TEC/Peltier based chilled water cooling system
TEC/Peltier based chilled water cooling system
This discussion is meant to inform those interested about Peltier/TEC CPU cooling. It highlights the current state and advancements in this cooling method, along with the setup shown below which is functioning properly.
Warning: Peltier technology enables operation below ambient temperature, depending on your objectives and the number of units used. With anti-freeze coolant, it's possible to reach temperatures below 0°C. Initially, the aim was to operate just above condensation points to avoid issues with motherboard insulation. You can safely experience around 13°C below ambient without worrying about condensation, but you must be responsible for how you apply this knowledge.
For those wanting a deeper understanding of the process, refer to the "Exploring Below Ambient Water Cooling" thread.
What does this water cooling method enable?
It’s likely the main interest lies in its ability to surpass standard cooling setups. If your current systems aren’t handling higher loads, this could be a viable alternative. The tests below were conducted with a 2500K overclocked at 4500MHz @ 1.325V using one 580GTX at 23°C ambient. Four core temperatures were averaged for an overall score, tested on WinXP 32-bit.
Air Cooling;
Noctua NH-D14: Idle = 32.75°C, Load = 54.75°C
Thermalright 120 Extreme 2 fans (push/pull), Idle = 32°C, Load = 51.75°C
Standard Water Cooling Closed Loop;
XSPC Rasa RS240 kit: Idle = 30.75°C, Load = 50°C
XSPC Rasa with Black Ice 240 Radiator: Idle = 30.25°C, Load = 48.75°C
Tests were performed at 2700K with disabled hyper-threading, matching the 2500K results in terms of temperature, while other parameters remained consistent across identical motherboards.
TEC/Peltier Water Cooling
Water temperatures reached 12°C, which is 12°C below ambient (no condensation). Idle = 14°C, Load = 31.25°C. At 9°C, it was 15°C below ambient, also without condensation.
Performance tests at 2700K with hyper-threading off equated to a 2500K rating, all other factors identical and tested on the same board.
Peltier Explanation:
The peltier operates by passing electricity through dissimilar metals, creating heat on one side and cooling on the other. If the hot side isn’t cooled, it overheats. The cold side can then be used to chill water flowing through a modified block, storing the chilled liquid for CPU cooling. The device functions as a compact freezer/heater with no moving parts—its value lies in creative application.
In my experience, the hot side exhaust was initially mounted directly on the CPU, often using water cooling there. This caused issues like ice formation around the motherboard, which could short circuits. In winter, it handled the load well; in summer, it required additional AC to offset heat from the TEC unit.
For more detailed insights, refer to xtremesystems.org.
When first integrating a peltier into CPU overclocking setups, mounting it directly on the CPU was common, usually with water cooling on the hot side. This sometimes led to undesirable side effects, necessitating motherboard insulation to prevent shorts from ice buildup.
Ice forms when surface temperatures drop enough to freeze airborne moisture. Higher humidity worsens the problem. Earlier peltiers were smaller in size compared to those used today.
The peltier itself is a compact unit with no moving parts—its true potential lies in smart application. Currently, many prefer direct mounting methods, but exploring TEC-based solutions is worthwhile.
When powered on, the peltier draws 277W, making it an added load. The actual temperature rise depends on voltage and load conditions, varying across models.
Logically, keeping the hot side as cool as possible is ideal, but in practice, balancing both sides is essential. The challenge lies in finding the optimal operating range—close to its performance limits—to avoid overheating while maintaining efficiency.
The TEC Assembly includes a Peltier module placed between a heat pipe cooler with a cold plate, ensuring full coverage of the Peltier's hot surface, and a water block that absorbs cold from the Peltier's cold side.
Close Up
Power Supply Details:
A single 12v rail works best.
The PC available with 12v output is ideal for powering a constant load from the Peltiers. Ensure it can handle the amperage, which is a positive aspect. With a compatible PC, you should draw power from 14g main wires—typically from the 8pin or 4pin motherboard connector, which are usually 14g.
Warning: Avoid using the 18g 4-pin Molex connectors, as they won’t manage the load and may damage the supply unit. It’s crucial to select a power supply with sufficient amperage capacity for safety.
When powering a Peltier, ensure your power source matches the output requirements of the device. I opted for 2 yellow positive 14g wires from the 8pin connector as the primary supply and paired them with 2 black 14g negative wires as the secondary supply.
You don’t need a standard PC you can buy; specialized models rated for voltage and amperage are available online, though they can be tricky to use when the system powers up or shuts down.
The TECBOX power supply connects directly to the main computer’s power supply, mirroring this connection when the main computer starts or stops.
Cooling the Hot Side:
Managing the hot side of the TEC presents its own challenge. Optimal performance requires allowing the hot side to reach higher temperatures. My TEC’s maximum heat tolerance is 125°C (257°F), which is well above boiling water. Initially, I considered water cooling, but it proved too risky due to overheating issues—both the radiator and pump became dangerously hot.
