Little Giant Pumps

[Tom Droege <tdroege@veriomail.com>]

Sigh!  I have spent the last few hours with anti-freeze dripping off my 
chin.  Everything is on the floor and I have to crawl around to fix the 
water system.  I now have a bare trickle running through the system.  It is 
probably enough.  One does not need much.

Let's see:

Allow a 5 F rise through the system.  There is about 3 amps max drawn by 
the TECs.  This is 36 watts.  One has to get rid of this plus the heat 
pumped out of the cold side.  Let's guess 7 watts per camera.  That is then 
a total of 50 watts.  This is 170 btu/hr.  170btu/5F = 34 pounds per 
hour.  At 8 pounds per gal this is 4 1/4 gal per hour.  Hmmm!  I wonder 
what it is.

OK, I measured it.  I am getting 2.2 gph.  So the temperature rise is more 
like 10 F.  This means that the down stream camera is seeing 5 F hotter 
water than the upstream one.  This will cost 2.7 C over what I could get 
with higher flow.  2.2 gph is really just a trickle.

The problem is those nice self sealing disconnects that I use on the back 
of the camera.  They do not have a very large orifice, and it tends to get 
clogged.  So take care.  I have reconnected the water filter even though it 
causes a pressure drop.

I think I need a Medium Giant pump instead of a Little Giant.

Tom Droege