Dry Ice on Robot?

[M.O'Reilly]

I would rather touch dry ice than an 8 inch pneumatic wheel spinning at 5000 RPM...

[Woolly]

Originally Posted by Tom Line

We played with that for fun - we put a bunch of crushed up dry ice in the bottom of a shop vac and checked the output temperature. The sublimation rate is not nearly fast enough to affect the temperature.

You'd have a fun argument on your hands if you tried to hold it on the motors yourself. Just used a compressed air can and turn it upside down. Same thing, safer, and probably faster too.

Well if one had a water block that could easily/quickly clamp over a motor, they could set up a water cooling system, and then have the radiator sitting in a cooler full of dry ice. Maybe even have it set up so a robot battery could be used to run the pump...

That seems like it's so much overkill though.

[orangemoore]

Originally Posted by M.O'Reilly

I would rather touch dry ice than an 8 inch pneumatic wheel spinning at 5000 RPM...

It depends how hard and how long you have to touch each thing.

[dtengineering]

Originally Posted by Jeff Pahl

My opinion would be that if it is doing anything useful (providing cooling) then it is an illegal energy source, as the energy for creating the dry ice did not come from any of the allowed sources of energy that may be used on a robot, and the dry ice effectively becomes a stored energy device.

Hmm... I like the illegal energy source interpretation, but really... wouldn't it be a perfectly legal energy sink? Thermodynamically, energy would flow from the warm chassis and motors into the ice... the robot itself would be an energy source. <edit... I see a few other thermodynamically-inclined respones to this idea popped up while I was writing this!>

Further to this thought, even if dry ice were to be considered an "energy source", would it not be included under the "deformation of robot parts". After all, the energy would come from the thermodynamic expansion of a gas, which is specifically legal in a closed-loop gas shock... which means the gas is a robot part and it is allowed to deform. I challenge anyone to find a rule prohibiting phase changes!

A logical thought experiment... would it be legal to leave the dry ice on the motors while queuing, then remove it immediately before going on to the field? I'd say "yes"... which means that having thermal gradients is legal.

(An interesting thought... for teams using off-board compressors... chill the air in your aluminum storage tanks, and place them above your warm motors... as the match goes on you might get a bit more energy out of them.)

If we really wanted to find excuses to not allow Dry Ice on the robot, we could try classifying it as "compressed air", and as it was compressed by a source other than the compressor then it might not be legal. However since "air" is primarily nitrogen, and Dry Ice is CO2, that would really be stretching it.

In short, however, if the dry ice was handled safely, and placed on the robot in a secure manner, unlikely to injure competitors or officials, and unlikely to damage the field or other robots.... it would be up to the event officials to explain under what rule they were disallowing the dry ice. If they couldn't do that, then they would be obliged to rule the dry ice legal.

And why not? I mean, it's just dry ice! I shared the same "gut feeling" as the cat at the top of the page, but after looking at all the rules... I'd have to pass it at inspection.

Jason

[coalhot]

Originally Posted by dtengineering

it would be up to the event officials to explain under what rule they were disallowing the dry ice. If they couldn't do that, then they would be obliged to rule the dry ice legal.

This would probably be a major sticking point. I can't think of an RI that would look at a container of dry ice (even a completely safe one) and not question it. There also is a clause on the RI checklist about liquids and gasses used on the robot, and I can't think of what it exactly says off the top of my head.

Interesting arguments though

[jspatz1]

Originally Posted by RyanCahoon

Hmm would that classified as stored energy by deformation of a robot part (where in this case the deformation would be freezing)? IMO you also have a valid point about it not being stored energy; it seems like it would be "stored entropy."

As to how you could use dry ice to provide power to a robot... YouTube: Stirling Engine Running On Dry Ice. Maybe you could use the Stirling engine to power a fan to cool your motors? The energy for this would, as you point out, not be coming from the dry ice but from the ambient temperature, and under those terms could be ruled illegal.