After testing, I switched to a heat pipe air cooler. The first model I tried was a shelved Tuniq Tower with only three heat pipes, which struggled to handle the heat from the CPU in water.
I chose a Thermalright Ultra 120 Extreme, which has six heat pipes and performs well under load. An older Xigmatek S1283 HDT cooler also worked effectively.
I experimented with fan configurations in push/pull mode and settled on 110cfm Sanyo Denki San Ace 120mm fans controlled by a Sunbeam fan controller. These provide balanced cooling—quiet when idle, louder when needed.
A good heat pipe cooler can handle the task, but I prioritized reliability, opting for a cooler rated at least as effective as the TRUE or NH-D14 models. Overheating could destroy the TEC.
Water Block for Cold Side:
Modern water blocks like RASA are restrictive in flow. The base plate’s dispersion nozzle is positioned directly on the pins, forcing coolant through the dispersing pins.
This block was not suited to my needs—it aimed for precise cooling at the CPU die but failed to gather sufficient heat from the entire copper base.
I modified the RASA water inlet protrusion by shaving 1/8 inch off its depth and cutting diversion channels, allowing water to spread evenly across the base plate. This improved flow and ensured continuous cooling.
The Thermalright TRUE (Swiftech Apogee XT) or Noctua NH-D14 models are suitable choices. The TEC will burn if overheated, so maintaining proper flow is critical.
Note for those planning a similar setup:
The Swiftech Apogee XTL is the top choice for flow modification with a 50mm x 50mm Peltier. It outperforms the XSPC Rasa in this regard. The larger copper base of the XTL allows full contact, whereas the Rasa’s base matches the Peltier size, requiring extra thermal compound.
The XTL retains the original design but uses black Delrin for easier cutting and modification, and it’s more affordable. Its wider copper base enhances heat pickup from a 50mm x 50mm Peltier.
I must apologize as my camera is not functioning properly, so I lack images of the modifications. However, the setup performs well.
Additionally, a recent HDD failure cost me all unbacked-up photos—remember, things can break unexpectedly. Always back up regularly!
I’ll take new pictures once I resolve the camera issue and replace the old ones.
PerformancePCs is one of the few places where you can still get the Thermalright TRUE without fans, which is ideal if you already have the necessary fans. They also offer great pricing on the XSPC Rasa.
Below are images of the Swiftech water block assembly and the Rasa water block assembly.
I made significant changes to my Rasa Water Block more than I realized!
At first, I began with the wagon wheel design, but as the block started to freeze, not completely breaking it open, but enough to restrict water flow, I had to modify it again.
This is what I ended up with and what I've been working on.
Sorry about the photos!
My digital camera is causing some trouble right now—I took around 20 shots just to capture these two images, and I’m not sure why this is happening.
This camera has performed well so far; however, I might need to replace it eventually.
The first major change was removing the initial protrusion completely.
Insulated Reservoir:
After numerous trials, I opted for an insulated reservoir crafted from 4" PVC schedule 40 pipe, wrapped with aluminum-faced foam duct seals. This setup provided the optimal mix of water volume and Peltier cooling power. Early tests (referenced in the below thread) used a 54-quart 13.5-gallon tank, now down to half a gallon or 2 liters. Reducing the water volume lessens thermal mass, which speeds up heat transfer to the water.
This insulated reservoir functions as a cold water storage tank, serving as a buffer for the TEC cooling system. It helps the Peltier/TCE assembly manage and reduce the heat produced by the overclocked CPU. All tubing is also insulated to minimize heat loss to the room temperature and internal components.
Performance Variables:
Water Flow Rate:
The flow rate influences how quickly cold conduction occurs from the Peltier to the water passing through the block. Too fast, and it doesn’t cool sufficiently; too slow, and the block may freeze. Currently set at level 2 of 5 using a Swiftech MCP655 pump. The flow rate also plays a role in balancing the system, especially considering the CPU’s water block restrictions. The ideal setup ensures the Peltier water block can fully offset the heat generated by the CPU.
Peltier clamping pressure:
Initially estimated around 25psi to 35psi, which is typical for standard heat sinks. I increased to about 50psi, then further to approximately 100psi after finding higher requirements online. I’m quoting roughly 100psi since I can’t measure it directly—it’s extremely tight.
Addressing Condensation:
Condensation depends on your location, humidity levels, and dew point. In my area, condensation starts at around 8°C water temperature (15°C below ambient) and 16°C below the best radiator loops. As long as I keep the water above 8°C, it’s fine.
My office has an AC unit that helps maintain lower humidity, allowing less condensation risk. Positioned cooling fans can also help evaporate moisture if needed, though at around 3°C water temps, condensation builds up quickly even with fans. These fans can spray droplets from the block, which is undesirable.
