Warp Core Cooling---what do we know?

[Plecostomus]

Ok I'm working on a sort of overview of warp-core operations as an on-going project. The one area that is left vauge is cooling. A reactor like that would produce epic amounts of heat.

Now I'm assuming that some of it gets converted directly to electricity via thermoelectric conversion technologies, but where does the rest go? We know there is a cooling system but how does it operate? What is the heat transfer medium and what do they DO with the waste heat?

Lets get the ball rolling on what we DO know, and I'll use them to expand the ideas I have kicking around here

 

[Vanyel]

We know that coolant leaks occurred several times on the Enterprise D. Well at least twice anyway.

 

[Christopher]

As much as I love ST:TMP and its designs, the worst thing that movie ever did was to set the precedent for putting the warp core smack dab in the middle of the engine room with people walking right by it. That's just plain crazy. A matter-antimatter reactor would generate immense heat and radiation. Realistically, it would have to go in an entirely separate module of the ship from the populated section, as far removed from it as practical. That's the whole reason Guzman and Jefferies gave the ship nacelles on struts in the first place -- because the engines were supposed to be separate from the populated portions of the ship.

At least TMP had the marginal sense to put its engineering crew in radiation suits, but realistically it would've been a blast furnace in there. Air conducts heat. You don't want an annihilation reactor sitting around in the same air that the crew is moving through and breathing.

Okay, so Trek tries to pay lip service to this with references to "coolant." But that coolant would have to be incredibly, even impossibly efficient to do its job under the depicted circumstances. Plus it's always depicted as toxic. So where's the sense in that design at all? Wouldn't it be so much simpler and safer to have the engines entirely outboard? To rely on distance and the insulation of vacuum to protect the crew from their heat and radiation?

And then there's the question of what happens to the heat after it's shunted away from the engines. There's some discussion of the problems of cooling a spacecraft in the "Why is the bridge on top?" thread from a few weeks ago, as I recall. Basically, cooling a spaceship is harder than most people assume because vacuum is a fine insulator. Overheating is a serious problem. You need large radiator surfaces, ideally fins extending perpendicular to the ship and able to radiate heat from both sides. The more surface area devoted to heat radiation, the better. Unfortunately, this is something that no fictional spacecraft design anywhere in film or television has ever acknowledged, as far as I'm aware.

 

[Plecostomus]

I suppose we could dump the heat into "subspace" somehow... but I dislike the subspace copout.

Now try this on for size. Two seperate cooling systems. One draws heat away from the reaction chamber itself and a separate one to cool the containment field effectors/generators. THATS what we saw break down both times on TNG, with a gradual loss of containment as the field generators/electromagnets overheated and lost effectiveness. That's why we saw the secondary explosions around the core in Generations, things were breaking down and shorting out as they overheated.

An actual cooling system failure in the system that draws heat away from the core itself would result in instant explodey-time as the structure of the warp-core rapidly melted and vaporized.

 

[StarryEyed]

What ever that coolant is, it seems to be a liquid when it is contained but it evaporates into a dense gas when it is exposed to atmosphere.

It's probably safe to say that the coolant passes through some kind of converter where the heat is converted to some other form of energy. As Christopher pointed out, it's not easy to just dump that heat into space. It would be awfully hard to hide that in the case of cloaked ships too.

 

[Plecostomus]

Well it would be very very hot and under pressure.

I notice in DOH (heh) Torres gets a face full of it while trying to gimmic the core into shutting down and she doesn't die.

That's where I came up with my two cooling system idea... The coils/generators would be cooled with liquid nitrogen/helium/hydrogen (all in use in various applications now), all of which can be breathed without instant death like you'd get from a face full of sodium-vapor.

 

[Christopher]

StarryEyed said:
As Christopher pointed out, it's not easy to just dump that heat into space. It would be awfully hard to hide that in the case of cloaked ships too.

Oh yeah. Cloaking devices in space are essentially a thermodynamic impossibility. Energy has to go somewhere. A body's heat can be masked if there's a large heat sink to dissipate it, such as Arctic air or a big body of water. But in vacuum, all a ship can do with its heat is radiate it outward, making the ship itself a heat source that's easily detectable against the 3-Kelvin background of space. And that's not even counting radiation from its engines.

http://www.projectrho.com/rocket/rocket3w.html#nostealth

 

[nx1701g]

We know that the Warp Core is surrounded by forcefields to protect the engineering personnel from the intense heat and radiation that it gives off. In Nemesis you see them activate a secondary shield around the core.

