Boiling water is so 19th century. CO2 or liquid metal (lithium) phase change are where we want to go. Higher temperatures are what make this new cooling cycles possible. Boiling water is what is hard on the equipment.
On Mon, Jan 6, 2014 at 7:12 PM, James Bowery <[email protected]> wrote: > Its unclear to me whether going to supercritical CO2 would make mechanical > parts more wear resistant, but if phase change is what is driving the > erosion in steam turbines then it may be so. > > http://www1.eere.energy.gov/solar/sunshot/csp_sunshotrnd_nrel_turbine.html > > Moreover, I recall some speculation, if not statements from Rossi himself, > that he was working toward a supercritical CO2 generation -- IIRC a German > firm. > > > On Mon, Jan 6, 2014 at 3:48 PM, Jed Rothwell <[email protected]>wrote: > >> Rossi said that the latest e-cat operates at high temperatures and >> thereby achieves roughly 40% Carnot efficiency. It would be better to >> operate at lower Carnot efficiency. Conventional nuclear fission reactors >> operate at roughly 33%, and a much lower temperatures than Rossi describes. >> This is better because the fuel is very cheap, whereas increasing the >> operating temperature increases the wear and tear on the steam turbines. In >> the case of cold fusion, the fuel costs nothing, so you should optimize to >> produce the lowest equipment cost over the life of the machine. >> >> You do not want to go down to 5% Carnot efficiency because you would end >> up with a machine looking like a 19th-century steam tractor, with a >> gigantic engine. Like this: >> >> >> http://upload.wikimedia.org/wikipedia/commons/3/35/Ruston_and_Hornsby_steam_tractor_sn_115100_of_1922.JPG >> >> In other words, 40% efficiency would be an advantage only insofar as it >> allows compact engines, and it reduces waste heat. In many applications, >> waste heat is not a problem. >> >> If you can achieve 40% efficiency for the same equipment cost as 30%, >> then go for it. >> >> - Jed >> >> >
