{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T04:57:12Z","timestamp":1780376232380,"version":"3.54.1"},"reference-count":41,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,6,25]],"date-time":"2025-06-25T00:00:00Z","timestamp":1750809600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>TGA kinetic analysis can assess the thermal stability and degradation properties of PCMs by calculating activation energies and onset degradation temperatures, which are critical elements when developing optimal PCM composition and assessing long-term performance in thermal energy storage applications. In this study, we utilize a thermogravimetric analyzer to examine the thermal stability of both solar salt phase change material (i.e., commonly used in medium-temperature applications) (NaNO3 + KNO3) and a composite eutectic PCM mixture (i.e., PCM with 20% biochar). The activation energies of both the pure solar salt and composite solar salt PCM sample were evaluated using a variety of different kinetic models such as Kissinger\u2013Akahira\u2013Sunose (KAS), Flynn\u2013Wall\u2013Ozawa (FWO), and Starink. For pure PCM, the mean activation energies calculated using the KAS, FWO, and Starink methods are 581.73 kJ\/mol, 570.47 kJ\/mol, and 581.31 kJ\/mol, respectively. Conversely, for the composite solar salt PCM sample, the calculated experimental average activation energies are 51.67 kJ\/mol, 62.124 kJ\/mol, and 51.383 kJ\/mol. Additionally, various machine learning models, such as linear regression, decision tree regression, gradient boosting regression, random forest regression, polynomial regression, Gaussian process regression, and KNN regression models, are developed to predict the degradation behaviour of pure and composite solar salts under different loading rates. In the machine learning models, the mass loss of the samples is the output variable and the input features are PCM type, heating rate, and temperature. The machine learning models had a great prediction performance based on experimental TGA data, with KNN regression outperforming the other models by achieving the lowest RMSE of 0.0318 and the highest R2 score of 0.977.<\/jats:p>","DOI":"10.3390\/sym17070998","type":"journal-article","created":{"date-parts":[[2025,6,25]],"date-time":"2025-06-25T03:53:02Z","timestamp":1750823582000},"page":"998","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Numerical Investigation Using Machine Learning Process Combination of Bio PCM and Solar Salt for Thermal Energy Storage Applications"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5057-7786","authenticated-orcid":false,"given":"Ravi Kumar","family":"Kottala","sequence":"first","affiliation":[{"name":"Department of Data Engineering, MVGR College of Engineering (A), Vizianagaram 535005, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sankaraiah","family":"Mogaligunta","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronics Engineering, NBKR Institute of Science and Technology, Tirupati 524413, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Makham Satyanarayana","family":"Gupta","sequence":"additional","affiliation":[{"name":"Department of Aeronautical Engineering, MLR Institute of Technology, Hyderabad 500043, Telangana, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5667-9476","authenticated-orcid":false,"given":"Seepana","family":"Praveenkumar","sequence":"additional","affiliation":[{"name":"Department of Nuclear and Renewable Energy Sources, Ural Federal University, 620002 Yekaterinburg City, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ramakrishna","family":"Raghutu","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronics Engineering, GMR Institute of Technology (A), Rajam 532127, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kiran Kumar","family":"Patro","sequence":"additional","affiliation":[{"name":"Department of Electronics and Communication Engineering, Aditya Institute of Technology and Management (A), Tekkali 532203, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9960-6373","authenticated-orcid":false,"given":"Achanta Sampath Dakshina","family":"Murthy","sequence":"additional","affiliation":[{"name":"Department of Electronics and Communication Engineering, Vignan\u2019s Institute of Information Technology, Duvvada, Visakhapatnam 530049, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7788-5773","authenticated-orcid":false,"given":"Dharmaiah","family":"Gurram","sequence":"additional","affiliation":[{"name":"Department