Pub Date : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130026
Shuhan Wei , Chengzhi Yu , Lingwei Yi , Deng Line
This study presents a comprehensive multi-climate assessment of electrochromic (EC) and thermochromic (TC) smart glazing technologies for educational buildings across three Chinese cities: Urumqi (hot-arid), Harbin (cold semi-arid), and Guangzhou (humid subtropical). Using EnergyPlus building energy simulation validated against ASHRAE Guideline 14 criteria, five window configurations were evaluated: conventional double-pane, transparent electrochromic (ECC), tinted electrochromic (ECT), transparent thermochromic (TCC), and tinted thermochromic (TCT). Results demonstrate climate-dependent optimal glazing selection, with ECC achieving maximum energy reduction of 37.2% in cooling-dominated Harbin, while TCT achieved 32.4% CO₂ emission reduction in heating-dominated Tabriz. The TCC configuration delivered optimal thermal-visual balance, maintaining indoor temperatures of 25.5–26.3 °C and illuminance levels of 350–1600 lx conducive to student cognitive performance. Economic analysis reveals favourable investment returns, with a payback period of 12.6 years and an internal rate of return of 9.2%, supporting integration into national building energy codes. The findings demonstrate that climate-differentiated incentive structures are essential for optimal resource allocation, with policy implications for Iran's educational building retrofit programs and national decarbonization strategies aligned with Paris Agreement commitments.
{"title":"Smart windows for sustainable learning: a multi-climate assessment of adaptive glazing technologies","authors":"Shuhan Wei , Chengzhi Yu , Lingwei Yi , Deng Line","doi":"10.1016/j.applthermaleng.2026.130026","DOIUrl":"10.1016/j.applthermaleng.2026.130026","url":null,"abstract":"<div><div>This study presents a comprehensive multi-climate assessment of electrochromic (EC) and thermochromic (TC) smart glazing technologies for educational buildings across three Chinese cities: Urumqi (hot-arid), Harbin (cold semi-arid), and Guangzhou (humid subtropical). Using EnergyPlus building energy simulation validated against ASHRAE Guideline 14 criteria, five window configurations were evaluated: conventional double-pane, transparent electrochromic (ECC), tinted electrochromic (ECT), transparent thermochromic (TCC), and tinted thermochromic (TCT). Results demonstrate climate-dependent optimal glazing selection, with ECC achieving maximum energy reduction of 37.2% in cooling-dominated Harbin, while TCT achieved 32.4% CO₂ emission reduction in heating-dominated Tabriz. The TCC configuration delivered optimal thermal-visual balance, maintaining indoor temperatures of 25.5–26.3 °C and illuminance levels of 350–1600 lx conducive to student cognitive performance. Economic analysis reveals favourable investment returns, with a payback period of 12.6 years and an internal rate of return of 9.2%, supporting integration into national building energy codes. The findings demonstrate that climate-differentiated incentive structures are essential for optimal resource allocation, with policy implications for Iran's educational building retrofit programs and national decarbonization strategies aligned with Paris Agreement commitments.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130026"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186500","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}
<div><div>Global electricity generation continues to rely heavily on fossil fuels, with coal as the largest single source and natural gas (NG) contributing a substantial, second-largest share. To decarbonize this sector, hydrogen and ammonia are being explored as alternatives to natural gas; however, both face significant challenges. Safe and cost-effective transportation of hydrogen remains unresolved, while ammonia is limited by issues of toxicity and corrosiveness. This study proposes and evaluates the use of aqua-ammonia (A-A)—a liquid mixture of ammonia and water—as a novel fuel for decarbonizing steam power plants. A-A offers key advantages over hydrogen and pure ammonia, including safer transport, reduced corrosiveness and toxicity, and compatibility with existing NG infrastructure. Despite these advantages, its potential as a large-scale fuel for power generation has not been explored in the open literature, and no prior work has assessed its integration across production, transmission, separation, and combustion stages. This work explicitly addresses this research gap by evaluating A-A as a fully integrated energy carrier for utility-scale steam power plants and by introducing the concept of simultaneous energy and water delivery through a single pipeline—an aspect absent from previous studies. Given that A-A is a clean fuel capable of transporting both energy and water simultaneously through a single pipeline, this research demonstrates that A-A can offer solutions to two critical challenges: (1) providing a clean, safe, and practical alternative fuel to fossil fuels, and (2) supplying the required water for power plants operation — which is one of the most significant barriers to the development of steam power plants and a pressing issue in regions suffering from water scarcity. The study provides the first thermodynamic assessment of a full-scale Rankine cycle operating on ammonia extracted from A-A, modelling of a 200 MW Rankine cycle plant, powered by ammonia extracted from A-A, using Engineering Equation Solver (EES). The base case achieved a gross thermal efficiency of 41.26% and net efficiency of 35.07%, surpassing comparable NG-fired plants. The model evaluates multiple operational parameters—boiler pressure, condenser pressure, extraction pressures, and off-design operation—to identify optimal conditions. A 15% ammonia concentration in A-A is found to triple the volumetric energy delivery compared to NG at typical pipeline pressures, while simultaneously supplying sufficient water to meet plant cooling and process demands. Separation of ammonia from water is examined via three methods: Full evaporation, ammonia boiling-based, and membrane, with the latter demonstrating the best integration with condenser heat recovery and minimal efficiency penalty (∼1.2%). Lifecycle analysis indicates potential for near-zero CO₂ emissions using green ammonia, with total annual fuel demand estimated at 773,000 t. Overall, this study establishes
