Enhanced behaviour of a passive thermoelectric generator with phase change heat exchangers and radiative cooling

Heat exchangers are essential to optimize the efficiency of Thermoelectric Generators (TEGs), and heat pipes without fans have proven to be an advantageous design as it maintains the characteristic robustness of thermoelectricity, low maintenance and lack of moving parts. However, the efficiency of...

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Detalles Bibliográficos
Autores: Astrain Ulibarrena, David, Jaramillo Fernández, Juliana|||0000-0002-4787-3904, Araiz Vega, Miguel, Francone, Achille, Catalán Ros, Leyre, Jacobo Martín, Alejandra, Alegría Cia, Patricia, Sotomayor Torres, Clivia M.
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/397527
Acceso en línea:https://hdl.handle.net/2117/397527
https://dx.doi.org/10.1016/j.applthermaleng.2023.120162
Access Level:acceso abierto
Palabra clave:Thermoelectric generators
Radiative transfer
Thermistors
Radiative cooling
Heat-pipe
Thermoelectric generator
Thermal resistance
Generadors termoelèctrics
Termistors
Transferència radiativa
Àrees temàtiques de la UPC::Física::Termodinàmica
Descripción
Sumario:Heat exchangers are essential to optimize the efficiency of Thermoelectric Generators (TEGs), and heat pipes without fans have proven to be an advantageous design as it maintains the characteristic robustness of thermoelectricity, low maintenance and lack of moving parts. However, the efficiency of these heat exchangers decreases under natural convection conditions, reducing their heat transfer capacity and thus thermoelectric power production. This work reports on a novel heat exchanger that combines for the first time, phase change and radiative cooling in a thermoelectric generator to improve its efficiency and increase the production of electrical energy, specially under natural convection. For this, two thermoelectric generators with heat-pipes on their cold sides have been tested: one with the radiative coating and the other without it. Their thermal resistances have been determined and the electric power output was compared under different working conditions, namely, natural convection and forced convection indoors and outdoors. The experimental tests show a clear reduction of the heat exchanger thermal resistance thanks to the radiative coating and consequently, an increase of electric production 8.3 % with outdoor wind velocities of 1 m/s, and up to 54.8 % under free convection conditions. The application of the radiative surface treatment is shown to result in a more stable electrical energy production, suppressing the drastic decrease in the generated electric power that occurs in thermoelectric generators when they work under free convection.