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Peltier chilling system - Page 3

post #21 of 167
Thread Starter 
Quote:
Originally Posted by Puck View Post

Keep in mind most of us using those giant TECs are running them at roughly half their rated max for much higher efficiency and less waste heat. Also, chillers work better with multiple smaller TECs while direct-die TECs need to be much larger and more powerful to keep from stalling...just the nature of the beast.

Your build using a shared cold side block for each pair of TECs is a neat idea. Having that much centralized cooling though will need some pretty serious coolant to keep from turning to syrup or freezing - as you have noticed, since it sure sounds like the coolant is just freezing inside the blocks. Easy fix smile.gif.

FWIW a 655/D5 has no seals to mess up with the factory top, only the large body o-ring that does not come in contact with any coolant. The rest is just a heavy impeller with a graphite bushing riding on a single ceramic bearing, with the whole casing magnetized. I ran a pretty nasty Ethanol mix @ 0c through one for over a year and the pump didn't even flinch...until the pump ran dry and the ceramic bearing ate the bushing (the only moving part and wear item in the whole pump, and the 655s only real failure point). Keep in mind the pump was around 7 years old and was ran 24/7 and was still kicking up until that point!

IMO as long as you keep the fluid thin enough to not cause excessive stress on the graphite bushing I do not see any reasonable temps being an issue with a 655. I also trust their reliability a LOT more then any other DC pump because I have had at least 5 of them and they all lived at least 6 years before starting to rattle or vibrate from bushing wear. They usually give tons of warning before dying, and will go from a noticeable vibration to a full on death rattle, giving you plenty of warning to change it vs a pump that just quits one day.

I'm sure if swiftech released a replacement bushing or impeller then we would see plenty of 10yo 655s still running flawlessly.


Thanks! I sort of got the idea looking for water blocks and saw those side port mount blocks. They are some cheap copper blocks from china. Had a rough night tonight. I changed out to a higher glycol concentrate and the cold side pump stalled out even primed and everything. After a few resets i got it going again. Then my hot side pump stalled completely. Had to take it apart, remount the face-plate and it started working again. It has a bit of a rattle right now. My cold side temps are also stalling out around -8C now. I don't know whether to contribute that to the new glycol mixture or possibly the hot pump not working at 100%.
post #22 of 167
Thread Starter 
Quote:
Originally Posted by Puck View Post

Keep in mind most of us using those giant TECs are running them at roughly half their rated max for much higher efficiency and less waste heat. Also, chillers work better with multiple smaller TECs while direct-die TECs need to be much larger and more powerful to keep from stalling...just the nature of the beast.

Your build using a shared cold side block for each pair of TECs is a neat idea. Having that much centralized cooling though will need some pretty serious coolant to keep from turning to syrup or freezing - as you have noticed, since it sure sounds like the coolant is just freezing inside the blocks. Easy fix smile.gif.

FWIW a 655/D5 has no seals to mess up with the factory top, only the large body o-ring that does not come in contact with any coolant. The rest is just a heavy impeller with a graphite bushing riding on a single ceramic bearing, with the whole casing magnetized. I ran a pretty nasty Ethanol mix @ 0c through one for over a year and the pump didn't even flinch...until the pump ran dry and the ceramic bearing ate the bushing (the only moving part and wear item in the whole pump, and the 655s only real failure point). Keep in mind the pump was around 7 years old and was ran 24/7 and was still kicking up until that point!

IMO as long as you keep the fluid thin enough to not cause excessive stress on the graphite bushing I do not see any reasonable temps being an issue with a 655. I also trust their reliability a LOT more then any other DC pump because I have had at least 5 of them and they all lived at least 6 years before starting to rattle or vibrate from bushing wear. They usually give tons of warning before dying, and will go from a noticeable vibration to a full on death rattle, giving you plenty of warning to change it vs a pump that just quits one day.

I'm sure if swiftech released a replacement bushing or impeller then we would see plenty of 10yo 655s still running flawlessly.



