What's the best use of buildcraft fuel?

[Recon]

I used to understand the Railcraft steam boilers fairly well but since the rebalance, I'm not sure what the best route is. My understanding is that before they used to consume much less fuel when fully heated, but now after the rebalance, they consume the same amount of fuel but instead produce more steam after being fully heated. I'm not sure if this also results in a higher water consumption but that would make sense if it did.

It seems most people's understanding of the railcraft boilers is outdated, so I'm hoping to get a good understanding of it here if anyone's knowledge is up to date. I'm using Minecraft 1.6.4.

Given the choice, if my fuel source is Buildcraft fuel (the yellow stuff), I need to be able to decide whether to use combustion dynamos or build a railcraft boiler. If I go with the boiler, it will be high pressure, since you get twice as much output for the same amount of both iron and physical space that the boiler takes up. Turning iron into steel isn't an issue, as I'm using Mekanism and don't need the uber-slow railcraft blast furnace.

So what I'm after really, is knowledge about fuel usage and what you get out of it. Ignoring heatup time for the boiler, and assuming the boiler is already at 1000 degrees. As for the use of steam, I'm assuming the use of compression dynamos from Thermal Expansion to convert the steam to RF. This, as opposed to burning the fuel directly in TE's combustion dynamos.

I also understand that the boilers will consume a constant amount of fuel perpetually, regardless of usage, where the combustion dynamos will scale back from producing 80RF/t to 4RF/t making them the obvious choice for systems which are often not consuming power.

Ultimately, at max output, would I get more RF from a bucket of fuel from (a) combustion dynamos, or (b) a max size high pressure railcraft boiler outputting steam to compression dynamos?

 

[Celestialphoenix]

A full size HP boiler makes a LOT of power- unless you'll average that constant energy production go for something smaller.

 

[Recon]

Yes, I know it makes a lot of power. This is for advanced late-game energy usage.

I'm interested in what those numbers are, and nobody seems to know. To put it literally: How many RF can I get from a bucket of fuel in a full size HP boiler, using the steam in compression dynamos - and how many RF can I get from a bucket of fuel by burning it directly in a combustion dynamo?

Also does anybody happen to know exactly how long it takes a full size HP boiler at max temp to burn a bucket of fuel?

 

[Celestialphoenix]

This might be useful http://calculator.towerofawesome.org/

 

[belgabor]

I can't say for fuel, but as I basically wanted to know the same thing for ethanol I simply tested it in creative =)
For ethanol the boiler is about 17-18% more effective than compression dynamos (9.4 MRF vs. 8.0 MRF per 16 buckets).

Just fyi, for solid fuel (at least for charcoal) the boiler is a lot more effective than using steam dynamos directly, more than 100% (14.2 MRF vs. 6.1 MRF per 4 stacks of charcoal).

 

[SatanicSanta]

Just so ya know, all of the railcraft pages on the wiki are for 1.6.4. I would know, I wrote them

 

[kaovalin]

I can't say for fuel, but as I basically wanted to know the same thing for ethanol I simply tested it in creative =)
For ethanol the boiler is about 17-18% more effective than compression dynamos (9.4 MRF vs. 8.0 MRF per 16 buckets).

Just fyi, for solid fuel (at least for charcoal) the boiler is a lot more effective than using steam dynamos directly, more than 100% (14.2 MRF vs. 6.1 MRF per 4 stacks of charcoal).

The other day I found I could make ~50k RF from a single wood log by using a sawmill (TE3) on the log, then turning the planks(6) into slabs(12). It gives more than a single charcoal I would get from the log, is faster to process (sawmill->cyclicassembler->steamdynamo), and less energy is used to process the log. You get even more RF from the leftover sawdust that you can turn into charcoal as well. Total RF is without subtracting the processing overhead, and using a steam dynamo from a cold start without any steam in it.

