{"paper_id":"1244dc52-294e-4f20-8ca8-3c1c50416b0e","body_text":"Effect of Gradient Phase-Change Temperature on Thermal Performance of Floor Heating Systems with Encased Phase-Change Materials | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Effect of Gradient Phase-Change Temperature on Thermal Performance of Floor Heating Systems with Encased Phase-Change Materials Cuiping Zang, Yandong Tang, Zhenyu Wang, Yanna Gao This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9262324/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 17 You are reading this latest preprint version Abstract As phase-change materials (PCMs) are increasingly utilized in radiant floor heating system (RFHS), their benefits in reducing temperature variations and improving energy efficiency have been clearly proven. However, existing studies have primarily focused on the thermal behavior of PCMs with a single phase change temperature, while the application of gradient PCMs in encased floor systems remains underexplored. This study proposes an optimized design integrating gradient PCMs into a single-layer encased RFHS. Using CFD simulation, the effects of phase change temperature gradients in the inner and outer PCM layers on the thermal behavior of the RFHS were systematically investigated. The results indicate that the phase transition temperature of the outer PCM layer significantly influences the surface temperature response speed, average temperature, and temperature fluctuation. In contrast, the phase change temperature of the inner PCM layer primarily affects the heat dissipation rate and high-temperature retention duration. By optimizing the phase change temperature gradients of the inner and outer PCM layers, the optimal configuration was identified (outer layer: 32–37°C; inner layer: 38–43°C). Compared to conventional designs, the optimized system achieved a 9.89% increase in phase change rate, a 24.32% extension in high-temperature duration, a 1.8% rise in average temperature, and a 5.41% reduction in temperature fluctuation. This study offers theoretical guidance and technical support to improve the thermal efficiency of encased RFHS and promoting their application in green buildings. Physical sciences/Energy science and technology Physical sciences/Engineering Physical sciences/Materials science Physical sciences/Physics Radiant floor heating system (RFHS) Phase-Change Material (PCM) Gradient Numerical simulation Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 04 May, 2026 Reviews received at journal 04 May, 2026 Reviews received at journal 30 Apr, 2026 Reviews received at journal 22 Apr, 2026 Reviews received at journal 20 Apr, 2026 Reviews received at journal 19 Apr, 2026 Reviewers agreed at journal 10 Apr, 2026 Reviewers agreed at journal 10 Apr, 2026 Reviewers agreed at journal 10 Apr, 2026 Reviewers agreed at journal 08 Apr, 2026 Reviewers agreed at journal 08 Apr, 2026 Reviewers agreed at journal 08 Apr, 2026 Reviewers invited by journal 08 Apr, 2026 Editor invited by journal 06 Apr, 2026 Editor assigned by journal 31 Mar, 2026 Submission checks completed at journal 31 Mar, 2026 First submitted to journal 30 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-9262324\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Article\",\"associatedPublications\":[],\"authors\":[{\"id\":621249052,\"identity\":\"1797f257-ad16-4e57-80be-964ec3ef2b67\",\"order_by\":0,\"name\":\"Cuiping Zang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Sichuan Polytechnic University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Cuiping\",\"middleName\":\"\",\"lastName\":\"Zang\",\"suffix\":\"\"},{\"id\":621249053,\"identity\":\"ff2ba4d4-a10d-44fe-86a8-3f294cc2a8f1\",\"order_by\":1,\"name\":\"Yandong Tang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Sichuan Polytechnic University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Yandong\",\"middleName\":\"\",\"lastName\":\"Tang\",\"suffix\":\"\"},{\"id\":621249054,\"identity\":\"f6a85296-83d9-4115-a596-314ce81a4c47\",\"order_by\":2,\"name\":\"Zhenyu Wang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Qingdao University of Technology\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Zhenyu\",\"middleName\":\"\",\"lastName\":\"Wang\",\"suffix\":\"\"},{\"id\":621249055,\"identity\":\"cb386c75-5cc9-4134-a1b7-17875736e66f\",\"order_by\":3,\"name\":\"Yanna Gao\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAArklEQVRIiWNgGAWjYHACNhAhx8befoA0LcZ8PGcSSNOSOE/CwYA49fIRucce89TYpbdJMCQw/KjYRliL4Y28dGOeY8m5bdKNBxh7ztwmQsuMHDPJGWwHcttkDiQwM7YRreXfgXQ2iQQD4rTIS+SYSXxsO5BAvBYDnjdALX3Jhm3AQD5IlF/k24G2JHyzk5dvbz/44EcFMbZcSEBwDhBWD7Klnzh1o2AUjIJRMJIBAIzYOYZLQkn+AAAAAElFTkSuQmCC\",\"orcid\":\"\",\"institution\":\"Qingdao University of Technology\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Yanna\",\"middleName\":\"\",\"lastName\":\"Gao\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-03-30 04:23:50\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-9262324/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-9262324/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":106973163,\"identity\":\"e3cc4178-2d71-4811-9d69-4730dfc54ff0\",\"added_by\":\"auto\",\"created_at\":\"2026-04-15 10:26:37\",\"extension\":\"pdf\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":1776730,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"masnuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9262324/v1_covered_d86d3937-6e9e-4f0e-bcc6-39da34afb692.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Effect of Gradient Phase-Change Temperature on Thermal Performance of Floor Heating Systems with Encased Phase-Change Materials\",\"fulltext\":[],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":false,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":true,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":true,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"scientific-reports\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"scirep\",\"sideBox\":\"Learn more about [Scientific Reports](http://www.nature.com/srep/)\",\"snPcode\":\"\",\"submissionUrl\":\"\",\"title\":\"Scientific Reports\",\"twitterHandle\":\"\",\"acdcEnabled\":true,\"dfaEnabled\":true,\"editorialSystem\":\"stoa\",\"reportingPortfolio\":\"Scientific Reports\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Radiant floor heating system (RFHS), Phase-Change Material (PCM), Gradient, Numerical simulation\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-9262324/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-9262324/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eAs phase-change materials (PCMs) are increasingly utilized in radiant floor heating system (RFHS), their benefits in reducing temperature variations and improving energy efficiency have been clearly proven. However, existing studies have primarily focused on the thermal behavior of PCMs with a single phase change temperature, while the application of gradient PCMs in encased floor systems remains underexplored. This study proposes an optimized design integrating gradient PCMs into a single-layer encased RFHS. Using CFD simulation, the effects of phase change temperature gradients in the inner and outer PCM layers on the thermal behavior of the RFHS were systematically investigated. The results indicate that the phase transition temperature of the outer PCM layer significantly influences the surface temperature response speed, average temperature, and temperature fluctuation. In contrast, the phase change temperature of the inner PCM layer primarily affects the heat dissipation rate and high-temperature retention duration. By optimizing the phase change temperature gradients of the inner and outer PCM layers, the optimal configuration was identified (outer layer: 32\\u0026ndash;37\\u0026deg;C; inner layer: 38\\u0026ndash;43\\u0026deg;C). Compared to conventional designs, the optimized system achieved a 9.89% increase in phase change rate, a 24.32% extension in high-temperature duration, a 1.8% rise in average temperature, and a 5.41% reduction in temperature fluctuation. This study offers theoretical guidance and technical support to improve the thermal efficiency of encased RFHS and promoting their application in green buildings.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Effect of Gradient Phase-Change Temperature on Thermal Performance of Floor Heating Systems with Encased Phase-Change Materials\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-04-15 10:13:49\",\"doi\":\"10.21203/rs.3.rs-9262324/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Revision 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