Case Studies in Thermal Engineering最新文献

{"title":"Optimization of thermal storage characteristics in molten salt phase change thermal storage units: A numerical analysis based on heat pipe arrangement patterns","authors":"Zhaoyu Wu ,&nbsp;Chuang Zhu ,&nbsp;Yanchao Gao ,&nbsp;Yubing Tao ,&nbsp;Jingyi Zhao","doi":"10.1016/j.csite.2026.107815","DOIUrl":"10.1016/j.csite.2026.107815","url":null,"abstract":"<div><div>The application of thermal storage units is one approach to mitigate the intermittency of clean energy, where heat transfer efficiency and thermal storage capacity are critical parameters. To enhance heat transfer and thermal storage performance, three models—Uniform-type, U-type, and V-type—were constructed, using NaNO₃-KNO₃-NaNO₂ (7:53:40 wt%) as the phase change material (PCM). The impact of these different arrangements on the PCM melting process was investigated through computational fluid dynamics simulations. The results indicate that the model with the Uniform-type arrangement requires 91.76 min to achieve complete melting of the PCM. The optimal V-type arrangement achieved a phase change completion time of 45.16% relative to the Uniform-type arrangement with no significant increase in cost for the thermal storage unit component. After 40 min of thermal storage, its energy storage capacity reaches 24.14 × 10³ kJ, which is 1.38 times that of the Uniform-type model. Mechanism analysis revealed that the temperature difference between the heat source and the PCM, along with their contact area, are two critical factors affecting the system's heat transfer efficiency. These findings provide a basis for the structural optimization of the thermal energy storage unit.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107815"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160130","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":"Improving heat transfer capability and thermal stability of polyalphaolefin introducing Fe3O4/CNTs hybrid nanomaterials","authors":"Xianjun Hou ,&nbsp;Kangjun Tan ,&nbsp;Chen Chu ,&nbsp;Hua Jiang","doi":"10.1016/j.csite.2026.107800","DOIUrl":"10.1016/j.csite.2026.107800","url":null,"abstract":"<div><div>To address the common problem of insufficient heat dissipation performance of lubricants in the power systems of new energy vehicles, this study investigated the physicochemical properties of Fe₃O₄/CNTs composite nanomaterials as an additive for PAO7 lubricating oil. The wettability and rheological properties of different nanofluids were studied. In addition, the thermal stability and thermal conductivity of the nanofluids were further evaluated. The results showed that the addition of Fe₃O₄/CNTs composite nanomaterials significantly reduced the contact angle with the steel interface by 42.7%. The viscosity of the nanofluids decreased slightly with increasing shear rate, exhibiting significant shear-thinning behavior. Simultaneously, the high-temperature oxidative degradation time was prolonged, showing excellent high-temperature stability. The thermal conductivity of hybrid nanolubricant (HL) was increased by approximately 11.04% compared to the base oil, significantly improving heat transfer performance. This composite nano-lubricant is expected to be applied to the cooling system of new energy vehicles, thereby improving their overall performance.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107800"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A developed design of thermoelectric multi-effect air gap membrane distillation for seawater desalination","authors":"Adnan Alhathal Alanezi ,&nbsp;Hakobyan Arsen ,&nbsp;Mustafa M. Aljumaily ,&nbsp;Hakobyan Arusyak ,&nbsp;Jaber M. Asiri ,&nbsp;Qusay F. Alsalhy","doi":"10.1016/j.csite.2026.107849","DOIUrl":"10.1016/j.csite.2026.107849","url":null,"abstract":"<div><div>This work represents a paradigm breakthrough in the design of compact desalination systems by offering the first direct integration of thermoelectric elements into a multi-stage air gap membrane distillation (TE-MS-AGMD) module. Herein, the novelty lies in the dual functionality of the thermoelectric element: it simultaneously serves as a heat pump for latent heat recovery and as an integrated thermal energy source, eliminating the need for separate heat exchangers to preheat feed solution and external refrigeration systems for vapor condensation. This innovative arrangement resolves the