{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/125717"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/125717","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Measuring and modeling thermal conductivity of hydrogel phase change materials for thermal energy storage","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-08-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-08-01","abstract_has_math":false,"creators":["Hsieh, Daniel Hwai-En"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Sinha, Sanjiv","Braun, Paul V","Cai, Lili","Smith, Kyle"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024-07-12","date_published":"2024-07-12","updated_at":"2026-07-22T22:25:02Z","subjects":["Phase Change","3-omega","Hydrogel","Thermal Conductivity","Thermal Storage"],"languages":["en","eng"],"rights":["Copyright 2024 Daniel Hsieh"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/125717","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Sinha, Sanjiv","Braun, Paul V","Cai, Lili","Smith, Kyle"]},{"key":"dc:creator","label":"Author","values":["Hsieh, Daniel Hwai-En"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2024-07-12","2024-08"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Phase Change","3-omega","Hydrogel","Thermal Conductivity","Thermal Storage"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2024 Daniel Hsieh"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/125717"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-08-01","The student, Daniel Hsieh, accepted the attached license on 2024-07-11 at 09:45.","The student, Daniel Hsieh, submitted this Dissertation for approval on 2024-07-11 at 09:59.","This Dissertation was approved for publication on 2024-07-12 at 07:57.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21066 on 2025-02-04 at 21:17:03","Glauber's salt, a salt hydrate, possesses a relatively high volumetric latent heat (~0.3 GJ per cubic meter in solid form) but suffers from supercooling and phase segregation. Recent work on integrating the salt into a polymer hydrogel shows that phase segregation and supercooling can be mitigated over hundreds of cycles. Future practical realization of the salt-hydrogel complex as a thermal storage material requires an accurate characterization of thermal conductivity and strategies for enhancement since the rate of absorption and release of thermal energy increases with higher thermal conductivity. Here, we report a method for measuring the thermal conductivity of polymer hydrogels that improves over existing methods in accuracy. Specifically, we use a modified 3-omega method where heat flow from a microfabricated heater is split between that through the gel and that through its substrate. We report measurements on both gels and liquids and discuss advantages compared to existing transient plane heat source or transient hot-wire methods. We also use the 3-omega method on samples with and without a thin film to measure the thermal conductivity of a porous silicon film. Next, we present measurements of salt-hydrogel complexes as a function of temperature. Lastly, to investigate the origin of peaks in thermal conductivity during the phase transition, we compare data with analytical models of heat conduction with and without phase change. Our thermal conductivity setup and measurements combined with measurements of stored thermal energy, transition temperature range and physical stability are essential to develop models for thermal storage systems for efficient provision of heating and cooling in buildings."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Measuring and modeling thermal conductivity of hydrogel phase change materials for thermal energy storage"]}]}],"canonical_facts":{"dc:contributor":["Sinha, Sanjiv","Braun, Paul V","Cai, Lili","Smith, Kyle"],"dc:creator":["Hsieh, Daniel Hwai-En"],"dc:date":["2024-07-12","2024-08"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-08-01","The student, Daniel Hsieh, accepted the attached license on 2024-07-11 at 09:45.","The student, Daniel Hsieh, submitted this Dissertation for approval on 2024-07-11 at 09:59.","This Dissertation was approved for publication on 2024-07-12 at 07:57.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21066 on 2025-02-04 at 21:17:03","Glauber's salt, a salt hydrate, possesses a relatively high volumetric latent heat (~0.3 GJ per cubic meter in solid form) but suffers from supercooling and phase segregation. Recent work on integrating the salt into a polymer hydrogel shows that phase segregation and supercooling can be mitigated over hundreds of cycles. Future practical realization of the salt-hydrogel complex as a thermal storage material requires an accurate characterization of thermal conductivity and strategies for enhancement since the rate of absorption and release of thermal energy increases with higher thermal conductivity. Here, we report a method for measuring the thermal conductivity of polymer hydrogels that improves over existing methods in accuracy. Specifically, we use a modified 3-omega method where heat flow from a microfabricated heater is split between that through the gel and that through its substrate. We report measurements on both gels and liquids and discuss advantages compared to existing transient plane heat source or transient hot-wire methods. We also use the 3-omega method on samples with and without a thin film to measure the thermal conductivity of a porous silicon film. Next, we present measurements of salt-hydrogel complexes as a function of temperature. Lastly, to investigate the origin of peaks in thermal conductivity during the phase transition, we compare data with analytical models of heat conduction with and without phase change. Our thermal conductivity setup and measurements combined with measurements of stored thermal energy, transition temperature range and physical stability are essential to develop models for thermal storage systems for efficient provision of heating and cooling in buildings."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/125717"],"dc:language":["en","eng"],"dc:rights":["Copyright 2024 Daniel Hsieh"],"dc:subject":["Phase Change","3-omega","Hydrogel","Thermal Conductivity","Thermal Storage"],"dc:title":["Measuring and modeling thermal conductivity of hydrogel phase change materials for thermal energy storage"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:02Z"}