[0.23.5] Realism Overhaul: ROv5.2 + Modlist for RSS 6/30/14

[jrandom]

I need to do a spot-check on some numbers. What would be considered proper energy usage for a water purifier that can output 4kg water / day?

(I've discovered I can add more than one converter module to a part, so to keep the number of parts down I'm combining them into life support modules with individually-triggerable functions: Bosch, electrolyzer, purifier.)

[drtedastro]

Snack Machine. Can not forget the Snack Machine.....

[jrandom]

Snack Machine. Can not forget the Snack Machine.....

I've got those!... they're uh... labeled "Food Container".

[eggrobin]

I've corrected the CO2 density order-of-magnitude problem (dammit, I know co2 is heaver than o2, why did I not spot that??), and updated the module to this:

@PART[TacCarbonExtractor]
{
    @MODEL
    {
        @scale = 1.25, 1.25, 1.25
    }

    @rescaleFactor = 0.8
    @title = Bosch Reactor
    @description = A closed-circuit life support recycling module that runs CO2 through a water stage and back into oxygen.

    @MODULE[TacGenericConverter]
    {
        @conversionRate = 8

        @inputResources = CarbonDioxide, 1, ElectricCharge, 43000
        @outputResources = Oxygen, 0.969, false, Waste, 0.3240741, true
    }
}

If you want to produce 0.969 Oxygen, the amount of Waste produced should be 0.27247150997151004; 0.32407407 Waste was for 0.9 Oxygen (basically sending 0.069 Oxygen to waste). 0.969 seems quite reasonable, as the losses in these reactions seem to be far below 1% for all practical purposes.

There is no harm in leaving a lot of significant figures by the way, the numbers are double-precision floating point.

Right now there's no way to turn down the output of a recycler -- it's either always-on-full-power or always-off. To better support long-term missions, would it be better to have an array of recyclers that run at rates for 2, 4, 8, 16 kerbals instead of the current selection of 8 and 16? Or some other numeric progression? (This is one area where IonCross still beats TACLS -- you can tune your recycler for however many kerbals you need to support via right-click context menu.)

I would advocate making small recyclers (3-4 kerbals, maybe some 1-kerbal units) and using several of these. This is what happens in real life: the ISS has 3 Elektron units which supply oxygen for 3-4 crewmembers each, the Apollo service module had 3 fuel cells, Mir had 2 Elektron units, the STS had 3 fuel cells, etc.

(I've discovered I can add more than one converter module to a part, so to keep the number of parts down I'm combining them into life support modules with individually-triggerable functions: Bosch, electrolyzer, purifier.)

This is an alternative. I prefer the small single use parts approach though, since this allows for more realistic technology evolution: Fuel cells have been around since Apollo, electrolysers were present on Mir, water purifiers on Mir were very primitive, while those of the ISS reuse 93% of the water, and Bosch reactors are still being experimented on and have yet to go to space (finding a catalyst that doesn't get clogged by the graphite seems hard, some recent results are promising though).

What would be considered proper energy usage for a water purifier that can output 4kg water / day?

From an older post of mine on the TACLS thread:

The average power consumption by the ISS water recovery system is (http://ntrs.nasa.gov/archive/nasa/ca...2006249861.pdf) 560 W. However, if we do not average over time, the consumption when in use seems to be 700 W (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1332000/).

Using the figures from this last article, the ISS produces 1.5 gallons of water (5.68 l, or 3.46 kerbal * days) in one hour, using 2520 kJ in the process.

That's about 1 775 kJ for 4l.

Edited December 15, 2013 by eggrobin

[jrandom]

I'll try to figure out a good partitioning scheme with the existing parts (as opposed to adding a bunch of new ones). I still can't find a good solid number on water purification, probably because WasteWater and Waste aren't really well-defined so I don't know what numbers to aim for.

[jrandom]

WIP numbers. I've been crawling through a lot of technical documents, but since TAC isn't full real-world I don't really know how to make the translation. Eggrobin, your help has been invaluable.

I'd like to get a basic update out today with the combined converters, with new individual-function new parts to follow later (which I can create easily once I've got these combined-converter settings all hammered out.)

The purifier obviously needs changes, and hydrogen waste I'm currently just venting. It would help if I knew what WasteWater actually is. It's currently got a per-kerbal-per-day output mass of 3.888... kg.

    @MODULE[TacGenericConverter]
    {
        @converterName = Bosch Reactor
        @conversionRate = 2
        @inputResources = CarbonDioxide, 1, ElectricCharge, 43000
        @outputResources = Oxygen, 0.969, false, Waste, 0.2724715, true
    }

    MODULE
    {
        name = TacGenericConverter
        converterName = Water Electrolyser
        conversionRate = 2
        inputResources = Water, 1, ElectricCharge, 51776
        outputResources = Oxygen, 3.7215675, false
    }

    MODULE
    {
        name = TacGenericConverter
        converterName = Water Purifier
        conversionRate = 2

        inputResources = WasteWater, 1, ElectricCharge, 73.92
        outputResources = Water, 0.9722222, false
    }

[eggrobin]

I edited my post while you were replying to it, so you missed the consumption for the Water Purifier: 1 775 kJ for 4l. The WasteWater is sewage and grey water (and sweat &c) I think. Standard TAC assumes 2 kerbals have the same requirements as 1 human.