limitations of current MD practices by enabling internal heat recovery across multiple stages while maintaining a minimal footprint. A comprehensive experimental investigation evaluated the influence of key operational parameters—energy input, average operating temperature, temperature gradient, and number of distillation stages—on system performance. Results demonstrate that the three-stage TE-MS-AGMD system, with a membrane area of 96.4 cm² per stage and an energy input of 40 W, stabilizes at an average temperature of 64.9 °C, achieving a maximum permeate water flux of 5.7 kg/m²h with a corresponding Specific Energy Consumption (SEC) of 0.73 kWh/kg. At optimized conditions with reduced power input of 10 W, the system reaches a minimum SEC of 0.52 kWh/kg alongside a gain output ratio (GOR) of approximately 1.3. The obtained performance metrics, combined with the system's compact and integrated design, could bestow significant potential for sustainable, decentralized seawater desalination applications, particularly in off-grid and remote locations where conventional multi-component systems are impractical.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107849"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146777424","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-perspective assessment of solar water heating systems in regions with hot summers and cold winters—thermal, economic and environmental perspectives","authors":"Yan Yan ,&nbsp;Zepeng Liu ,&nbsp;Liping Zeng ,&nbsp;Wenjing Li ,&nbsp;Xinru Chen ,&nbsp;Huan Su ,&nbsp;Xiaohua Li","doi":"10.1016/j.csite.2026.107776","DOIUrl":"10.1016/j.csite.2026.107776","url":null,"abstract":"<div><div>The intermittent and seasonal characteristics of solar water heating systems motivate the development of auxiliary heating equipment. In this study, an experimental study was carried out on a solar water heating system in Xiangtan with hot summers and cold winters. The effects of meteorological parameters such as local solar irradiance and ambient temperature on the heat storage capacity of the system were tested, and the economy and carbon emissions of three types of coupled auxiliary solar heating equipment were comprehensively analyzed. The experimental results reveal that the hot water generated by solar water heating system meets the needs of residents in summer and autumn; the remainder of the season requires the support of auxiliary heating equipment. Among the three integrated systems, the carbon emission of the biomass-coupled solar water heating system is 188.26kg/year, and the net present value is 259 $ in 18 years. A sensitivity analysis of the three integrated systems revealed that the electric water heater coupled with solar water heating system and the natural gas coupled with solar water heating system are more sensitive to the service life, whereas the biomass coupled with solar water heating system is more sensitive to the discount rate. The policy environment is very important for the development of a biomass-coupled solar water heating system.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107776"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146778798","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 inhibition effect of inhibitors on coal spontaneous combustion during long-term low-temperature oxidation process","authors":"Xiaoyuan Zhang ,&nbsp;Hanzhong Deng ,&nbsp;Xun Zhang ,&nbsp;Fengwei Dai ,&nbsp;Ge Huang ,&nbsp;Bing Lu ,&nbsp;Huimin Liang ,&nbsp;Chen Yu","doi":"10.1016/j.csite.2026.107862","DOIUrl":"10.1016/j.csite.2026.107862","url":null,"abstract":"<div><div>To elucidate the long-term inhibitory effects of inhibitors on coal spontaneous combustion in mines and their underlying mechanisms, programmed heating, thermogravimetric analysis, and Fourier-transform infrared spectroscopy were employed to investigate the effects of magnesium chloride, resveratrol, and tea polyphenols during prolonged low-temperature oxidation. The results show that the inhibitory effects of all three inhibitors initially increase and then decline with oxidation time. Based on CO and CO₂ evolution, CO inhibition rates, and apparent activation energy, the inhibitory performance reaches an optimum at approximately 1000 h. At this stage, tea polyphenols exhibit the strongest inhibitory effect, achieving a maximum CO inhibition rate of 39.71% and increasing the apparent activation energy