Pub Date : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.tsep.2026.104544
Hamza Coşkun , Emine Oğur , Hüseyin Yağlı , İlker Mert
This study investigated the effects of water injection into a high-pressure turbofan engine operating under normal conditions on performance. The analysis focused on exergy, exergy sustainability and energy. The analyses were performed on the basis of the take-off altitude. Water injection was performed in a high-pressure compressor (HPC) in the range of 2–32 kg/s. Accordingly, the engine’s energy and thrust efficiency increase with increasing HPC water injection. These values were 65.90% and 53.38% at 32 kg/s which is accepted as the most efficient operating point of the water-injected engine. In addition, this application increased thrust efficiency by 15% compared with that of the engine operating under normal conditions. The specific fuel consumption (SFC) decreased as water was injected, provided a 13.07% gain to the engine at maximum performance. Injecting water into the HPC component reduced the compressor temperature and work consumption, increasing the overall thrust power of the turbofan engine from 59587.87 kW to 68537.09 kW.
{"title":"How water injection affects high-pressure turbofan engine performance? A comprehensive energy, advanced exergy and exergy sustainability analyses","authors":"Hamza Coşkun , Emine Oğur , Hüseyin Yağlı , İlker Mert","doi":"10.1016/j.tsep.2026.104544","DOIUrl":"10.1016/j.tsep.2026.104544","url":null,"abstract":"<div><div>This study investigated the effects of water injection into a high-pressure turbofan engine operating under normal conditions on performance. The analysis focused on exergy, exergy sustainability and energy. The analyses were performed on the basis of the take-off altitude. Water injection was performed in a high-pressure compressor (HPC) in the range of 2–32 kg/s. Accordingly, the engine’s energy and thrust efficiency increase with increasing HPC water injection. These values were 65.90% and 53.38% at 32 kg/s which is accepted as the most efficient operating point of the water-injected engine. In addition, this application increased thrust efficiency by 15% compared with that of the engine operating under normal conditions. The specific fuel consumption (SFC) decreased as water was injected, provided a 13.07% gain to the engine at maximum performance. Injecting water into the HPC component reduced the compressor temperature and work consumption, increasing the overall thrust power of the turbofan engine from 59587.87 kW to 68537.09 kW.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104544"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-02-16DOI: 10.1016/j.tsep.2026.104589
Montaser Mahmoud , Ohood H.K. Adhari , Mohammad Ali Abdelkareem , Abdul Ghani Olabi
The integration of solar and geothermal energy technologies presents a promising pathway to enhance the reliability and efficiency of renewable energy systems. By combining the intermittency of solar power with the stability of geothermal energy, hybrid solar–geothermal systems can deliver more consistent outputs while reducing greenhouse gas emissions. Although individual technologies have been extensively studied, integrated configurations remain underexplored. Despite their advantages, widespread adoption is still limited by various economic, technical, and environmental challenges. This study provides a comprehensive examination of integrated solar–geothermal technologies, focusing on recent technical developments, key performance indicators, and major deployment barriers. A two-stage methodology is applied: qualitative and bibliometric analysis. First, a detailed technical assessment investigates design elements, configurations, and operational principles of standalone and integrated systems, highlighting technological progress. The second stage involves an in-depth bibliometric analysis using the Scopus database, processed through Biblioshiny and VOSviewer to analyze scientific research since 2000 up to mid-2025. The integrated approach shows that hybrid configurations are considerably progressing, reflected by the consistent rise in publications, reaching 809 in 2024. Findings confirm that while solar-geothermal energy systems offer significant potential, deployment is hindered by high capital costs, integration complexity, operational expenses, land-use demands, water consumption, and limited policy and financing support.
