exhaust waste heat in marine applications, allowing concurrent electricity and refrigeration production with improved overall performance. A detailed thermodynamic model is created using Aspen HYSYS to simulate and optimize the system under real marine operating conditions. System performance is evaluated based on net power output, refrigeration capacity, the coefficient of performance (COP) of the refrigeration cycle, and energy/exergy efficiencies. Different working fluids, including synthetic refrigerants (R245fa, R1233zd(E), R1234yf, R1336mzz-Z) and hydrocarbons (n-butane, n-octane, toluene), are compared. Results show notable improvements, with a maximum net power output of 11.8 MW, a refrigeration capacity of 3.9 MW, a COP of 4.2, and energy and exergy efficiencies of 72.5 and 96 %, respectively. Under optimal conditions, energy efficiency reaches 76.07 %, with a COP of 5.2. Among the ORC working fluids studied, R-1233zd(E) is identified as the most sustainable and environmentally friendly, achieving 77 % energy efficiency. N-butane and other hydrocarbons achieve slightly higher efficiencies of 79 %, but they pose significant safety risks due to flammability. R-245fa is considered environmentally unsustainable. Although NOVEC-649 demonstrates high efficiency, its discontinuation limits its future relevance.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128604"},"PeriodicalIF":6.9,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265122","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":"Dynamic heat transfer model for thermal energy storage using metal wool–phase change material composites","authors":"Pablo D. Tagle-Salazar ,&nbsp;Luisa F. Cabeza ,&nbsp;Anton López-Román ,&nbsp;Cristina Prieto","doi":"10.1016/j.applthermaleng.2025.128548","DOIUrl":"10.1016/j.applthermaleng.2025.128548","url":null,"abstract":"<div><div>Decarbonisation of the energy sector is critical for climate change mitigation, with the power sector remaining a major contributor to global emissions. Concentrating solar power (CSP) technology combined with thermal energy storage (TES) presents a promising solution to overcome this challenge. TES systems, particularly those utilising phase change materials (PCMs), offer efficient energy storage by harnessing latent heat, enabling reliable power generation, and providing high-temperature heat for industrial processes. This research introduces a heat transfer model designed to simulate the thermal behaviour of TES systems utilising wool–PCM composites as storage medium. The mathematical model was implemented on the OpenModelica platform and it is intended to be incorporated into a simulation tool currently being developed by the authors to assess the performance of CSP plants under dynamic conditions. The model was validated by comparing the simulation results with the experimental measurements of the temperature within the composite domain during both the charging and discharging cycles. The simulations replicated key experimental parameters, including geometry, material properties, and boundary conditions, and evaluated two configurations with coarse and fine wool fibres. The results demonstrated good agreement with the experimental data for coarse wool, with a root mean square error (RMSE) of up to 2.29 K. For fine fibres, the RMSE increased to 5.31 K, indicating a larger deviation. Despite these challenges, the model successfully captured the overall thermal response trend and phase transition behaviour observed experimentally. The findings highlight the efficacy and limitations of the proposed thermal model and emphasise the necessity for advanced macroscopic-scale effective thermal conductivity modelling approaches for such composites that integrate the influence of pore-scale characteristics (i.e., volume change). This research will advance the current state-of-the-art in this field and will mitigate the discrepancies identified in this study when these models are applied in practice. This integration is crucial for enhancing the accuracy and improving the time simulation of large-scale TES systems in CSP applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128548"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264216","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":"Multi-scale performance evaluation of direct and indirect-heated supercritical CO2 Brayton cycles for solar power tower plants with alternative high-temperature chloride salt","authors":"Ning Ma ,&nbsp;Pan Zhao ,&nbsp;Wenpan Xu ,&nbsp;Aijie Liu ,&nbsp;Huichao Zhu ,&nbsp;Yangsheng Lou ,&nbsp;Jiangfeng Wang","doi":"10.1016/j.applthermaleng.2025.128634","DOIUrl":"10.1016/j.applthermaleng.2025.128634","url":null,"abstract":"<div><div>The adoption of high-temperature chloride salt as alternative heat transfer and storage medium has been demonstrated to enable indirect-heated solar power tower (SPT) plants to achieve operational temperature parity with direct-heated SPT plants. In this paper, two classical supercritical CO₂ (S-CO₂) Brayton