by 31%. Microstructural analysis indicates that all three inhibitors effectively suppress the formation or consumption of four key reactive functional groups (–CH₂, –CH₃, C=O, and –COOH) during long-term oxidation. Compared with MgCl₂, the two natural antioxidants—resveratrol and tea polyphenols—exhibit stronger inhibitory effects, particularly on aliphatic side chains (–CH₂ and –CH₃), with tea polyphenols achieving a maximum inhibition rate of 58.34% for –CH₂ groups. In addition, resveratrol shows more pronounced inhibition toward carbonyl (C=O) groups, whereas tea polyphenols exhibit greater selectivity toward carboxyl (–COOH) groups, with maximum inhibition rates of 35.12% and 46.61%, respectively. Overall, MgCl₂ demonstrates comparatively weaker inhibitory performance. These results confirm that inhibitors suppress coal spontaneous combustion primarily by disrupting chain-reaction pathways and reducing the concentration of reactive functional groups.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107862"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147278938","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":"Dual enhancement of solar distiller using phase change material and internal fans: An experimental 11-E study for sustainable water production","authors":"A.E. Kabeel ,&nbsp;Khaled Ramzy ,&nbsp;Abdulrhman Alshaabani ,&nbsp;Eslam Ahmed abdelAziz ,&nbsp;Mohamed Bassyouni ,&nbsp;Mohamad A. Alawad","doi":"10.1016/j.csite.2026.107882","DOIUrl":"10.1016/j.csite.2026.107882","url":null,"abstract":"<div><div>This research conducts a comprehensive experimental study of a solar distillation configuration enhanced with phase change material and internal electric fans, in a single-slope solar stills. Despite their operational simplicity, conventional single-slope solar stills are fundamentally limited by low distillate yields due to significant thermal losses and the formation of a stagnant vapor boundary layer that impedes efficient mass transfer. An experimental arrangement was constructed and tested at Faculty of Engineering, Sinai University, Egypt, and analyzed using 11-E framework, which encompasses assessments of energetic, exergetic, economic, environmental, and sustainability aspects. Four operating scenarios were examined: (i) conventional solar still (CSS), (ii) Enhanced solar still with fans only (ESSF), (iii) Enhanced solar still with paraffin wax only (ESSP), and (iv) Enhanced solar still with both paraffin wax and fans (ESSPF). The results indicated that integrating PCM beneath the absorber plate extended operation into post-sunset hours by providing latent heat storage. At the same time, fans improved internal convection, accelerated vapor transport, and enhanced condensation. The combined configuration (ESSPF) yielded the highest performance, with a supreme daily freshwater productivity of 5.26 ± 0.01 kg/m², representing an 87.90 ± 0.01% increase compared with the conventional one. Energy and exergy productivity rates for ESSPF reached 49 ± 0.05% and 2.0 ± 0.05%, respectively, while the water production cost decreased to 0.00772 $/L, resulting in a reduced payback period of 5.25 months. An environmental analysis confirmed a substantial decrease in CO₂ emissions resulting from a decrease in dependence on traditional fuel-based water production. Furthermore, sustainability and improvement potential indices indicated that the enhanced stills provide a more viable long-term solution. Overall, the integration of paraffin wax and internal fans provides a cost-effective, reliable, and scalable modification to conventional solar stills, supporting global strategies for sustainable and environmentally friendly water desalination.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107882"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330037","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":"Study on structural design and heat transfer characteristics of biomimetic honeycomb heat exchanger","authors":"Yixin Zhang ,&nbsp;Bao Meng ,&nbsp;Jinquan Han ,&nbsp;Yu Zhu ,&nbsp;Min Wan","doi":"10.1016/j.csite.2026.107881","DOIUrl":"10.1016/j.csite.2026.107881","url":null,"abstract":"<div><div>With the continuous rise in the power of chips for electric vehicle controllers, traditional air or liquid cooling can no longer meet the current heat dissipation requirements of such controllers. To meet the thermal management requirements