{"title":"Hybrid solar-geothermal energy systems: Technological developments, challenges, and scientific research dynamics","authors":"Montaser Mahmoud , Ohood H.K. Adhari , Mohammad Ali Abdelkareem , Abdul Ghani Olabi","doi":"10.1016/j.tsep.2026.104589","DOIUrl":"10.1016/j.tsep.2026.104589","url":null,"abstract":"<div><div>The integration of solar and geothermal energy technologies presents a promising pathway to enhance the reliability and efficiency of renewable energy systems. By combining the intermittency of solar power with the stability of geothermal energy, hybrid solar–geothermal systems can deliver more consistent outputs while reducing greenhouse gas emissions. Although individual technologies have been extensively studied, integrated configurations remain underexplored. Despite their advantages, widespread adoption is still limited by various economic, technical, and environmental challenges. This study provides a comprehensive examination of integrated solar–geothermal technologies, focusing on recent technical developments, key performance indicators, and major deployment barriers. A two-stage methodology is applied: qualitative and bibliometric analysis. First, a detailed technical assessment investigates design elements, configurations, and operational principles of standalone and integrated systems, highlighting technological progress. The second stage involves an in-depth bibliometric analysis using the Scopus database, processed through Biblioshiny and VOSviewer to analyze scientific research since 2000 up to mid-2025. The integrated approach shows that hybrid configurations are considerably progressing, reflected by the consistent rise in publications, reaching 809 in 2024. Findings confirm that while solar-geothermal energy systems offer significant potential, deployment is hindered by high capital costs, integration complexity, operational expenses, land-use demands, water consumption, and limited policy and financing support.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104589"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal management is critical to ensure the performance, safety, and lifespan of Li-ion cells. The best cooling system for electric vehicles should have balance between thermal performance and overall weight. This study presents a liquid cooling solution through the multi-objective optimization of T-shaped cold plate combined with graphite sheet. Optimization is performed using combined strategy using latin hypercube sampling, artificial neural network and non-dominated sorting genetic algorithm on the 3S1P module by numerical simulations. The objective is to minimize the maximum temperature, temperature non-uniformity of the module, and cold plate weight. The best design, identified, features a horizontal height of 25.76 mm, a vertical width of 34.78 mm, and a channel depth of 3.77 mm. Experimental investigation of the optimized cold plate along with graphite sheets on the single cell reduces maximum temperature by 3.3 to 4.8 °C and temperature non-uniformity by 1.8 to 2.7 °C across various flow rates while reducing cold plate weight by 12.3% compared to the baseline design. The integrated optimized cooling system is numerically scaled to module level and tested under a realistic drive cycle, demonstrating a 2 °C reduction in peak temperature and a 2.1 °C reduction in non-uniformity at coolant temperature of 40 °C. This configuration achieves baseline thermal performance with a 71.25% reduction in mass flow rate. The final design is tested using graphene nanofluid with ethylene glycol (30%) and water (70%) as base fluid, showing thermal performance comparable to water at 1% mass fraction. The proposed design offers a lightweight and efficient solution for next-generation battery cooling systems in electric vehicles.
{"title":"Lightweight thermal management strategy for Li-ion pouch cells using localised cold plate and graphite sheet","authors":"Hemanth Dileep, Pallab Sinha Mahapatra, Arvind Pattamatta","doi":"10.1016/j.tsep.2026.104570","DOIUrl":"10.1016/j.tsep.2026.104570","url":null,"abstract":"<div><div>Thermal management is critical to ensure the performance, safety, and lifespan of Li-ion cells. The best cooling system for electric vehicles should have balance between thermal performance and overall weight. This study presents a liquid cooling solution through the multi-objective optimization of T-shaped cold plate combined with graphite sheet. Optimization is performed using combined strategy using latin hypercube sampling, artificial neural network and non-dominated sorting genetic algorithm on the 3S1P module by numerical simulations. The objective is to minimize the maximum temperature, temperature non-uniformity of the module, and cold plate weight. The best design, identified, features a horizontal height of 25.76 mm, a vertical width of 34.78 mm, and a channel depth of 3.77 mm. Experimental investigation of the optimized cold plate along with graphite sheets on the single cell reduces maximum temperature by 3.3 to 4.8 °C and temperature non-uniformity by 1.8 to 2.7 °C across various flow rates while reducing cold plate weight by 12.3% compared to the baseline design. The integrated optimized cooling system is numerically scaled to module level and tested under a realistic drive cycle, demonstrating a 2 °C reduction in peak temperature and a 2.1 °C reduction in non-uniformity at coolant temperature of 40 °C. This configuration achieves baseline thermal performance with a 71.25% reduction in mass flow rate. The final design is tested using graphene nanofluid with ethylene glycol (30%) and water (70%) as base fluid, showing thermal performance comparable to water at 1% mass fraction. The proposed design offers a lightweight and efficient solution for next-generation battery cooling systems in electric vehicles.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104570"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.tsep.2026.104546
