Using solar energy to generate heat at 1050°C high temperatures
ethz.ch
ethz.ch
> Summary: Common semi-transparent materials like quartz and water feature spectral optical properties characterized by low attenuation of visible radiation and strong absorption of infrared (IR) radiation emitted by hot surfaces. This leads to the thermal trap effect, exploitable in solar-concentrating applications to attain higher absorber temperatures and thermal efficiencies. Here, we demonstrate this effect at high temperatures with a quartz rod attached to an opaque absorber plate reaching 1,050°C when exposed to 135 suns of concentration, while the quartz front face remains at 450°C. A 3D heat transfer model, validated against the experimental data, is applied to determine the performance map of solar receivers exploiting thermal trapping. These are shown to achieve the target temperature with higher efficiency and/or needing a lower concentration than the reference unshielded absorber. Solar process heat at above 1,000°C can decarbonize key industrial applications such as cement manufacturing and metallurgical extraction.
"Synthesis of Clean Hydrogen Gas from Waste Plastic at Zero Net Cost" (2023) https://onlinelibrary.wiley.com/doi/10.1002/adma.202306763 PDF: https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/...
"Making hydrogen [and graphene] from waste plastic could pay for itself" (2023) https://news.rice.edu/news/2023/making-hydrogen-waste-plasti...
> 3100 Kelvin [ = 2827 C ]
gscholar citations for: https://scholar.google.com/scholar?cites=1338501696868292077...
What are the fundamental frequencies of plastic?
Is it possible yield Hydrogen and Graphene from plastic at lower than 3100K / 2827C?
Is it possible to generate 3100K / 2827C with this solar thermal trap design?
(edit) Other solar concentrator specs:
NREL's High-Flux Solar Furnace (HFSF) https://www.nrel.gov/csp/facility-hfsf.html L
> The solar furnace can quickly concentrate solar radiation to 10 kilowatts over a 10-cm diameter (2,500 "suns"), achieving temperatures of 1,800°C—and up to peak solar fluxes of 20,000 suns with specialized secondary optics to produce temperatures of up to 3,000°C. Secondary concentrators can modify the focal point and tailor flux levels and distributions to suit the needs of each research activity.
When the sun shines brightly, a concentrator with specialized secondary optics should thus be enough to flash heat plastic to yield hydrogen and graphene.
OT is quartz with 135 suns of concentration.
Quartz (SiO2) melting points, according to wikipedia: https://en.wikipedia.org/wiki/Quartz :
> 1670 °C (β tridymite); 1713 °C (β cristobalite)
Granite melting points too due to a recent geopolymer research interest: https://en.wikipedia.org/wiki/Granite :
> 1215–1260 °C [at ambient pressure]
> Composition: SiO2 72.04% (silica), Al2O3 14.42% (alumina), K2O ~4%
Granite and Quartz and Silicic magmas.