The Earth Cooler Project

The Earth Cooler

Date Log: March 17, 2009

Performance Results

It would be prudent to start off by saying that my first impression of this project was it was essentially a wacky idea. Putting something into the ground to cool a computer was just over the top. I suppose though that's why we called ourselves Radiical in the first place so that we could do wacky things in water cooling that had not been done before. Sure people have Earth cooled their computer systems for years using a variety of measures similar to those that we mentioned in Part One of the project. This is, however, our own prototype design and as such is a first.

There was an initial element of concern over the relative performance of an Earth cooler over the more traditional form of liquid cooled computer systems. Radiators and fans are portable, reasonably efficient and above all easy to setup and dismantle. The Earth cooler is not really any of those it is cumbersome and definitely not portable. After pulling this thing down and putting it back up for testing on so many occasions I can confirm the Earth Cooler really does take a bit of work. When the system is setup and running it is elegant and without doubt has no peer in the radiator and fan world. Having tested this unit in ambient's of 31 degrees Celsius plus I can vouch for its efficiency,ruggedness and great performance.The thermal efficiency of this particular system has surprised and pleased all of us here.

During testing the ability to directly apply heated coolant to the Earth Cooler and then read off changes has certainly redefined for us the direction that our cooling systems product testing should take in the future. The traditional method of emulating a computer systems heat inflow and the hit and miss mounting of a water block simply to transfer the heat produced to the coolant for temperature measurement needed review. The practice of applying heated coolant to the water block at a known temperature range during water block testing is the direction we will now favor.

There should be no confusion about the results presented below. The 648 watts applied by this method is 648 Watts at the cooling element unlike the overly inflated wall measured wattage of say a computer where only a fraction of the measured wattage reaches the coolant.

During testing we used a watt meter and verified the wattages at the plug end for each heater used. Defective or erratic heaters were removed and replaced. A PT100 thermal probe and an alcohol bulbed wall thermometer were used for ambient's. The coolant temperatures were measured inline as close to the Earth Cooler as possible. An additional measurement of the coolant bath temperatures was used to verify the inline probes.

I might just say here in preface to presenting the results that the Earth cooler does not react in any way like a conventional radiator and fan cooling system. Any idea that the two can be compared would be a very difficult argument to sustain. The Earth cooler reacts extremely slowly to all but the most massive increase in wattage. Given the relatively tiny size of the Earth cooler we have used I can only speculate what a larger unit could handle.

Results

178 Watt testing

Pump Eheim; 1250

Ambient; 30.60 degrees Celsius

Earth Cooler Return Water Temperature; 32.60 degrees Celsius

Delta Ambient to Water Return; 2 degrees Celsius above ambient

Run Time; 5 hours.

397 Watt testing

Pump; Eheim 1048

Ambient; 27.60 degrees Celsius

Earth Cooler Return Water Temperature; 31.50 degrees Celsius

Delta Ambient to Water Return; 3.90 degrees Celsius above ambient

Run Time; 5 hours

416 Watt Testing

Pump; Eheim 1250

Ambient; 30.90 degrees Celsius

Earth Cooler Return Water Temperature; 33.90 degrees Celsius

Delta Ambient to Water Return; 3 degrees Celsius above ambient

Run Time; 5 hours

648Watt Testing

Pump; Eheim 1250

Ambient; 24.60 degrees celsius

Earth Cooler Return Water Temperature; 34.60 degrees celsius

Delta Ambient Return Water Temperature; 10 degrees Celsius above ambient

Run Time; 5 hours