{"title":"Utilizing aqua-ammonia as a clean and scalable fuel in steam power plants","authors":"Ramin Mehdipour , Zahra Baniamerian , Hassan Ali Ozgoli , Seamus Garvey , Alasdair Cairns , Agustin Valera-Medina , Sivachidambaram Sadasivam , Bruno Cardenas","doi":"10.1016/j.applthermaleng.2026.130132","DOIUrl":"10.1016/j.applthermaleng.2026.130132","url":null,"abstract":"<div><div>Global electricity generation continues to rely heavily on fossil fuels, with coal as the largest single source and natural gas (NG) contributing a substantial, second-largest share. To decarbonize this sector, hydrogen and ammonia are being explored as alternatives to natural gas; however, both face significant challenges. Safe and cost-effective transportation of hydrogen remains unresolved, while ammonia is limited by issues of toxicity and corrosiveness. This study proposes and evaluates the use of aqua-ammonia (A-A)—a liquid mixture of ammonia and water—as a novel fuel for decarbonizing steam power plants. A-A offers key advantages over hydrogen and pure ammonia, including safer transport, reduced corrosiveness and toxicity, and compatibility with existing NG infrastructure. Despite these advantages, its potential as a large-scale fuel for power generation has not been explored in the open literature, and no prior work has assessed its integration across production, transmission, separation, and combustion stages. This work explicitly addresses this research gap by evaluating A-A as a fully integrated energy carrier for utility-scale steam power plants and by introducing the concept of simultaneous energy and water delivery through a single pipeline—an aspect absent from previous studies. Given that A-A is a clean fuel capable of transporting both energy and water simultaneously through a single pipeline, this research demonstrates that A-A can offer solutions to two critical challenges: (1) providing a clean, safe, and practical alternative fuel to fossil fuels, and (2) supplying the required water for power plants operation — which is one of the most significant barriers to the development of steam power plants and a pressing issue in regions suffering from water scarcity. The study provides the first thermodynamic assessment of a full-scale Rankine cycle operating on ammonia extracted from A-A, modelling of a 200 MW Rankine cycle plant, powered by ammonia extracted from A-A, using Engineering Equation Solver (EES). The base case achieved a gross thermal efficiency of 41.26% and net efficiency of 35.07%, surpassing comparable NG-fired plants. The model evaluates multiple operational parameters—boiler pressure, condenser pressure, extraction pressures, and off-design operation—to identify optimal conditions. A 15% ammonia concentration in A-A is found to triple the volumetric energy delivery compared to NG at typical pipeline pressures, while simultaneously supplying sufficient water to meet plant cooling and process demands. Separation of ammonia from water is examined via three methods: Full evaporation, ammonia boiling-based, and membrane, with the latter demonstrating the best integration with condenser heat recovery and minimal efficiency penalty (∼1.2%). Lifecycle analysis indicates potential for near-zero CO₂ emissions using green ammonia, with total annual fuel demand estimated at 773,000 t. Overall, this study establishes","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130132"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186249","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130107
Sirine Dhaoui , Abdallah Bouabidi , Mohammed El Hadi Attia , Moataz M. Abdel-Aziz , Saif Ali Kadhim
This study experimentally and numerically investigates the thermal performance and freshwater productivity of a conventional pyramid solar still (CPSS) versus five modified designs (MPSS) with varying cylindrical fin heights (25, 35, 45, 55, and 65 mm). Through comprehensive testing under real solar conditions in Gabes, Tunisia, the 45 mm fin configuration demonstrated optimal performance, achieving an 18.46% higher absorber temperature (77 °C vs. CPSS's 65 °C) and 46.2% greater evaporative heat transfer coefficient (42.50 vs. 29.07 W/m2·K). Among the five MPSS variants, the 45 mm fins provided the ideal balance between heat transfer enhancement and fluid dynamics, yielding 80.9% more daily distillate (3443.07 vs. 1903.29 mL/m2) while maintaining efficient vapor circulation. Computational fluid dynamics (CFD) simulations of all five MPSS configurations revealed that while shorter fins (25–35 mm) provided limited improvement, taller fins (55–65 mm) caused flow disruptions despite their larger surface area. The 45 mm MPSS doubled energy efficiency (34.8% vs. 16.98%) and tripled exergy efficiency (3.04% vs. 1.21%) compared to CPSS, with CFD validation showing excellent agreement (R2 > 0.95) for all five models. These findings demonstrate that cylindrical fin height critically impacts solar still performance, with the 45 mm MPSS emerging as the most effective design.