Sarula Chen , Tianhang Chen , Yang Yang
Pipe-embedded energy walls represent a paradigm shift in opaque-envelope design, leveraging low-grade thermal energy to deliver advanced thermal regulation. However, conventional pipe-embedded energy walls (CPEWs) exhibit localized overheating, reducing energy efficiency and economic viability. This study aims to develop modular pipe-embedded energy walls (MPEWs) with thermal-diffusive filler cavities to eliminate heat accumulation and numerically conduct the first comprehensive energy-economic-environmental (3E) performance quantification. A numerical model for MPEW was established and validated, integrating uncertainty analysis (UA) and global sensitivity analysis (GSA) to evaluate impacts of 10 risk parameters across structural, operational, and material categories on eight 3E indices. The UA findings indicate that, with optimized design and operating parameters, MPEWs can significantly reduce the internal surface thermal load of the wall, and even achieve supplemental heating under optimized conditions. GSA identified insulation thickness, pipeline diameter, and control strategy as dominant parameters. The adoption of multi-pulse injection strategies can enhance operating energy efficiency while maintaining equivalent thermal performance under long-term injection strategy. For practical applications, it is recommended to optimize the inlet velocity within the range of 0.2–0.4 m/s, to set the vertical size of the filler cavity between 150–200 mm, and to control the thermal conductivity of the pipe-embedded layer within 1.1–3.1 W/(m·K). A scientific basis is provided for optimizing building envelopes with balanced energy-saving, economic, and environmental outcomes.
{"title":"Numerical study on energy, economic and environmental performance of modular pipe-embedded energy walls with thermal diffusion filler cavities","authors":"Sarula Chen , Tianhang Chen , Yang Yang","doi":"10.1016/j.tsep.2026.104546","DOIUrl":"10.1016/j.tsep.2026.104546","url":null,"abstract":"<div><div>Pipe-embedded energy walls represent a paradigm shift in opaque-envelope design, leveraging low-grade thermal energy to deliver advanced thermal regulation. However, conventional pipe-embedded energy walls (CPEWs) exhibit localized overheating, reducing energy efficiency and economic viability. This study aims to develop modular pipe-embedded energy walls (MPEWs) with thermal-diffusive filler cavities to eliminate heat accumulation and numerically conduct the first comprehensive energy-economic-environmental (3E) performance quantification. A numerical model for MPEW was established and validated, integrating uncertainty analysis (UA) and global sensitivity analysis (GSA) to evaluate impacts of 10 risk parameters across structural, operational, and material categories on eight 3E indices. The UA findings indicate that, with optimized design and operating parameters, MPEWs can significantly reduce the internal surface thermal load of the wall, and even achieve supplemental heating under optimized conditions. GSA identified insulation thickness, pipeline diameter, and control strategy as dominant parameters. The adoption of multi-pulse injection strategies can enhance operating energy efficiency while maintaining equivalent thermal performance under long-term injection strategy. For practical applications, it is recommended to optimize the inlet velocity within the range of 0.2–0.4 m/s, to set the vertical size of the filler cavity between 150–200 mm, and to control the thermal conductivity of the pipe-embedded layer within 1.1–3.1 W/(m·K). A scientific basis is provided for optimizing building envelopes with balanced energy-saving, economic, and environmental outcomes.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104546"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.tsep.2026.104533
Shahad S. Ibrahim , Hudhaifa Hamzah , Ali Alkhabbaz , Ahmed Albojamal , Kambiz Vafai
This study numerically simulates the thermal regulation of a photovoltaic (PV) module by combining phase change materials (PCMs) with various curved metal foam arrangements. In this simulation, both the charging (melting) and discharging (solidification) behaviors of the PCM were investigated. Five arced fin configurations were analyzed, featuring arc numbers of 1, 2, 4, 6, and 8 for three different porosities (ε = 0.85, 0.9, and 0.95). The ANSYS Fluent software, based on a finite volume approach, was used to solve the melting process of PCM, and the implemented code was verified against available experimental data. This study illustrates the importance of arced metal foam structures for maximizing thermal regulation and energy storage in a PV module. The results of this study indicate that combining arc metal foam with PV-PCM modules can significantly enhance cooling and heat storage capabilities, improving PV performance compared to conventional modules. Among the considered cases, Case-E achieves the highest temporal enhancement ratio of 43% when ε = 0.85 compared to the conventional PV module design.
