And the heat transfer to the fluid s better too. However, boiling has it's own serious issues.
-John ============= > 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 >>>> >>>> >>>> >>>> ______________________________**_________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/** >>>> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >>>> and follow the instructions there. >>> >>> >>> >>> -- >>> >>> Tom Harris <[email protected]> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
