Iron is far from the best heat storage medium. Graphite can store up to 1.5kWh/kg or nearly 3kWh/l in a vacuum enclosure. 1.5GJ from 50 modules would only require about 16kg or 8 liters per module.
There are also a lot of high heat of fusion materials: LiH that requires about 1.6kWh/kg to heat from room temp to melt at 960K (~1.3kWh/L) Silicon metal that releases 0.8kWh/kg to heat up and melt at 1700K (~1.9kWh/l) LiF that releases 0.6Wh/kg heating to melt at 1120K (~1.5kWh/L). Other posiblities on p17: dspace.mit.edu/bitstream/handle/1721.1/35343/20099220.pdf It would also be easy to create a thermal storage vessel that would only release significant heat when immersed in water, just insulate it and use a carefully designed heat transfer area or tube that penetrates the insulation. Air has such low density compared to water that this would cut heat loss massively until immersed thereby allowing heating during startup phase or hours beforehand before it needed to deliver the goods. The chimney unit in the early demos could hide such a thermal store, and there is more than enough space in later fat-cat modules to do this sort of thing. All unlikely, but does raise the bar on standards required for an unambiguous demonstration. On 16 November 2011 20:55, Berke Durak <berke.du...@gmail.com> wrote: > On Wed, Nov 16, 2011 at 3:48 PM, Joshua Cude <joshua.c...@gmail.com> > wrote: > > Excess, or stored, or chemically produced? > > As Albert said, the ecats were heated for 2 hours beforehand, and the > power > > was not given, but at 250 kW input for 2 hours, less an average of (at > most) > > 35 kW output during that time, that gives 215 kW x 2 hours x 3600 J/Wh = > 1.5 > > GJ > > Yeah, but the modules probably don't have enough heat capacity to hold 1.5 > GJ, > unless you assume they hold iron bricks heated to 1500 degrees celsius. > Quite > an unlikely scamming technique. Also, that would be too heavy for the > way they > were mounted in the container. Quoting my own Nov. 9th mail: > > > Cement has more specific heat capacity per mass, but not > > per volume. > > > > One cubic meter of iron can hold something like 3.5 MJ per > > kelvin, while the same volume of cement can hold something > > like 2.33 MJ per kelvin. > > > > In addition I'm not sure cement can go above 800 > > degrees Celsius, while iron melts at 1500 degrees. > > > > So one cubic meter of cement at 800 degrees celsius above > > background can hold 800 x 2.33 MJ = 1.86 GJ. One cubic > > meter of iron at 1500 degrees can hold 5.25 GJ. > > > > Now take the 9.5 GJ that has been reported. > > With cement, you need 9.5e9/1.86e9 = 5.11 cubic meters. > > With iron, you need 9.5e9/5.25e9 = 1.81 cubic meters. > > > > Assume you have 50 modules of 70 cm x 30 cm x 45 cm. > > That makes 4.7 cubic meters. Not enough space for cement > > (unless you know of some special kind of cement.) > > > > Using iron, it would fit, but it would weight way too much, at > > 250 kg per module. > > -- > Berke Durak > >
