Overclock.net › Forums › Cooling › Specialized Cooling › Peltiers / TEC › TEC Chill Box Chamber Build log
New Posts  All Forums:Forum Nav:

TEC Chill Box Chamber Build log - Page 75

post #741 of 1668
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

honestly, just buy 3 x 331w 50mm TEC's from custom thermo electric http://customthermoelectric.com/tecs/pdf/26311-5M31-17CW_spec_sht.pdf use your current water blocks, run the 331w TEC's at 16v x 6-9amps, ditch the relays and get a PWM controller, you can buy 1 of the controllers I use and it will handle all 3 of those TEC's with a heat sink on the mosfet. use neoprene to insulate around the TEC's rather than the clay. You have the ingredients right in front of you, just buy some quality TEC's and a controller and use what you have more effectively.

You have a potentially very very good chiller. Quality TEC's, a controller, and some simplification will vastly improve the results.

Those 3 tecs and one of the controllers I use will set you back USD$200 total. you'll be able to hold 240w of heat to a 30*c delta below hot side temp. If you want to go colder or your heat load is higher, double the amount of TEC's and blocks. Your rad space is fine.

do you really think that a quality TEC will make that much of a difference?
I am not asking to be a dick I really don't know what the difference between getting quality TEC's and non quality TEC's will be.
what about the 12711-5P31-26CW TEC's there comparable to what I have, I think or would these work a whole lot better than the ones I have?
Edited by toolmaker03 - 7/13/16 at 9:56pm
post #742 of 1668
its not so much that it is a quality TEC, more so that it is a 31.5v TEC that you are undervolting to 50% of it's umax, putting it in a much more efficient zone than running your 12730's at 13.8v 23amps. getting 31.5v 263 couple TEC as opposed to 127 couple 15.4v TEC's is the difference between quality and ebay generic TEC's

13.8 x 23 = ~320w of heat from the TEC x 3 TEC's = 960w of heat that your radiators need to dissipate, plus the extra heat when you add a heat load to the cold side. Your radiators will keep coolant to 10-15*c above ambient and the actual hot side of the TEC 5-10*c above that. You are losing more than half of your potential dT above ambient temp before you even start.

To keep the total heat load down and allow your radiators to keep your water temp closer to ambient, move to more efficient TEC setup, aim for no more than 5*c above ambient water temp, and hopefully 5*c above that TEC hot side temp.

15v x 7a = 105w x 3 TEC's = 315w, thats cut your heat load from TEC's by 2/3rds, this will mean water temp drops, tec hot side temp drops and therefore cold side temp is colder.
Edited by LiamG6 - 7/13/16 at 9:59pm
post #743 of 1668
Thread Starter 
**
Edited by toolmaker03 - 7/13/16 at 10:13pm
post #744 of 1668
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

its not so much that it is a quality TEC, more so that it is a 31.5v TEC that you are undervolting to 50% of it's umax, putting it in a much more efficient zone than running your 12730's at 13.8v 23amps. getting 31.5v 263 couple TEC as opposed to 127 couple 15.4v TEC's is the difference between quality and ebay generic TEC's

13.8 x 23 = ~320w of heat from the TEC x 3 TEC's = 960w of heat that your radiators need to dissipate, plus the extra heat when you add a heat load to the cold side. Your radiators will keep coolant to 10-15*c above ambient and the actual hot side of the TEC 5-10*c above that. You are losing more than half of your potential dT above ambient temp before you even start.

To keep the total heat load down and allow your radiators to keep your water temp closer to ambient, move to more efficient TEC setup, aim for no more than 5*c above ambient water temp, and hopefully 5*c above that TEC hot side temp.

15v x 7a = 105w x 3 TEC's = 315w, thats cut your heat load from TEC's by 2/3rds, this will mean water temp drops, tec hot side temp drops and therefore cold side temp is colder.

ok, so if I am understanding this right a higher volt TEC that is under volted will get me to a below 0C temp on my water with a heat load on the water, but I would still need more than 3 TEC's to do that. the real difference is that I would not be using as much electricity to do the same job?
so how many of these higher volt TEC's do you think I would need, to achieve 0C or lower water temp, with a 900W heat load dropped into the cold side water loop?
post #745 of 1668
if you keep using 127 couple 15.4v TEC's at umax then you are just going to have troubles with heat. If you want to keep using 12730's, buy 3 more, buy 6 more water blocks, and run them at 8v a piece, ie wire 2 tecs in series with your 16v PSU

I think this is a more costly option than buying 3 more appropriate TEC's.

