Importance of the spectral emissivity measurements at working temperature to determine the efficiency of a solar selective coating

The total emissivity of the absorbing surfaces is a critical parameter in the calculation of the radiative thermal losses in solar thermal collectors. This is because the radiative heat losses have a significant economic impact on the final cost of the electricity produced in a solar thermal plant....

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Detalles Bibliográficos
Autores: Echániz Ariceta, Telmo, Setién Fernández, Iñigo, Pérez Sáez, Raúl Benjamín, Prieto, Carlos, Escobar Galindo, Ramón, Tello León, Manuel
Tipo de recurso: artículo
Fecha de publicación:2015
País:España
Institución:Universidad del País Vasco
Repositorio:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:addi.ehu.eus:10810/64321
Acceso en línea:http://hdl.handle.net/10810/64321
Access Level:acceso abierto
Palabra clave:thermal solar energy
solar selective coatings
efficiency
infrared radiation
spectral emissivity
Descripción
Sumario:The total emissivity of the absorbing surfaces is a critical parameter in the calculation of the radiative thermal losses in solar thermal collectors. This is because the radiative heat losses have a significant economic impact on the final cost of the electricity produced in a solar thermal plant. This paper demonstrates the need to calculate the total emissivity from spectral emissivity measurements at the working temperature of the solar thermal collector, instead of using extrapolated values from spectral emissivities measured at room temperature. Usual uncertainties produced by the estimation of the total emissivity, in which its temperature dependence is only introduced by the Planck function, are analyzed.