[time-nuts] OT question about liquid cooling
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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
5KW of power but that is only 1/4 of the spec. What temperature will the loads operate at? It is quite hard to cool anything to ambient with water. The cooler the operating point the larger the heat sink. Using a very oversize heat exchanger s not unreasonable of you want a relative low temperature. The other side of the loop matters LOT also. How will you cool the water? Do you have chilled water that can run open loop or do you need to chill and re-cycle the water in a closed loop system. Then again temperature matters. What is the inlet temperature? How much flow rate can your system provide. If you don't wnt to learn a loot about this the easy solultion it to simply over-spec the components by a large factor. This also gives you some margin for accients like a plumbing leak or a pump failure. Do plan for these practical issues.When a pump fails the 5KW load can boil water in the heat exchanger quickly and then your plumbing comes apart. To prevent that use enough water volume and thermal mass. Again an over sized heat exchanger is good. As is a thermal shutdown switch. These are cheap and work just like a fuse. They open the AC mains power at a set temperature, you bolt them to the heat sink. They are common in high power audio amplifiers. I don't have experience with a system like you need. Mine is with water cooling that involved TEC (thermo electric, or Peltier devices.) But I know that you do need to plan for mechanical failures, water leaks and so on.Just like with a domestic hot water heaters you place a basin and drain under them. On Wed, Oct 3, 2012 at 9:01 AM, Javier Herrero jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
If you let the water boil, it takes even (much) less. Tom - Original Message - From: J. Forster j...@quikus.com To: Discussion of precise time and frequency measurement time-nuts@febo.com 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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
Perhaps, but unless you plan on just draining the water, you need a liquid to air heat exchanger (LAHE) to cool the water in your loop. Perhaps for a lab it's no big deal, but if you intend to operate where it can get cold (needing glycol) or where there is very limited water supply (remote locations) this matters. I'm installing a 96.5% efficient 9 MVA inverter right now and it needs a minimum of 65 GPM through the LAHE of a 40% glycol solution (glycol moves less heat than water). The heat exchanger is *substantial*, much larger than the items + cold plates it's keeping cool. On 10/3/2012 8:14 PM, J. Forster wrote: 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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1427 / Virus Database: 2441/5308 - Release Date: 10/03/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
9 MVA is somewhat bigger than 5 kW. I was assuming fairly short duration tests, perhaps a few hours, where open-cycle water is practical. If you are going to use a water loop, getting rid of the heat is certainly an issue. -John == Perhaps, but unless you plan on just draining the water, you need a liquid to air heat exchanger (LAHE) to cool the water in your loop. Perhaps for a lab it's no big deal, but if you intend to operate where it can get cold (needing glycol) or where there is very limited water supply (remote locations) this matters. I'm installing a 96.5% efficient 9 MVA inverter right now and it needs a minimum of 65 GPM through the LAHE of a 40% glycol solution (glycol moves less heat than water). The heat exchanger is *substantial*, much larger than the items + cold plates it's keeping cool. On 10/3/2012 8:14 PM, J. Forster wrote: 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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1427 / Virus Database: 2441/5308 - Release Date: 10/03/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT question about liquid cooling
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 j...@quikus.com To: Discussion of precise time and frequency measurement time-nuts@febo.com 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 celephi...@gmail.com 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 jherr...@hvsistemas.es 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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
