[Research] Detailed Heat Mechanics

Time for another research thread by your favorite furry friend, Frenotx! This time, it's time to tackle the heat mechanics. This one's a bit unusual, though- I'm looking for some assistance from viewers like you! So, without further ado:

Highlights:
-1 heat unit = 1 BTU.
-Each ship has a baked in “thermal capacity”. In general, bigger ship = bigger thermal capacity.
-The heat efficiency stat for power plants = how many BTUs are generated per second, per MW being consumed.
-Cooling rate function seems to be universal to all ships. At low temperatures, the cooling rate is very low. It increases at an increasing non-linear rate as temperature rises, until it caps out at ~66%.
-Maximum cooling rate appears to be about 9% per second.
-Higher thermal capacity ships have lower resting heat at a given MW consumption, take more BTUs to heat up, and can dump more BTUs per second (9% of a bigger number gives you a bigger result)

What I need help with:
-Testing the thermal capacity of more ships
-Pinning down the exact cooling function

Heat Mechanics: What I've figured out so far
The current temperature of this ship is based on the sum of “heat in”, and “heat out”. For the sake of discussion, let’s call one unit of heat 1 BTU. Looking at the in-game numbers and units, and doing a bit of poking around regarding fusion efficiency, makes this seem reasonable enough.
Each ship has an assigned heat capacity. For example, the Hauler’s capacity is ~185 BTU. If you pump 185 BTU into a hauler, then at that moment, the temperature gauge will read 100%. This capacity varies from ship to ship, and appears to be baked into the ship / independent of module selection.
The rate at which a ship cools down is dependent on its current heat load. At low %s, the cooling rate is very low. As the heat load increases, so does the cooling rate. I haven’t quite pinned down the formula, but it’s definitely non-linear. The closest I’ve been able to approximate is the following:

-.2156x^2 + .005x -.0011


I think I've pinned down the cooling rate formula. Upon further review of my data,
y = -.2x2
seems to fix extremely well
, where x is the current heat percentage (.5 = 50%), and y is the % max heat cooling rate (-.02 = -2% per second). Cooling follows this formula very closely until the temperature reaches ~66%, at which point the cooling rate caps out at -8.7% per second.

Where the X axis is the current % heat load of the ship, and the Y axis is resulting cooling rate (% max per second). I’m sure the actual formula used is something much cleaner, but that one will at least demonstrate the rough shape.

Something to note on that cooling formula, though: Your cooling rate caps out when you hit somewhere between 60% and 70% heat load. You can still get hotter after that point (obviously), but you ship stops cooling any faster. The maximum cooling rate appears to be about -9% per second.

I believe the exact point at which the cooling rate caps is at 66%. The reason I believe this is because the heat scale used to be a bit different, back in the day. Around the time of 1.2, the scale was changed such that the old 150% registered as 100% on the new scale. That means the old 100% (a perfectly reasonable place for the cooling rate to cap out) is the new 66%.

The resting heat of a ship is a matter of equilibrium. For each MW of power consumed by modules, some number of BTUs is generated per second, based on the heat efficiency stat of the power plant. For grade E power plants, the heat efficiency is 1, so 1 BTU is generated per second per MW consumed by modules. For grade A power plants, the heat efficiency is .4. Your power plant dumps some number of BTUs into the ship per second, until your heat rises enough that the cooling rate matches the heating rate. Since the cooling formula seems to be consistent across all ships and be percentage based, the higher the heat capacity of the ship, the larger the number of BTUs it can dump per second. Lowering the heat efficiency stat, or decreasing the number of MW being consumed will give you a lower resting heat.

Additionally, because the cooling rates are all percentage based, the higher the heat capacity of a given ship, the more BTU per second it can eliminate. With this in mind, having a high heat capacity is doubly beneficial. Not only does it take more heat to push you into critical temperatures, but you can also dump excess heat more quickly. Still the same % per second as every other ship, but a fixed percent of a bigger number gives you a bigger result.

So, on to some numbers. Those marked as unverified (N) have only been tested by one person. Those marked with a Y have been confirmed by at least one other party:
ShipCapacity (BTU)CMDRVerified
Hauler185Frenotx / wenkmanY
Sidewinder211wenkman / WinterwalkerY
Dolphin248drakhyr / KonnivarY
Eagle249wenkman / drakhyrY
Adder255Frenotx / drakhyrY
Type-6270drakhyrN
Viper III292drakhyrN
V IV315Frenotx / drakhyrY
Asp S317wenkmanN
Keelback323FrenotxN
FDL336moose666 / KonnivarY
Cobra III339wenkman / drakhyrY
Type-7340Konnivar / ErichZannY
Cobra IV344wenkmanN
Courier345Frenotx / moose666Y
Vulture356Frenotx / wenkmanY
Asp X410wenkman / drakhyrY
Beluga421moose666N
FAS430moose666N
Chieftain434LyneiraN
Gunship442FoxtrotFN
Krait448CMDR Lucienn / Drakin138Y
Python450moose666 / drakhyrY
Clipper455moose666 / marxY
T9472wenkmanN
Challenger474Drakin138N
Cutter490moose666 / marxY
Conda493FrenotxN
Dropship498drakhyrN
Corvette498Cablefast / moose666Y
Type-10503marxN
DBS520Frenotx / moose666Y
DBX527wenkmanN

*Updated 6/30/2018

In general, bigger ships have higher thermal capacities. This makes sense, as the bigger the ship, the higher the MW load, and thus the higher the base heat load. The ship needs a higher thermal capacity to keep the resting heat too high. These numbers also show why the DBS is such a fantastic stealth ship; despite it being a small ship with low MW consumption, it still has a thermal capacity that’s on par with beasts like the anaconda. It’s no wonder the DBS’ resting heat is so low, and that it preforms as well as it does in silent running.