本研究通过实验和数值研究了传统金字塔太阳能蒸馏器（CPSS）与五种不同圆柱翅片高度（25、35、45、55和65 mm）的改进设计（MPSS）的热性能和淡水生产力。通过在突尼斯Gabes的真实太阳能条件下的综合测试，45毫米翅片结构表现出最佳性能，吸收温度提高18.46%(77°C)，蒸发换热系数提高46.2% （42.50 vs 29.07 W/m2·K）。在五种MPSS变体中，45毫米的鳍片在传热增强和流体动力学之间提供了理想的平衡，在保持有效蒸汽循环的同时，每日馏分增加80.9% （3443.07 mL/m2 vs. 1903.29 mL/m2）。计算流体动力学（CFD）模拟表明，虽然短鳍（25-35 mm）的改善效果有限，但长鳍（55-65 mm）的表面积更大，但会导致流动中断。与CPSS相比，45 mm MPSS的能源效率翻了一番（34.8%对16.98%），火用效率翻了三倍（3.04%对1.21%），CFD验证显示所有五种模型的一致性都很好（R2 > 0.95）。这些发现表明，圆柱形翅片高度对太阳能静止器的性能有重要影响，其中45毫米的MPSS是最有效的设计。
{"title":"Geometric optimization of solar stills: How fin height dictates heat transfer and fluid dynamics in pyramid designs","authors":"Sirine Dhaoui , Abdallah Bouabidi , Mohammed El Hadi Attia , Moataz M. Abdel-Aziz , Saif Ali Kadhim","doi":"10.1016/j.applthermaleng.2026.130107","DOIUrl":"10.1016/j.applthermaleng.2026.130107","url":null,"abstract":"<div><div>This study experimentally and numerically investigates the thermal performance and freshwater productivity of a conventional pyramid solar still (CPSS) versus five modified designs (MPSS) with varying cylindrical fin heights (25, 35, 45, 55, and 65 mm). Through comprehensive testing under real solar conditions in Gabes, Tunisia, the 45 mm fin configuration demonstrated optimal performance, achieving an 18.46% higher absorber temperature (77 °C vs. CPSS's 65 °C) and 46.2% greater evaporative heat transfer coefficient (42.50 vs. 29.07 W/m<sup>2</sup>·K). Among the five MPSS variants, the 45 mm fins provided the ideal balance between heat transfer enhancement and fluid dynamics, yielding 80.9% more daily distillate (3443.07 vs. 1903.29 mL/m<sup>2</sup>) while maintaining efficient vapor circulation. Computational fluid dynamics (CFD) simulations of all five MPSS configurations revealed that while shorter fins (25–35 mm) provided limited improvement, taller fins (55–65 mm) caused flow disruptions despite their larger surface area. The 45 mm MPSS doubled energy efficiency (34.8% vs. 16.98%) and tripled exergy efficiency (3.04% vs. 1.21%) compared to CPSS, with CFD validation showing excellent agreement (R<sup>2</sup> > 0.95) for all five models. These findings demonstrate that cylindrical fin height critically impacts solar still performance, with the 45 mm MPSS emerging as the most effective design.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130107"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186340","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130112
Adili Aliya , Yan Gong , Yin Chen , Ruichao Wei , Mingyi Chen
Rapid economic development has led to a significant increase in the demand for new energy across countries. Due to their high energy density and long cycle life, lithium-ion batteries are widely used in new-energy vehicles and renewable energy storage systems. However, lithium-ion batteries exhibit significant sensitivity to temperature fluctuations, highlighting the necessity of effective and energy-efficient thermal management. Phase change materials (PCMs) offer a promising passive cooling solution but are hindered by inherent drawbacks such as low thermal conductivity and leakage, which significantly limit their application in thermal management. In this study, a novel flexible composite phase change material (FCPCMs) is developed, which utilizes polyethylene glycol as the phase change core. It is effectively encapsulated and supported by a rigid matrix of styrene-ethylene-propylene-styrene block copolymer and the flexibility of polyolefin elastomer, which confers excellent form stability. Furthermore, a ternary thermally conductive network comprising expanded graphite, carbon nanotubes, and copper powder is incorporated, dramatically enhancing the thermal conductivity of the FCPCM to 1.47 W/m K, with an increase of 374%. The FCPCMs reduce the peak battery temperature by up to 19.1 °C (corresponding to a 26.6% decrease from the natural air-cooling baseline of 71.7 °C) and the maximum temperature difference by up to 78.43%. This work provides an effective material strategy for developing high-performance, leakage-resistant PCMs for enhanced battery safety and longevity.