8v x 15a = 120 x 6 tecs = 720w of heat plus your heat load on cold side.

this would have 240w of Qc, ie can handle a 240w heat load on the cold side and hold it to a 30*c dt minus any thermal inefficiencies. so, the same as 3 x 331w tecs with twice the power consumption and therefore twice the heat load the rads need to dissipate which in turn means higher water temp which in turn means higher cold side temp.

power consumption of the TEC's needs to be brought under control before you will see the temps you want to reach.
post #746 of 1668
Thread Starter 
**
Edited by toolmaker03 - 7/13/16 at 10:36pm
post #747 of 1668
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

if you keep using 127 couple 15.4v TEC's at umax then you are just going to have troubles with heat. If you want to keep using 12730's, buy 3 more, buy 6 more water blocks, and run them at 8v a piece, ie wire 2 tecs in series with your 16v PSU

I think this is a more costly option than buying 3 more appropriate TEC's.

8v x 15a = 120 x 6 tecs = 720w of heat plus your heat load on cold side.

this would have 240w of Qc, ie can handle a 240w heat load on the cold side and hold it to a 30*c dt minus any thermal inefficiencies. so, the same as 3 x 331w tecs with twice the power consumption and therefore twice the heat load the rads need to dissipate which in turn means higher water temp which in turn means higher cold side temp.

power consumption of the TEC's needs to be brought under control before you will see the temps you want to reach.

don't get me wrong here, I don't mind doing any thing at this point, I know that with the current setup I will be at -10C or a little better on the cold side with all three TEC's running and they should be able to handle about 600W of load on the cold side in theory, before they start to heat up. so, before I start up the PC system, and start clocking it any further than it already is. I will need more TEC's, I plan to build a second TEC assembly already. what I am asking you, is what TEC's would you put into that second TEC assembly to handle the hot side of the 12726's that are in there now? or what 6 TEC's would you use to handle a 900W load being dumped into the cold side, and still be able to handle keeping the water temps below 0C on the cold side water loop?
Edited by toolmaker03 - 7/13/16 at 10:53pm
post #748 of 1668
If you are talking cascade, basically, don't, for such a large heat load, it isn't really workable. To get colder on your cold side there are 2 pathways, more tecs, or make it more efficient.

3 x 331w tecs at 16v is more efficient. 6 x 12726's at 8v is also more efficient (i thought you had 12730's)

continuing along the same path with 12726's at 16v will over load your hot side cooling, they also just add heat for virtually no benefit, ie run them at 12v and you'll get similar cold side temps once you add a load to be cooled.

Power = heat, save power = less heat = colder.

lets see what you have to work with, and go from there. you have 16v PSU's,s o lets stick with that, you have 6 x 50mm waterblocks, so lets stick with that. Knowing that undervolting TEC's to 50-67.5% of umax is a far better way to use TEC's, lets aim for TEC's that are ~24v or ~32v, so 199 or 263 couple TEC's. So, drop the ebay tecs, start trawling data sheets to find out if there are 3 tecs that can handle your heat load at some sort of dT, aim for 20-30*c dT for realistic temp difference once you add a load on the cold side. I've suggested 331w TEC's, at 20v they'd have 360w of Qc at 30*c dT, but you don't have a 20v PSU.

6 of these at 16v would have ~525w of Qc at ~30*c delta with 960w power consumption http://customthermoelectric.com/tecs/pdf/19911-5L31-15CQ_spec_sht.pdf

from what I can see, your 3 12726's currently use ~960w and have a qc of about 360w at 30*c delta. So less qc but same power/heat.

I think If I was you, with 16v in mind, and 50mm water blocks in mind, I would get 6 x 331w tecs, thats 450w of Qc at 30*c delta, and ~620-720w of power consumption, more Qc, less power, less heat density so the water blocks on the hot side will keep the tec hot side's cooler, so more delta on cold side.
post #749 of 1668
Thread Starter 
well for right now then, I will try more TEC's on the loop, and see how well the hot side radiators, can hold the hot side of 6 X TEC's down to a decent level.
post #750 of 1668
If you get 6 more water blocks and 3 more 12726's and wire 2 TEC's in series by 3 sets in parallel, ie 8v each, an estimate based on this http://customthermoelectric.com/tecs/pdf/12711-5P31-26CW_spec_sht.pdf CTE TEC gives you 330w of Qc at 30*c delta at ~528w of power consumption, or 600w of Qc at 20*c delta at ~576w of power consumption. You say you have a 600w heat load, factor in your large reservoirs keeping a buffer of chilled water, you can probably hold a 20 to 30 degree delta once the reservoir drops down to temperature.

How much will 6 of those water blocks cost you?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Peltiers / TEC
Overclock.net › Forums › Cooling › Specialized Cooling › Peltiers / TEC › TEC Chill Box Chamber Build log