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-Mud
ex-Jade Falcon
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 Posted: 01-Feb-2004 01:27 Post subject: 'mech Coolant (technical discussion and new rules) |
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This is something I have been fooling with for some time now. Although 'mechs do not need to be refueled in the course of a campaign, I rather suspect they go through prodigious amounts of coolant. Overheating a 'mech is like overheating a car. Large amounts of coolant would be vaporized every time you started climbing the heat chart. Keep abusing your 'mech like this, and before too much longer your heat sinks will not function as effectively. Normal operation will also cause some coolant loss, primarily due to leakage, although this loss will be nowhere near at the extreme rates caused by combat.
Now for the rules; this is just a rough draft at this point.
Each heat sink carries 2 points of coolant. Thus a 'mech with ten normal heat sinks will carry ten coolant points. Normal operation of the 'mech will burn this coolant off at a rate of one point per twelve hours of continuous operation. Mechs equipped with double heat sinks carry the same amount of coolant per heat sink, but burn this coolant off at double the normal rate. (in a shameless attempt to bring some balance to DHS).
Any time the 'mech seriously stresses its cooling system by allowing the heat level to raise to four or more on the heat scale, it risks loosing some coolant either to evaporation or coolant lines bursting under the increased pressure of super-heated coolant. For every round in which a 'mech's heat level at the end of the heat phase is four or greater, the 'mech looses a single point of coolant on a roll of 10+. The chance of loosing coolant increases at higher heat levels, in four point increments. At heat level 8, the roll becomes 9+, at level 12, the roll is 8+, at level 16, the roll is 7+, at level 20, the roll is 6+, at level 24, the roll is 5+, at level 28 the roll is 4+, at at level thirty coolant loss is automatic.
Coolant can also be lost to critical hits to heat sinks or to the engine. Each heat sink critical hit destroys two points of coolant, and each engine hit destroys 10 points of coolant.
Lost coolant decreases the effectiveness of the entire radiator system. A 'mech with 20% coolant loss suffers a +1 heat penalty; 40% loss inflicts a +2 penalty, 60% coolant loss inflicts a +3 penalty, 80% coolant loss inflicts a +4 penalty, and total coolant loss totally disables all heat sinks. All of these penalties are doubled for 'mechs carrying double heat sinks.
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Vampire
Free Worlds League
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| Posted: 01-Feb-2004 04:33 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Been there, done that, printed the t-shirt
you are referred to my site
http://rt000pui.eresmas.net/Battletech/Halstead_Station/Technology/cooling_sys.html
Now commenting on your rules:
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| Although 'mechs do not need to be refueled in the course of a campaign, I rather suspect they go through prodigious amounts of coolant. |
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They would need coolant refills, and of lubricants, too, but this doesn't mean they have to be serviced every few hours.
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| Large amounts of coolant would be vaporized every time you started climbing the heat chart |
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Yes and no. If you mean the nitrogen used for emergencies, yes, that gets vaporized very fast and that's why coolant trucks are used to support Battlemechs.
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| Normal operation will also cause some coolant loss, primarily due to leakage, although this loss will be nowhere near at the extreme rates caused by combat |
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Coolant is not vaporized like the water in a steam engine, rather, if the 'Mech overheats it becomes too hot to be of use as a cooling fluid, at least for a time.
This is what happens when a car engine overheats, the water in the radiator absorbs more heat than it can dissipate and turns to steam.
Some people erroneously argue that 'Mech coolant should be a gas like freon in a freezer. The basic flaw of their reasoning (aside from a gas not absorbing as much heat as a liquid)
is that in a system with so much length of piping, (hundreds of meters of pipeline) there are going to be inevitably leaks, and these are more serious in a gas based circuit than a liquid one. Moreover, the circuit would be a high pressure one, wich would recquire stronger and heavier lines, and compounds the dangers of a leak or a breach due to battle damage. A compressed gas line or tank can burst with explosive force.
About your rules. Well, it's a nice idea but I doubt people will want to bother with the added complexity.
I think it's a nice idea to factor in campaign games 3025 style when each individual 'Mech is as important as a player character, or for campaigns in desert worlds where coolant is an issue worth keeping track of.
It can also give some more use to coolant trucks that as they are now are little more than "portable water holes" for games in mapboards without water hexes.
Nice idea, but so far the only thing you got right is
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| Lost coolant decreases the effectiveness of the entire radiator system. A 'mech with 20% coolant loss suffers a +1 heat penalty; 40% loss inflicts a +2 penalty, 60% coolant loss inflicts a +3 penalty, 80% coolant loss inflicts a +4 penalty, and total coolant loss totally disables all heat sinks. |
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Ruger
Lyran Alliance
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| Posted: 01-Feb-2004 15:40 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Have you taken a look at the BattleTech Companion? In addition to the rather nice Battle Armor construction rules, you can also find a section detailing alot of the inner workings of BattleMechs (and battle armor), including coolant and heat sinks...
Ruger
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Vampire
Free Worlds League
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| Posted: 01-Feb-2004 16:00 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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You mean that drivel authored by Cray? I talked about this particular subject with him. His arguments failed to convince me. I honestly don't know what exact kind of cooling fluid should be used in a 'Mech heat sinks, what I know for certain is that any high pressure system that uses a liquid that turns into gas and then back into liquid is not practical for combat use. It's simply too fragile and sensitive to leaks and combat damage.,
Remember, the liquid cooled piston engine disappeared after World War II for that same reason, while air cooled engines are still around.