{"title":"Thermal management of the PV-PCM module via arc-porous fins","authors":"Shahad S. Ibrahim , Hudhaifa Hamzah , Ali Alkhabbaz , Ahmed Albojamal , Kambiz Vafai","doi":"10.1016/j.tsep.2026.104533","DOIUrl":"10.1016/j.tsep.2026.104533","url":null,"abstract":"<div><div>This study numerically simulates the thermal regulation of a photovoltaic (PV) module by combining phase change materials (PCMs) with various curved metal foam arrangements. In this simulation, both the charging (melting) and discharging (solidification) behaviors of the PCM were investigated. Five arced fin configurations were analyzed, featuring arc numbers of 1, 2, 4, 6, and 8 for three different porosities (ε = 0.85, 0.9, and 0.95). The ANSYS Fluent software, based on a finite volume approach, was used to solve the melting process of PCM, and the implemented code was verified against available experimental data. This study illustrates the importance of arced metal foam structures for maximizing thermal regulation and energy storage in a PV module. The results of this study indicate that combining arc metal foam with PV-PCM modules can significantly enhance cooling and heat storage capabilities, improving PV performance compared to conventional modules. Among the considered cases, Case-E achieves the highest temporal enhancement ratio of 43% when ε = 0.85 compared to the conventional PV module design.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104533"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-02-12DOI: 10.1016/j.tsep.2026.104569
Amir Zivariravan , Giulio Santori , Alessia Arteconi
Design, optimization, and control of adsorption-based systems are constrained by a fidelity–portability trade-off in dynamic modelling: geometry-specific formulations rarely transfer across adsorber configurations or operating regimes, whereas simplified surrogates can obscure the rate-controlling physics. This work introduces a dimensionless framework for adsorber dynamics that unifies vapour-phase exchange among cycle components, fluid–solid heat transfer, and intraparticle diffusion. Intraparticle kinetics are obtained analytically by solving the Fickian problem with a time-varying boundary concentration via a convolution kernel, replacing the customary heat-affected linear-driving-force approach. Nondimensionalization on characteristic geometric, kinetic, and thermodynamic scales yields a compact set of dimensionless groups that separates design from operation. A stable, memory-lean implicit solver integrates the coupled balances and evaluates the kernel efficiently over long horizons. Capability of the approach is demonstrated on a closed-vessel, near-isothermal step for silica gel–water, constructing a performance map of the dimensionless time to 90% the final uptake () in the {mass transfer Biot (), adsorption Damköhler ()} plane that delineates surface-barrier- and diffusion-limited regimes and highlights high-gain directions for rapid equilibration. In the baseline simulated case, while the map identifies a high-sensitivity band at , where modest parameter shifts yield disproportionate reductions in , results show that the adsorbent mean temperature increases by only and the heat-carrier outlet by . The framework is portable across scales and operating modes, enabling comparative benchmarking, design–operation co-optimization, and model-based control in adsorption processes.