 

[Jacobbelveder]

my personal favourite use involves rotary craft, refine it into jet fuel & pump it into a gas turbine, it'll output 1100mj/t as RF, which as long as you can keep up the supply of fuel, completely dwarfs boilers. Having said that it takes about 60 refineries to keep up with one turbine, so it's not exactly practical

 

[MeinerEiner]

Are you sure about 60?
I tried the setup some days ago in creative and started getting more jet fuel at about 8 refineries.

 

[Jacobbelveder]

I too fiddled with in creative, and it took 60. 8 Is waaaay better, how did you have it set up? what am I doing so wrong?


I've got infinite oil coming from a mystcraft ocean age, pumping into a massive rail craft tank, which is then pumped into my refinery array, then the fuel goes into another tank, then from there the fuel goes into 3 fuel enhancers. and after that into the turbine & any excess into a third tank?

whats your 8 refinery set up look like?

 

[MeinerEiner]

I use only one enhancer und stopped adding refineries after the timer inside the gas turbine startet rising.
No Tank anywhere in the loop.

 

[Jacobbelveder]

goddamn tanks, I'll give it a shot, but it sounds like my giant warehouse stuffed with 40 refineries is gonna need a dramatic redesign.

 

[Reika]

I use only one enhancer und stopped adding refineries after the timer inside the gas turbine startet rising.
No Tank anywhere in the loop.

The gas turbine burns 89mB of fuel a tick, and it takes 2 units of BC fuel for every unit of jet fuel. Thus, the gas turbine effectively burns 178mB of fuel a tick, or 3.56 buckets a second.

 

[willis936]

The RC boiler is hard to compete with when it comes to BC power. With MFR's oil generator you can make oil but has a high energy cost. Coupled with a distillery to make fuel you can make net energy gain but there are better methods even though fuel burned in a 36 boiler is hands down the most powerful fuel per bucket. With a gtech distillation tower you can get some booster mats that further increase the energy gain if you use them but you need gtech and a big multiblock and quite a bit of EU.

I personally like forestry's fermenter's for ethanol because the energy cost is low (net energy gain is large) and it's fun to scale up. You can do it with wheat or other small plants though you'd need a huge (I mean HUGE) farm though. Saplings seem to a better choice. Plus you also get wood which is used for lots of stuff and charcoal which isn't a bad energy source in itself. There are lots of methods for farming trees from steve's carts, MFR, forestry, etc. If you use MFR a lot of the energy resource collection systems are easy to automate. Note you will need some sort of wheat farm to create the fermenter's catalyst (fertilizer or something). Oak is a pretty good choice but you can choose for yourself here:
http://minecraft.gamepedia.com/Tutorials/Tree_Farming
Another bonus of oak is that it gives apples. If you're squeezing all of the apples and fermenting all of the saplings you'll get about an eighth of the fruit juice production necessary to avoid using water in fermentation altogether.
A lot of mods add a lot of trees and you'll want to experiment with what's available if you think you can get more. I will say that the MFR rubber tree's growth rate is a little op


As for how much MJ you can get out a RC HU: you'll often see 9.091 MJ/HU quoted a lot. That's a lot of power. There's a post floating around (here http://forum.feed-the-beast.com/threads/the-final-word-on-steam-boiler-efficiency.13506/ ) that shows just how much more fuel is required to heat up a HP vs an LP. It's safe to say that 2x 36 LP is much, much better than 1x 36 HP. Though the "theoretical max" of 9.091 is wrong and I can prove it. RC boilers use more fuel AND gain heat more slowly when they're cool. When they're hot the opposite is true: they use fuel more slowly AND lose heat more slowly. That coupled with the fact that it produces the same amount of steam as long as the temperature is above 100C. This can be exploited if you have computercraft/open peripherals or some other clever method of vibrating fuel on and off at max temperature. I modified a script I found from the post talking about the startup cost of HP boilers to see what I could actually get out of RC boilers. It turns out it's actually around 11. You could get about half a percent better with an HP boiler than an LP boiler because you stay closer to the max temperature after one tick of no fuel but that does very little to offset the startup cost.