cycles are integrated into direct and indirect-heated SPT plants. A multi-scale evaluation framework, combining design-point optimization with off-design operation analysis, is employed to determine optimal configurations for next-generation concentrated solar power deployment. The results indicate that employing a direct-heated layout in a SPT plant can enhance both specific work and overall thermal efficiency compared to those of an indirect-heated layout under identical conditions, regardless of the cycle configuration. Exergy analysis reveals that superior performance is achieved by the direct-heated layout through the reduction of exergy destruction at the receiver and heat exchanger. The optimization results confirm that the recompression cycle is more suitable for the direct-heated layout in SPT plants, demonstrating the highest specific work of 0.314 MJ/kg and a greater thermal efficiency of 38.06 %. However, under actual operating conditions, the indirect-heated SPT plant using a recompression cycle demonstrates the most stable performance, with an efficiency variation of only 18.09 %. Therefore, it is recommended that the indirect-heated layout with a recompression cycle be considered the optimal solution for next-generation SPT plant deployment.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128634"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the influence of vortex tube structure on performance—cold flow rate, length-diameter ratio, nozzle type","authors":"Li Wen,&nbsp;Qiqi Ning,&nbsp;Huang Li,&nbsp;Hao Li,&nbsp;Ben Zhang,&nbsp;Nantian Wang,&nbsp;Weiwei Min","doi":"10.1016/j.applthermaleng.2025.128508","DOIUrl":"10.1016/j.applthermaleng.2025.128508","url":null,"abstract":"<div><div>This study conducted experimental investigations on the effects of nozzle structure, length-to-diameter ratio (L/D), and the number of nozzle flow channels on the performance of vortex tubes. The nozzle structures include the ordinary type (OT) and the convergent type (COT). Including 2, 4, and 6 flow channels. Both the convergent nozzle and the ordinary nozzle had 3 flow channels. Exploring the effects of convergent nozzles and ordinary nozzles with different L/D on the performance of vortex tubes; exploring the influence of nozzle flow channel numbers on the performance of vortex tubes at the optimal L/D of the convergent nozzle and the ordinary nozzle, and studying the effects of different L/D on the optimal flow channel numbers of the convergent nozzle and the ordinary nozzle. With the inlet pressure set at 0.4 MPa, and the cold flow rate varying between 0.5 and 0.9. The results showed that the performance of the convergent nozzle was superior to that of the ordinary nozzle. The Optimal combination was a 6-flow channel convergent nozzle and a vortex tube with an L/D of 26.7, achieving a maximum cold temperature difference of 48.6 ℃ and an isentropic efficiency of 0.49 when the cold flow rate was approximately 0.53.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128508"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264385","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":"Molten pool thermodynamics in laser-powder-bed-fusion aluminum alloys and thermal strengthening mechanisms of ceramic particles","authors":"Xiaonan Ni ,&nbsp;Ansen Wang ,&nbsp;Zijian Hu ,&nbsp;Wenxin Yang ,&nbsp;Xin Deng ,&nbsp;Yongkang Luo ,&nbsp;Yanxun Liang ,&nbsp;Shanghua Wu ,&nbsp;Jinyang Liu ,&nbsp;Hongwei Wang ,&nbsp;Li He","doi":"10.1016/j.applthermaleng.2025.128549","DOIUrl":"10.1016/j.applthermaleng.2025.128549","url":null,"abstract":"<div><div>Laser Powder Bed Fusion (LPBF) of aluminum alloy 6061 (AA6061) faces serious challenges including poor processability and defect formation, which significantly degrade mechanical properties. This study investigates the unique effects of incorporating 5 vol% low-cost, micron-sized TiCN particles to AA6061 through LPBF experiments and numerical simulations. The experiments reveal that TiCN significantly improves printability and reduces defects. The simulations reveal that increasing scanning speed shifts molten pool dynamics from keyhole mode to conduction mode, with transitional states in between. It is identified that unstable flow and strong reverse motion of the melt pool cause deep keyhole truncation, forming isolated spherical voids. In addition, the insufficient laser energy leads to poor molten pool wetting and spreading, resulting in defects like necking, fracture, and balling. Thermodynamic analysis of the metal-ceramic composite molten pool clarifies the TiCN strengthening mechanism. TiCN particles increase the local molten pool’s temperature, velocity, and heat flux. They also intensify re-circulation zones and velocity gradients around themselves, while reducing overall flow velocity and re-circulation strength. This enhances central thermal transfer efficiency and stabilizes flow. The heat storage and buffering of TiCN particles, along with their absorption and dissipation of turbulent motion, help stabilize molten pool dynamics and suppress printing defects. This study offers a versatile material design strategy and effective simulation method for LPBF processing of high-strength aluminum alloys.