{"title":"Advanced polyethylene glycol based flexible composite phase change materials enabling stable and efficient lithium-ion battery thermal safety management","authors":"Adili Aliya , Yan Gong , Yin Chen , Ruichao Wei , Mingyi Chen","doi":"10.1016/j.applthermaleng.2026.130112","DOIUrl":"10.1016/j.applthermaleng.2026.130112","url":null,"abstract":"<div><div>Rapid economic development has led to a significant increase in the demand for new energy across countries. Due to their high energy density and long cycle life, lithium-ion batteries are widely used in new-energy vehicles and renewable energy storage systems. However, lithium-ion batteries exhibit significant sensitivity to temperature fluctuations, highlighting the necessity of effective and energy-efficient thermal management. Phase change materials (PCMs) offer a promising passive cooling solution but are hindered by inherent drawbacks such as low thermal conductivity and leakage, which significantly limit their application in thermal management. In this study, a novel flexible composite phase change material (FCPCMs) is developed, which utilizes polyethylene glycol as the phase change core. It is effectively encapsulated and supported by a rigid matrix of styrene-ethylene-propylene-styrene block copolymer and the flexibility of polyolefin elastomer, which confers excellent form stability. Furthermore, a ternary thermally conductive network comprising expanded graphite, carbon nanotubes, and copper powder is incorporated, dramatically enhancing the thermal conductivity of the FCPCM to 1.47 W/m K, with an increase of 374%. The FCPCMs reduce the peak battery temperature by up to 19.1 °C (corresponding to a 26.6% decrease from the natural air-cooling baseline of 71.7 °C) and the maximum temperature difference by up to 78.43%. This work provides an effective material strategy for developing high-performance, leakage-resistant PCMs for enhanced battery safety and longevity.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130112"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122579","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130095
Huihui Wang , Xiying Niu , Qinghua Deng , Zhenping Feng
Abstract
This study proposes a novel impingement drainage cooling (IDC) configuration with multiple jets for gas turbine blades. The IDC cell integrates baffles and drainage channels, enabling isolated jet impingement and efficient removal of spent coolant. Three jet configurations are analyzed using large eddy simulations to explore unsteady flow and heat transfer mechanisms with jet interaction. The transient behavior and statistical results are first examined. The investigation reveals that adjacent wall jet collisions cause the boundary layer to rupture and produce secondary stagnation zones, which presents intense turbulence anisotropy. Spectral proper orthogonal decomposition identifies low-frequency coherent structures in collision zones. Heat transfer in collision zones is regulated by the axial velocity gradients and the spanwise Reynolds stress component. The latter intensifies local heat transfer variations. Increasing the number of jets dampens the unsteady behavior of the spanwise-averaged Nusselt number (Nu) but intensifies that of the circumferential-averaged Nu. Double/triple jets improve significantly leading-edge area-averaged Nu by 7.07% and 10.48%, respectively, with greater gains in drainage channels caused by elevated coolant flow rates. Flow loss sub-linearly increases with jet count, with the total pressure loss coefficient rising by 3.70% for double jets and 5.71% for triple jets. The Multi-jet IDC design demonstrates superior heat transfer performance and flow stability by leveraging multi-jet synergy and effective coolant management, offering valuable insights for the thermal design of high-efficiency cooling systems.