[jrandom]

I edited my post while you were replying to it, so you missed the consumption for the Water Purifier: 1 775 kJ for 4l. The WasteWater is sewage and grey water (and sweat &c) I think. Standard TAC assumes 2 kerbals have the same requirements as 1 human.

I've been going with human numbers, so I hope I didn't screw up too badly and mix in any kerbal rates. My confusion with WasteWater is figuring out the split between how much water the purifier should output, and how much waste.

Edited December 15, 2013 by jrandom

[eggrobin]

You used my numbers for the Electrolyser, so that was based on kerbals. If you want to replicate the performance of Elektron, your Water Electrolyser should read

        inputResources = Water, 1, ElectricCharge 86400, // 1 kW * 1 day
        outputResources = Oxygen, 4.229055504417308397, false // Assuming 100% oxygen recovery. Reduce to your liking. I think 4 would be fine.

Elektron does this in a day, so if you want to go with the small parts approach, setting conversionRate=1 allows for fine tuning of the capacity of your station by adding the right number of electrolysers. Again, as Mir had 2 of those and the ISS has 3, this seems to be a nice way to partition stuff.

[jrandom]

You used my numbers for the Electrolyser, so that was based on kerbals. If you want to replicate the performance of Elektron, your Water Electrolyser should read

        inputResources = Water, 1, ElectricCharge 86400, // 1 kW * 1 day
        outputResources = Oxygen, 4.229055504417308397, false // Assuming 100% oxygen recovery. Reduce to your liking. I think 4 would be fine.

Sold! 96.7% recovery rate sound okay?

Elektron does this in a day, so if you want to go with the small parts approach, setting conversionRate=1 allows for fine tuning of the capacity of your station by adding the right number of electrolysers. Again, as Mir had 2 of those and the ISS has 3, this seems to be a nice way to partition stuff.

Excellent point! Now for the mass. I'm seeing things like 3.whatever tons for electrolysers, is that for a 3-4 human crew? Should I just aim for 1-ton-equipment per recycling tech per kerbal? 500 kg?

[eggrobin]

The various models of Elektron have weighed between 150 kg and 110 kg (http://www.jamesoberg.com/elektron2_tec.html). Stuff outside of stock KSP is light!

(Well, light considering it has a pressurised hull with an inert atmosphere and a blast-proof housing).

[jrandom]

The various models of Elektron have weighed between 150 kg and 110 kg (http://www.jamesoberg.com/elektron2_tec.html). Stuff outside of stock KSP is light!

(Well, light considering it has a pressurised hull with an inert atmosphere and a blast-proof housing).

Oooh! Even better! This does kind of explain why I'm having so much trouble. I read a bunch of data sheets and each one has a perfectly reasonable and explained number and each document uses a different number.

[jrandom]

I've added the new TACLS setup to my Realism Overhaul Additional Configs package. I couldn't quite come up with an arrangement of parts I was happy with, but I settled on some small single-purpose 1-kerbal parts, and two larger multi-purpose parts. The all-in-one 3-kerbal unit is this collection's sort-of elektron system. Three of each of the smaller single-purpose units should be functionally equivalent to the large one, and weigh the same when put together.

I'm either going to have to add new PART modules for different configurations in the future, or just get my butt in gear and brush up on those 3D modeling "skills".

I wasn't able to figure out what the waste output of the water purifier should be, so at present it doesn't output any.

[eggrobin]

Elektron is actually just the electrolyser. The ISS Water Recovery System is called the Water Recovery System (they plan to extend it. It will be called the Extended Water Recovery System), and Bosch reactors don't quite exist yet (in space). The conversion rate is too high if you just want to sustain three kerbals though: conversionRate=1 supplies 4.23 kerbals with oxygen, and is thus equivalent to Elektron. conversionRate=n is equivalent to n Elektrons.

The water purifier should get between .8 and .94 Water out of 1 WasteWater, and the Waste should be the mass difference (the stuff you send down in a Progress). See http://forum.kerbalspaceprogram.com/threads/40667-0-22-WIP-TAC-Life-Support-0-6-8Dec?p=807493&viewfull=1#post807493.

Edited to add: I'm almost done with my electrolyser model (see some WIP screenshots: http://forum.kerbalspaceprogram.com/threads/40667-0-22-WIP-TAC-Life-Support-0-6-8Dec?p=831724&viewfull=1#post831724). It's Elektron (12 electrolytic cells with a pump-driven KOH loop) without any of these fancy unkerbal safety features such as a blast-proof housing or a pressure hull with an inert atmosphere (what could go wrong with hot gaseous hydrogen and oxygen aboard a spacecraft anyway?).

