You have radiators in the cold loop right? This will limit your cold side temp to basically ambient as the radiators are trying to get the coolant as close to ambient as possible, when the coolant is above ambient they lower the temp, when it is below ambient they raise the temp, this is because the air flowing through the rads is ambient temp and is trying to get the rad/coolant to ambient temp, this negates most of the effect your chiller has.
Also, there are a few things you could improve other than removing the radiators from the cold side loop. Don't run the TEC's so close to Umax, ie 13.67v is 90% of Umax, typically with voltage this close to Umax the TEC is creating excessive heat compared with minimal increase in Qc over say you were running the TEC at 12v, which is about 80% of Umax.
Ideally TEC's should be chosen so that your voltage is no more than about 67.5% of Umax, 50-67.5% is a good range, and use more of them to get the Qc and delta you want as Toolmaker has said. I wouldn't go more than 75% Umax. These 12712 TEC's are not suitable for your needs if you want noticeable gains unless you use say 6 of them at about 7-10v. 199xx TEC's are 24v and would be more suited to your needs.
With these 2 x 12712 TEC's at 13.67v and 22amps (11amps each) you have a Qmax of 220w (110w each) ie you can handle a heat load of 220w and there will be zero difference in temp from hot side to cold side of TEC. Actually because of the thermal losses of the water block and the delta of the coolant on the hot side above ambient this situation usually results in lots of power being used and higher temps than plain water cooling. If your total heat load was more like 150w, you could theoretically get a 20*c delta from hot to cold side of TEC, but most of this delta is lost in reality to hot side coolant delta above ambient and thermal losses in the water block. What I'm saying is you want to chose TEC's that can handle your heat load with a theoretical delta of 30-40*c across the TEC, this way you have a bit of headroom for losses etc. You also want the best waterblocks you can find to limit thermal losses. and you want as much radiator space as possible on the hot side loop to keep the delta above ambient as low as possible.
Your RAM water blocks are ok for low powered devices like RAM which is about 10w, but for a serious chiller they are not very efficient. ie if you had a 220w heatload, and your TEC power consumption is 300w, that is 520w of heat to be transferred through a very basic water block, this will result in a temperature difference between the water block and the hot side coolant probably greater than 15-20*c. This is a thermal loss of about 0.028*c/w-0.038*c/w (ie for every watt of heat being transferred through this block there will be a temp difference of 0.028-0.038*c between the block and the coolant) this basically wastes the delta the TEC creates, or in this case where there is no delta because the heat load is at Qmax, results in an increase in temps over plain water cooling. You want to aim for water blocks that can handle the total heat load (ie CPU+GPU+TEC) and have a thermal loss of about 0.01-0.015*c/w and have enough radiator space to keep the hot side coolant about 5*c above ambient, 10*c above ambient is absolute max otherwise you are just wasting too much of the delta across the TEC.
If you wanted to get some nice temps you could get 4 more ram blocks, 4 more 12712 TEC's, run them in 3 x 2 TEC's wired in series, ie 2 tecs wired in series to your 14v meanwell will get ~7v each x 3 pairs. This distributes the heat load across more TEC's, which helps with the thermal losses of the water blocks, puts the TEC's in a very efficient voltage range lowering power consumption of each TEC, but still maintaining a decent possible delta across the TEC. Then remove all your rads from the cold side loop and add them to the hot side loop to keep your hot side coolant as close to ambient as possible.
I'm not sure what your heat load is or how far below ambient you want to go and if you want to deal with condensation etc but those are all things you need to consider when messing with TEC chillers.
Edited by LiamG6 - 3/26/17 at 8:56pm