Date:
Monday , March 29, 2004
Author:
Steve Lynch
Editor:
Kyle Bennett
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VapoChill XE "Xtreme Edition"

Asetek brings their VapoChill line of vapor phase CPU cooling packages to new levels.

continued...

VapoChill XE Changes

Since the only major differences between this VapoChill and the one we reviewed in 2002 is the new refrigerant and CPU kit ( cooling head ) we thought we would focus our time on looking at these changes before we got too far into the review. First up, we look at the refrigerant:

As we mentioned earlier, the only real changes found in the cooling ability of the new VapoChill XE is the difference in refrigerant used in the compressor. Through the use of the R404A, VapoChill is getting a huge boost in cooling power compared to the previous VapoChill unit. If it was simply a matter of using a different refrigerant in the compressor to attain such a massive increase in cooling power, why hasn’t this been done before? We did some digging and the results are surprising.

The first thing we found out is that the new refrigerant being used is made up of equal parts of R125 and 143A. Most people do not know this, but this means that the new refrigerant operates at a much higher pressures than the standard R134A because of the chemical composition of the mixture of these two refrigerants. Seeing that this could have serious implications, we contacted DanFoss USA. I spoke to a representative at DanFoss USA and asked him what the ramifications of using R404A in the BD35F compressor and this was his response:

"The BD35F is not approved for use with R404A because the added pressure of this refrigerant causes premature failure of the compressor. Furthermore, the BD35F when used with the R404A also results in the compressor failing to start."

We had a long discussion with the representative from DanFoss USA about the use of R404A instead of the approved R134A. The talk of compressor failure and units failing to start left us more than a little alarmed. You can see from the photo below that Asetek has added a few modifications to the XE by adding a 60mm fan to the control unit as well as a second 120mm fan to help provide better airflow to the compressor.

Article Image

The original VapoChill SE in the top of the photo has only a single fan on the BD35F condenser. The VapoChill XE, shown on the bottom, has the added fans for the control unit of the BD35F and a large exhaust fan in the rear of the case. At this point, we did not know how these improvements would help with the condenser failure issues raised by DanFoss USA.

Armed with what we heard from DanFoss USA, we decided to contact Andre Eriksen of Asetek to get clarification on the issue. We voiced our concerns about the shutdown issues and premature compressor failure and allowed Asetek to respond to these issues. We submitted a half dozen questions to Mr. Eriksen and these are the answers we received:

1.) The VapoChill XE makes use of a new refrigerant R404A as opposed to the original refrigerant R134A. Why the change?

As you know by our long-term relationship we listen to the market (press and end users). During the last months we have seen an increasing demand For even more powerful solutions than we had in our product portfolio.

2.) What are the benefits of the new refrigerant?

In asetek we are of that opinion that size DOES matter! If we wanted the same performance as the XE with 134a as refrigerant, we would need a much bigger, heavier and more power consuming compressor. Furthermore it would be a 115V/230V compressor and not a 12VDC. R404a is capable of removing the CPU heat at much lower temperatures than R134a, why we are able to keep the small sizes and the following advantages.

3.) According to Danfoss USA, the BD35F is not officially approved for R404A refrigerant. What aspects of the compressor or refrigerant keep the BD35F from being approved for use together?

There are several reasons why R404a isn’t approved with the BD lines of compressors. One of them is, that Danfoss never actually tested it, as demand wasn’t there. Secondly they were in doubt whether and if the BD compressors would be able to start up with R404a due to the increased pressure. However in our application we run with lower evaporator temperatures (and hence lower pressure inside the system) than for instance a fridge, why the potential start up issue doesn’t apply to us.

4.) R404A is comprised of equal parts R125 and 143A meaning it operates at a much higher pressures than R134A. Does this in any way impact the life of the compressor?

Well of course a higher pressure wear more on bearings etc., on the other hand these compressors last for 10-15 years with R134a even at high evaporator temperature / high pressure. However when living on the edge as an overclocker, there are greater risks for impacting the life of your CPU by overclocking /over volting.

5.) Does the fact that the new refrigerant is not officially approved affect the warranty for this product in any way.

Absolutely no! The 24 month warranty stands.

6.) New to the VapoChill XE is the added fan on the control unit. This fan helps dissipate added heat generated by the extra load put on the BD35F from the use of R404A. Is there a failsafe in place in case of fan failure?

No there is not any failsafe utility as such. If you imagine the fan fails, the compressor will overheat (under constant 100% CPU load) and then the ChillControl will show a compressor over heating message. Nothing will be harmed, as the compressor electronics / ChillControl will get into action beforehand. If you are concerned about an overheated CPU, this will not happen as well, as you have set a shut down temperature in the ChillControl as well.

We called DanFoss USA back to get clarification on question number #3. DanFoss USA again reaffirmed their stance that R404A would lead to damage and premature failure of the BD35F compressor. When asked if DanFoss USA had actually tested these units with R404A, DanFoss USA replied:

"We have tested the compressor extensively under these circumstances and higher pressure caused the unit to kick off, shut down and / or prematurely fail. In some cases, keeping the evaporator temps down and control unit cooled as you described might help, but we have tested this thoroughly and to suggest otherwise is ludicrous."

We gave Asetek the chance to respond to this new information from DanFoss USA and Andre Eriksen responded with this:

"As you maybe know I used to work for Danfoss. Not only for Danfoss, but I also worked for the compressor plant in Germany where ALL BD compressors are made. I know the constructor / designer of the BD series in person. There is actually 3 former Danfoss employees with asetek.

Also the office in USA don't have test facilities to test a compressor. Maybe I need to clarify a bit - when I say "they never tested it with R404a" it does not mean that they never charged a system with R404a - of course they did. No what I mean is that Danfoss never made extensive life time tests to see the long-term impact. They have these data from other compressors of course, but as I said demand was never there.

Remember the BD series is 12VDC, and intended for mobile applications such as trucks and boats. However Danfoss is beginning to see a demand for the BD series and R404a, and we are not the only customers using R404a in the BD series. There are for instance organic transportations, and they use low evaporator temperatures as well.

Furthermore you cannot compare a VapoChill system with any other cooling system. In a fridge (where the BD compressors are intended to be installed) you have a huge evaporator (the big white plate in the back of your fridge) with a lot of coolant inside. In the VapoChill you have a tiny evaporator with the size of a dime and almost no coolant inside. Therefore you cannot just generalise....

Look, I think I know more about the compressors than most people. All I know is either from my time at Danfoss or from my good contacts there. I'm often in contact with the engineers in Germany, and they know what we are doing. Consider it like Intel - they like overclocking, but they do not support it in public. Consider it like we are overclocking the compressor. Look I've discussed this with Danfoss several times, and I wouldn't really jeopardize the whole company if I was in doubt...So as I know what I'm talking about, I have no reason to change answer 3. You are more than welcome to include my comments about to further clarify it."

After weeks of batting these questions back and forth between Asetek and DanFoss USA, we came to this conclusion. R404A is not approved for the BD35F compressor that it is being used in. The average life of a compressor using R134A can be as long as 10 – 15 years under optimal circumstances. Asetek is comfortable with the fact that R404A is not approved for use in the BD35F but they obviously feel that the compressor, even with a shortened lifespan, should last for the 24 months that they warranty their machines. DanFoss does not recommend anyone purchase a BD35F with refrigerant that has been found to damage their compressors.

Asetek feels that overclockers are more than used to the risk involved with overclocking, and that what they are doing with the BD35F amounts to the same thing you are doing with your processor when you overclock it.