In DS9 O'Brien talks about the Warp Core for a few seconds and warns the NCO with him to give the Core a wide berth because he has to take the forcefield down around it. They said engineering's temperature rose quickly from the heat.

So, apparently, the forcefields contain the heat or at least help to protect from heat and radiation exposure.

 

[shipfisher]

I've always assumed that warp cores in populated areas of the ship meant previous thermodynamic efficiency breakthroughs that allowed m:am reaction energy conversion with little waste heat (ie. you'd hope they'd have figured out how to keep nearly all the energy in the plasma right out to the warp coils - to me, warp drive capability infers this sort of efficiency - excess heat production seems so 21st century). I'd expect to see warp cores parked right by the coils in the nacelles if energy losses in lengthy plasma conduits were still a factor, so the force-fields referred to above must be able to form quite an effective thermal barrier/containment (not to mention harmful radiation shield). The coolant would be the energy transfer medium for the 1:1 m:am reaction, which should have no material products to form plasma with. The coolant would act like refrigerant in a heat pump, making the core an evaporator, flashing the liquid coolant to plasma, and the nacelles would be condensers, transferring energy to subspace as the plasma condenses. The liquid return lines in the nacelle struts would be quite small in relation to the main plasma feed conduits (vapour lines), just as in a heat pump (thus not featuring in most small scale drive system diagrams). I figured the NX-alpha of 2143 was the first with this closed-loop arrangement ( ie. 2063 Phoenix - big rocket nozzle on it's tail; NX-alpha - closed dome), with previous ships having a greater mass of matter than anti-matter in the drive reaction as a plasma medium, along with greater fuel mass requirements and probable subspace drag associated with plasma exhaust transitting out of the warp field and leaving a wake - this perhaps being a factor in that troublesome warp 2 barrier thing.

Any substance capable of withstanding this drive cycle would be artificial, exotic and understandably toxic. Perhaps "lithium crystal" containment components were impervious to this highly corrosive coolant, explaining the TOS reference to such before dilithium crystals were referred to.

P.S. Thermal containment tech would also be a major tactical component of workable cloaking devices regarding the associated "I'm right here" type heat signature of ships that weren't cloaked across the entire EM spectrum (and let's not forget that in ST we're allowed to explain things with equal parts sci and fi in the classic 1:1 ratio ).

 

[Ronald Held]

I always thought the extra energy got dumped into subspace, but do not recall an episode or movie with that mentioned.
I probably got it from a novel.

 

[Deks]

Well we ARE talking about 22nd, 23rd and 24th centuries here.
The technological differences between that universe and our own (of course future ones) are big enough to assume that the materials from which the Warp cores are made of act as natural shielding.
Also take into consideration that cores come with containment fields when activated (Which presumably have a failsafe to only go down when the core itself is off-line unless there is extreme damage and it affects the warp containment fields).

As for the extra energy ...
Voyager explained that easily enough when they first encountered the Malon.
Nothing is wasted.
Energy is effectively recycled and then used to power all other systems on board such as replicators.

 

[Christopher]

nx1701g said:
We know that the Warp Core is surrounded by forcefields to protect the engineering personnel from the intense heat and radiation that it gives off. In Nemesis you see them activate a secondary shield around the core.

How does that even work? How does an energy field block heat and radiation? This is part of the tendency of ST and other sci-fi to treat "forcefields" as magical barriers that can do whatever the story requires. In reality, an EM forcefield could deflect particle radiation but would have no effect on EM radiation such as gamma, x-rays, or infrared thermal emissions. And if it absorbed the kinetic energy of heated air molecules, say, then it would gain in energy itself and that energy would be radiated into the air it came into contact with. Not to mention that the energy used to generate the forcefield in the first place would be another source of heat. The greater the amount of heat the forcefield is supposed to block, the hotter the forcefield generator would have to get in order to block it. It just wouldn't work.

Even if there were some magic-future-tech way to get around that problem, why is that better than just designing the ship in such a way that the warp reactor is in a separate compartment from the inhabited sections, with vacuum and distance providing the insulation? Too many works of science fiction ignore "Keep It Simple, Stupid" in the name of being all flashy and futuristic.

Deks said:
Well we ARE talking about 22nd, 23rd and 24th centuries here.
The technological differences between that universe and our own (of course future ones) are big enough to assume that the materials from which the Warp cores are made of act as natural shielding....

As for the extra energy ...
Voyager explained that easily enough when they first encountered the Malon.
Nothing is wasted.
Energy is effectively recycled and then used to power all other systems on board such as replicators.

