[Gasification] Vapor systems: Carnot cycle

[Art Krenzel]

Jim,

As a pilot, I can tell you that the 400 Hz power on aircraft was a 
compromise based on making smaller, lighter motors and actuators - not 
problems with gearing the alternator.

Art Krenzel

----- Original Message ----- 
From: "jim mason" <jimmason at whatiamupto.com>
To: "Zietsman, Rex" <Rex at process.co.za>
Cc: <mike at unidyn.co.za>; "Gasification" <gasification at listserv.repp.org>
Sent: Thursday, February 08, 2007 10:49 PM
Subject: Re: [Gasification] Vapor systems: Carnot cycle


>i don't think you are going to have much luck trying to gear down a
> turbo to regular alternator speeds.  this is the usual sticking point
> on the home made turbine generator scenario.
>
> i think you would have more luck trying to figure out how to make an
> alternator spin at turbine speeds.  this is why so much military power
> is 400hz AC.  that is a reasonable hz rate to take off a spinning
> turbine.
>
> as you are likely going to rectify it in the end anyway to dc, then
> such a high hz rate is fine.
>
> but what alternator media will spin at 30,000rpm i do not know.  there
> is likely info out there for turbine alternators.  maybe the capstone
> microturbine company has some revealed info.  ormat has clearly
> figured it out, but little information is offered.
>
> j
>
>
>
> On 2/8/07, Zietsman, Rex <Rex at process.co.za> wrote:
>> Kermit wrote:
>> "Turbines must run at high speed in order to be efficient. One could
>> make a working unit by using an old vacuum cleaner fan for the turbine
>> and casting a turbine race. The problem would be high speed bearings. A
>> gear train of possibly 10/1 would be necessary. This could drive a car
>> alternator or induction generator and would charge batteries. With a
>> simple single expansion using steam or an organic vapor efficiency would
>> be low but if all waste heat is using for space heating that is not so
>> important."
>>
>> Kermit: I like your thinking. It is down in the weeds where most of us
>> operate. A challenge for you: I have written about a Carnot cycle we
>> have been looking at. If we have hot air leaving the exhaust of a
>> turbo/compressor, what can we use that is "off the shelf" to drive the
>> generator? I suppose we could always modify a larger turbo but that does
>> not make sense as it would become unbalanced if you took off the
>> compressor turbine.
>>
>> Rex
>>
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