Study on solar absorptance and thermal stability of solid particles materials used as TES at high temperature on different aging stages for CSP applications

Abstract

The use of solid particles as heat transfer fluid (HTF) presents a great potential to overcome drawbacks addressed in commercial Concentrated Solar Power (CSP) plants. The solid particles thermal energy storage (TES) system allows achieving both high thermal performance at high temperature and low cost from the material perspective. The conversion efficiency of CSP solid particles-based systems at high temperatures strongly depends on the optical properties and thermophysical properties of materials used both as HTF and as storage medium. The present study is aimed to provide more experimental data and evidences of the potential in using particulate solids for CSP application. The solar absorptance and the specific heat capacity of silicon carbide (SiC), silica sand (SiO2), and hematite (Fe2O3) are studied after different aging times at 750ºC and 900ºC. The solar absorptance slightly increases over the aging process except for the silica sand, which decreases its absorptance in the first 100 hours, reaching a plateau. After the aging treatment, the specific heat capacity is increased for both SiC and silica sand. However, for the iron oxide the specific heat capacity is lower after aging. The black silicon carbide SiC is proven to be the best option to be used up to 900ºC as it shows the highest solar absorptance (96%) and the highest heat storage capacity.

Assessment of Solid Wastes and By‐Products as Solid Particle Materials for Concentrated Solar Power Plants

“…Also, C p and solar absorptance measurements have been performed following a methodology already verified with other materials. [ 15,25 ]…”

“…[ 8–10 ] Until now, solid particle selection and characterization have been focused on synthetic and natural raw materials. [ 11–15 ]…”

Numerical Investigations of a Counter-Current Moving Bed Reactor for Thermochemical Energy Storage at High Temperatures

“…With the specific heat capacity of Mn 2 O 3 [23] and thermal diffusivity [24] of manganese ores, the intrinsic thermal conductivity is estimated for a temperature range between 400 K and 1400 K. A polynomial fit function for this temperature range (listed in Table 1) is used as an input value for the determination of the effective thermal conductivity of the bulk λ bulk,e f f according to the extended Zehner-Bauer-Schlünder model [20,21]. Furthermore, the emissivity of the manganese-iron oxide particles was approximated to 0.87, based on measured values for Fe 2 O 3 particles [25] and a Mn-Fe-Zr-coating [26].…”

Silicon Oxycarbide and Silicon Oxycarbonitride Materials under Concentrated Solar Radiation

“…A large number of studies are currently focused on the reliability and long-term stability of CSP components, especially receivers, during service in order to determine the commercial and industrial suitability and viability of both the receiver and new candidate materials. These studies are based on numerical models and predictions which take into account material properties and other characteristics of receiver design as well as ageing factors and should be completed with accelerated ageing tests that can evaluate the receiver behaviour under real operational conditions [ 6 , 7 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. The important and not easy issue is to develop testing methods and standards of validation of materials employed for solar energy applications, which is usually limited by solar testing facilities and also characterization methods available within laboratories [ 16 , 17 ].…”

“…Recently, Mazo et al [ 18 ] analysed the thermal shock behaviour of ceramic materials (i.e., SiC and silicon oxycarbide (SiOC)) using the same solar concentrator facility. Palacios et al [ 15 ] carried out an isothermal ageing treatment over the samples (SiC, sand and Fe 2 O 3 ) and studied the changes by the variation of colour, specific heat capacity, absorptance and XRD. Finally, a solar accelerated ageing facility was employed by Lalau et al [ 7 ], who studied the ageing of INCONEL and SiC exposed to thermo-mechanical stresses employing a numerical model and a non-destructive acoustic-emission technique.…”