Jean-Louis Sans

Hafnium and tantalum carbides for high temperature solar receivers

Solar thermal technology is a safe, sustainable, and cost-effective energy supply. The present paper reports on the comparative high-temperature emissivity characterization of hafnium and tantalum carbide ultra-high temperature ceramics to evaluate their potential as novel absorbing materials for concentrating solar power plants. For a more meaningful property assessment, ultra-high temperature ceramic samples have been compared also with silicon carbide, a material already used in volumetric solar receivers.

Concentrated Solar Energy to Study High Temperature Materials for Space and Energy

In this paper, the concentrated solar energy is used as a source of high temperatures to study the physical and chemical behaviors and intrinsic properties of refractory materials. The atmospheres surrounding the materials have to be simulated in experimental reactors to characterize the materials in real environments. Several application fields are concerned such as the aerospace and the energy fields: examples of results will be given for the heat shield of the Solar Probe Plus mission (NASA) for the SiC/SiC material that can be used as cladding materials for next nuclear reactor (gas-cooled fast reactor-GFR, Generation IV) and for new advanced materials for solar absorbers in concentration solar power (CSP) plant. Two different facilities-REHPTS and MEDIASE-implemented at the focus of two different solar furnaces of the PROMES-CNRS laboratory-5 kW and 1 MW-are presented together with some experimental results on the behavior of high temperature materials.

Optical properties of boride ultrahigh-temperature ceramics for solar thermal absorbers

Abstract. It is a known rule that the efficiency of thermodynamic solar plants increases with the working temperature. At present, the main limit in temperature upscaling is the absorber capability to withstand high temperatures. The ideal solar absorber works at high temperatures and has both a low thermal emissivity and a high absorptivity in the solar spectral range. The present work reports on the preparation and optical characterization of hafnium and zirconium diboride ultrahigh-temperature ceramics for innovative solar absorbers operating at high temperature. Spectral hemispherical reflectance from the ultraviolet to the mid-infrared wavelength region and high-temperature hemispherical emittance reveal their potential for high-temperature solar applications. Boride samples are compared with silicon carbide (SiC), a material already used in solar furnaces.

On-sun first operation of a 150 kWth pilot solar receiver using dense particle suspension as heat transfer fluid

A 50-150 kWth pilot solar rig comprising the key equipments of a real plant and that uses silicon carbide Dense Particles Suspension as the heat transfer fluid has been tested at the 1 MW solar furnace at Odeillo-Font Romeu, France. The tests were carried out under large ranges of operating parameters and controlling the mass flow rate when higher temperature was required and when changes on DNI (direct normal irradiation) occurred. This paper presents experimental results on particle outlet temperature, dynamic response of the system to solid mass flow rate and solar power variations, and receiver thermal efficiency (η). Mean and maximum particles’ temperature up to 585°C and 720°C respectively was reached. The receiver thermal efficiency was measured in the range 50-90%.