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Post by aetreus on Nov 12, 2016 22:24:01 GMT
2600 K is generally better than 2700 K. Someone did the math, and for minimum radiative area you want your efficiency to equal 25% and the core temperature to be as high as possible. We're limited by the properties of high-temperature thermocouples to 2600 K with maximum core temperature, going to 2700 K leaves you with more loss in efficiency than you get back in radiated power. Peak possible efficiency is probably 3120 K -> 2600 K, 16.6%(real efficiency is lower because achieving 3120 K will require significant pumping costs). 3120 K -> 2700 K gives 13.5%, therefore generating 23% more heat per unit power, while dissipating only 16% more for ideal radiators. Note that real radiators lose efficiency as temperature increases, though for some materials this is very little.
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Post by apophys on Nov 13, 2016 0:55:59 GMT
did you know a 25% change in outlet temperature results in a 100% change in required radiator mass? Actually... A 25% increase in temperature results in a 60% decrease in radiator mass. Equivalently, a 25% decrease in temperature results in a 150% increase in radiator mass. Here's the 2700k version. It requires 64% the radiator surface area of the 2000k version. Your 2700K reactor should require only 30% of the 2000K reactor's radiators, not 64%. EDIT: Indeed, I hadn't noticed the efficiency. I stand corrected. Smaller radiators also have the benefit of sticking out less (i.e. less rotational inertia) and providing less of a target to shoot at. Btw, my 1MW reactor + radiator combo weighs in at 34 kg at 2500K. Haven't updated my design to 1.0.7 yet, though. Also, I tend to use redundant radiators, in lieu of radiator armor, so that skews the optimum more to higher temperatures for me. |
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Post by tophattingson on Nov 13, 2016 1:20:10 GMT
The reason the 2700k reactor requires 64% is because of the change in efficiency.
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Post by amimai on Nov 13, 2016 3:20:07 GMT
OK I made a range of reactors for 2500-2800k, they are by no means the "most efficient" but they are close enough to be serviceable i.imgur.com/JG17Og2.png?2i.imgur.com/my9LgyI.png?1i.imgur.com/iviQqz7.png?1i.imgur.com/o1Nvd6W.png?1I did the math on them for combined radiator+reactor mass/kW, looks like once you pass 2600K you really start taking hits to mass efficiency because reactors start getting less efficient and simply bigger due to pump size. Although this will be heavily offset of you are using armoured radiators, if you are using x3 or x4 mass in armoured radiators going up to even 2800 could be doable. When I tried it 2600 came out marginally ahead but if you use even more redundancy 2800 or higher temperatures may become viable using no redundant radiators, 2cm armour temp : kg/MW 2800K : 461 2700K : 321 2600K : 268 2500K : 256 using quad redundant 2cm armour radiators, 8cm armour 2800K : 4048 2700K : 4294 2600K : 3703 2500K : 3761 |
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Post by kaiserwilhelm on Nov 13, 2016 14:32:45 GMT
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Post by dragonkid11 on Nov 13, 2016 15:15:45 GMT
Goddammit RTG, step up you damn game or else nobody has reason to use you anymore.
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Post by kaiserwilhelm on Nov 13, 2016 16:27:44 GMT
Why make RTGs when you can have more power at a cheaper cost with this bad boy here  Edit :The Reactor is named Snickers because it has roughly the size of a snickers. |
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Post by beta on Nov 13, 2016 16:33:58 GMT
I like RTGs because they do not add additional crew for the power they create. They do cost more though.
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Post by dragonkid11 on Nov 13, 2016 16:36:08 GMT
The only reason I don't use RTG is that I can't figure out on how to make a decent version of them and nobody actually put their RTG design here because everyone just want super micro nuclear reactor.
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Post by kaiserwilhelm on Nov 13, 2016 16:46:31 GMT
RTGs cost exponentially more then a decent reactor.
I put these reactors on drones because they are not only exponentially cheaper they are also exponentially ligther and smaller.
I dont see your point about crew tough.
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Post by beta on Nov 13, 2016 16:49:49 GMT
I use the RTG as a backup reactor for when damage is done to the radiators/main reactors. It allows the crew compartments to remain powered and can often power low draw weapons like launchers and chemical guns. This allows a severely damaged spacecraft to still remain a threat.
The nil crew cost can be the difference between having crew to run 3-5 conventional guns and being unable to.
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Post by kaiserwilhelm on Nov 13, 2016 16:57:27 GMT
I use the RTG as a backup reactor for when damage is done to the radiators/main reactors. It allows the crew compartments to remain powered and can often power low draw weapons like launchers and chemical guns. This allows a severely damaged spacecraft to still remain a threat. The nil crew cost can be the difference between having crew to run 3-5 conventional guns and being unable to. Still real backupreactors are better then backupRTGs because again cost and weight. If you need more crew then just design your own crew compartments. |
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khenderson
New Member
my god, it's full of missiles
Posts: 40 
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Post by khenderson on Nov 13, 2016 18:13:34 GMT
tophattingson: Can you post the module details, instead of just the summary screen? Since tophattingson wont share his toys, here's a similar reactor. It's a bit heavier, but significantly cheaper. Presumably you could shave a bit of weight by switching to the more expensive U-235 dioxide.  |
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Post by kaiserwilhelm on Nov 13, 2016 19:51:53 GMT
 If you can have a reactor this small why bother with RTGs |
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Post by Pttg on Nov 13, 2016 21:40:50 GMT
If you can have a reactor this small why bother with RTGs This thing has to be breaking physics somehow, right? Otherwise, I mean, Fallout-style nuclear cars would not be a problem. |
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