{"title":"A novel multi-jet impingement drainage cooling: unsteady dynamics and heat transfer mechanisms using large eddy simulation","authors":"Huihui Wang , Xiying Niu , Qinghua Deng , Zhenping Feng","doi":"10.1016/j.applthermaleng.2026.130095","DOIUrl":"10.1016/j.applthermaleng.2026.130095","url":null,"abstract":"<div><div>Abstract</div><div>This study proposes a novel impingement drainage cooling (IDC) configuration with multiple jets for gas turbine blades. The IDC cell integrates baffles and drainage channels, enabling isolated jet impingement and efficient removal of spent coolant. Three jet configurations are analyzed using large eddy simulations to explore unsteady flow and heat transfer mechanisms with jet interaction. The transient behavior and statistical results are first examined. The investigation reveals that adjacent wall jet collisions cause the boundary layer to rupture and produce secondary stagnation zones, which presents intense turbulence anisotropy. Spectral proper orthogonal decomposition identifies low-frequency coherent structures in collision zones. Heat transfer in collision zones is regulated by the axial velocity gradients and the spanwise Reynolds stress component. The latter intensifies local heat transfer variations. Increasing the number of jets dampens the unsteady behavior of the spanwise-averaged Nusselt number (<em>Nu</em>) but intensifies that of the circumferential-averaged <em>Nu</em>. Double/triple jets improve significantly leading-edge area-averaged <em>Nu</em> by 7.07% and 10.48%, respectively, with greater gains in drainage channels caused by elevated coolant flow rates. Flow loss sub-linearly increases with jet count, with the total pressure loss coefficient rising by 3.70% for double jets and 5.71% for triple jets. The Multi-jet IDC design demonstrates superior heat transfer performance and flow stability by leveraging multi-jet synergy and effective coolant management, offering valuable insights for the thermal design of high-efficiency cooling systems.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130095"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186204","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130056
Wencong Wu, Shifang Huang, Xiaosong Zhang
Distributed integrated energy systems enable coupled conversion and coordinated dispatch of electricity, heating, and cooling, supporting the low-carbon transition of industrial parks. However, most planning studies adopt one-shot investment or evenly spaced multi-period schemes, which overlook the curve-shaped, year-to-year growth of park loads and may cause redundant capacity in early stages and energy supply shortfalls in later stages. Therefore, this paper proposes a multi-stage investment planning framework. First, k-means clustering is applied to the life-cycle load-growth curve to adaptively partition the planning horizon into stages, ensuring that the investment schedule is aligned with the evolving load-growth trend. Second, self-organizing map networks are employed to compress the 8760-hour year-round source–load data into a multi-typical-day scenario tree that captures seasonality and short-term variability. On these basic, a linear programming model is formulated that integrates multi-stage investment decisions with multi-typical-day operational constraints, thereby enabling demand-driven capacity expansion and dynamic consistency between system configuration and operation. A simulation case demonstrates that, relative to one-shot planning, the proposed approach reduces the total life-cycle cost by 32%, and keeps the payback period of each stage within 4 years. Furthermore, the proposed framework yields shorter payback horizons and more reliable long-horizon operational evaluation, mitigating early-stage overcapacity and improving supply–demand matching in later stages.
{"title":"Life-cycle demand-aware multi-stage dynamic planning for integrated energy system","authors":"Wencong Wu, Shifang Huang, Xiaosong Zhang","doi":"10.1016/j.applthermaleng.2026.130056","DOIUrl":"10.1016/j.applthermaleng.2026.130056","url":null,"abstract":"<div><div>Distributed integrated energy systems enable coupled conversion and coordinated dispatch of electricity, heating, and cooling, supporting the low-carbon transition of industrial parks. However, most planning studies adopt one-shot investment or evenly spaced multi-period schemes, which overlook the curve-shaped, year-to-year growth of park loads and may cause redundant capacity in early stages and energy supply shortfalls in later stages. Therefore, this paper proposes a multi-stage investment planning framework. First, k-means clustering is applied to the life-cycle load-growth curve to adaptively partition the planning horizon into stages, ensuring that the investment schedule is aligned with the evolving load-growth trend. Second, self-organizing map networks are employed to compress the 8760-hour year-round source–load data into a multi-typical-day scenario tree that captures seasonality and short-term variability. On these basic, a linear programming model is formulated that integrates multi-stage investment decisions with multi-typical-day operational constraints, thereby enabling demand-driven capacity expansion and dynamic consistency between system configuration and operation. A simulation case demonstrates that, relative to one-shot planning, the proposed approach reduces the total life-cycle cost by 32%, and keeps the payback period of each stage within 4 years. Furthermore, the proposed framework yields shorter payback horizons and more reliable long-horizon operational evaluation, mitigating early-stage overcapacity and improving supply–demand matching in later stages.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130056"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186185","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130120
Dong Li , Xinhang Yang , Tianxiao Chen , Jiafei Zhang , Yuhe Shang
The surface of power transmission line frequently experiences icing in cold and wet environment, which not only affects the stability of regional electricity consumption, but also poses a huge threat to the safety of related infrastructure. Twisted surface of transmission lines has obvious uneven areas, which exert additional forces on the flow and icing processes, resulting in complex heat transfer and icing mechanisms. Currently, researches on the icing mechanism of this surface remain incomplete. Therefore, we conducted experimental research on the freezing behavior mechanism of liquid droplets impacting the twisted surface of cold power transmission line at different heights, and also explored the relationship between the initial droplet impact dynamics and freezing morphology. Experiments showed that five types of frozen forms were formed on twisted surface. The presence of surface grooves trigger the freezing front between adjacent sub-conductors to be discontinuous, resulting in a non-circular freezing front and the transformation of frozen forms on sub-conductors exhibits temporal differences. We quantitatively analyzed the effects of the Weber number and base temperature on the transformation of the ice formation. These findings contribute to a better understanding of icing mechanisms on complex twisted surfaces, laying the foundation for developing effective power grid anti-icing measures and more efficient de-icing methods.