{"title":"A dimensionless framework for adsorber dynamics","authors":"Amir Zivariravan , Giulio Santori , Alessia Arteconi","doi":"10.1016/j.tsep.2026.104569","DOIUrl":"10.1016/j.tsep.2026.104569","url":null,"abstract":"<div><div>Design, optimization, and control of adsorption-based systems are constrained by a fidelity–portability trade-off in dynamic modelling: geometry-specific formulations rarely transfer across adsorber configurations or operating regimes, whereas simplified surrogates can obscure the rate-controlling physics. This work introduces a dimensionless framework for adsorber dynamics that unifies vapour-phase exchange among cycle components, fluid–solid heat transfer, and intraparticle diffusion. Intraparticle kinetics are obtained analytically by solving the Fickian problem with a time-varying boundary concentration via a convolution kernel, replacing the customary heat-affected linear-driving-force approach. Nondimensionalization on characteristic geometric, kinetic, and thermodynamic scales yields a compact set of dimensionless groups that separates design from operation. A stable, memory-lean implicit solver integrates the coupled balances and evaluates the kernel efficiently over long horizons. Capability of the approach is demonstrated on a closed-vessel, near-isothermal step for silica gel–water, constructing a performance map of the dimensionless time to 90% the final uptake (<span><math><msubsup><mi>t</mi><mrow><mn>90</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span>) in the {mass transfer Biot (<span><math><msub><mrow><mi>B</mi><mi>i</mi></mrow><mi>m</mi></msub></math></span>), adsorption Damköhler (<span><math><msub><mrow><mi>D</mi><mi>a</mi></mrow><mrow><mi>a</mi><mi>d</mi></mrow></msub></math></span>)} plane that delineates surface-barrier- and diffusion-limited regimes and highlights high-gain directions for rapid equilibration. In the baseline simulated case, while the <span><math><msubsup><mi>t</mi><mrow><mn>90</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span> map identifies a high-sensitivity band at <span><math><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>6</mn></mrow></msup><mo>≲</mo><msub><mrow><mi>D</mi><mi>a</mi></mrow><mrow><mi>a</mi><mi>d</mi></mrow></msub><msub><mrow><mi>B</mi><mi>i</mi></mrow><mi>m</mi></msub><mo>≲</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>3</mn></mrow></msup></mrow></math></span>, where modest parameter shifts yield disproportionate reductions in <span><math><msubsup><mi>t</mi><mrow><mn>90</mn></mrow><mrow><mo>∗</mo></mrow></msubsup></math></span>, results show that the adsorbent mean temperature increases by only <span><math><mrow><mo>∼</mo><mn>1.4</mn><mo>%</mo></mrow></math></span> and the heat-carrier outlet by <span><math><mrow><mo><</mo><mn>0.1</mn><mo>%</mo></mrow></math></span>. The framework is portable across scales and operating modes, enabling comparative benchmarking, design–operation co-optimization, and model-based control in adsorption processes.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104569"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To reduce the heat gain of the building and enhance the thermal stability of residents, a composite wall (APCM) is proposed in this study, which integrates autoclaved aerated concrete (AAC) with phase change materials (PCM). First, the new APCM wall testing rig was designed, constructed, and rigorously tested. Subsequently, numerical models of the APCM wall were developed to accurately simulate its thermal behavior and were validated by comparing with the experimental results. Afterwards, a numerical study was conducted to investigate the parameters of phase change temperature, latent heat, thickness, location, and carbon dioxide emissions (CO2ES). The simulation results illustrated that: (1) Compared to phase change temperatures of 25 °C and 35 °C, APCM walls at 31 °C exhibit reduced diurnal temperature fluctuations, with corresponding PCM effective utilization efficiencies increasing by 12.8% and 39.8% respectively. (2) the thermal inertia of APCM can be improved by increasing the latent heat of PCM, whereas the effective utilization rate of PCM decreases; (3) the daily temperature difference of interior wall surface of the APCM wall with a phase change material thickness of 20 mm is lower than that of the walls with thicknesses of 10 mm and 30 mm. Correspondingly, the cumulative heat gain is decreased by 2.2% and 4.5% compared with the walls with thicknesses of 10 mm and 30 mm; (4) the heat gain of APCM wall when PCM is located in the inner layer is 35.2% and 50.7% lower than that when PCM is located in the middle layer and the outer layer, respectively; (5) the CO2ES of the building envelope is optimized by precisely regulating the phase change temperature, latent heat, thickness, and installation position of the PCM. In conclusion, the APCM wall demonstrates promising potential for engineering applications.
