Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers

Thermoelectric generators are a highly suitable alternative for applications that require robustness, reliability and low maintenance, such as power supply in remote volcanic regions and extreme environments. However, in order to broaden the scope of this technology, it is essential to adapt its des...

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Autores: Pascual Lezaun, Nerea, Alegría Cía, Patricia, Catalán Ros, Leyre, Martínez Echeverri, Álvaro, Astrain Ulibarrena, David
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Universidad Pública de Navarra
Repositorio:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
OAI Identifier:oai:academica-e.unavarra.es:2454/55851
Acceso en línea:https://hdl.handle.net/2454/55851
Access Level:acceso abierto
Palabra clave:Geothermal energy
Hybrid heat exchanger
Passive thermoelectric generator
Phase change fluid
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spelling Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangersPascual Lezaun, NereaAlegría Cía, PatriciaCatalán Ros, LeyreMartínez Echeverri, ÁlvaroAstrain Ulibarrena, DavidGeothermal energyHybrid heat exchangerPassive thermoelectric generatorPhase change fluidThermoelectric generators are a highly suitable alternative for applications that require robustness, reliability and low maintenance, such as power supply in remote volcanic regions and extreme environments. However, in order to broaden the scope of this technology, it is essential to adapt its design and performance to variable operating conditions. In this context, the present study has developed an innovative system of geothermal passive thermoelectric generators based on a phase change heat exchanger, aimed at the continuous generation of electricity from low-enthalpy geothermal sources, specifically volcanic fumaroles. Experimental tests have evaluated different heat exchanger configurations under a wide range of operating conditions, including different ambient temperatures and wind speeds. The analysis included the power produced, the conversion efficiency and the thermal resistance of the heat exchangers. On the hot side, a heat pipe-based exchanger was compared with a thermosyphon-based exchanger, with the former producing an average of 17% more electricity. To adapt the system to adverse meteorological conditions, both water and methanol were used as working fluids. Water was more efficient, with a 49% lower thermal resistance, resulting in a 17% increase in electricity generation. Nevertheless, when freezing occurs, the performance of the water-based system drops by 90%, while the methanol-based system continues to operate effectively. As a solution, a hybrid system combining water and methanol heat pipes on the cold side has been developed, achieving power outputs of up to 1 W and generating between 600% and 710% more power than the water-based system under freezing conditions.The authors would like to acknowledge the support of the Spanish State Research Agency and FEDER-UE, Spain for funding under the PID2021-124014OB-I00 research project.ElsevierIngenieríaIngeniaritzaInstitute of Smart Cities - ISC2025info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2454/55851reponame:Academica-e. Repositorio Institucional de la Universidad Pública de Navarrainstname:Universidad Pública de NavarraInglésinfo:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/PID2021-124014OB-I00© 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.https://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessoai:academica-e.unavarra.es:2454/558512026-06-17T12:41:47Z
dc.title.none.fl_str_mv Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
title Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
spellingShingle Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
Pascual Lezaun, Nerea
Geothermal energy
Hybrid heat exchanger
Passive thermoelectric generator
Phase change fluid
title_short Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
title_full Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
title_fullStr Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
title_full_unstemmed Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
title_sort Experimental analysis of geothermal passive thermoelectric generators combining water and methanol based heat exchangers
dc.creator.none.fl_str_mv Pascual Lezaun, Nerea
Alegría Cía, Patricia
Catalán Ros, Leyre
Martínez Echeverri, Álvaro
Astrain Ulibarrena, David
author Pascual Lezaun, Nerea
author_facet Pascual Lezaun, Nerea
Alegría Cía, Patricia
Catalán Ros, Leyre
Martínez Echeverri, Álvaro
Astrain Ulibarrena, David
author_role author
author2 Alegría Cía, Patricia
Catalán Ros, Leyre
Martínez Echeverri, Álvaro
Astrain Ulibarrena, David
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Ingeniería
Ingeniaritza
Institute of Smart Cities - ISC
dc.subject.none.fl_str_mv Geothermal energy
Hybrid heat exchanger
Passive thermoelectric generator
Phase change fluid
topic Geothermal energy
Hybrid heat exchanger
Passive thermoelectric generator
Phase change fluid
description Thermoelectric generators are a highly suitable alternative for applications that require robustness, reliability and low maintenance, such as power supply in remote volcanic regions and extreme environments. However, in order to broaden the scope of this technology, it is essential to adapt its design and performance to variable operating conditions. In this context, the present study has developed an innovative system of geothermal passive thermoelectric generators based on a phase change heat exchanger, aimed at the continuous generation of electricity from low-enthalpy geothermal sources, specifically volcanic fumaroles. Experimental tests have evaluated different heat exchanger configurations under a wide range of operating conditions, including different ambient temperatures and wind speeds. The analysis included the power produced, the conversion efficiency and the thermal resistance of the heat exchangers. On the hot side, a heat pipe-based exchanger was compared with a thermosyphon-based exchanger, with the former producing an average of 17% more electricity. To adapt the system to adverse meteorological conditions, both water and methanol were used as working fluids. Water was more efficient, with a 49% lower thermal resistance, resulting in a 17% increase in electricity generation. Nevertheless, when freezing occurs, the performance of the water-based system drops by 90%, while the methanol-based system continues to operate effectively. As a solution, a hybrid system combining water and methanol heat pipes on the cold side has been developed, achieving power outputs of up to 1 W and generating between 600% and 710% more power than the water-based system under freezing conditions.
publishDate 2025
dc.date.none.fl_str_mv 2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2454/55851
url https://hdl.handle.net/2454/55851
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/PID2021-124014OB-I00
dc.rights.none.fl_str_mv https://creativecommons.org/licenses/by-nc-nd/4.0/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-nd/4.0/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
instname:Universidad Pública de Navarra
instname_str Universidad Pública de Navarra
reponame_str Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
collection Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
repository.name.fl_str_mv
repository.mail.fl_str_mv
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