RE: Source for cooling? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 21 Oct 2007 02:17:40 -0400
From: Nick Andrews <nicothefabulous@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: Source for cooling? (fwd)

Yeah, I am familiar with these limitations, but I was looking at it from the perspective of free stuff which might be available to folks, like MOTs and such...you know how no one likes to repair anything these days!

Nick A





> Date: Sat, 20 Oct 2007 20:26:11 -0600
> From: tesla@xxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: RE: Source for cooling? (fwd)
> 
> 
> ---------- Forwarded message ----------
> Date: Fri, 19 Oct 2007 23:07:20 -0700
> From: Dave Halliday <dh@xxxxxxxxxxxxxx>
> To: 'Tesla list' <tesla@xxxxxxxxxx>
> Subject: RE: Source for cooling? (fwd)
> 
> Two nits:
> 
> Scott -- Nick mentioned that this was a Peltier Fridge.
> This is the correct description of what you are looking to explain.
> 
> http://en.wikipedia.org/wiki/Thermoelectric_cooling
> 
> Nick -- Unfortunately, these are only about 5% to 10% efficient and they
> will only support a gradient of about 40 degrees.  A Rankine compressor
> (standard refrigerator) is about 50% to 60% efficient.  If you need to cool
> anything more than 20-30 watts, you need to look at something other than
> Peltier junctions. 
> 
> Read the first part of this PDF:
> 
> http://www.tinaja.com/glib/hack68.pdf
> 
> And this entire PDF (for general info)
> 
> http://www.tinaja.com/glib/ratholes.pdf
> 
> 
> 
> Dave
> 
> 
> > -----Original Message-----
> > From: Tesla list [mailto:tesla@xxxxxxxxxx] 
> > Sent: Friday, October 19, 2007 11:50 AM
> > To: tesla@xxxxxxxxxx
> > Subject: RE: Source for cooling? (fwd)
> > 
> > 
> > ---------- Forwarded message ----------
> > Date: Fri, 19 Oct 2007 12:24:16 -0400
> > From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: RE: Source for cooling? (fwd)
> > 
> > 
> > Hi Nick,
> >      The reason your freezer does not have a compressor is that it
> > operates by a thermocouple, two dissimilar pieces of metal 
> > laid side by
> > side, with an electric current passed through them.  Somehow 
> > this cools
> > the fridge, as one heats up faster than the other (and the 
> > hot one gets
> > cooled by a fan, which draws heat from the other piece of 
> > metal and the
> > fridge, I am unsure of the exact details).  As for the fans, 
> > make sure you
> > figure out how much power they need, they may be electronically
> > controlled, and supplying them with a non regulated power 
> > source may be
> > bad for them (or it may not, I am no expert).  I personally use small
> > squirrel cage fans for everything I want cooled, similar to those in
> > microwaves.  Good luck.
> > 
> > Scott Bogard.
> > 
> > > Date: Fri, 19 Oct 2007 08:57:17 -0600
> > > From: tesla@xxxxxxxxxx
> > > To: tesla@xxxxxxxxxx
> > > Subject: Source for cooling? (fwd)
> > > 
> > > 
> > > ---------- Forwarded message ----------
> > > Date: Thu, 18 Oct 2007 21:22:34 -0400
> > > From: Nick Andrews <nicothefabulous@xxxxxxxxxxx>
> > > To: tesla@xxxxxxxxxx
> > > Subject: Source for cooling?
> > > 
> > > I got a dorm-size fridge, Avanti brand off of the local 
> > freecycle group for free.  It was purchased but quit working 
> > after a few months by a local office.  They cut the cord and 
> > got their money back, and I got the fridge.  I spliced a cord 
> > on to check it out and guess what?  It has no compressor, but 
> > it does have a 4" fan central in the back inside which runs 
> > air over an aluminum heat sink.  Peltier-fridge!  
> > > 
> > > I opened the back, and there is a PWM power supply (SMPS) 
> > to run the interior fan and two fans at the bottom of a 
> > bigger heat sink on the back of the unit.  Bad design has the 
> > fans blowing the air up through the heat sink and onto the 
> > power supply.  It has an interior light.  I need to look for 
> > a sticker to see how much power it uses...
> > > 
> > > The point is, though, that these may be a source of 
> > good-size Peltier junctions for possible use of cooling IGBTs 
> > or other semiconductors.
> > > 
> > > Nick A 
> > > 
> > > 
> > 
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> 
> 
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