Hey i had a question actually on your setup. When you say you run half the power.. are you stepping down the voltage? Roughly 8V? Or are you somehow limiting the amperage? I snagged a boost converter and stepped up my 12V supply. I tested it at 12v 14v and 16v. 12v still seems to get me the lowest temps, at anything higher i couldn't cool the hot side nearly enough to get a big drop on the cold side.
post #23 of 167
Quote:
Originally Posted by mrkubanftw View Post

Hey i had a question actually on your setup. When you say you run half the power.. are you stepping down the voltage? Roughly 8V? Or are you somehow limiting the amperage? I snagged a boost converter and stepped up my 12V supply. I tested it at 12v 14v and 16v. 12v still seems to get me the lowest temps, at anything higher i couldn't cool the hot side nearly enough to get a big drop on the cold side.

They are ran at 12v for the most part. Performance at 14v was better, but as you notice it gets real hard to cool the hot side at higher voltages like 16-24v smile.gif.
Behemoth
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CPUMotherboardGraphicsGraphics
Intel i7 4790K "Relidded" @ 5ghz <50c Asus Sabertooth Z97 MK1 Custom WC'd 7970 3GB @ 1100/1500 stock volts Custom WC'd 7970 3GB @ 1100/1500 stock volts 
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2X4GB Patriot Viper Extreme 1TB Velociraptor 10k RPM w/ 64MB Cache Two Arqtik TEC Chillers in Series Archimedes TEC block w/TN660 TEC 
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Two Ported/tapped MCP655 Pumps 2x Black Ice GTX 480 Gen2 Rads DD dual drive bay Res with LCD water temp monit... GPU Loop: Modded Enzotech Sapphire CPU blocks, ... 
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Behemoth
(25 items)
 
  
CPUMotherboardGraphicsGraphics
Intel i7 4790K "Relidded" @ 5ghz <50c Asus Sabertooth Z97 MK1 Custom WC'd 7970 3GB @ 1100/1500 stock volts Custom WC'd 7970 3GB @ 1100/1500 stock volts 
RAMHard DriveCoolingCooling
2X4GB Patriot Viper Extreme 1TB Velociraptor 10k RPM w/ 64MB Cache Two Arqtik TEC Chillers in Series Archimedes TEC block w/TN660 TEC 
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Two Ported/tapped MCP655 Pumps 2x Black Ice GTX 480 Gen2 Rads DD dual drive bay Res with LCD water temp monit... GPU Loop: Modded Enzotech Sapphire CPU blocks, ... 
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post #24 of 167
Thread Starter 
Quote:
Originally Posted by Puck View Post

They are ran at 12v for the most part. Performance at 14v was better, but as you notice it gets real hard to cool the hot side at higher voltages like 16-24v smile.gif.


Okay that makes total sense and i'm glad it aligns with my findings. I think my lack of performance up at 14v is just due to these water blocks not being of the best quality or the pump not moving a good enough flow. Or both really. I'm ordering some new pumps and i'm working on designing a waterblock for the 40mm TEC's, one designed for the hot side and another designed for the cold side. Hopefully i can a few machined up in the next week or two. Need some copper.
post #25 of 167
Thread Starter 
Due to unlimited recommendation of the 655, i ordered one today. I think i'm going to snag a RIO aquarium submersible for now. I've used that with mineral oil in the past and they maintain very good head. I'm going to get a few more 655's in the future as well but i'd like to try it with my hot side before i grab one for the cold side. For now i'll tie both of the cheap pumps i have in series on the cold side and see if that improves flow at all.

Also do you think running my pump right after the hot side tec's is a bad idea? I figured i didnt want the pump to interfere with water temp so I wanted the radiator to be last in the loop before the TECs. This of course runs hot water through the pump. I wouldn't think 100-120F water , if that, would affect nor kill a pump. Any thoughts?
post #26 of 167
Thread Starter 
Installed RIO pump last night. She's rated to 600 lph at around 1ft of head. Numbers got better but not much. Cold side planed out around -11. Hot side water was moving MUCH faster, but my radiator outlet temp rose because of this. The water simply doesn't have enough time to drop all the way down, its close though, still lower than with only 1 rad. Hot side inlet sits around 27C.