EDIT: Some of Cray ideas have merit , but temember Battletech is about the future of the 80s, since then we have figured out a lot of smarter ways to do things. The good thing about Battletech is that it doesn't get outdated because you can use the excuse of technological decline for any advancements post the date of writing of the game that aren't reflected in the setting.
[ This Message was edited by: Vampire on 2004-02-01 16:05 ]
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Motown Scrapper
Clan Ice Hellions
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| Posted: 01-Feb-2004 19:51 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Here is a thought Mech heat sinks do not contain any liquid or gas but rather are like the cooling vanes on air cooled piston engine (reference Most motorcycles ,lawn equipment chainsaws radial and rotary aircraft engines old style Volkswagens and Porshes) they could be made from aluminum,copper,or brass.DHS could just be ones with integral fans.
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-Mud
ex-Jade Falcon
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| Posted: 01-Feb-2004 23:40 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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| There are a lot of sources suggesting 'mechs use some sort of liquid coolant. Liquid nitrogen or some sort of petroleum coolant seem to be the two most likely candidates to me. I kind of wonder about liquid nitrogen however; it has to be kept cold in order to remain a liquid, and the interior of a 'mech is anything but cold, which leads me to question its ability of absorb large amounts of heat. Also, I do not think pumping liquid nitrogen through a coolant vest is an especially good idea, given that the tubes could be ruptured during combat and the mechwarrior exposed to large amounts of ultra-cold nitrogen. What about using water? Arn't modern nuclear reactors water-cooled?
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Motown Scrapper
Clan Ice Hellions
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| Posted: 02-Feb-2004 00:21 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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An aqueous solution of Glycol either Etheline or Propylene could very well be used that is what is used in current ICE engines the most officiant means to do this in a combat machine would to make them modular so that if one is damaged the others would not be effected.
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Alexander
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| Posted: 02-Feb-2004 00:31 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Looking back into my copy of the Tech Readout 3025 (the one with the unseens), page 192 - Coolant Trucks (Class 135-K Kurita Model).
"Coolant trucks, better known as 'coolers' among Mechwarriors, station themselves close to the battlefield, where they can be hooked up to overheated 'Mechs for the purpose of flushing away the excess heat with super-cold liquid nitrogen."
The 135-K carries nine tons of coolant seven tons of liquid nitrogen, and two tons of liquid oxygen in armoured tanks kept cold with small recirculation motors.
A 'Mech has two uses for liquid nitrogen. The first is as a coolant for it's reactors.. In most 'Mechs, a twin-jacketed fusion core is insulated by a surrounding reservoir of liquid nitrogen. This nitrogen reserve is kept in constant circulation to keep the heat of the reactor within performance norms. As the 'Mech exerts more energy, it's heat rises, which causes the liquid nitrogen to expand to dangerous pressures. Sensing this rise in pressure, the control system will vent a portion of the nitrogen into the air until the pressure falls....
A Battlemech also uses liquid nitrogen to cool other of its parts. By diverting a portion of the liquid nitrogen through tubes called 'arteries', the liquid is spread throughtout the 'Mech's structure.
The truck also mounts two turret mounted flamers, which can spew liquid nitrogen onto an overheating 'Mech if need be.
Alexander (Hoping this helps!  )
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Sir Henry
Team Bansai
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| Posted: 02-Feb-2004 06:49 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Talk about the Zorg Ice cube system.... A new Anti-Flamer.... 
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Alexander
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| Posted: 02-Feb-2004 21:28 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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I don't know about new... but, definately different! And FROSTY! Just like an Edmonton winter! (It was minus 35 with a windchill dipping it down to minus 50 for a few days... Minus 19 feels warm now!   )
Alexander
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Motown Scrapper
Clan Ice Hellions
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| Posted: 03-Feb-2004 04:21 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Quote:
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On 2004-02-02 21:28, Alexander wrote:
I don't know about new... but, definitely different! And FROSTY! Just like an Edmonton winter! (It was minus 35 with a windchill dipping it down to minus 50 for a few days... Minus 19 feels warm now! )
Alexander
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That Fahrenheit or Celsius?
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Sir Henry
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| Posted: 03-Feb-2004 06:30 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Mo, he's a Canuck, Celsius of coarse...
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Vampire
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| Posted: 03-Feb-2004 06:50 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Problem with water based coolant is that it may be conductive, you don't want a spill to short circuit your myomers, right? Hence why I think the best fit solution to what the fluff says is an oil based coolant.
Glycol has the same problem with any pressurized sytems, yes, heat sinks are modular, but the circuit is a closed loop, you can shut off damaged radiators to avoid coolant loss, but you are still having tens of meter of pipelines going into and out the reactor. It's a vicious circle, the more redundancy you add with more pipes, the higher the chances of a leak or puncture.
Anyway, I rest my case, whatever the coolant is (take your pick) it's a thing it would be interesting to reflect in game play so let's focus in the question of devising a couple playable rules for this. Mud's draft looks good.
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js
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| Posted: 03-Feb-2004 11:46 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Quote:
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On 2004-02-03 04:21, Motown Scrapper wrote:
That Fahrenheit or Celsius?
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Motown, -40° is the same in either Fahreneit or Celsius - those temperatures are not too far off from that - so it doesn't matter that much!
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Alexander
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| Posted: 03-Feb-2004 19:23 Post subject: RE: 'mech Coolant (technical discussion and new rules) |
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Besides, when it gets that cold, it doesn't really matter! 
Alexander
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