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128549"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264709","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":"Techno-economic and environmental evaluation of a dynamic solar-biofuel trigeneration system for sustainable building energy applications","authors":"Suqi Wang ,&nbsp;Chao Zhou ,&nbsp;Yejong Xing ,&nbsp;Junyi Yu ,&nbsp;Yanheng Li","doi":"10.1016/j.applthermaleng.2025.128537","DOIUrl":"10.1016/j.applthermaleng.2025.128537","url":null,"abstract":"<div><div>The building sector is a major energy consumer and a key contributor to greenhouse gas emissions, making the transition to renewable energy essential for achieving sustainable development. This study investigates a hybrid solar-biofuel trigeneration system designed to supply heating, cooling, and electricity for buildings, aiming to reduce fossil fuel reliance and improve environmental performance. The system integrates photovoltaic thermal (PVT) panels, a biofuel-fired boiler, an absorption chiller, and thermal storage tanks, with its transient performance simulated under real climatic conditions in Beijing, characterized by hot summers and harsh winters. The analysis incorporates techno-economic, environmental, and exergoeconomic assessments, as well as a sensitivity analysis of key parameters, including boiler efficiency, chiller COP, and discount rate. Results show that during winter, biofuel heating ensures reliable supply with peak outputs up to 1980 kW, while in summer, solar energy contributes up to 70 % of cooling demand, reducing biofuel consumption. The system achieves CO₂ emission reductions of up to 0.37 kg/kWh and delivers a levelized energy cost (LEC) between 0.15 and 0.48 $/kWh, depending on seasonal conditions. Novel contributions include the integration of sensitivity and exergoeconomic analyses, as well as an evaluation of the system’s alignment with international green building standards (LEED/BREEAM), providing insights beyond previous studies.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128537"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264310","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":"Comparative study of conical and cylindrical draft tubes in PAT applications: Enhancing energy efficiency and flow stability","authors":"Chuan Wang ,&nbsp;He Yu ,&nbsp;Chenglong Niu ,&nbsp;Tao Wang ,&nbsp;Pengcheng Guo ,&nbsp;Yulong Yao","doi":"10.1016/j.applthermaleng.2025.128602","DOIUrl":"10.1016/j.applthermaleng.2025.128602","url":null,"abstract":"<div><div>Pump as Turbine (PAT) is an economical and effective technology widely applied in chemical processing, oil refining, and seawater desalination for liquid energy recovery and environmental protection. This study presents a novel investigation of the effects of draft tube geometry on PAT performance, comparing a conical draft tube with a traditional cylindrical draft tube through combined experimental validation and numerical simulation. The originality of this work lies in systematically analyzing not only the external hydraulic performance but also the internal flow structures, total entropy production, and pressure pulsation characteristics, providing a comprehensive assessment of energy efficiency and flow stability. Results indicate that at the high-efficiency operating point, the conical tube reduces turbulence intensity by 0.5 % and lowers the required head by 0.22 m compared with the cylindrical tube. The internal flow is more stable, with a more uniform static pressure distribution, lower turbulent kinetic energy, and significantly reduced central and eccentric vortices. Moreover, the conical tube effectively decreases total entropy production and reduces pressure pulsation amplitudes, with a maximum reduction of 47.5 % at key monitoring points. Overall, this study provides new insights into optimizing draft tube design in PAT systems, highlighting practical guidelines for enhancing both energy efficiency and operational stability.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128602"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264312","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":"Innovative design and behavior investigation of the Carnot battery energy storage system: A pathway towards efficient utilization of renewable energy","authors":"Shurong Zhang ,&nbsp;Yeshan Sun","doi":"10.1016/j.applthermaleng.2025.128581","DOIUrl":"10.1016/j.applthermaleng.2025.128581","url":null,"abstract":"<div><div>To address the electricity supply–demand imbalance caused by the inherent volatility and intermittency of renewable energy sources, a supercritical Brayton cycle is coupled with a CO₂ heat pump for energy storage and power generation. This configuration represents an innovative exploration of Carnot battery