That's a handwave. It's cheating to invoke "futuristic technology" as a way of disregarding fundamental, inviolable laws of physics. That's just another way of saying "And then a miracle happens."

There's always going to be some waste heat from any process, no matter how efficient it gets. Otherwise you've got a perpetual motion machine. Sure, you can theoretically recover a fair amount of energy from engine heat and use it to power other systems, but powering those systems will produce waste heat. And the same goes if you recover energy from that waste heat and use it to power something else -- every time, you have to lose some energy to heat. Heat buildup is a fundamental reality for any closed system in space. Ultimately, it's gonna come down to how big your radiators are.

 

[StarryEyed]

I think you're being a little too critical, Christopher. I'd prefer that Star Trek be much tighter when it comes to real science too but how far can we go with that before the loss of storytelling options and visual aesthetics becomes unacceptable? We have to strike a balance.

I think we have some wriggle room when it comes to seemingly magical things like force fields. String theory posits that all particles are made of one-dimensional strings oscillating in ten spatial dimensions. Assuming the theory is more or less correct, might it be possible to manipulate a string to create particles that would not normally exist in nature? Zap! instant exotic matter and energy with seemingly magical properties.

 

[shipfisher]

The laws of thermodynamics aren't exactly the first to be messed with in trek. That any system in the ship produces excess heat isn't in question - how efficiently future technology manipulates and transfers it is. Agreed that "pure energy" force-fields would be lousy insulation, so as used in trek, they're obviously something more (partial holo-matter analog, etc. - place your treknobabble here). The heat all goes somewhere of course, so something as trek-tech mythical as subspace could be the greatest heat sink you could ever hope for...let's keep it appropriately "not real" here. In saying that, I think of warp coils as the main energy "radiators" in starships - dump energy where it's needed - Al Gore would love it.

 

[Christopher]

Even if all that's true, even if it's possible to use some magically advanced technology to deal with the killing heat that would be produced by a warp reactor inside the ship's pressurized section, the question remains: why bother? Why go to such convoluted lengths when it would be so much simpler, safer, and more efficient just to put the warp engine in a separate module from the crew section?

 

[shipfisher]

^ That's a question for the "all knowing" TV/movie set designers.

 

[Plecostomus]

Just want to point out that a 1:1 deuterium/antihydrogen annihilation reaction will get net you one excess neutron assuming every single pair of atoms gets a chance to collide.

WHICH BRINGS UP AN INTERESTING POINT ABOUT WARP PLASMA! Bear with me folks this came to me during church. A fellow who I know who works at a real nuclear thingy has the idea that maybe warp plasma consists of pairs of particles and antiparticles that are in a state of suspension... the magical properties of Dilithium might force a strange union of particles with a short life. The conditions have to be just right in the core... very hot, very high pressure, and the crystal aligned and energized just right... simulating conditons in the days just after the Big Bang. This soup, "plasma" consisting of gamma rays, neutrons, strange-particles and union-pairs is what is fed to the warp-coils.

Otherwise at 1:1 ratios all you get is gamma and neutrons. Different velocity factors require different ratios of material to be fed to the nacelles.

If we go by this strange musing this explains why warp-plasma can ignite. Whatever is suspending the particle interaction dissipates and you get a huge matter-antimatter explosion.

 

[Christopher]

Plecostomus said:
Just want to point out that a 1:1 deuterium/antihydrogen annihilation reaction will get net you one excess neutron assuming every single pair of atoms gets a chance to collide.

Presumably it would be a deuterium/antideuterium reaction, though.

Of course, an annihilation reaction wouldn't necessarily get you 100% conversion, because nuclei are small and have a lot of open space between them. Even in a tightly confined interaction, there's no guarantee that every particle would collide with an antiparticle or vice-versa. So there could be stray deuterons and antideuterons flying about, some of which might escape magnetic confinement.

 

[Plecostomus]

I'm going by the tech manual I have. It implies that the antimatter is hydrogen while the matter is deuterium.

Was that overrode on screen? I bet if anything it would be in Voyager if it was.

 

[shipfisher]

Plecostomus said:
Just want to point out that a 1:1 deuterium/antihydrogen annihilation reaction will get net you one excess neutron assuming every single pair of atoms gets a chance to collide.

I wondered about that in assuming that warp "plasma" had to be more than a fancy neutron stream.

I must say I'm liking that exotic particle/energy suspension idea for the warp plasma. I'd like to reconcile that with my closed-loop coolant idea, but I'll admit to that being a bit beyond my intellectual pay grade.