So i haven't been able to hit that freezing -15c since I increased my glycol/water mixture. Either the pump just cant handle the thickness and the flow is far too slow... or the increased concentration dropped its thermal properties enough to where i'm losing the cold gained before it hits my res. Today i think i'm going to grab another RIO, perhaps a smaller one. Triple check my concentration and bleed the system again. After that ill give it another go.
post #27 of 167
I think it's is due to radiated loss of coldness, when the cold side mixture was thickening up, and freezing. just before it would freeze completely, the mixture was like a slushy, while this is not a good thing for water pumps, a mixture at that consistency is very good at retaining coldness.
try covering the center water blocks, and hosing that goes to and from the reservoir as well as the reservoir, in A/C foam to prevent this loss of coldness that you are currently experiencing.
http://www.homedepot.com/p/MD-Building-Products-3-4-in-x-72-in-Black-Self-Sealing-Pipe-Wrap-Insulation-50162/205129980
http://www.homedepot.com/p/E-O-2-in-x-15-ft-Foam-and-Foil-Pipe-Wrap-Insulation-Tape-FV15H/100174724

or you can do what I am doing, I am using molding clay as my insolate for all of my piping and components that are on the outside of the ice chest. michaels has it at a good price
http://www.michaels.com/craftsmart-plastalina-modeling-clay-4-neon-colors/10138308.html?productsource=PDPZ1
Edited by toolmaker03 - 7/2/16 at 1:42pm
post #28 of 167
here is a cool cheap little experiment for you, this will make it easier to visualize what was actually occurring inside of the water loop.
go to the store and get a 6 pack of good drinkable water, not the off brand, but a good name brand of bottled water, you want the water to be as pure as possible. when you get home place the individual bottles of water in the freezer, separate each of the bottles so that it will be easy to remove any of the bottles from the freezer, without disturbing the water that is in the bottle.(don't put the bottles in the freezer door) leave the bottles In the freezer for a full day, what your going to see, is that not all of the bottles are frozen, in fact most of them will not be frozen at all. slowly remove one of the unfrozen bottles, and carefully remove the cap, again try not to disrupt or move the liquid inside of the bottle. with the cap off of the water bottle, try to pure the liquid out of the bottle, what you will notice is that as soon as the liquid inside the bottle becomes disrupted, it turns into a slushy mixture. this is also what was happening inside your water loop, a slushy holds the cold in better than a fluid liquid, a fluid mixture can radiate the coldness away very quickly, if it not insolated well enough to prevent it.

https://www.bing.com/videos/search?q=bottled+water+that+will+not+freeze&&view=detail&mid=08E8F231A94A292C94E008E8F231A94A292C94E0&FORM=VRDGAR
Edited by toolmaker03 - 7/2/16 at 3:12pm
post #29 of 167
what kind of antifreeze are you using on the cold side water loop?

standard antifreeze the green stuff, gets too thick for water pumps when it is at below freezing temperatures.



I tested several different types of antifreeze for my cold side water loop, and this stuff was the only antifreeze that did not get thicker as it got colder. also I could not add any type of additive to the mix, because adding any type of additive to the mix, would cause this antifreeze to thicken up when it got colder as well.
post #30 of 167
for your setup I'd use 12715's and run them in sets of 2 wired in series so they get about 6v each, same Qc wattage at 20*c delta as you have now, but half the power usage from TEC's, half the power means half the heat dump from the tec, so hot side water is cooler, so your hot side of TEC will be cooler, which means you'll see more of your delta below ambient rather than wasting it on the hot side temps above ambient.

Once you add a heat load to your current setup you'll get about half the delta you currently are, which is why I suggested 12715's as you'll get the same or greater delta but with literally half the power usage. ie 12708's at 12v x 6amps x 4 tec's = 288watts or 12715's at 6v 6a x 4 tecs = 144watts. Each setup has approximately 160w of Qc at 20*c delta below ambient. 12708's have COP of ~.55, 12715's have COP of 1.1, twice as efficient for the same or better temp drop.
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