of Mathematics, Vasireddy Venkatadri International Technological University, Guntur 522508, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,6,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Wan, Y., Chen, Y., Cui, Z., Ding, H., Gao, S., Han, Z., and Gao, J. (2019). A Promising Form-Stable Phase Change Material Prepared Using Cost Effective Pinecone Biochar as the Matrix of Palmitic Acid for Thermal Energy Storage. Sci. Rep., 9.","DOI":"10.1038\/s41598-019-47877-z"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"111102","DOI":"10.1016\/j.diamond.2024.111102","article-title":"A Novel PCM\/Expanded Graphite Composite Sphere with High Thermal Conductivity and Excellent Shape Stability Used for a Packed-Bed Thermal Energy System","volume":"145","author":"Ma","year":"2024","journal-title":"Diam. Relat. Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4451","DOI":"10.1007\/s10973-021-10839-7","article-title":"A Review on the Use of Coconut Oil as an Organic Phase Change Material with Its Melting Process, Heat Transfer, and Energy Storage Characteristics","volume":"147","author":"Saleel","year":"2022","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"111392","DOI":"10.1016\/j.solmat.2021.111392","article-title":"A Comprehensive Review on Phase Change Materials for Heat Storage Applications: Development, Characterization, Thermal and Chemical Stability","volume":"234","author":"Tyagi","year":"2022","journal-title":"Sol. Energy Mater. Sol. Cells"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"109435","DOI":"10.1016\/j.compositesb.2021.109435","article-title":"Excellent Heat Transfer and Phase Transformation Performance of Erythritol\/Graphene Composite Phase Change Materials","volume":"228","author":"Yan","year":"2022","journal-title":"Compos. Part. B Eng."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Hassan, N., Minakshi, M., Ruprecht, J., Liew, W.Y.H., and Jiang, Z.-T. (2023). A Binary Salt Mixture LiCl\u2013LiOH for Thermal Energy Storage. Materials, 16.","DOI":"10.3390\/ma16041434"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Hassan, N., Minakshi, M., Liew, W.Y.H., Amri, A., and Jiang, Z.-T. (2023). Thermal Characterization of Binary Calcium-Lithium Chloride Salts for Thermal Energy Storage at High Temperature. Energies, 16.","DOI":"10.3390\/en16124715"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2487","DOI":"10.1007\/s10973-020-09521-1","article-title":"Characterization of Form-Stable Phase-Change Material for Solar Photovoltaic Cooling","volume":"141","author":"Senthilkumar","year":"2020","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_9","first-page":"11","article-title":"Experimental Analysis and Neural Network Model of MWCNTs Enhanced Phase Change Materials","volume":"43","author":"Balasubramanian","year":"2021","journal-title":"Int. J. Thermophys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"113646","DOI":"10.1016\/j.est.2024.113646","article-title":"Novel Nano-Y2O3\/Myristic Acid Nanocomposite PCM for Cooling Performances of Electronic Device with Various Fin Designs","volume":"100","year":"2024","journal-title":"J. Energy Storage"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1080\/1536383X.2022.2123800","article-title":"Preparation and Characterisation of Binary Eutectic Phase Change Material\/Activated Porous Bio Char\/Multi Walled Carbon Nano Tubes as Composite Phase Change Material","volume":"31","author":"Ramaraj","year":"2023","journal-title":"Fuller. Nanotub. Carbon. Nanostruct."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1007\/s10765-016-2116-3","article-title":"Preparation and Thermal Characterization of Nitrates\/Expanded Graphite Composite Phase-Change Material for Thermal Energy Storage","volume":"37","author":"Li","year":"2016","journal-title":"Int. J. Thermophys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.enconman.2018.02.057","article-title":"Ca(NO3)2-NaNO3\/Expanded Graphite Composite as a Novel Shape-Stable Phase Change Material for Mid- to High-Temperature Thermal Energy Storage","volume":"163","author":"Ren","year":"2018","journal-title":"Energy Convers. Manag."