You're right! I see graphite insulation exists and is stable up to 3000C in a vacuum/inert atmosphere, but it looks very expensive. Graphite is not expensive. Perhaps there's a way to make graphite foam cheaply.
What about trying to buy from NASA used plates from heat-shield-layer of the space shuttle or similar?
Here you go. https://www.ebay.com/itm/196652863982. But it's only rated up to 2000C or so, because it's silicon-based. The best things in life can't be bought.What about trying to buy from NASA used plates from heat-shield-layer of the space shuttle or similar?
How about calling them and go "Hey guys, wanna sell us your used pads? 1$/lb, nice price, lets go!"
I saw a demo video of that material. They put it some kind of super charged oven on steroids, heated to I don't know much, same temperature shield experience on re-entry maybe, took it out (it was almost white-glowing?) and still one could hold that hot as hell material with palm, even straight from oven. Because heat flow through that material is so insane slow.
Hence very easy and not expensive at all, hence not at all impossible?
Of course. That relies on you being a hella of cassanova-charmer when calling NASA...
Assuming you would get your hands on latest NASA AETB-8 Rigid Tiles: https://tpsx.arc.nasa.gov/MaterialProperty?id=5&property=4
Thinking I could drop a couple elements into a couple of 275 gallon IBCs in the basement. Alternatively power my oil filled portable radiators from batteries.Assuming you would get your hands on latest NASA AETB-8 Rigid Tiles: https://tpsx.arc.nasa.gov/MaterialProperty?id=5&property=4
Max temperature 1860K, thermal conductivity 0,316 W/m-K IN VACUUM!
Graphite tile storage with temperature swing between 1860K to 860K (1586c to 586c)
100kWh storage would be 507 kg of graphite
Volume 230 liters
Cube dimensions 61*61*61cm
Insulated with 200 mm of AETB-8 space shuttle tile material IN VACUUM
Insulation surface area at insulation midline = 3,0m2
Insulation power loss 8,8kW
Almost 10% power loss per hour.
AETB-8 in nitrogen would have over twice as high losses. 20kW and 20% lost per hour.
Smaller storage would perform even worse. 3000K storage temperature would also perform lot worse as insulators get worse with increasing temperatures.
Compare this with water storage tank of similar dimensions:
temperature swing 100cel to 40 cel
water mass 730kg
insulation thickness 50mm, thermal conductivity de-rated to 0,03 W/m-K
Stored energy 51kWh
Insulation power loss 288W
Power loss per hour 0,5%
One of the above is feasible and commonly used. Another is not that popular and the smartest ones have probably fiqured out already the reasons why.
Probably simpler to put radiant floor heating in via liquid loops, insulation under the slab to avoid the heat being leached away, vapor barrier plus eps foam seems popular:
Mine doesn't have radiant heat but the slab in the walkout basement is similarly freestanding, with french drains along the inside and outside perimeters with gravity drain to outdoorsThat's what's common here. This is mine being poured over the heating pipes:
The 'slab' really is a floating floor disconnect from the rest of the foundation and walls.
Without insulation the earth would act as an infinite heatsink it seems like.
I'm saying the ground will leach away any heat you apply prior to it warming the slab, due to lack of insulation/thermal break.
Your slab is already sucking heat out of the air inside your building. If you can insulate the outside edge of the slab from the cold outside air you would slow down the transfer of heat into the slab.
www.noraelectric.org
The earth if cooler will pull that heat away.i.e. let's say the earth is at 60F, along with the slab. Any heat applied to the slab will move to the earth, whether heated from above or below.