{"title":"Parametric thermal analysis of a phase change material wall combining with autoclaved aerated concrete","authors":"Cairui Yu , Dongmei Shen , Jinsong Tu , Lintao Fang","doi":"10.1016/j.tsep.2026.104563","DOIUrl":"10.1016/j.tsep.2026.104563","url":null,"abstract":"<div><div>To reduce the heat gain of the building and enhance the thermal stability of residents, a composite wall (APCM) is proposed in this study, which integrates autoclaved aerated concrete (AAC) with phase change materials (PCM). First, the new APCM wall testing rig was designed, constructed, and rigorously tested. Subsequently, numerical models of the APCM wall were developed to accurately simulate its thermal behavior and were validated by comparing with the experimental results. Afterwards, a numerical study was conducted to investigate the parameters of phase change temperature, latent heat, thickness, location, and carbon dioxide emissions (CO<sub>2ES</sub>). The simulation results illustrated that: (1) Compared to phase change temperatures of 25 °C and 35 °C, APCM walls at 31 °C exhibit reduced diurnal temperature fluctuations, with corresponding PCM effective utilization efficiencies increasing by 12.8% and 39.8% respectively. (2) the thermal inertia of APCM can be improved by increasing the latent heat of PCM, whereas the effective utilization rate of PCM decreases; (3) the daily temperature difference of interior wall surface of the APCM wall with a phase change material thickness of 20 mm is lower than that of the walls with thicknesses of 10 mm and 30 mm. Correspondingly, the cumulative heat gain is decreased by 2.2% and 4.5% compared with the walls with thicknesses of 10 mm and 30 mm; (4) the heat gain of APCM wall when PCM is located in the inner layer is 35.2% and 50.7% lower than that when PCM is located in the middle layer and the outer layer, respectively; (5) the CO<sub>2ES</sub> of the building envelope is optimized by precisely regulating the phase change temperature, latent heat, thickness, and installation position of the PCM. In conclusion, the APCM wall demonstrates promising potential for engineering applications.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104563"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Various thermal collector designs have been investigated to enhance the thermal and electrical efficiency of photovoltaic/thermal (PV/T) systems. These designs often incorporate plates and tubes made of high thermal conductivity metals such as copper and aluminum. However, the use of large quantities of these expensive materials significantly increases the capital cost of PV/T systems. In this study, a simple and cost-effective thermal collector design is introduced. The proposed collector was fabricated using polyvinyl chloride (PVC) tubes to reduce costs, with the heat tranfer fluid (HTF) in direct contact with the backside of the PV module to maximize heat transfer. The PV/T system was tested using CuO nanofluids and pure water as the heat transfer fluids (HTFs). The impact of nanofluid concentration on PV/T performance was also studied. The highest electrical efficiency of the PV system was achieved using 0.15 wt% CuO nanofluid, with improvements in electrical efficiency ranging from 4 to 27.1% compared to the system using water, and 23.3–42% compared to a conventional uncooled PV system. The overall efficiency of the PV/T using CuO nanofluid was 5.9–11.6% higher than that of the corresponding system using water. Despite the superior performance of the nanofluid, water is recommended as the HTF in PV/T systems intended for applications requiring both electricity and heat. This recommendation is based on economic analysis, which shows a payback period of 7.2 years for the water-based system, compared to 11 years for the CuO nanofluid system. Additionally, the water-based system achieves a comparable annual cash flow with no significant difference relative to the nanofluid system.
