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-   -   Liquid Gases on Robot as coolant (http://www.chiefdelphi.com/forums/showthread.php?t=93251)

james7132 05-03-2011 17:06

Liquid Gases on Robot as coolant
 
We were having some heat problems with some of the electronic circuits on our robot. Is it legal to have liquid gases (nitrogen, helium, etc) as a coolant on our minibot or hostbot?

theprgramerdude 05-03-2011 17:41

Re: Liquid Gases on Robot as coolant
 
In what ways are you having heating problems on the robot? Although liquid nitrogen may be possible (and likely the safest of all liquid gases, it probably won't pass inspection on your robot. The reasoning would be that LN can be a major safety hazard due to it's low temperature, although there is no explicit rule saying it isn't allowed (assuming the no hydraulic fluid rule doesn't apply in this case).

Supposedly, it might be allowed for you to spray the stuff down before a match with compressed, supercooled gas, to lower the initial temperature well below zero, and hopefully it'll slow any overheating during a match. Just a theory, though.

kevin.li.rit 05-03-2011 17:43

Re: Liquid Gases on Robot as coolant
 
I believe this would be illegal under the the rules that govern stored energy.

<R01> Energy used by FRC ROBOTS, (i.e., stored at the start of a MATCH), shall come only from the following sources:
A. Electrical energy derived from the onboard 12V battery (see Rule <R34> for specifications and further details).
B. Compressed air stored in the pneumatic system, stored at a maximum pressure of 120 PSI.
C. A change in the altitude of the ROBOT center of gravity.
D. Storage achieved by deformation of ROBOT parts.

Try using the muffin fans that came with the kit.

Vikesrock 05-03-2011 17:44

Re: Liquid Gases on Robot as coolant
 
What kind of circuit are you using that the heat generated can't be disipated by a heatsink/fan?

Chris_Ely 05-03-2011 17:44

Re: Liquid Gases on Robot as coolant
 
the kit of parts gives you four large fans and alot of smaller ones, try using those

also, I think you are overlooking the legal and logistical aspect of liquid gases; they are expensive and I believe you need a license of some sort to get them.

theprgramerdude 05-03-2011 17:51

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by Coffeeism (Post 1035058)
I believe this would be illegal under the the rules that govern stored energy.

<R01> Energy used by FRC ROBOTS, (i.e., stored at the start of a MATCH), shall come only from the following sources:
A. Electrical energy derived from the onboard 12V battery (see Rule <R34> for specifications and further details).
B. Compressed air stored in the pneumatic system, stored at a maximum pressure of 120 PSI.
C. A change in the altitude of the ROBOT center of gravity.
D. Storage achieved by deformation of ROBOT parts.

Try using the muffin fans that came with the kit.

There's no way this could break R01, if it's only a coolant.

Ether 05-03-2011 17:52

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by theprgramerdude (Post 1035057)
there is no explicit rule saying it isn't allowed

There are many rules which in all likelihood will be interpreted, either individually or in combination, to implicitly disallow it:

<R01>B
<R69>
<R87>
<R90>



Ether 05-03-2011 17:56

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by theprgramerdude (Post 1035061)
There's no way this could break R01, if it's only a coolant.

Yes way. Try it and see.

The energy stored in the compressed N2 tank is what causes the coolant to spray out.

This, in combination with other rules (see earlier post) will almost certainly disallow your idea.



theprgramerdude 05-03-2011 18:10

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by Ether (Post 1035063)
Yes way. Try it and see.

The energy stored in the compressed N2 tank is what causes the coolant to spray out.

This, in combination with other rules (see earlier post) will almost certainly disallow your idea.


But if it's in a tank, it's not going to be a coolant. I was picturing an open container, which, while dangerous, can only absorb energy and evaporate (similar to a heatsink, so this question confuses me unless it's for electronics which cannot be easily accessed), NEVER store it. So yes, theoretically it can store energy if the heat absorbed from the environment is not allowed to escape back in the form of N2 gas.

Compressed air, as I am led to believe, means compressed air, not a liquid form of a gas. The rules on de-pressurizing gas would be incapable of being applied.

Ether 05-03-2011 18:23

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by theprgramerdude (Post 1035070)
But if it's in a tank, it's not going to be a coolant. I was picturing an open container, which, while dangerous, can only absorb energy and evaporate (similar to a heatsink

Are you saying you want to submerge your circuit board in an open container of liquid nitrogen?



kevin.li.rit 05-03-2011 18:26

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by Ether (Post 1035062)
There are many rules which in all likelihood will be interpreted, either individually or in combination, to implicitly disallow it:

<R01>B
<R69>
<R87>
<R90>


R02 also applies as liquid n2 is caustic to the skin.

theprgramerdude 05-03-2011 18:30

Re: Liquid Gases on Robot as coolant
 
No, although I suppose someone might be capable of doing that. I was rather suggesting that pouring a rather minute amount of LN, or a similar supercooled, non-toxic gas onto the circuitry, and letting it evaporate in place of the circuits heating up, is technically the only feasible way to keep the circuitry cooled without completely enclosing the system, and thus removing most of liquid gas's benefits.

I'm not advocating doing any of this, aside from spraying it down with compressed air every so slightly before a match if circuit heating is a real issue, due to the extreme dangers of burning if it's mishandled and the usage is done poorly; just saying it could, ever so possibly, be legal.

Ether 05-03-2011 18:32

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by theprgramerdude (Post 1035079)
I was rather suggesting that pouring a rather minute amount of LN, or a similar supercooled, non-toxic gas onto the circuitry, and letting it evaporate

Pouring liquid N2 directly on your circuitry will almost certainly destroy it.



theprgramerdude 05-03-2011 18:55

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by Ether (Post 1035081)
Pouring liquid N2 directly on your circuitry will almost certainly destroy it.


Most likely. It's why I mentioned using canned air and spraying it upside down prior to a match, rather than storing it on the robot.

nighterfighter 05-03-2011 19:02

Re: Liquid Gases on Robot as coolant
 
Quote:

Originally Posted by Ether (Post 1035077)
Are you saying you want to submerge your circuit board in an open container of liquid nitrogen?


What could go wrong!


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