Edited December 16, 2013 by eggrobin

[jrandom]

Oh hell, I've been looking at inputs but not outputs with regard to rates. Also, I missed a number change in the electrolyser part, that conversionRate should have been 1.

Edit: Updated file has been uploaded. And as always -- notice something wrong with my configs? Tell me and I shall fix them!

Edited December 16, 2013 by jrandom

[eggrobin]

It probably makes sense to match the outputs rather than the inputs for these. If you have a CO2 supply (on Duna) and a Bosch reactor rated for 3 kerbals, it would be embarrassing to have them suffocate, same if you are shipping water (as on the ISS).

[jrandom]

It probably makes sense to match the outputs rather than the inputs for these. If you have a CO2 supply (on Duna) and a Bosch reactor rated for 3 kerbals, it would be embarrassing to have them suffocate, same if you are shipping water (as on the ISS).

Yep. This has NOT been my day. Gimme a sec, I'll fix up the other outputs...

Edited December 16, 2013 by jrandom

[eggrobin]

Do not forget to rescale the ElectricCharge requirements

(Also, I had not yet downloaded the latest version. I keep missing posts and edits in this conversation...)

[jrandom]

Do not forget to rescale the ElectricCharge requirements

(Also, I had not yet downloaded the latest version. I keep missing posts and edits in this conversation...)

It's a bit of a frenzy.

File has been updated.

[eggrobin]

The numbers look good. I'll check them in more detail (and finish my electrolyser model) when it is not 04:44.

[jrandom]

KSP is hell on the ol' sleep schedule. Thanks for all your help! This is at least a good start. Eventually I'd like to have fuel cells that get their hydrogen from the LiquidH2 fuel (so I don't have to add yet another resource), and then work on some kind of algae/whatever processor that can convert waste into food. Growing food seems to be the last big missing piece and will allow for very extended missions.

[eggrobin]

I'm not sure what to think about that. On the one hand, there are projects to use hydrogen from electrolysis as fuel, and that would allow for accurate modeling of the Sabatier reaction. (It just has to produce LiquidMethane. There are plans to use that as fuel too.) On the other hand, you then need to use the Oxygen from the electrolysis as fuel too, so it should be LiquidOxygen, but that interferes with the nice kerbal*day numbers. Moreover, for most applications, you want to keep the O2 and H2 life support circuits separate from the propulsion system. You wouldn't want the fuel cells to start drawing from your transmunar injection fuel...

I think the way forward is to keep O2 and H2 as separate resources, as they are used in fuel cells, kerbals etc., and to have a life support to propulsion interface that converts Oxygen to LiquidOxygen and Hydrogen to LiquidH2 (I think they are supposed to be gases in the TACLS system, so this could just model the liquefaction). Methane can be LiquidMethane without any harm. (Unless you want to model methane pyrolysis. Actually this is a very realistic alternative to the Bosch reaction for closed-circuit life support. We are doomed.)

Edited December 16, 2013 by eggrobin

[jrandom]

Good point. I'll look at a life-support Hydrogen resource. So... that means new liquid oxygen and hydrogen resources. Think I can use the same H2 boil-off rate as the one currently found in MFS?

[eggrobin]

I'm confused... That means a new (life support) Hydrogen resource, the LiquidOxygen and LiquidHydrogen are already in MFS/RF. Do you mean additional liquid life support O2 and H2? That would be terribly complicated, you would have 3 kinds of oxygen and hydrogen (LS gas, LS liquid, propulsion liquid) and you would need converters between the 3. I was thinking about having 2 kinds of those: the life support variant (gas) and the existing liquid propellant. The problem is of course that some life support systems use LOX and LH2, but we can ignore that (just make tanks that have the right density).

Boiloff shouldn't be too much of a problem for the life support O2/H2 if the Wikipedia article on Apollo 13 is to be believed:

The Service Module oxygen tanks were so well insulated that they could safely contain supercritical hydrogen and oxygen for years.

Edited December 16, 2013 by eggrobin

[NathanKell]

jrandom: very cool!

Check out the fuel cell in the Gemini service module in FASA.cfg

You can add the output resource Water in addition to electricity (in the proper mass ratio, considering the kg/sec of LH2 and LOx being used).

Regarding pod electricity: note that the ~4kWh figure for Apollo is because it had massive fuel cells. Mercury, for example, had 13.5kWh (48600EC) in batteries. So (while I'm sorry to say this) you might be better served hand-rolling the battery capacity for each pod. MM really needs a "is this value < this" check, then you could detect unchanged pods.

Second, that 2kW figure I quoted is for Apollo with all its guidance and comms; Soyuz makes do on less than 1.3kW from solar panels, and Mercury used only a bit over 500W.

Also, in FAR, incompressibleRearAttachDrag should be 0.01

Finally, regarding the pFairing rings. Are you using my modified masses? I use less than cubic scaling, and a smaller original mass anyway, since the masses don't seem to follow real fairing/base/interstage masses that well.