The Final Word on Steam Boiler Efficiency

[hotblack desiato]

@omicron: a question regarding the oil fabricator that was added with minefactory reloaded (is it just ultimate, or even the other modpacks?)

this machine produces one bucket of oil for 600.000 MJ or 1.500.000 EU.

since it was balanced against combustion engines, which give (according to the wiki) 600.000 MJ per bucket of fuel, and the oil can be refined to fuel for 10.000 MJ (again just an info from the wiki) and you wrote that the combustion engine gives an efficiency of 6,25. this would mean, one bucket of fuel gives at the full efficiency of a steam boiler 871776 MJ per bucket.

would that mean, that the setup 36LP/HP boiler + refinery + oil fabricator produces more oil/fuel than it consumes?

if this excess-fuel powers a second boiler, this would be free energy after the initial effort of powering that system up.

 

[Omicron]

Are you sure that is part of Minefactory Reloaded, and not Power Converters? Both were added to the ultimate pack, and I thought that I remember Power Converters having these production machines for lava and oil. May have misremembered though.

In any case - yes, you are completely right. This is what's called a "cross-mod exploit", where two individual game mechanics that are innocent on their own come together to create an infinite resource loop.

There are other such exploits, though often modders attempt to work together to minimize or avoid the problem. For example, the same thing used to be possible by using lava from TE's magma crucibles to power boilers which in turn power the magma crucibles while having excess energy and/or lava available. CovertJaguar and King Lemming eventually made changes to both their mods that made this kind of loop impossible.

 

[hotblack desiato]

I hope that they fix that loop. I'm not going to exploit it (I have plenty of oil wells near my base, and I want to play just with non renewable energy... I think it's part of the fun, that energy sources need to be explored) but even the option of producing oil out of nuclear energy is interesting.

http://ftbwiki.org/Oil_Fabricator

 

[Omicron]

Yeah, that's the intended application of the Oil Fabricator... using the extremely high energy density of Buildcraft fuel as a way to store energy created out of other sources. A Railcraft tank full of fuel makes for an impressive battery that stores almost 10 million MJ per block... the equivalent of 16 RECs jammed into the same space.

(Also thanks for the link, I stand corrected.)

 

[Growle]

Few questions...Let's say I make the smallest hp boiler I can (1hp I believe)...If it has heated up and I'm ready to expand into a larger one, can I add the extra blocks to the existing boiler while it's on? Or do I have to wait for said 1 hp boiler to cool down before I can do anything...

Also, if I break the block when it is at 100% heat, will it explode? Or will I get the boiler blocks and just lose the saved up steam?

 

[Omicron]

If you break the multiblock, it will cease existing without any other effects; if you then restore it, it will still have the same state as when you broke it.

(However, things like fuel items might have popped out, I'm not too sure on that.)

If you expand (or shrink) a boiler to a different size, it will re-initialize at 0% heat with no contents.

 

[Jacobblue34]

Just curious what is the best set-up for a LP 32 boiler? Looking for a decent setup that doesnt mind being under water in a forcefield dome or underground. I saw your page and went WOW! Good work and the information you have here is amazing And I thought my LP boiler would be super easy. Its sad but ive been working on it for a little over a month off and on...

 

[Omicron]

Do you mean 36? There's no 32 configuration...

As for setup, what kind of information are you looking for? Building a boiler is as easy as plopping down the fireboxes and tanks on top, connecting constant water and fuel supplies, and hooking up steam consumers. Building the fuel supply is usually the more involved/complex part, even if you use an infinite fuel loop likecharcoal or biofuel. Thankfully, there are many tutorials on this forum already which help you construct a tree farm using Forestry or Steve's Carts.

 

[Jacobblue34]

Woops typo. Yes I did mean 36 and I was looking to find info on what the best set-ups are as this is my first attempt with steam boilers. I cant seem to get enough fuel into the boiler and I'm looking for a setup that is pretty much set it up and forget it. Thought I would come here to look for a better set up as even with a decent-sized steve's carts farm I cant seem to get it to work. Anyways Thanks.

 

[MilConDoin]

Woops typo. Yes I did mean 36 and I was looking to find info on what the best set-ups are as this is my first attempt with steam boilers. I cant seem to get enough fuel into the boiler and I'm looking for a setup that is pretty much set it up and forget it. Thought I would come here to look for a better set up as even with a decent-sized steve's carts farm I cant seem to get it to work. Anyways Thanks.

You need 170 buckets of biofuel to get a 36LP boiler from a cold start to max heat. After that it needs ~17.8 buckets/hour to keep running. One still running at max speed all the time can keep over two 36LP boilers running without problems. It should be no problem to feed it with a steve's cart farm.

 

[un worry]

Woops typo. Yes I did mean 36 and I was looking to find info on what the best set-ups are as this is my first attempt with steam boilers. I cant seem to get enough fuel into the boiler and I'm looking for a setup that is pretty much set it up and forget it. Thought I would come here to look for a better set up as even with a decent-sized steve's carts farm I cant seem to get it to work. Anyways Thanks.

