3 ms·
> can generate electricity from a heat source of between 1,900 to 2,400 degrees Celsius [...] plan to incorporate the TPV cell into a grid-scale thermal battery
by tomxor 5y ago
> can generate electricity from a heat source of between 1,900 to 2,400 degrees Celsius [...] plan to incorporate the TPV cell into a grid-scale thermal battery. The system would absorb excess energy from renewable sources such as the sun and store that energy in heavily insulated banks of hot graphite. When the energy is needed, such as on overcast days, TPV cells would convert the heat into electricity, and dispatch the energy to a power grid.
Heating graphite based thermal batteries to >1900C using the Sun for long term storage? I'm not sure why the article is refraining from being explicit, but i'm guessing the intended application here is to replace the steam turbine usually found at the centre of high temperature solar thermal collectors.
I wonder how feasible and cost effective it is to insulate a battery well enough to maintain over 2000C for multi day periods without substantial loss? The heat storage strategies used for steam turbines doesn't require such high temperatures.
- wrycoder 5y agoI attended a paper given at MIT around 1980 which discussed using photovoltaic cells collecting energy from incandescent graphite in a solar collector. There is not really any advance here. The paper discussed using multiple bandgap stacked PV with backside gold reflectors, as discussed in the linked Nature paper. One of the difficulties is keeping the semiconductors cool. They definitely don't operate at 2000 degrees. One envisions a solar power tower[1] with this technology, but with more graphite mass at the collector. So, not much progress in 40 years. [1] https://en.wikipedia.org/wiki/Solar_power_tower https://en.wikipedia.org/wiki/Solar_power_tower
- jillesvangurp 5y agoIt's not that hard. All you need is a lot of mass surrounded by a good insulator. The heat has nowhere to go and leaks out at a rate controlled by how efficient the insulator is. But only at the surface area of the mass which relative to the volume is quite small. There's a basalt based thermal storage system in the Netherlands that is used for seasonal storage. It's heated up over the summer using solar energy and during the winter they pump water through it for heating. It's Basalt in a metal box surrounded by wool and it stays warm through the winter. The temperatures for this system are much lower (500 degrees) but the principle is about the same. https://materialdistrict.com/article/battery-natural-stone/ https://materialdistrict.com/article/battery-natural-stone/ So, if you can heat the mass to the desired temperature, keeping it there is relatively easy. It would slowly cool over time but not at a rate that is problematic and only very slowly. A large enough system might store heat for months/years.
- runeks 5y agoSure, but how many meters of wool insulation do you actually need to keep some mass of graphite at 2000C for a month? It’s obviously possible. The question is whether it’s cost effective.
- idontwantthis 5y agoI wonder if aerogels would be worth the expense or if the added insulation is too minor.