of electric vehicle controllers, this study designs and optimizes a novel biomimetic honeycomb microchannel heat exchanger (HMHE) based on the leaf vein fractal network and honeycomb structure. Computational Fluid Dynamics (CFD) was employed to establish the simulation model of HMHE, and the effects of honeycomb grade, channel width ratio (<em>r</em>_<em>c</em>), channel width (<em>a</em>_<em>1</em>) and channel depth (<em>H</em>_<em>ch</em>) on the performance of HMHE were investigated. The comprehensive performance of HMHEs was compared using Figure of Merit (<em>FOM)</em>, determining that the three-level Honeycomb Microchannel Heat Exchanger (L3-HMHE) exhibits the optimal performance. Meanwhile, through single-parameter optimization, it was confirmed that the optimal structural parameter range of L3-HMHE is around <em>r</em>_<em>c</em> = 0.9, <em>a</em>_<em>1</em> = 8 mm and <em>H</em>_<em>ch</em> = 18 mm. Based on the optimization strategy combined with the Response Surface Methodology (RSM), a quantitative correlation model between the structural parameters of L3-HMHE and <em>FOM</em> was established. It was found that the channel width has the most significant impact on the comprehensive performance of the heat exchanger, while the optimal channel structural parameters are <em>r</em>_<em>c</em> = 0.8, <em>a</em>_<em>1</em> = 9 mm and <em>H</em>_<em>ch</em> = 18 mm, respectively. By comparing the results of numerical simulations and actual experiments, the temperature performance errors and pressure drop errors of the L3-HMHE between numerical simulations and actual experiments are maintained within 6.5% and 11%, respectively, at the load powers of 100 W, 120 W and 140 W, which validates the established numerical simulation model of the L3-HMHE. The <em>FOM</em> of the optimized L3-HMHE reaches 1.283, representing a 77.2% improvement compared with the traditional U-shaped heat exchanger, and it can satisfy the heat transfer requirements under a stable heat generation power of 200 W. The research results provide new insights into the structural design of HMHEs and promote the application of L3-HMHEs in the thermal management of electric vehicle controllers.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107881"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance and energy implications of a reconfigurable multi-mode dehumidification and reheating heat pump for electric vehicles","authors":"Haifeng Lu ,&nbsp;Dandong Wang ,&nbsp;Junye Shi ,&nbsp;Yuan Pan ,&nbsp;Mingli Shang ,&nbsp;Jiangping Chen ,&nbsp;Zhongqin Lin","doi":"10.1016/j.csite.2026.107883","DOIUrl":"10.1016/j.csite.2026.107883","url":null,"abstract":"<div><div>The performance of heat pump air-conditioning systems is crucial for electric vehicles (EVs), particularly under cold and humid conditions, where maintaining cabin comfort while minimizing energy consumption is a significant challenge. However, existing systems often suffer from an energy trade-off between dehumidification and reheating, leading to high energy consumption and reduced driving range in such environmental conditions. In this study, a multi-mode heat pump dehumidification and reheating system for EVs was developed, integrating four operational modes—Parallel Evaporator Dehumidification Mode (PEDM), Parallel Condenser Dehumidification Mode (PCDM), Whole Series Dehumidification Mode (WSDM), and Partial Series Dehumidification Mode (PSDM)—controlled by dynamic refrigerant flow regulation through solenoid valves and electronic expansion valves. A high-fidelity model was developed in AMESim and validated across a wide temperature range from −10 °C to 25 °C, coupled with a vehicle-level energy flow model for evaluating the effects on HVAC and overall vehicle energy consumption under the Worldwide harmonized Light-duty Test Cycle (WLTC).The results indicate that PEDM achieves the highest dehumidification coefficient of performance (DHCOP) and the lowest HVAC energy consumption (20.4 Wh/km), improving driving range by 11% compared to conventional single-mode systems. PCDM, while offering the highest moisture extraction rate (MER), incurs significantly higher energy consumption (45.5 Wh/km). WSDM strikes a balance between energy efficiency and performance (22.6 Wh/km), while PSDM operates stably but with lower efficiency. The study provides valuable insights into the coupling mechanism between dehumidification performance and vehicle energy flow, laying a foundation for designing adaptive, energy-efficient heat pump systems for EVs in cold and humid environments.