Excellent example. This makes my head hurt. I can just see the new rule now:

"G53: Ambient energy of any form present within the boundaries of the PLAYING FIELD may not be harvested and employed by a ROBOT. This includes; thermal energy present in FIELD ELEMENTS, carpet, atmosphere, or other ROBOTS; radiant or photon energy from venue lighting; acoustic energy from the PA system or spectators; and magnetic or cosmic energy fields or streams which may exist within the venue. Violation: TECHINCAL FOUL"

[seg9585]

Interesting topic. On the line of dry ice, would liquid nitrogen used for the purpose of motor cooling violate any rules?

How about room-temperature mercury for the purpose of electrical conductivity (or if you have a lot of it, liquid-based weight distribution)?

I would think R37 specifically permits the use of ferrofluids as a way to store energy.

[nicholsjj]

According to this MSDS http://avogadro.chem.iastate.edu/MSD...xide_solid.htm Dry Ice can be toxic in a gaseous state. So therefore your team would have to prove that no fumes can escape your robot during operation. The problem then would become the dreaded "what-if" questions that inspectors like to ask.

[David Brinza]

Originally Posted by coalhot

This would probably be a major sticking point. I can't think of an RI that would look at a container of dry ice (even a completely safe one) and not question it. There also is a clause on the RI checklist about liquids and gasses used on the robot, and I can't think of what it exactly says off the top of my head.

Interesting arguments though

From the 2013 Inspection Checklist:

No Prohibited Materials – e.g. sound, lasers, noxious or toxic gases or inhalable particles or chemicals <R08>

Referring to Sec 4 of the Game Manual:

R08 ROBOT parts shall not be made from hazardous materials, be unsafe, cause an unsafe condition, or interfere with the operation of other ROBOTS.

Dry ice poses handling and asphyxiation risks. Also, if dry ice is put in a tightly closed container, the container may burst.

The grey area is if the dry ice is not part of the robot, but instead is used to cool components between matches, etc. In this case, dry ice is no longer an inspection issue, but the safety advisers may prohibit its use in the pits.

[MooreteP]

Originally Posted by fb39ca4

It would of course be protected so a human could not accidentally touch it.

Also, wouldn't the water be then considered a hydraulic fluid?

Dry Ice is frozen Carbon Dioxide.
Dry ice, sometimes referred to as "Cardice" or as "card ice" (chiefly British English), is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere). It is useful for preserving frozen foods, ice cream, etc., where mechanical cooling is unavailable. (wikipedia)

Originally Posted by nicholsjj

According to this MSDS http://avogadro.chem.iastate.edu/MSD...xide_solid.htm Dry Ice can be toxic in a gaseous state. So therefore your team would have to prove that no fumes can escape your robot during operation. The problem then would become the dreaded "what-if" questions that inspectors like to ask.

If CO2 is toxic to humans, then the drive team could be disqualified.

There are far better ways to cool motors. Cooling fins, Heat sinks, airflow.

Did you want to create a mystery mist around your Robot? Kind of like the lighting schemes that many teams use?

[jvriezen]

I'm surprised no one has yet mentioned that if you release any CO2 gas, then you are violating rule G13:

G13:




ROBOTS may not intentionally detach or leave parts on the FIELD.
Violation: TECHNICAL FOUL

[EricS-Team180]

Originally Posted by orangemoore

It would look cool

Precisely....we joked about using dry ice to create smoke trails for our frisbees ...one can dream...

[Nirvash]

Originally Posted by jvriezen

I'm surprised no one has yet mentioned that if you release any CO2 gas, then you are violating rule G13:

G13:




ROBOTS may not intentionally detach or leave parts on the FIELD.
Violation: TECHNICAL FOUL

Do we now have to capture any air released from pneumatics?

[jspatz1]

Originally Posted by Nirvash

Do we now have to capture any air released from pneumatics?

Just go to the question box and ask to be shown the detached part(s).

[Woolly]

Originally Posted by jspatz1

Just go to the question box and ask to be shown the detached part(s).

So if all goes as planned, they will waive the foul or you will get a free balloon every match.