{"title":"Experimental study on frozen forms of the impact of droplet on cold power transmission line","authors":"Dong Li , Xinhang Yang , Tianxiao Chen , Jiafei Zhang , Yuhe Shang","doi":"10.1016/j.applthermaleng.2026.130120","DOIUrl":"10.1016/j.applthermaleng.2026.130120","url":null,"abstract":"<div><div>The surface of power transmission line frequently experiences icing in cold and wet environment, which not only affects the stability of regional electricity consumption, but also poses a huge threat to the safety of related infrastructure. Twisted surface of transmission lines has obvious uneven areas, which exert additional forces on the flow and icing processes, resulting in complex heat transfer and icing mechanisms. Currently, researches on the icing mechanism of this surface remain incomplete. Therefore, we conducted experimental research on the freezing behavior mechanism of liquid droplets impacting the twisted surface of cold power transmission line at different heights, and also explored the relationship between the initial droplet impact dynamics and freezing morphology. Experiments showed that five types of frozen forms were formed on twisted surface. The presence of surface grooves trigger the freezing front between adjacent sub-conductors to be discontinuous, resulting in a non-circular freezing front and the transformation of frozen forms on sub-conductors exhibits temporal differences. We quantitatively analyzed the effects of the Weber number and base temperature on the transformation of the ice formation. These findings contribute to a better understanding of icing mechanisms on complex twisted surfaces, laying the foundation for developing effective power grid anti-icing measures and more efficient de-icing methods.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130120"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186206","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130076
Yangfan Xu , Qimeng Duan , Jun Jia , Xibin Wang , Xiaojun Yin , Hao Duan , Ke Zeng
The HEHC rotary engine exhibits distinctive advantages including a compact structure, high power-to-weight ratio, superior combustion efficiency, and robust endurance, attributes critical to improving the dynamic performance of unmanned aerial vehicles (UAVs) and broadening their application scenarios. In this study, a three-dimensional simulation model was constructed via CONVERGE software combined with an orthogonal experimental design. This model was then employed to systematically elucidate the influence mechanisms of spray cone angle, injection timing, and injection position on mixture formation and combustion characteristics, with the aim of providing a theoretical foundation for the combustion performance optimization of HEHC engines. The simulation scenarios are designed with three spray cone angles (40°, 60° and 80°), three injection timings (−280 °CA aTDC, −250 °CA aTDC and − 220 °CA aTDC) and three injection positions (left side, right side and top of the combustion chamber). The results show that when the spray cone angle is 60°, the standard deviation of the excess air coefficient in the combustion chamber is minimized. The peak cylinder pressure reaches 4.4 MPa, 14.4% higher than that at 40° and 18.9% higher than that at 80°. Delaying the injection timing to −220 °CA aTDC (late intake stroke) further optimizes mixture uniformity, elevating the peak cylinder pressure to 5.6 MPa and shortening the combustion duration to 10 °CA. Selecting the right side of the combustion chamber as the injection position results in the most uniform mixture distribution and avoids fuel loss caused by flow into the intake port. This research provides a quantitative basis for parameter optimization of direct injection technology in HEHC rotary engines, offering significant guidance for enhancing engine power performance and combustion efficiency.