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"133913","DOI":"10.1016\/j.colsurfa.2024.133913","article-title":"Salt-Resistant, Environment-Friendly Silk\/Melanin Composite Aerogel with Directional Channel for Solar-Driven Evaporation","volume":"691","author":"Zhai","year":"2024","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"101403","DOI":"10.1016\/j.est.2020.101403","article-title":"A Novel Form Stable PCM Based Bio Composite Material for Solar Thermal Energy Storage Applications","volume":"30","author":"Das","year":"2020","journal-title":"J. Energy Storage"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Zhang, H.-C., Kang, B., Sheng, X., and Lu, X. (2019). Novel Bio-Based Pomelo Peel Flour\/Polyethylene Glycol Composite Phase Change Material for Thermal Energy Storage. Polymers, 11.","DOI":"10.3390\/polym11122043"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"102690","DOI":"10.1016\/j.tsep.2024.102690","article-title":"Using Metal Foam and Nanoparticle Additives with Different Fin Shapes for PCM-Based Thermal Storage in Flat Plate Solar Collectors","volume":"52","author":"NematpourKeshteli","year":"2024","journal-title":"Therm. Sci. Eng. Prog."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e36105","DOI":"10.1016\/j.heliyon.2024.e36105","article-title":"Optimization of the Thermal Performance of a Lobed Triplex-Tube Solar Thermal Storage System Equipped with a Phase Change Material","volume":"10","author":"NematpourKeshteli","year":"2024","journal-title":"Heliyon"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"012038","DOI":"10.1088\/1755-1315\/1281\/1\/012038","article-title":"Thermodynamic and Thermal Degradation Kinetics Analysis of Coconut Shell Biomass Based Phase Change Material","volume":"1281","author":"Kalidasan","year":"2023","journal-title":"IOP Conf. Ser. Earth Environ. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"111278","DOI":"10.1016\/j.est.2024.111278","article-title":"A Comprehensive Assessment on Bio-Mass Derived Form-Stabilized Composite Phase Change Materials for Solar Thermal Energy Storage Systems","volume":"86","author":"Prabhu","year":"2024","journal-title":"J. Energy Storage"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"116656","DOI":"10.1016\/j.est.2025.116656","article-title":"Synthesis and Characterization of High Thermal Conductive Leak Resistant Phase Change Material for Solar Photovoltaic Panel Cooling Applications","volume":"122","author":"Hari","year":"2025","journal-title":"J. Energy Storage"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.est.2019.01.017","article-title":"Experimental Thermal Degradation Analysis of Pentaerythritol with Alumina Nano Additives for Thermal Energy Storage Application","volume":"22","author":"Venkitaraj","year":"2019","journal-title":"J. Energy Storage"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1016\/j.polymdegradstab.2011.12.003","article-title":"Co-Microencapsulate of Ammonium Polyphosphate and Pentaerythritol and Kinetics of Its Thermal Degradation","volume":"97","author":"Sun","year":"2012","journal-title":"Polym. Degrad. Stab."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Xiang, L., Luo, D., Yang, J., Sun, X., Qi, Y., and Qin, S. (2019). Preparation and Comparison of Properties of Three Phase Change Energy Storage Materials with Hollow Fiber Membrane as the Supporting Carrier. Polymers, 11.","DOI":"10.3390\/polym11081343"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Kottala, R.K., Chigilipalli, B.K., Mukuloth, S., Shanmugam, R., Kantumuchu, V.C., Ainapurapu, S.B., and Cheepu, M. (2023). Thermal Degradation Studies and Machine Learning Modelling of Nano-Enhanced Sugar Alcohol-Based Phase Change Materials for Medium Temperature Applications. Energies, 16.","DOI":"10.3390\/en16052187"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"15733","DOI":"10.1002\/er.8272","article-title":"Thermal Degradation Studies and Hybrid Neural Network Modelling of Eutectic Phase Change Material Composites","volume":"46","author":"Balasubramanian","year":"2022","journal-title":"Int. J. Energy Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"110292","DOI":"10.1016\/j.ress.2024.110292","article-title":"Adaptive Maintenance Window-Based Opportunistic Maintenance Optimization Considering Operational Reliability and Cost","volume":"250","author":"Lu","year":"2024","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e33681","DOI":"10.1016\/j.heliyon.2024.e33681","article-title":"A Review on Machine Learning Implementation for Predicting and Optimizing the Mechanical Behaviour of Laminated Fiber-Reinforced Polymer Composites","volume":"10","author":"Sorour","year":"2024","journal-title":"Heliyon"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"126001","DOI":"10.1088\/1402-4896\/ad0587","article-title":"Machine Learning Approach on the Prediction of Mechanical Characteristics of Pristine, Boron Doped and Nitrogen Doped Graphene","volume":"98","author":"Shahbaz","year":"2023","journal-title":"Phys. Scr."