View Full Version : Liquid Gases on Robot as coolant
james7132
05-03-2011, 17:06
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
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
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
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
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
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.
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>
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
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.
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
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
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.
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
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
Are you saying you want to submerge your circuit board in an open container of liquid nitrogen?
What could go wrong!
What could go wrong!
I believe that's supposed to be:
What could go wrong... go wrong... go wrong...
nighterfighter
05-03-2011, 19:17
I believe that's supposed to be:
What could go wrong... go wrong... go wrong...
Well, at least it isn't electrically conductive.
Sure, it might make everything brittle and shatter, but at least you won't have a short! :p
Hawiian Cadder
05-03-2011, 20:40
how is your electronic board heating up in the first place, nothing should overheat except perhaps a breaker, batteries can get a little warm too i guess.
team 20 was actually packing ice on their motors (or i assume it was the motors) between the matches in the finals at BAE
DonRotolo
06-03-2011, 14:17
This wins this week's award for "Most Bizarre Thread".
Carry on.
MrForbes
06-03-2011, 15:01
Is it legal to have liquid gases (nitrogen, helium, etc) as a coolant on our minibot or hostbot?
I don't recall seeing liquid nitrogen, helium, etc on the list of approved materials for minibots.
The pneumatic compressor would probably move a lot more air in a small area than the muffin fans....
DonRotolo
06-03-2011, 15:20
A Peltier Device would also move a lot of heat onto a heat sink, which could then use a fan to dump into atmosphere.
Not sure if a water-cooled system would be allowed, like they use in some computers.
Al Skierkiewicz
06-03-2011, 17:26
<R02> ROBOT parts shall not be made from hazardous materials, be unsafe, or cause an unsafe condition. Items specifically prohibited from use on the ROBOT include (but are not limited to):
And the various rules in several sections that speak to damaging the playing field, floors, etc.
As unlikely as you think it might be, robot parts break, robots tip over, and other people are always present. Liquid gasses in any form pose such a hazard. Liquid coolants of any type cannot satisfy the above rules for safety and preventing damage to field or venue.
While teams will go to any length to try and cool motors between matches, any external method does little to remove the internal heat stored in the motor. The path for conduction of the heat in the armature is only through the two end bearings and brush assembly or from direct radiation to the case and magnet structure of the motor. Teams that use freeze spray, run the risk of the material used in making the spray cold, flushing lubricants from exposed motor bearings. Extremely cold surfaces will also condense humidity out of the air like on the outside of a cold drink. Use freeze spray with caution.
scottydoh
06-03-2011, 20:33
Still, no ones answered what/why the circuitry is overheating in the first place. I feel that this should be the really issue here.
Still, no ones answered what/why the circuitry is overheating in the first place. I feel that this should be the really issue here.
Precisely. But the OP - James from Marietta - has not posted any follow-ups since his original post was made 27 hours ago.
Matt Krass
06-03-2011, 22:29
Precisely. But the OP - James from Marietta - has not posted any follow-ups since his original post was made 27 hours ago.
I'm starting to suspect this thread was more of a gag than a serious question...
I can't think of anyway to heat something that much without breaking a few robot rules that way, but that could be a failure of imagination on my part.
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