Balancing Hot and Cold:
The cooler/reservoir lets the TEC operate at a cooler hot-side temperature, controlled by fan speed on the heat pipe cooler. This balancing act is crucial—letting the hot side heat up while keeping the cold side cold.
This highlights how effective the Thermalright TRUE is, delivering significant cooling control without needing voltage adjustments to the TEC.
Radiators and Peltiers in the Same Loop:
Some suggested combining a radiator with the Peltier, but that turned out problematic. The idea was to chill the water and then let the radiator negate it—initially appealing, but ultimately counterproductive.
I’ve learned this lesson; it’s not worth the effort.
There’s no need for an in-depth explanation of these points—it’s simply counterproductive for a chilled water cooling setup!
I swapped my GPU RadBox for a Watercool MO-RA3 and installed it on the back side panel of the TecBox. The 2 580GTX with full coverage Heat Killer water blocks are now being cooled by the MO-RA3.
I avoided taking pictures during installation because it would have greatly delayed the process. Once I had this large radiator, I felt like a child with a toy on Christmas, eager to get it set up!
The MO-RA3 is a big radiator measuring 15 inches wide, 16 1/2 inches high, and 2 1/2 inches thick, made of copper tubing with four complete passes through the fin field.
To make the setup easier, here’s a quote from the website: I bought four 180mm units, which let me run 180mm cooling fans. These are much quieter than the 5, 120mm, 2,000rpm fans used on the RadBox. The MO-RA3 outperformed the RadBox by five celsius.
My graphics load stays under 40%, while the RadBox pushed it to 45%. At 40% it’s half of the stock air cooler’s 80°C temperature, thanks to the louder 180mm fans—now the only thing making noise in my office is the air conditioner.
Here are some photos of the completed installation.
The MO-RA3 includes four case mounting brackets with 3/4" standoffs, but I needed more clearance, so I chose mounting brackets that sit 1 1/4" above the case for better airflow.
The reservoir is a Bitspower Water Tank Z-Multi 400, along with four Alphacool angled adapters (double 45s) and a revolving design.
The pump is a Swiftech MCP655 variable speed unit.
I’m also using four 180mm Phobya 20mm clear plexi fan shrouds, four 180mm x 32mm Silverstone FM181 High Performance Fans, and four Silverstone 180mm wire fan grills.
Fabricated Reservoir began with a 4-inch PVC drain pipe, trimmed to 13 inches for an internal volume just over half a gallon or two litres. I selected a mounting bracket using a PVC commode 4-inch test flange with a knockout, as it made it easier to position the flange deeper in the pipe and protrude outward as required. A 4-inch PVC cap was used to cover the bottom of the tube. My mitre box helped shape the side of the cap for smoother drilling, tapping, and fitting installation. PVC cement was applied to secure everything together. Inside view shows the barbed outlet fitting and holes for the 5/8 OD Return Line and a temperature sensing probe. Water testing confirmed no leaks after full assembly with the 4-inch test cap left open at the top.
Swiftech Apogee XTL Water Block Flow Modifications. (After the fact)
The block has already been altered as described before; all my earlier images were lost after my HDD failed. I’ll now demonstrate the tools employed and the components involved, along with their purposes and locations.
Caution: Always wear eye protection, particularly when operating the Dremel Tool.
The equipment utilized included a Dremel Tool and a Screw Gun Drill.
Dremel bits applied on the left
Step bit used on the right
The step bit enabled drilling from the bottom side to enlarge the opening without damaging the G14 Threads of the water block. Proceed with this stage slowly and with great care!
A Dremel Steel Bur cutter was employed for deep cutting and initial shaping of the channels.
A larger Dremel diamond-coated ball was used for finishing the surfaces.
The dremel diamond ball taper served to smooth the inner perimeter.
The dremel diamond cone helped shape the outer edge within the boundary.
A small buffing wheel from the Dremel was utilized for polishing, operating at medium speed with light pressure.
Completed results are ready for reassembly.
The maximum clock speed ever recorded was 8.429Ghz on an FX-8150. The people who achieved it used Liquid Helium and believed the processor was close to 0 Kelvin. I believe reaching 10Ghz would require a shift in CPU technology instead of more cooling solutions.
Ryan it seems you're running three techniques together. Is that right?
I'm working with an old K56 Lian Li case and this configuration.
The setup includes 2.243.5w Pelteirs cooled by Xigmatek Gaia heatsinks, using Ek Supreme LXTs for blocks.
I'm planning to cut two square holes on the top of the case and mount the heatsinks inside with the WB's.
The loop will handle a 2500k and GTX 670 FTW card.
I own three peltiers but only use two in the TecBox. One operates continuously while the computer is powered, another is activated via a switch when required. For online activities or social media, just one peltier is enough to keep the water at 10°C. When playing games, I activate the second peltier assembly or TEC to maintain a steady 10°C water temperature. The TecBox handles only the CPU cooling.