If you let the water boil, it takes even (much) less.
Tom
----- Original Message -----
From: "J. Forster" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Wednesday, October 03, 2012 8:14 PM
Subject: Re: [time-nuts] OT question about liquid cooling
It actually takes supprisingly little water flow to dissipate 5 kW.
Very roughly 5 kW = 1250 cal/sec (4.18 J/cal)
so, for a 1 C degree = 1.25 liters/sec
at 50C degrees = 25 mL / sec. = 1.5 L/min.
-John
======================
BWIWY (back when I was young) we needed a dummy load for a supercomputer
(think Cray YMP size) that drew many many kw.
Our test load was about 250' of 3/4" copper tubing coiled at about 12" dia
and 1" spacing. The load was varied by changing where the + and - leads
were bolted onto the coil with u bolts.
The whole mess was cooled by running water through it. A hose barb on the
input connected up to the cold water supply and the output was run into a
drain. You had too little resistance dialed in when all thy came out the
output end was steam. :)
Anyway such a test load could be replicated using 1/4" ice machine copper
tubing available at the hardware store, some hose clamps, and or hose
barbs.
Bob
On Oct 3, 2012, at 19:35, Tom Harris <[email protected]> wrote:
My day job is large industrial power supplies. The test racks have large
resistive loads with big fans exhausting to the outside. Cheap & simple.
Safety is by several strings of temperature cutouts wired in series. We
usually get work experience students in to wire them up.
Tip: to make a funny valued power resistor, just get the next value up
and
wrap some nichrome wire around it to bring it down to the correct value.
I met an engineer who made a battery charger for one of our submarines.
This was tested by putting the load bank in a dumpmaster, and keeping it
filled up with water using a firehose!
On 4 October 2012 02:01, Javier Herrero <[email protected]> wrote:
Hello all,
Please excuse me for the OT, but since this list is plenty of very
knowledgeable colleagues, I'm tempted to ask...
I need to cool several resistive loads, in the order of 5kW, and I plan
to
use a cold plate and a liquid-to-liquid heat exchanger like the Lytron
LCS-20, but this unit is quite big, and an overkill (it has 20kW
capability).
If someone could suggest me a smaller liquid-to-liquid heat exchanger,
and
preferably a rack mount unit (and share any experience), it would be
most
welcome.
Since this has not too much to do with time and frequency, please
answer
off list.
Thank you very much! Best regards,
Javier
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Tom Harris <[email protected]>
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