Re: How to make money fast (in science fiction)

On Tue, 8 Apr 2008 19:05:00 -0700 (PDT), Luke Campbell wrote:

> On Apr 8, 5:35 pm, Ric Locke <warlo...@[EMAIL PROTECTED]
> wrote:
>> On 8 Apr 2008 9:34:39 -0500, Ash Wyllie wrote:
>>
>>> The Stirling engine is by far and away the most efficient device that
converts
>>> heat into mechanical work. Up to 80% of Carnot potential can be
obtained.
>>
>> Quite true.
> 
> I suppose this is a bad place to mention that some gas turbines can
> get within 90% of the Carnot efficiency?
> 
> Luke

Not at all.

The downside of that is that the Carnot efficiency is low because the
temperature differential isn't large enough, so the throughput
efficiency (output energy divided by fuel heat energy) is low. Given a
material that is immune to heat and suitable for making turbine blades,
a gas turbine can be almost arbitrarily efficient. Alas, unobtainium is
rare in Nature.

Regards,
ric
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