{"title":"Experimental study on the effect of copper oxide nanofluid on thermal and electrical efficiency of the PV/T system","authors":"S.M. Shalaby , Radisav Vidic , Vikas Khanna , M.K. Elfakharany , E. El-Bialy","doi":"10.1016/j.tsep.2026.104574","DOIUrl":"10.1016/j.tsep.2026.104574","url":null,"abstract":"<div><div>Various thermal collector designs have been investigated to enhance the thermal and electrical efficiency of photovoltaic/thermal (PV/T) systems. These designs often incorporate plates and tubes made of high thermal conductivity metals such as copper and aluminum. However, the use of large quantities of these expensive materials significantly increases the capital cost of PV/T systems. In this study, a simple and cost-effective thermal collector design is introduced. The proposed collector was fabricated using polyvinyl chloride (PVC) tubes to reduce costs, with the heat tranfer fluid (HTF) in direct contact with the backside of the PV module to maximize heat transfer. The PV/T system was tested using CuO nanofluids and pure water as the heat transfer fluids (HTFs). The impact of nanofluid concentration on PV/T performance was also studied. The highest electrical efficiency of the PV system was achieved using 0.15 wt% CuO nanofluid, with improvements in electrical efficiency ranging from 4 to 27.1% compared to the system using water, and 23.3–42% compared to a conventional uncooled PV system. The overall efficiency of the PV/T using CuO nanofluid was 5.9–11.6% higher than that of the corresponding system using water. Despite the superior performance of the nanofluid, water is recommended as the HTF in PV/T systems intended for applications requiring both electricity and heat. This recommendation is based on economic analysis, which shows a payback period of 7.2 years for the water-based system, compared to 11 years for the CuO nanofluid system. Additionally, the water-based system achieves a comparable annual cash flow with no significant difference relative to the nanofluid system.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104574"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-02-16DOI: 10.1016/j.tsep.2026.104590
Aakash Gupta , Ida Shafagh , Simon Rees , Fleur Loveridge
Embedded retaining walls in the buildings can be converted to energy walls by incorporating embedded heat exchanger pipes connected to a heat pump system, which can assist in decarbonising heating. To support the effective design of such systems, fast and reliable models are required to predict the thermal performance of energy walls. Analytical shape factors provide a convenient and computationally efficient method for estimating steady-state heat transfer rates within the wall. These shape factors are mathematical expressions that relate the temperature difference between surfaces to the resulting heat flux under steady conditions. While analytical shape factor equations have been successfully applied to other types of ground heat exchangers, their application and validations for energy walls, which have more complex thermal boundary conditions, remain unexplored. This study investigates the suitability of shape factor equations, originally developed for fuel transportation pipelines and other applications which share similar geometries, to the thermal analysis of energy walls. Given that energy walls may encounter varying thermal boundary conditions, e.g. air-exposed vs. fully embedded, both scenarios are analysed. The results present the first systematic parametric validation across realistic energy wall geometric variations (pipe spacing, diameter, wall thickness and cover depth) and thermal conductivity ratios to evaluate shape factors for practical design applications. The performance of analytical shape factors is benchmarked against results from steady-state and transient numerical models. The findings demonstrate that, with the developed methodology, existing shape factor equations can be successfully extended to energy walls and other energy geostructures exhibiting planar thermal behaviour.
{"title":"Conduction shape factors for thermal analysis of energy walls under varying boundary conditions","authors":"Aakash Gupta , Ida Shafagh , Simon Rees , Fleur Loveridge","doi":"10.1016/j.tsep.2026.104590","DOIUrl":"10.1016/j.tsep.2026.104590","url":null,"abstract":"<div><div>Embedded retaining walls in the buildings can be converted to energy walls by incorporating embedded heat exchanger pipes connected to a heat pump system, which can assist in decarbonising heating. To support the effective design of such systems, fast and reliable models are required to predict the thermal performance of energy walls. Analytical shape factors provide a convenient and computationally efficient method for estimating steady-state heat transfer rates within the wall. These shape factors are mathematical expressions that relate the temperature