Posted my simple setup for you here:
http://forum.feed-the-beast.com/thr...-an-automated-boiler.15575/page-2#post-180294

 

[Jacobblue34]

Thanks

 

[HUAAAANG]

Basically, right around the 500 Cº mark, you have a sharp drop on efficiency, followed by a large rise in efficiency. Why is that? It's because of the steam saturation. Even when you have steam that's over the boiling point of water, you still get a small amount of water that hasn't reached the gas stage, and this creates drag on the turbines, reducing efficiency. As you rise the temperature, you get a higher saturation point, because more of the steam is gas and not liquid, so you can burn more water, and it gets to a higher speed, with lower drag, spinning the turbines faster. What the graph also shows, is that after the steam has gone past the turbine, it's recollected and turned back into liquid water, so it can be fed again to the machine, so that you won't lose all of your water to the atmosphere..

This is close, but not quite right. The drag on the turbine blades is more dependent upon the general state of repair of the turbine, not the water content of the steam(water droplets erode the turbine blades, making them less efficient). Additionally, most boilers have a self contained cycle to eliminate the majority of the remaining water in the steam(moisture separators) producing dry saturated steam regardless of steam temperature and pressure. Third, steam turbines do not operate more efficiently at higher speeds, they have a design optimal speed that will not be exceeded even under situations of higher pressure(in the case of electrical power generation). Raising the temperature of steam increases the amount of work the steam can do before being turned back into water in the condenser, improving efficiency.

You can sum up the efficiency of a heat engine quite concisely by comparing the difference in temperature between the heat source and the heat sink. What is this sharp drop in efficiency you speak of?
The Rankine cycle is not a representation of heat engine efficiency, it is a representation of the heat engine's process. Efficiency must be derived from the various values included in the cycle.

To the OP: nice study, it points out MANY flaws in the mod's construction which implies a lack of understanding of thermodynamics. There could be a simple fix of adding multi-stage turbines that only work with HP boilers.

Corrections welcome.

 

[brujon]

This is close, but not quite right. The drag on the turbine blades is more dependent upon the general state of repair of the turbine, not the water content of the steam(water droplets erode the turbine blades, making them less efficient). Additionally, most boilers have a self contained cycle to eliminate the majority of the remaining water in the steam(moisture separators) producing dry saturated steam regardless of steam temperature and pressure. Third, steam turbines do not operate more efficiently at higher speeds, they have a design optimal speed that will not be exceeded even under situations of higher pressure(in the case of electrical power generation). Raising the temperature of steam increases the amount of work the steam can do before being turned back into water in the condenser, improving efficiency.

You can sum up the efficiency of a heat engine quite concisely by comparing the difference in temperature between the heat source and the heat sink. What is this sharp drop in efficiency you speak of?
The Rankine cycle is not a representation of heat engine efficiency, it is a representation of the heat engine's process. Efficiency must be derived from the various values included in the cycle.

To the OP: nice study, it points out MANY flaws in the mod's construction which implies a lack of understanding of thermodynamics. There could be a simple fix of adding multi-stage turbines that only work with HP boilers.

Corrections welcome.

Thanks for enlightening me on the subject. That's what i get for getting my information out of poorly written wikipedia articles and my own poor understanding of physics.

In any case, a rework of the mod that reflected the higher efficiency of the HP boiler operating at higher temperatures should be made. I mean, the data is THERE. HP Boilers are actually less efficient right now, they're only space savers at the moment.

Since you're more knowledgeable about this stuff, what would you suggest Huaaang?

 

[PonyKuu]

Oh, nice wall of text! I think the reason why people build 36HP is that they need one ^_^
I plan to use boilers primary for IC2 power, and for IC2 more power == better.
And the other thing is that boilers are hard to upgrade - you will have to heat it up again, so it is simpler to wait a bit and make the largest one.

Guys, does anyone use tons of boilers with steam turbines? That's what I want to do eventually, but I'm not sure about it...
36HP produces 720 steam. That's 2 turbines and 80 extra steam. So, if you build 4 boilers, you can run 9 turbines and that's 900 Eu/t. That's might be not enough for matterfabricator, but it can at least help to make quantum armor... I just not quite sure. I don't want to use powerconverters because I just feel that it is kinda "cheating". CovertJaguar introduced steam and device to convert it to Eu, and then powerconveters: "guys, that's too expensive! Use this, it's 10 times cheaper and 3 times more efficient". I feel it like using those mods that convert dirt to diamond blocks at 1:1 ratio...

 

[Omicron]

Yeah, I'm not going to let overPowered Converters anywhere near any of my worlds. Way too easy...

 

[PonyKuu]

I also heard that in the future saplings->fermenter->still->boiler won't really be an option. Am I missing something?

 

[Omicron]

Where did you hear that? That's news to me.

 

[PonyKuu]

There was a thread about some treefarming, and a message that conversion saplings->biomass will be significantly nerfed.

 

[Zjarek_S]

Well, vanilla saplings will produce less, but you are able to make better ones using tree breeding, up to twice the value that you get now (with current trees, there may be better ones in the future).