{"title":"Effect of injection parameters on performance of a novel HEHC rotary engine with gasoline direct injection","authors":"Yangfan Xu , Qimeng Duan , Jun Jia , Xibin Wang , Xiaojun Yin , Hao Duan , Ke Zeng","doi":"10.1016/j.applthermaleng.2026.130076","DOIUrl":"10.1016/j.applthermaleng.2026.130076","url":null,"abstract":"<div><div>The HEHC rotary engine exhibits distinctive advantages including a compact structure, high power-to-weight ratio, superior combustion efficiency, and robust endurance, attributes critical to improving the dynamic performance of unmanned aerial vehicles (UAVs) and broadening their application scenarios. In this study, a three-dimensional simulation model was constructed via CONVERGE software combined with an orthogonal experimental design. This model was then employed to systematically elucidate the influence mechanisms of spray cone angle, injection timing, and injection position on mixture formation and combustion characteristics, with the aim of providing a theoretical foundation for the combustion performance optimization of HEHC engines. The simulation scenarios are designed with three spray cone angles (40°, 60° and 80°), three injection timings (−280 °CA aTDC, −250 °CA aTDC and − 220 °CA aTDC) and three injection positions (left side, right side and top of the combustion chamber). The results show that when the spray cone angle is 60°, the standard deviation of the excess air coefficient in the combustion chamber is minimized. The peak cylinder pressure reaches 4.4 MPa, 14.4% higher than that at 40° and 18.9% higher than that at 80°. Delaying the injection timing to −220 °CA aTDC (late intake stroke) further optimizes mixture uniformity, elevating the peak cylinder pressure to 5.6 MPa and shortening the combustion duration to 10 °CA. Selecting the right side of the combustion chamber as the injection position results in the most uniform mixture distribution and avoids fuel loss caused by flow into the intake port. This research provides a quantitative basis for parameter optimization of direct injection technology in HEHC rotary engines, offering significant guidance for enhancing engine power performance and combustion efficiency.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130076"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186297","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130079
Xinglan Hou, Yongheng Yang
To address the significant temperature rise caused by local heat accumulation in high-power electronics, this study proposes a novel hybrid staggered arrangement petal-shaped pin-fin microchannel heat sink (HSAPP). First, the optimal configuration was identified as HSAPP6, a HSAPP design with six petal-shaped pin-fins,through numerical simulations. Furthermore, we compared the thermal and flow performance of the straight parallel microchannel (SPMC), hybrid circular pin-fin (HCP), and HSAPP6 heat sinks. Finally, we analyzed the effects of the flow rate and local heat flux on HSAPP6. The results show that the proposed HSAPP6 performs excellently in suppressing hotspot temperature rise. At = 400, the maximum temperature on the substrate surface of the HSAPP6 is 322.8 K, representing reductions of 23.1 K and 7.3 K compared with the SPMC and HCP, respectively. The thermal resistance decreases by 50.3% and 24.2%, while the temperature non-uniformity coefficient improves by 54.5% and 27.0%. Under an equal-cooling criterion defined by matching the peak substrate temperature, HSAPP6 requires 23.83 mW at = 400, whereas HCP requires 81.45 mW at = 900 to achieve the same cooling performance. Moreover, when increases from 200 to 1000, the maximum temperature decreases by 16.4 K, the thermal resistance decreases by 50.9%, while the total average pressure drop across the entire heat sink rises to 31.73 kPa. When subjected to a local heat flux as high as 900 W/cm2, the substrate temperature rises to 360.5 K, accompanied by a significant 165.8% increase in thermal resistance. Therefore, the design provides an efficient solution for local thermal management of high-power electronics.