difference between surfaces to the resulting heat flux under steady conditions. While analytical shape factor equations have been successfully applied to other types of ground heat exchangers, their application and validations for energy walls, which have more complex thermal boundary conditions, remain unexplored. This study investigates the suitability of shape factor equations, originally developed for fuel transportation pipelines and other applications which share similar geometries, to the thermal analysis of energy walls. Given that energy walls may encounter varying thermal boundary conditions, e.g. air-exposed vs. fully embedded, both scenarios are analysed. The results present the first systematic parametric validation across realistic energy wall geometric variations (pipe spacing, diameter, wall thickness and cover depth) and thermal conductivity ratios to evaluate shape factors for practical design applications. The performance of analytical shape factors is benchmarked against results from steady-state and transient numerical models. The findings demonstrate that, with the developed methodology, existing shape factor equations can be successfully extended to energy walls and other energy geostructures exhibiting planar thermal behaviour.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104590"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-01Epub Date: 2026-02-12DOI: 10.1016/j.tsep.2026.104581
Usame Demir , Samet Çelebi , Salih Özer
This study investigated the effectiveness of solvent use in improving the combustion and emissions of Diesel-Fuel Oil 6 (FO6) mixtures. We operated a direct-injection diesel engine at 3000 rpm over 0%–75% load, using a baseline heavy blend (DF40: diesel with 40% FO6) and DF40 with 10% or 20% (v/v) N, N-dimethylformamide (DMF) or diacetone alcohol (DAA). Adding FO6 increased BSFC by 2.7–9.0% relative to diesel across all tested loads. This confirms that high-viscosity FO6 fractions are bad for fuel economy. Adding solvents mostly canceled out this effect. DF40–DMF20 lowered BSFC by 10.99–17.48% (depending on load), while DF40–DAA20 lowered it by 8.38–15.05%. Dosing the solvent also affected the combustion process. DF40–DMF20 raised the temperature of the exhaust gas by 9.02–12.55% (DAA20: 6.38–11.07%) and, at the same time, made combustion less harsh by lowering the peak pressure rise rate by 18% and the maximum cumulative heat release by 11%. Emission responses were good for particulates and products of incomplete combustion: smoke opacity dropped by 14.7–28% with DMF20 and 10.5–20% with DAA20. DMF20 also lowered HC (2–10.2%) and CO (18.6–31.6%). NOx levels increased slightly (DMF20: 8–14.8%; DAA20: 4.5–8.9%), consistent with improved oxidation and higher local temperatures. In general, solvent-assisted mixing enables efficient use of FO6 without preheating; however, NOx reduction remains necessary.
{"title":"Effects of dimethylformamide (DMF) and diacetone alcohol (DAA) additives on combustion parameters and exhaust emissions in diesel-fuel oil 6 mixtures","authors":"Usame Demir , Samet Çelebi , Salih Özer","doi":"10.1016/j.tsep.2026.104581","DOIUrl":"10.1016/j.tsep.2026.104581","url":null,"abstract":"<div><div>This study investigated the effectiveness of solvent use in improving the combustion and emissions of Diesel-Fuel Oil 6 (FO6) mixtures. We operated a direct-injection diesel engine at 3000 rpm over 0%–75% load, using a baseline heavy blend (DF40: diesel with 40% FO6) and DF40 with 10% or 20% (v/v) N, N-dimethylformamide (DMF) or diacetone alcohol (DAA). Adding FO6 increased BSFC by 2.7–9.0% relative to diesel across all tested loads. This confirms that high-viscosity FO6 fractions are bad for fuel economy. Adding solvents mostly canceled out this effect. DF40–DMF20 lowered BSFC by 10.99–17.48% (depending on load), while DF40–DAA20 lowered it by 8.38–15.05%. Dosing the solvent also affected the combustion process. DF40–DMF20 raised the temperature of the exhaust gas by 9.02–12.55% (DAA20: 6.38–11.07%) and, at the same time, made combustion less harsh by lowering the peak pressure rise rate by 18% and the maximum cumulative heat release by 11%. Emission responses were good for particulates and products of incomplete combustion: smoke opacity dropped by 14.7–28% with DMF20 and 10.5–20% with DAA20. DMF20 also lowered HC (2–10.2%) and CO (18.6–31.6%). NO<sub>x</sub> levels increased slightly (DMF20: 8–14.8%; DAA20: 4.5–8.9%), consistent with improved oxidation and higher local temperatures. In general, solvent-assisted mixing enables efficient use of FO6 without preheating; however, NO<sub>x</sub> reduction remains necessary.</div></div>","PeriodicalId":23062,"journal":{"name":"Thermal Science and Engineering Progress","volume":"71 ","pages":"Article 104581"},"PeriodicalIF":5.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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