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"090601","DOI":"10.1063\/5.0230677","article-title":"Material Discovery and Modeling Acceleration via Machine Learning","volume":"12","author":"Zuccarini","year":"2024","journal-title":"APL Mater."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"194106","DOI":"10.1063\/5.0171540","article-title":"Gradient Boosted and Statistical Feature Selection Workflow for Materials Property Predictions","volume":"159","author":"Jung","year":"2023","journal-title":"J. Chem. Phys."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Liu, F., Wu, H., Wu, X., Xiang, Z., Huang, S., and Chen, M. (2024). Data-Driven Bi-Directional Lattice Property Customization and Optimization. Materials, 17.","DOI":"10.3390\/ma17225599"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Guo, P., Moghaddas, S.A., Liu, Y., Meng, W., Li, V.C., and Bao, Y. (2025). Applications of Machine Learning Methods for Design and Characterization of High-Performance Fiber-Reinforced Cementitious Composite (HPFRCC): A Review. J. Sustain. Cem.-Based Mater., 1\u201324.","DOI":"10.1080\/21650373.2025.2462183"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"216350","DOI":"10.1016\/j.ccr.2024.216350","article-title":"Naphthalenediimide and Perylenediimide Based Donor-Acceptor Crystalline Hybrid Materials: Structures and Applications","volume":"526","author":"Liu","year":"2025","journal-title":"Coord. Chem. Rev."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"590","DOI":"10.1016\/j.dyepig.2018.10.053","article-title":"Deep Red PhOLED from Dimeric Salophen Platinum(II) Complexes","volume":"162","author":"Zhang","year":"2019","journal-title":"Dye. Pigment."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Jia, Y., Chen, G., and Zhao, L. (2024). Defect Detection of Photovoltaic Modules Based on Improved VarifocalNet. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-66234-3"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"155933","DOI":"10.1016\/j.cej.2024.155933","article-title":"Green Recycling of End-of-Life Photovoltaic Modules via Deep-Eutectic Solvents","volume":"499","author":"Yu","year":"2024","journal-title":"Chem. Eng. J."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"101366","DOI":"10.1016\/j.est.2020.101366","article-title":"Preparation and Thermal Property of Unusual Morphology NaNO3 Modified by Solution Combustion for Thermal Energy Storage","volume":"29","author":"Zheng","year":"2020","journal-title":"J. Energy Storage"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/j.solener.2023.04.048","article-title":"NaNO3-KNO3\/EG\/Al2O3 Shape-Stable Phase Change Materials for Thermal Energy Storage over a Wide Temperature Range: Sintering Temperature Study","volume":"258","author":"Ji","year":"2023","journal-title":"Sol. Energy"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1007\/s10765-022-03069-y","article-title":"Experimental Investigation of Nano-Encapsulated Molten Salt for Medium-Temperature Thermal Storage Systems and Modeling of Neural Networks","volume":"43","author":"Kumar","year":"2022","journal-title":"Int. J. Thermophys."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7101","DOI":"10.1007\/s10973-023-12219-9","article-title":"Experimental Investigation and Machine Learning Modelling of Phase Change Material-Based Receiver Tube for Natural Circulated Solar Parabolic Trough System under Various Weather Conditions","volume":"148","author":"Kottala","year":"2023","journal-title":"J. Therm. Anal. Calorim."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/17\/7\/998\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:58:07Z","timestamp":1760032687000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/17\/7\/998"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,25]]},"references-count":41,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["sym17070998"],"URL":"https:\/\/doi.org\/10.3390\/sym17070998","relation":{},"ISSN":["2073-8994"],"issn-type":[{"value":"2073-8994","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,6,25]]}}}