So, what can you do to help? Well, as you can clearly see, quite a few ships need to be tested. Determining the thermal capacity is easy. All you need to do is follow these steps:


  1. Note the heat efficiency of the power plant, and the energy consumption of your thrusters. If you’ve modified either, don’t just use the listed value- it’s likely rounded. Apply the listed percentage change (on the “modifications” screen, in outfitting) to the base value for the real number.
  2. Make sure you have at least 1 heat sink launcher equipped.
  3. Launch your ship, and power down all modules but the heatsink launcher
  4. Engage silent running, fire the heatsink, then turn off the heatsink launcher while the coolant is purging. This will dump all the heat out of your ship (coolant purge), eliminate all heat load (turning off the heat sink launcher), and prevent all cooling. Note: Your temperature may not display as 0%, but this is apparently just a display bug. If you’ve done everything as listed, you’ll dump all the heat out of your ship.
  5. Grab a stop watch. Press the start button at the exact same time as you re-enable your thrusters.
  6. Sit perfectly still, and wait. Your heat will slowly rise. Shortly after your heat hits the high 90’s, you’ll see a visual warning in the top-right corner of your screen saying “heat levels critical”. Stop the stopwatch as soon as this pops up. You can disable silent running at this point, and turn everything back on.
  7. Note the number of seconds. Multiply the number of seconds by the heat efficiency value of your power plant, and the MW usage of your thrusters. The resulting value is that ship’s thermal capacity.
The other thing I could use help with is determining the exact (or at least a better) cooling formula. Here is my data detailing the cooling rates. I engaged silent running on a hauler, and waited until all the modules burned out. At this point, with no modules running, my heat stopped increasing. 0 seconds is when I first disengaged silent running. I’m so-so at math and function manipulation, so I’ll leave this is more capable hands:
http://pastebin.com/55DDHqVC
Edit: I think I figured out the formula. y = -.2x2, where x is the current heat percentage, and y is the percent max heat cooling per second. This formula is still not dev-confirmed, so I certainly wouldn't mind some volunteer fact checking.

Thanks everyone! Thoughts? Questions? Ideas on what I should work on next?
 
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Huh. Figured there'd be a bit more interest on this subject. Any suggestion on what mechanics everyone would be more interested in understanding?
 
I'll try and go through your process on my corvette and post it here later today. Very interesting read; thanks for posting. Fantastic work you've done here.
----Test Results----
Ship: Federal Corvette
Power Plant: Unmodified 8B (0.5 Thermal Efficiency)
Thrusters: Clean Drive Tuning 7D (7.87 Advertised Power Draw/7.866 Calculated Power Draw)
Heat Level Critical Time: 140 Seconds
Estimated Thermal Capacity: 550.62
*Thanks again for posting Frenotx!
 
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Huh. Figured there'd be a bit more interest on this subject. Any suggestion on what mechanics everyone would be more interested in understanding?
Sry but my intrest on heat stops when i can cruise around a star with it's yellow line at the upper side of my screen and scoop without overheating :|

If this works, all is okay. If this sucks....i need something to do.

In pvp it is just "taking heat damage" and that's all i need to know "shoot 'em fast or run" :D
 
Sry but my intrest on heat stops when i can cruise around a star with it's yellow line at the upper side of my screen and scoop without overheating :|

If this works, all is okay. If this sucks....i need something to do.

In pvp it is just "taking heat damage" and that's all i need to know "shoot 'em fast or run" :D
One interesting thing about this research in that regard, odd that assuming thermal attack weapons dump a flat amount of heat into the target (as I suspect they do), then smaller ships with lower thermal capacities are far more vulnerable to those attacks than larger ships.

From a fuel scooping perspective, its also good to see the importance of having a good heat efficiency value for your power plant (lower is better), and keeping your MW usage as low as possible.
- - - - - Additional Content Posted / Auto Merge - - - - -

I'll try and go through your process on my corvette and post it here later today. Very interesting read; thanks for posting. Fantastic work you've done here.
That would be wonderful. I imagine the big three, the fer-de-lance, and possibly the FAS are the ones people are most interested in.
 