technology. An in-depth study on working fluid selection and parameter optimization to maximize the energy utilization efficiency and minimize the investment cost for the combined system was conducted. The results indicate that the CO₂-Xe/CO₂ system outperforms the CO₂-Kr/CO₂ and CO₂/CO₂ systems, achieving a round-trip efficiency of 65.8 % and a payback period of 9.23 years under design conditions. The system also demonstrates an improvement in round-trip efficiency and a reduction in investment cost when compared to the energy storage systems documented in the existing literature. System performance declines under off-design conditions but can be enhanced by adjusting operating parameters. The system demonstrates effective operation within partial load (80 %-100 %) and partial input power (80 %-105 %) ranges, with round-trip efficiency experiencing minor variations between 65.8 %-62.85 % and 65.8 %-63.87 %, respectively. The findings indicate the feasibility of the proposed combined energy storage and power generation system.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128581"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264393","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":"Thermal behavior and performance evaluation of a 5-cell PEMFC stack operating with and without active cooling","authors":"B. Mullai Sudaroli,&nbsp;V. Vasanthkumar","doi":"10.1016/j.applthermaleng.2025.128627","DOIUrl":"10.1016/j.applthermaleng.2025.128627","url":null,"abstract":"<div><div>This study presents a detailed experimental investigation of the performance characteristics of a 5-cell Proton Exchange Membrane Fuel Cell (PEMFC) stack, with each cell having an active area of 100 cm², under two operating conditions: with and without active cooling. A liquid cooling system using deionized (DI) water and a heat exchanger was employed to regulate the stack temperature. Without active cooling, the stack temperature rose to 70 °C within 30 min at load currents ranging from 5 A to 25 A, leading to significant voltage losses and performance degradation, thereby highlighting the necessity of effective cooling. Under active cooling, the stack was operated at higher loads of 20 A to 30 A, maintaining a stable temperature of approximately 55 °C as the coolant removed the heat generated by the stack. Thermal equilibrium between the stack and coolant was achieved, ensuring stable voltage throughout operation. Additionally, a thermal management system model was developed to predict coolant temperature variations across components over time. The model results indicated a predicted heat removal ratio between 1 and 2, and the heat exchanger demonstrated effective heat rejection. These thermal management improvements contributed to enhanced stack performance and greater operational durability.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128627"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264405","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":"Regulating humidification-dehumidification systems via machine learning based on quasi-digital twin","authors":"Juxin Du ,&nbsp;Senshan Sun ,&nbsp;Tianhao Li ,&nbsp;A.W. Kandeal ,&nbsp;Guilong Peng ,&nbsp;Nuo Yang","doi":"10.1016/j.applthermaleng.2025.128542","DOIUrl":"10.1016/j.applthermaleng.2025.128542","url":null,"abstract":"<div><div>Solar humidification-dehumidification technology is advantageous due to its ease of maintenance and clean operational profile. Integrating a digital twin into these systems enables timely and precisely control capabilities for enhanced system optimization. This work implements a quasi-digital twin optimization framework driven by machine learning models into the solar humidification-dehumidification system. The machine learning model was trained and validated using experimental data, achieving R² values of 0.96 for freshwater production predictions and 0.93 for temperature forecasts. Leveraging the machine learning-assisted quasi-digital twin, this study explores the real-time optimization of operational parameters across four distinct modes: production-maximized, energy-saving, efficiency-optimized, and balanced. Genetic algorithms were employed to determine optimal configurations under varying weather conditions. Results indicate significant performance improvements: under the production-maximized mode, hourly freshwater output increased by up to 25% during a sunny clear day and 49 % during a cloudy day. In energy-saving mode, daily energy consumption was reduced by 58 % on a clear day and 52 % on a cloudy day, respectively, relative to baseline operations. This research not only elevates the performance of solar humidification-dehumidification systems but also underscores the broader applicability of the optimization framework by using digital twin to diverse engineering challenges.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128542"},"PeriodicalIF":6.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264308","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}