Lennart Thornros <lenn...@thornros.com> wrote:
> I might have missed something but I thought LENR has high energy density. > Not that high. It is roughly at the level of a fission reactor core, which is actually a lot cooler and less dense than, say, inside an internal combustion engine cylinder, or a gas turbine. The temperature of a fission reactor pellet is around 300 deg C. A gas turbine runs at ~900 deg C. See: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Power-Reactors/Nuclear-Power-Reactors/ *Water or heavy water *must be maintained at very high pressure (1000-2200 psi, 7-15 MPa, 150 atmospheres) to enable it to function well above 100°C, up to 345°C, as in present reactors. This has a major influence on reactor engineering. However, supercritical water around 25 MPa can give 45% thermal efficiency – as at some fossil-fuel power plants today with outlet temperatures of 600°C, and at ultra supercritical levels (30+ MPa) 50% may be attained. Aerospace engines call for the highest possible power density, and very high temperatures. Perhaps a cold fusion engine could have less power density than a liquid fuel combustion engine. You could make it bigger and less efficient because you do not have to carry chemical fuel. But even at that, I do not think any system demonstrated up to now would work. An earth-to-orbit rocket is the most demanding aerospace application. It is not clear whether a Pd or Ni cold fusion reaction can even occur with enough power density for this. Deep space propulsion systems, on the other hand, would be easy with cold fusion, as Eugene Mallove pointed out. The specific impulse is out-of-this-world. Something like a propeller driven C-130 transport airplane could perhaps soon be be made with cold fusion as the primary energy source. Today's C-130 is a turbo-prop (a gas turbine engine turning a propeller). That has a top speed of 368 mph, much slower than a jet airplane. Even if you can make this work, it would take many years to develop it to the point where it would be safe enough for manned aircraft or spacecraft, as I said. Small unmanned craft (drones) are another matter. - Jed