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107883"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147359840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of a gas–steam–power system linked with energy storage devices in steel enterprises","authors":"Wei Tan ,&nbsp;Xin Liu ,&nbsp;Fupeng Song ,&nbsp;Dong Wang ,&nbsp;Zhaoyi Huo ,&nbsp;Zhuo Yao ,&nbsp;Yixuan Han ,&nbsp;Xiaoling Zhang","doi":"10.1016/j.csite.2026.107889","DOIUrl":"10.1016/j.csite.2026.107889","url":null,"abstract":"<div><div>In the \"dual-carbon\" strategy, steel enterprises' energy systems meet changeable electricity demand and rigorous carbon emission rules. This study integrates several types and scales of energy storage devices while optimizing a gas–steam–electric multi-energy network. A mixed integer non-linear programming (MINLP) approach is applied to generate an ideal strategy for energy storage arrangement and a dynamic scheduling technique. Four scenarios are evaluated: Scenario C1 serves as the initial optimal design; Scenario C2 builds on C1 by incorporating molten salt (MS) energy storage device (ESD) with a 25 MW generator set; Scenario C3 incorporate thermal conductive oil (TCO) ESD with a combined cycle power plant (CCPP); and Scenario C4 builds upon C2 by coupling MS–ESD of different scales with CCPP. Comparing scenario C4 with C1, it can be concluded that through ESD configuration, single-objective optimization yields monthly economic benefits of 2.45 × 10⁵ CNY. The C2 scenario enhances the high-efficiency unit's operating ratio through dynamic fuel allocation. Scenario C3 reduces the pressure on the power grid during peak electricity consumption periods. Using multi–objective optimization, ESD can achieve a cumulative economic benefit of 3.15 × 10⁷ CNY and an emission reduction of 3.41 × 10⁵ t_CO2 during its lifetime. Through detailed analysis of multi-scenario and multi-cycle optimization results, ESD-1 improves energy efficiency through fuel redistribution, and ESD-2 mainly plays the role of power peaking.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107889"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387372","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":"Waste-to-energy in CRDI engines: A case study on optimized biodiesel-ethanol-TBHQ blends for enhanced thermal performance and reduced emissions","authors":"Manish Kumar,&nbsp;Naushad Ahmad Ansari,&nbsp;Raghvendra Gautam","doi":"10.1016/j.csite.2026.107907","DOIUrl":"10.1016/j.csite.2026.107907","url":null,"abstract":"<div><div>Integrating waste-derived biofuels into common rail direct injection (CRDI) diesel engines presents a thermal engineering challenge in balancing performance and emissions while promoting circular economy principles. This case study investigates a novel blend of waste cooking oil and plastic oil biodiesel, ethanol, and tert-butyl hydroquinone (TBHQ) in a CRDI diesel engine. A hybrid Response Surface Methodology (RSM) and Grey Relational Analysis (GRA) framework optimized engine characteristics for performance and emissions. The optimized blend demonstrated improved brake thermal efficiency (15.17%) and exhaust gas temperature (168.27 °C), alongside significant reductions in CO (0.307% vol.), HC (29.05 ppm), and smoke opacity (15.37%). Crucially, while NO_x emissions (262 ppm) remained a challenge, TBHQ effectively mitigated oxidation-driven spikes, showcasing a targeted solution within this specific thermal system. Model robustness was confirmed with high statistical significance (R² &gt; 0.97) and low experimental validation errors (&lt;5%). This study, by integrating waste-derived feedstock, strongly aligns with circular economy goals, reducing reliance on petroleum oils. It offers a replicable, validated framework for multi-objective optimisation in sustainable thermal energy systems. Practical implications include enhanced urban air quality and a pathway for industries to meet stringent environmental regulations, accelerating sustainable biodiesel adoption in power sectors.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"80 ","pages":"Article 107907"},"PeriodicalIF":6.4,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147387373","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}