Trials and Tribulations in Peltier Application (or What You Get for a $100 Prize, Thanks Overclockers.com!)

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An interesting compilation of four experiments — Owen Stevens

OK, I was very, very happy when I won $100 from Overclockers.com (thanks!) so I decided I would put the money to its best use – tweaking my system! The stuff I bought is listed below:

  • Four – 80mm Panaflo ‘L’ fans @ $4.50/ea = $18
  • Six – 80mm fan grills @ $1.25/ea = $8.50
  • Four – Jumbo Rubber Feet @ $0.25/ea = $ 1.00
  • Four – 1/2″ brass pexi-pipe elbows @ $1.50/ea = $6
  • Two – 1/2″ pexi-pipe end caps @ $1/ea = $2
  • One – 72W peltier @ $15
  • One – 122W peltier @ $25
  • One – 3 gram tube of Arctic Alumina @ $4
  • One – PCMCIA 10/100 NIC @ $34
  • Shipping – I paid that I figure it’s only fair

Grand total: $113.5 (OK so I chipped in a few bucks – can you blame me??)

OK, the NIC wasn’t really for Overclocking – it’s for my wife’s laptop so she can get on the net and leave me to play with my system in peace. Now that was money well spent!

So what did I do with all this stuff?

Attempt One: Failure One

I attempted to make a case air chiller first.

I figured I could use a peltier attached to the top of my case and a heat sink I had to make the chiller. I used the first peltier I bought – 72 watts. Being a cheapskate, I bought only the 72W one which, we will see, was not enough – but hindsight is always 20/20.

I have this Panaflo Orb that I modded with a YS tech fan.

PanaFlow

These Panaflo heatsinks were originally installed to the HP cpu via a back plate. I know because I “pulled” this one from a surplus mother board. Hear is a pic of me playing with the pelt and Panaflo Orb and plate with the pelt sandwiched between it.

PanaFlow Pelt

This cooler works really well so I figured it would be great for a pelt cooler.

I used the plate as a template to drill holes in a old Taisol heatsink I had.

Plate

To the drill press – my favorite tool!

Press

I removed a few top fins and counter sunk the holes to make the bolts work.

Sink

Hole

I used the heatsink as a template and drilled the holes to mount the heatsinks.

Template

I ‘attached’ the pelt to the case with some copper based thermal compound I had.

Pelt

Here’s a shot of the bolts I was trying to avoid cutting a hole in the case, so I didn’t, in hind sight this was a bad idea.

Base

Owen Stevens

The heatsinks are bolted together with four bolts to get the right contact pressure.

Bolt

Originally the orb was on the outside and the Taisol was on the inside with a 14CFM ducted fan. Note: I did reverse the Taisol flow from blowing on the HSF to sucking air through it.

Install

With this set up the case temp kept increasing until it was about 5C higher than ambient. Normally my case is only 2C above ambient. Drat it didn’t work! Now in hind sight I might have used the 122W pelt but at this point I hadn’t bought it yet.

I switched it around with the cold side of the pelt outside the case because it seemed like the warm case might be warming the cold side HSF air.

Switch

I also switched the Panaflo to be inside and the Taisol to be outside with an 80mm 24CFM fan attached.

On Case

Case Inside

This worked a little better but my case was still 2C hotter with the chiller than without. Still not what I had hoped and of course it didn’t help my overclock at all. I grumbled for a bit and then re-grouped.

Attempt Two: Failure Two

I have wondered “what if I cool the rad with the 72W pelt?”

I carefully measured where my rad touched the top of my case and the drew the pattern for a hole that could put the 72W pelt on the top of my rad for direct rad cooling.

Template

OK I took a swag at it!

Swag

Again I used the heatsink as a template to drill four mounting holes.

Holes

I was careful when I cut out the ‘pelt-hole’! First I drilled a big hole.

Hole 1

{mospagebreak}

Owen Stevens

Then I tin-snipped it out!

Snip

This is what the installed new ‘pelt-hole’ and bolts looked like.

Bolts

I put a 40mm cold plate on the rad (with grease of course!) and bolted the pelt and heatsink on. I tried both heatsinks and I didn’t get any positive results (well it didn’t heat the case air at least!) I was a bit discouraged so I decided to go on to another project I had thought up.

Attempt 3: Success!

Enter 120mm to 160mm fan upgrade (sort of).

Ever since I made my four fan combo to cool my rad I have wanted to replace my two 120mm fans with four 80mm fans. These are the same kind of fans I have as exhaust fans in the top back of my case (four hooked together there too). I connected the four 80mm fans together with zip ties and then soldered all the leads into a single molex connector.

Quad

Here is where my 120mm intake fan used to be.

Case

I can just fit the four 80mm fans in the same place as the 120mm was.

In Case

So how do you get the hole? I first clamped the four fans to the front of the case like so.

Clamp

Then I drilled a hole through each mounting hole and put in a nail to keep the alignment.

Nail

Once all the holes were made I used tin snips to cut a hole being careful to leave the four corner holes attached.

Hole

I attached the fans with nuts and bolts with rubber grommets between the fan bodies and the case. Here is a peek though my earlier fan grill at them installed.

Grill

{mospagebreak}

Owen Stevens

This worked great but I then realized that I could probably get my rad a lot cooler if it had outside air drawn into it instead of the case air that flowed through it now. I had to abuse the mobo mounting tray a bit but the end result was this.

Fini

Here is a pic of the abuse I mentioned to the mobo tray.

Side

Success at last! This lowered my load cpu temps a full 2C! Yahoo! What can I do next? I decided to make a water chiller.

Attempt Four: Success!

Flush with my success at fan replacement I decide to perform my fourth and final upgrade with my Overclockers.com prize money. First I bought a new 50mm 122W pelt. By now I had learned my lesson and knew I needed more power! I have read here and there about water chillers and since I have some experience with water cooling and air chillers (ok, not good air chiller experience but hey it was educational) I decided to take a shot.

I dug out some old friends of mine; a 80mm x 60mm copper water block that is ‘hollow’ inside and my modified Taisol heatsink from my air chiller. I bolted them together with the 122W pelt in between.

Sink

I put this on the back of my case after relocating my pump power plugs. Here it is with a 80mm Panaflo L fan attached.

Mounted

Here is the back of the chiller.

Back

An inside view of the plumbing. The flow path is pump -> rad -> chiller -> cpu -> north bridge -> pump.

Case View

I decided to switch to a 92mm Panaflo H fan half way through. It is ducted with a piece of gutter extender from Home Depot. An suspended with high tech zip ties!

Zips

Here is a closer shot from above.

Above

I powered the set up with an old 400W power supply I have that I hot wired always on and adjusted the voltage up as much as it would go. It is set neatly on top of my case. (OK, so it looks cheesy it works!)

Cheesy

Now this worked pretty darn good! Another 2C for a grand total of 4-5C drop in cpu temp. My temps used to be 30 idle to 35 load now I am at 27C idle and 30C load in a 23C room. An interesting thing to note is that my delta between load and idle are closer now than before, only 3C difference. I use hot potato to load the cpu to 100% over night and read temps with the onboard thermistor bent to touch the cpu back.

I know what you are thinking, a lot of pain for marginal gain, but it was a ton of fun and I learned a few things too, like 11A is quite a lot of current and 122W pelts need lots of cooling. I think it was a good time for me and hopefully you think my $100 prize was well spent. Thanks again!

Owen Stevens

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