{"title":"A novel hybrid staggered arrangement petal-shaped pin-fin microchannel heat sink for hotspot mitigation","authors":"Xinglan Hou, Yongheng Yang","doi":"10.1016/j.applthermaleng.2026.130079","DOIUrl":"10.1016/j.applthermaleng.2026.130079","url":null,"abstract":"<div><div>To address the significant temperature rise caused by local heat accumulation in high-power electronics, this study proposes a novel hybrid staggered arrangement petal-shaped pin-fin microchannel heat sink (HSAPP). First, the optimal configuration was identified as HSAPP6, a HSAPP design with six petal-shaped pin-fins,through numerical simulations. Furthermore, we compared the thermal and flow performance of the straight parallel microchannel (SPMC), hybrid circular pin-fin (HCP), and HSAPP6 heat sinks. Finally, we analyzed the effects of the flow rate and local heat flux on HSAPP6. The results show that the proposed HSAPP6 performs excellently in suppressing hotspot temperature rise. At <span><math><mrow><mi>Re</mi></mrow></math></span> = 400, the maximum temperature on the substrate surface of the HSAPP6 is 322.8 K, representing reductions of 23.1 K and 7.3 K compared with the SPMC and HCP, respectively. The thermal resistance decreases by 50.3% and 24.2%, while the temperature non-uniformity coefficient improves by 54.5% and 27.0%. Under an equal-cooling criterion defined by matching the peak substrate temperature, HSAPP6 requires 23.83 mW at <span><math><mrow><mi>Re</mi></mrow></math></span> = 400, whereas HCP requires 81.45 mW at <span><math><mrow><mi>Re</mi></mrow></math></span> = 900 to achieve the same cooling performance. Moreover, when <span><math><mrow><mi>Re</mi></mrow></math></span> increases from 200 to 1000, the maximum temperature decreases by 16.4 K, the thermal resistance decreases by 50.9%, while the total average pressure drop across the entire heat sink rises to 31.73 kPa. When subjected to a local heat flux as high as 900 W/cm<sup>2</sup>, the substrate temperature rises to 360.5 K, accompanied by a significant 165.8% increase in thermal resistance. Therefore, the design provides an efficient solution for local thermal management of high-power electronics.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"291 ","pages":"Article 130079"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146187735","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 : 2026-02-05DOI: 10.1016/j.applthermaleng.2026.130128
C. Tempesti , S. Grasa , L. Romani , F. Ciccateri , G. Ferrara , G. Paniagua
Pressure Gain Combustion (PGC) is a promising technology to significantly enhance the thermal efficiency of gas turbines by increasing stagnation pressure across the combustor. While most PGC research has focused on detonative-based systems such as Rotating Detonation Engines (RDEs), this study investigates an alternative deflagrative-based approach inspired by pistonless internal combustion engines. A comprehensive numerical analysis is presented, utilizing a dedicated simulation tool developed within the GT-Power environment to model the unsteady thermodynamic behavior of a deflagrative-based hydrogen-fueled PGC prototype. The combustor model was validated against high-frequency experimental data and then scaled to represent a real-engine application. To complete the system, a multi-stage axial turbine was specifically designed to accommodate the strongly pulsating outflow from the combustor. Despite significant fluctuations, the turbine maintained an average efficiency of 90% over the pulsation cycle. The combustor and turbine models were integrated into a full-cycle simulation framework, enabling the assessment of the complete system performance under transient operating conditions. The results indicate a cycle efficiency of 32.1%, representing a 7.7% improvement over conventional constant-pressure combustion systems. Despite being limited to a single operating condition, the modeling results are highly promising and provide a solid basis for future investigations. This work provides a viable alternative to detonation-based PGC technologies and shows potential for the feasibility of deflagrative-based systems for practical power generation applications. The modeling framework developed herein offers a scalable, computationally efficient tool for system optimization and supports further investigation of the proposed combustor concept.
{"title":"Numerical modeling of a deflagrative-based pressure gain combustor integrated with an axial turbine","authors":"C. Tempesti , S. Grasa , L. Romani , F. Ciccateri , G. Ferrara , G. Paniagua","doi":"10.1016/j.applthermaleng.2026.130128","DOIUrl":"10.1016/j.applthermaleng.2026.130128","url":null,"abstract":"<div><div>Pressure Gain Combustion (PGC) is a promising technology to significantly enhance the thermal efficiency of gas turbines by increasing stagnation pressure across the combustor. While most PGC research has focused on detonative-based systems such as Rotating Detonation Engines (RDEs), this study investigates an alternative deflagrative-based approach inspired by pistonless internal combustion engines. A comprehensive numerical analysis is presented, utilizing a dedicated simulation tool developed within the GT-Power environment to model the unsteady thermodynamic behavior of a deflagrative-based hydrogen-fueled PGC prototype. The combustor model was validated against high-frequency experimental data and then scaled to represent a real-engine application. To complete the system, a multi-stage axial turbine was specifically designed to accommodate the strongly pulsating outflow from the combustor. Despite significant fluctuations, the turbine maintained an average efficiency of 90% over the pulsation cycle. The combustor and turbine models were integrated into a full-cycle simulation framework, enabling the assessment of the complete system performance under transient operating conditions. The results indicate a cycle efficiency of 32.1%, representing a 7.7% improvement over conventional constant-pressure combustion systems. Despite being limited to a single operating condition, the modeling results are highly promising and provide a solid basis for future investigations. This work provides a viable alternative to detonation-based PGC technologies and shows potential for the feasibility of deflagrative-based systems for practical power generation applications. The modeling framework developed herein offers a scalable, computationally efficient tool for system optimization and supports further investigation of the proposed combustor concept.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"290 ","pages":"Article 130128"},"PeriodicalIF":6.9,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186208","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}
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