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Rick,

1000 to 1400 degrees F. would provide enough efficiency to make a heat recovery cost effective (reasonable payback time).

This is based on the Carnnot equasion. (Google it for more).

Rick

<t>Rod,<br/> <br/> Efficiency in what terms?<br/> In Stirling's time they measured in tons of coal per hour, per HP.<br/> <br/> I have seen HP values of less than 1 to over 3 given to this engine. I would question any account of actual horsepower over 1 HP from that time. A very detailed analysis of...

<t>Joel,<br/> <br/> The question should read "Why doesn't anyone sell a Stirling that produces power for cheap?"<br/> <br/> They are out there, they are not cheap.<br/> Sunpower has offered a 1 Kw freepiston in the past for $10 grand.<br/> <br/> You may also ask "why are they so expensive?" That is ...

<r>Lee,<br/> <br/> It is hard to judge how serious your proposal is when you don't use the proper spelling of the engine.<br/> <br/> I have reviewed many "claims" of potecial heat/cold sources only to find out the claimee has not done any serious research. Chances are its been done before.<br/> <br/...

<r>To power a house (>1K ) a Stirling engine running at with atmosphic pressures would probably need to be larger than the house itself.<br/> <br/> You can get more power from a smaller size by using a higher internal pressure, but a heavy pressure vessel is needed.<br/> <br/> I don't think 40 degre...

<t>John,<br/> <br/> There are few hard and fast rules for buffer space volume. It usually depends on the particular configuration. Engines with kinimatic linkages normaly require substancial space to fit the drive linkage. These would typically be much larger volumes and not a problem for buffer spa...

Tim,

There are several avaliable but you need $10,000 or more for them.

Try googling:
Sunpower
Infina
Whispertech

Rick

<r>Wilhelm,<br/> <br/> Geothermal is generally not considered to have high enough temperatures to make Stirling practical. Stirling engines typically have compact heat exchangers but use high temperatures for high Carnot efficiency. Since geothermal can easily reach steam temperatures, a Rankine cyc...

<t>David,<br/> <br/> The answer to this one could be very different depending of the other operating conditions. <br/> <br/> For engines with lower temperature differences the problems is not as difficult because there are more material choices. Also, thermal expansion of the piston and cylinder are...

<t>Zach,<br/> First, a Stirling engine requires at least two pistons with phase angle between pairs set at around 90 degrees.<br/> <br/> Next problem, a Stirling is an external combustion machine. There are no valves and no exchange of working gas (air) from the inside to the outside. The heat excha...