Stephen A. Lawrence wrote: > > [email protected] wrote: >> In reply to Kyle Mcallister's message of Mon, 23 Mar 2009 15:53:48 -0700 >> (PDT): >>> /Can we build a damn thing that will make a cup of >>> warm coffee or tea?/ If not, why not??? >> I suspect not. CF (or LENR) is finicky, and no one is yet certain of the >> precise >> requirements (though there are now a few claims of complete replicability). >> Those who can achieve it have been trying for quite a while to get it right. >> Even then, I think a reasonably well equipped lab is a prerequisite. It's not >> something you can do in your garage, and expect to work. > > There is something else as well. > > There are some reproducible, repeatable experiments which work, if not > every time, then a good fraction of the time. But reliability is not > what stands in the way of making a tea heater. There are two other > problems with making a gadget which does something useful. > > First, the repeatable experiments all produce very low-grade heat; it's > hard to do much with it beyond just detect it. > > Second, and more important, the same bugaboo that plagues hot fusion is > at work here: The best of the wet-cell CF experiments is nowhere near > breakeven. > > With that said, I should add that gas-phase CF at room temperature, > which operates without a large external energy source, *might* produce > enough heat to run a Stirling engine -- but I don't think so. As I said, > these experiments produce low-grade heat; I don't think the heat output > of the gas-phase experiments is large enough to do that.
In fact, IIRC the gas-phase experiments start with compressed D2. If we account for the energy used compressing the gas then they're also well below break-even (never mind the energy cost of refining the D2, which is also far from free). It will be a red letter day when *any* controlled fusion experiment, hot, cold, or luke-warm, passes breakeven on the operating energy budget. (By the "operating energy budget", I mean, not including the cost of fabricating the system -- just the cost of making the fuel and operating the reactor).
