Measuring High Surface Temperature in Concentrated Solar Radiation Environments

Jesús Ballestrín

doi:10.11648/j.ajetm.20170203.12

Abstract

Surface temperature is a highly desired but difficult measurement especially in concentrated solar context. In this work a method for surface temperature measurement based on contact sensors is presented. In the case of materials with high thermal conductivity, contact sensors positioned in the back of the material sample and very close to the surface is the most accurate way to measure surface temperature. Computational Fluid Dynamics simulations have shown the truth of this statement. The higher thermal conductivity of the material, the lower the uncertainty in the measurement of surface temperature using this methodology. This measurement procedure has been applied to AISI 310S steel samples in the Plataforma Solar de Almeria vertical axis solar furnace SF5 confirming the validity of the simulations.

Highlights

The measurement of the temperature of a surface, when this temperature differs considerably from that of the environment, offers difficulties not encountered in the usual kind of temperature measurements, and many special devices and refinements of technique have been applied in problems of this kind
This paper presents Computational Fluid Dynamics (CFD) simulations showing that, in the case of materials with good thermal conductivity, contact sensors positioned in the back of the material sample and very close to the surface is the most accurate way to measure surface temperature
The CFD model was validated by the comparison between the temperature measured experimentally for an AISI 310 steel sample and the numerical values obtained at the same thermocouple locations considering the same steel as sample material

Summary

Introduction

The measurement of the temperature of a surface, when this temperature differs considerably from that of the environment, offers difficulties not encountered in the usual kind of temperature measurements, and many special devices and refinements of technique have been applied in problems of this kind. Non-contact or infrared or pyrometric sensors, though relatively expensive, are appropriate when the temperatures are extremely high. They are available for up to 3000 K far exceeding the range of contact devices. A difficulty with pyrometric temperature measurement is, that the detector responds to solar radiation which is directly reflected from the irradiated sample, as well as re-radiation. This problem has been partially resolved with the design and manufacturing of solar-blind pyrometers and cameras [1524]. In these cases the uncertainty in the temperature measurement is unknown and must be used a more reliable measurement technique as contact sensors

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Conclusion