Make the LV-N produce power when it's NOT producing thrust

[wizzlebippi]

The LV-N is basically a nuclear reactor that super heats fuel (specifically hydrogen) to produce thrust. When it's not producing thrust, it should be able to produce power like one of the nuclear geneators. When it's producing thrust, I don't think it should produce power at all because all that energy is going into thrust.

[Kasuha]

Standard nuclear reactors generate electricity by boiling water, creating steam, and running a steam turbine. Of course there are other ways to generate electricity, but the matter is that a radioactive core cannot generate anything but heat and radiation and when it is not producing thrust, it's better to keep it inactive and cool, therefore not generating anything that could be turned to electricity.

Of course KSP is a game and in games anything is possible but I don't think there's a reason for LV-N to act also as an eternal electricity generator.

What -might- help would be an engine which burns fuel, generates electricity, but produces no thrust. Something like emergency electricity generator.

[Guest]

Wrong. It's better to keep the reactor running at all times. Why? It's simple. Less startup cycles mean more reliability. This is the basic idea behind a bimodal NTR. When thrusting, the heat is used to heat the propellant. When coasting, this same heat drives the power generator. This means you've got the reactor cooled at all times, and don't need a lengthy startup cycle. It'd a great idea for the NTR to be bimodal.

Oh, and we do have an eternal electricity generator-the RTG. So it's not like KSP has problems with those. NERVA could be somewhat heavier, but other than that, I think it would be a good idea to make it also produce power when throttled down to zero.

[BudgetHedgehog]

You could add a generator module to it and remove the alternator module - you could then pretend that when the ship is throttled up, that power is now coming from the alternator instead of the generator and vice versa for zero throttle.

I do agree with you though, it's better to not shut down nuclear reactors if you can avoid it (if KSPI has taught me anything, it's that you'd then have to wait at least 3 days before you can start your engine again )

[Sirrobert]

Wrong. It's better to keep the reactor running at all times. Why? It's simple. Less startup cycles mean more reliability. This is the basic idea behind a bimodal NTR. When thrusting, the heat is used to heat the propellant. When coasting, this same heat drives the power generator. This means you've got the reactor cooled at all times, and don't need a lengthy startup cycle. It'd a great idea for the NTR to be bimodal.

Oh, and we do have an eternal electricity generator-the RTG. So it's not like KSP has problems with those. NERVA could be somewhat heavier, but other than that, I think it would be a good idea to make it also produce power when throttled down to zero.

Alright, so you keep it running

Why the hell would you add a heavy power generator to a rocket engine? You want to save on weight as much as possible

[BudgetHedgehog]

Alright, so you keep it running

Why the hell would you add a heavy power generator to a rocket engine? You want to save on weight as much as possible

It already has a power generator - the nuclear reactor. I'd suggest maybe making it a bit heavier if the generator/alternator additions I posted above were implemented to make it more balanced (and to take into account the fact you have all the extra gubbins to make electricity).

[Red Iron Crown]

Bimodal NTRs are a thing, in theory at least. Under thrusting operation the core is cooled by the propellant being expelled. When not thrusting, there is a much smaller closed coolant loop that runs a turbine to generate electricity and waste heat is expelled through radiators. More info here. A useful technology, if it ever matures.

While realistic, I don't think it's a great idea from a gameplay perspective. LV-Ns are so efficient in vacuum that they're almost always used for interplanetary missions, having them generate electricity only makes them more desirable.

What I would like to see is the LV-N running on liquid fuel only, without oxidizer.

Edited April 27, 2014 by Red Iron Crown

[The Error]

It could just act like an oversized RTG - little power, but a constant flow.

[architeuthis]

Wrong. It's better to keep the reactor running at all times. Why? It's simple. Less startup cycles mean more reliability. This is the basic idea behind a bimodal NTR. When thrusting, the heat is used to heat the propellant. When coasting, this same heat drives the power generator. This means you've got the reactor cooled at all times, and don't need a lengthy startup cycle.

These are the main advantages of bimodal NTR IMO, but KSP doesn't simulate reactor warmup times, coolant dynamics or thermal cycling so the point is lost somewhat. On a mass basis, at least for Mars missions solar panels make more sense than bimodal NTR. Bimodal NTR uses very low efficiency thermoelectric conversion cells, and requires heavy radiator mechanisms. In reality radiators are prone to breaking down (as we have seen on the ISS), but manual repairs in the immediate vicinity of a nuclear reactor are completely out of the questions for safety reasons. Solid state radiators are even less efficient on a per mass basis than the ammonia cooled ones. For these reasons, among others, the most recent NASA Mars design reference mission uses nuclear thermal for propulsion, and solar to generate electricity.

TLDR; Keep the LV-N like NERVA unless there is a waste heat management dynamic added to the game.

What I would like to see is the LV-N running on liquid fuel only, without oxidizer.

Seconded!

[BudgetHedgehog]

TLDR; Keep the LV-N like NERVA unless there is a waste heat management dynamic added to the game.

Ooh... I think that with some playing around of syntax from ModuleManager 2.0.3, having the LV-Ns generate electricity AND waste heat could be possible, but ONLY if Interstellar is installed (since that introduces waste heat management).