Supercritical CO2 is very interesting in MW sizes, but it doesn't scale down well to <50kW machines due to high fluid density that makes the compressors and turbines unfeasably tiny, and very high pressures that make the bearing, seal and heat exchanger very difficult or impossible to do cheaply.
On 20 October 2011 16:40, Axil Axil <janap...@gmail.com> wrote: > In terms of micro turbines, a good fit for the Rossi reactor would be the > supercritical carbon dioxide (S-CO2) Brayton-cycle micro turbines. > The supercritical CO2 Brayton cycle provides the same efficiency as helium > Brayton systems but at a considerably lower temperature (250-300 C). The > S-CO2 equipment is also more compact than that of the helium cycle, which in > turn is more compact than the conventional steam cycle. > The size of such a micro turbine operating at 65% efficiency might be > comparable to that that of an auto water pump matching the power production > of a Rossi reactor in the megawatt range. > > On Wed, Oct 19, 2011 at 2:47 PM, Jed Rothwell <jedrothw...@gmail.com>wrote: > >> Robert Lynn <robert.gulliver.l...@gmail.com> wrote: >> >> -Micro-turbines (capstone et al) have low efficiency compressor and >>> turbines and under 100kW probably won't work at all until the temperatures >>> are >600°C, and then only with very low efficiency (<15%). >> >> >> I have heard that a Rossi reactor can go to 600°C. It works well at that >> temperature. Most cold fusion reactions work better at higher temperatures. >> Proton conductor-types do not work at all at lower temperatures. They do not >> conduct protons (load). >> >> Anyway, efficiency does not matter much with cold fusion because the heat >> costs nothing. The only reason you need a modicum of efficiency is to keep >> the waste heat down to a reasonable level. You would not want a 30 kW home >> generator that produces 300 kW of waste heat. It would make the air around >> the house too hot. If it was compact, it would be dangerously hot, and might >> burn someone or start a fire, and if it was not compact it would take up a >> lot of space. >> >> >> >>> -Micro steam turbines are very inefficient, (steam's high specific heat >>> requires multi-stage due to blade speed limits) and with small sizes are far >>> more prone to water erosion damage. >> >> >> As I said, efficiency does not matter, but longevity and the lifetime cost >> of the equipment does matter. See chapter 14 of my book. >> >> - Jed >> >> >