Now of course boilers only make sense if you plan on using or storing every mB of steam you make, otherwise you're better off with an engine that uses your fuel/ethanol on demand. I don't care about that though, I like steam.
Why? Let's take a quick look at the numbers. A bucket of ethanol produces 4 MJ/t for 15k ticks in a combustion engine or 40k ticks in a biogas engine. That's 60kMJ and 160kMJ respectively. Not bad. Let's say we get 11 MJ/HU out of our 32 LP boiler which is achievable and realistic with careful control systems. You get 16kHU out of an ethanol cell, that's 160kMJ which is the same as the biogas engine but the steam is storeable. Biogas engines need to be heated up either by continuous use or lava. Steam boilers just run and run and if you have some way of storing billions of buckets of steam you can get billions of buckets of steam.


Oh and here's the modified script if anyone's interested in doing some of their own calculations or want to confirm the higher efficiency. I tested with turning fuel on and off over longer time periods but the best method seems to be to give it as little amount of fuel at a time then waiting until it's used that fuel to give it again. This script actually goes through the math that RC does so it shouldn't be giving wrong numbers. I modified it so that you can specify a starting temperature and so the cooldown period only goes until it reaches that starting temperature again. So let's say you've constantly fed your 36 LP boiler until it hits 500 (which you'd want to do, preferably ending with an empty fuel tank). Now it runs out of fuel and your CC computer with open peripherals sees the temperature hit 499.5, you send a 1 tick redstone pulse to a fluiduct connected to a BC tank filled with ethanol, it pulls out a very small amount of fuel, and you go back up to 500. You need to do a little calibration yourself as I never finished implementing my solution on my last server (I already had a fusion reactor by that point lol). The script runs for a specified number of ticks. I never got around to modifying it to find the number of ticks to reach max temperature so you need to play with that too. It's somewhat linear so it should be easy to work out how many ticks to set by multiplying change in fuel by the ticks set on a previous run. Note your efficiency will go back down to 9 fast if you feed too much fuel at a time and it stays at max temperature for any amount of time. Ideally it should be constantly changing temperature and be as close to the max temperature as possible.

http://pastebin.com/YeSVjKkm


Idk if that's easy to visualize. Here's the steam setup on my last server if you want a visual. Some of the stuff I say earlier about the RC boilers is wrong. I was still learning :x

Go to 10:41. I haven't figured out how to embed start times.

 

[Sidorion]

@willis936: Your concept may have been effectve in the older days, but now the amount of steam produced depends on the heat level of the boiler whereas the fuel consumption is constant. So the boiler needs to reach a certain temperature to overcome the fuel efficiency of a compression dynamo or combustion engine. To be most effective it has to be fully heated. Yes there is a way to tickle some more percent out of it if you turn it on and off but I don't think it's worth the effort. And even with maxsized steel tanks there is still the risk of loosing steam when the tank is full or to experience energy shortages if it's empty.

The most effective way to use buildcraft fuel is to use every single MJ (or RF or EU) produced.

In my setting 16 compression dynamos feed their RF into a redstone energy cell that is connected to a good old RS-nor-latch by comparator logic. That latch turns the dynamos on if the cell falls below 12% charge and off if the cell raises above 80%.
Powerhogs like the rolling machine or the lasers are always connected to the power net by leadstone energy cell set to output on redstone signal. That signal is provided by a gate on a structure pipe and the 'has work' condition.

 

[willis936]

Well (11-9)/9*100% = 22%

That's a pretty sizeable bump in efficiency. As you say though that only matters if you're using it. It's good for things like frameship miners. On my unhinged server I had multiple quantum tanks for storing steam (though even those were filled pretty rapidly). I'm not that far along tech wise on my 1.6.4 server so I haven't read up on the changes. Are there any good resources on the new RC boiler mechanics?

Also non steam based liquid power is definitely the best for small scale rapid power demands as mB are only burned as they're needed where as solid fuel (while easily produced) can be wasted if the operation isn't done at the exact time the solid fuel is finished. You have to weigh how much idle time you'll have with the loss in efficiency for on demand power though (look at the combustion engine vs biogas engine).

