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Re: Forced Gas Quenching



Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

One can look at it very simply in terms of energy balance.  The refrigerator
has to extract a certain number of watts from the gap and reject it to the
environment.  It will consume some electricity in doing so. The ratio of
watts moved to watts consumed is the COP (coefficient of performance) of the
refrigerator.. typical numbers are, say 3-5.  (You'll also see kW/ton... kW
is electrical power in, ton is 12000 BTU/hr.. kW=3413 BTU)

EER and SEER are other ratings you'll see.. EER is  (BTU/hr)/watt (a
dimensionally horrible thing...)  Typical EERs are 8-10 for A/C, perhaps up
to 15 for high performance systems.  COP of 3.5 is approximately EER=12 is
approximately 1kW/ton.

So... if my little refrigerator consumes 100W, and it has a COP of 3
(because it's little, the COP is low), I can pull 300W out of the system.
If, say, 30% of the energy is dissipated in the gap, that means I could cool
the gap for a 1kW system with it.

Aside from the numerous practical details, this looks like a possibility.
1) The gap itself could be the expansion point
2) You'd have to watch out for products of dissociating the refrigerant

You could run air or nitrogen or hydrogen or He, etc.  in such a system
using the Brayton cycle.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, May 05, 2004 7:28 AM
Subject: Re: Forced Gas Quenching


 > Original poster: Mddeming-at-aol-dot-com
 >
 > In a message dated 5/4/04 8:36:02 PM Eastern Daylight Time,
 > tesla-at-pupman-dot-com writes:
 >
 > Stop me if I'm on the wrong track, but how about using the guts of a
 > refrigerator for this?  High pressure/small bore tube leads into gap
 > manifold producing gas blast, gas passes through heat exchanger, then back
 > to pump and back to the gap again.  Would this not provide both quench and
 > cooling?
 >
 > It would obviously help if we were to use a high-dielectric strength gas
 > which is also a refrigerant.
 >
 > Equipment would not be too large or expensive.
 >
 > Hi M,
 >
 >      Yes, in principle this would work. The difficulty to be overcome, as
I
 > see it is the dT/dt on the cooling side. Most refrigerators operate
between
 > reservoirs of say 0 F. and 100 F. A TC gap works between an ambient temp
of
 > ~75 F and an arc temp of hundreds of degrees. Depending on how much heat
is
 > picked up from the quenching by how much of the gas per unit time, it may
 > be tricky determining the necessary volume and gas circulation velocity
 > which would allow the system to cool it sufficiently. Another possible
 > problem point is the duty cycle.  It seems that this system would have to
 > operate continuously while the coil is running. Most refrigerator
 > compressors are designed to run for only a few minutes each hour or so, in
 > a pattern of quick pull-down - slow warming, quick pull-down - slow
 > warming, etc. This makes it, if feasible, then not a trivial adaptation.
 > Anyone got a good thermodynamic/fluid mechanics simulator program out
there
 > to go with the TC models?
 >
 > Matt D.
 > Matt D.
 >
 >