 

[Sidorion]

Where did you get that formula from? What do the elevens and nines stand for?
Here you will find actual calculators for boilers: http://forum.feed-the-beast.com/threads/the-final-word-on-steam-boiler-efficiency.13506/
http://forum.feed-the-beast.com/threads/the-final-word-on-steam-boiler-efficiency.13506/
Since the great overhaul the production of steam scales with the temperature of the boiler and the fuel consumption is constant. Keeping the boiler cool simply reduces the steam output per bucket of fuel.
So the only way to get a better steam/fuel ratio than a fully heated boiler is to fully heat it up and then cut the fuel supply until it starts cooling down (as in: the next second it'll fall below maxtemp if it won't get new fuel) and then resupply fuel to prevent that cooling. This has to be timed very exactly and saves far less fuel than your 22% above.

Don't misunderstand me, I'm a huge fan of RC and its Boilers and steam engines (I go for multiblocks) but I miss some kind of power save mode when the steam isn't consumed (pumped out). The boiler should use more fuel if there's actually steam to produce (e.g. if the internal steam tank is empty). I'ts a huge difference between keeping water hot (and thus preventing existent steam from condensating) and producing new steam.

 

[willis936]

11 MJ/HU is my attainable max 1.5.x RC boiler efficiency. If you don't believe me I linked a modified version of the script from the post I linked to in my post (that you also referenced). Good settings are low number of ticks (less than a thousand) and high starting temperature (within a perecent of max). Having it just hit max temp before the cooldown period is ideal.
9 MJ/HU is the quoted theoretical max. The equation is how you generically calculate the percentage difference between two values: (new value - old value) / (old value) * 100% = difference in %.
What you described is exactly what my method is. It's not intuitive that vibrating fuel would save 22% fuel but it in fact does and an accurate simulation can show it.5

I couldn't tell you if 1.6.x RC boiler's can gain efficiency from vibrating fuel but my guess is they can't if steam production is directly related to heat. If heat is still lost slower at max temperature then there is room for a gain in efficiency but if the dev is smart they made the rate of fuel consumption proportional to heat lost. That is to say: if fuel consumption decreases exponentially with heat then the rate of heat lost decreases exponentially at the same rate. If that were the case then you would gain nothing. If fuel consumption decreases faster than the rate of heat loss as temperature rises then you could capture some extra efficiency. I'm not far enough along in my world to bother taking a closer look and doing calculations now but everything needed to work it out is available.

Also while the post we've both linked is helpful all of the information there is for 1.5.x. There hasn't been any decent 1.6.x RC boiler analysis that I have found so far. The FTB wiki and the calculator are the tools available.

 

[Sidorion]

You're talking about 1.5.2, I'm talking about 1.6.4. Your 22% was possible then but isn't anymore (and yes, I know how percentages are calculated, I just couldn't find a source for your numbers). The thread I posted is still up to date. You sould really read it to the end. Then you'll find a link to an actual calculator: http://calculator.towerofawesome.org/

Fuel consumption is actually constant. It does neither depend on time nor on temperature. So the only way to save fuel in a boiler would be providing it with exactly that amout of fuel that it'd need at minimum to maintain maximum heat. But the boiler does that already on it's own so no savings possible here, sorry.

Boilers can beat combustion enginges, but only if the run constantly over a long time AND every produced MJ is actually used:

I stole this image from ladderff in that boiler thread. Here you can see the fuel efficiency over time. Mind that all HP variants are less efficient than their LP counterparts. You have to run a boiler at least for two hours to beat combustion engines.

Though I love boilers and nearly always build one in my worlds I have to say it's better to use combustions if you have flexible needs. The boiler is a good way to provide your minimum needed energy per tick.
To manage peaks in Consumption you should rely on compression dynamos. They can be turned on and off frequently (e.g. have no cooldown or heatup period as the combustion engines) and scale themselves down to a minimum of 10% if the energy is not needed.