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wow. interesting post :) amazing work!

i still can't make up my mind about this test: https://forums.frontier.co.uk/showthread.php/192282-A-look-at-Diamondback-Explorer-heat-emissions-and-signature-detection

to me it looks as if the powerplant itself produces heat by running ... e.g. like a seperate modul not listed, so smaller powerplants make the build run cooler with the same moduls turned on/off (which meets the experience of many smugglers and explorers).

did your tests shed any light on that? how does powerplant size (or MW of a powerplant ... or whatever) effect the overall heat?

anyway .... I'm out exploring, but when i'm back in some weeks, i'll happily add data to this thread.
 
One interesting thing about this research in that regard, odd that assuming thermal attack weapons dump a flat amount of heat into the target (as I suspect they do), then smaller ships with lower thermal capacities are far more vulnerable to those attacks than larger ships.
Great work as ever, Mr Frenotx.

My own preliminary research into the effect of RNGineered heat weapons also causes me to believe that they probably provide a flat addition. It is partly for this reason that the theoretical counters often suggested by non-PvP players (such as clean drives and cool power plants) are so utterly irrelevant in practice.

And yes, as you suggest, in practice Cmdrs in small ships are far easier to paralyse than those in large ones, even accounting for numbers of heat sinks.
 
wow. interesting post :) amazing work!

i still can't make up my mind about this test: https://forums.frontier.co.uk/showthread.php/192282-A-look-at-Diamondback-Explorer-heat-emissions-and-signature-detection

to me it looks as if the powerplant itself produces heat by running ... e.g. like a seperate modul not listed, so smaller powerplants make the build run cooler with the same moduls turned on/off (which meets the experience of many smugglers and explorers).

did your tests shed any light on that? how does powerplant size (or MW of a powerplant ... or whatever) effect the overall heat?

anyway .... I'm out exploring, but when i'm back in some weeks, i'll happily add data to this thread.
The power plant doesn't produce any heat by itself. You can test this by firing a heat sink, turning everything off, and engaging silent running. Assuming you're not sitting by a star our getting shot with heat attack weapons, your temperature won't rise at all. That said, the powerplant does produce heat for every MW being used by activated modules, at a rate of [Heat Efficiency Stat] * [MW Used] per second. Note that the heat generated is based on flat MW consumption, not % utilization. If you want a lower resting heat, you can either improve (make smaller) your heat efficiency stat of your powerplant, lower your MW consumption by turning of unneeded modules, or fly a ship with a higher thermal capacity.

I will try to do the test tonight in my Python
Considering the popularity of the python, that would be much appreciated.
 
The power plant doesn't produce any heat by itself. You can test this by firing a heat sink, turning everything off, and engaging silent running. Assuming you're not sitting by a star our getting shot with heat attack weapons, your temperature won't rise at all. That said, the powerplant does produce heat for every MW being used by activated modules, at a rate of [Heat Efficiency Stat] * [MW Used] per second. Note that the heat generated is based on flat MW consumption, not % utilization. If you want a lower resting heat, you can either improve (make smaller) your heat efficiency stat of your powerplant, lower your MW consumption by turning of unneeded modules, or fly a ship with a higher thermal capacity.



Considering the popularity of the python, that would be much appreciated.
Hmmmm not complete right, i have done this myself to find out how cool my ship can stay in idle.
The moment you engage silent running, the heat rises. I tryed it even with deactivated life support. In these 25 minutes the heat was about 90% only coming from powerplant and canopy.
Pls test it again, it will take much time but the heat still raises :rolleyes:

Edit:
Did it with stock A powerplant and with modification to a 0.3 heat output instead of 0.4
 
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Hmmmm not complete right, i have done this myself to find out how cool my ship can stay in idle.
The moment you engage silent running, the heat rises. I tryed it even with deactivated life support. In these 25 minutes the heat was about 90% only coming from powerplant and canopy.
Pls test it again, it will take much time but the heat still raises :rolleyes:

Edit:
Did it with stock A powerplant and with modification to a 0.3 heat output instead of 0.4
Did a test to double check. Turned every module off in the courier. Engaged silent running. Turned on the heatsink launcher, fired a heatsink, then turned it off again. Sat there in space for 5 minutes, and saw no change in heat. It's possible that when you conducted your test you were near a star, or forgot to turn off a module. The powerplant definitely doesn't generate heat on its own, and if it does, the amount is so low as to be negligible. Incidentally, I've added the heat capacities of the courier and keelback.
 
Ship: Federal Corvette
Power Plant: Unmodified 8B (0.5 Thermal Efficiency)
Thrusters: Clean Drive Tuning 7D (7.87 Advertised Power Draw/7.866 Calculated Power Draw)
Heat Level Critical Time: 140 Seconds
Estimated Thermal Capacity: 550.62
*Thanks again for posting Frenotx!
 
Ship: Federal Corvette
Power Plant: Unmodified 8B (0.5 Thermal Efficiency)
Thrusters: Clean Drive Tuning 7D (7.87 Advertised Power Draw/7.866 Calculated Power Draw)
Heat Level Critical Time: 140 Seconds
Estimated Thermal Capacity: 550.62
*Thanks again for posting Frenotx!
Thanks for the help! The data has been added to the OP. Seems plausible that the Corvette and Conda would have similar thermal capacities. I bet the cutter is right in the same ballpark.
 
Heres a handful i've run

Imp. courier : 345
FDL : 335
Imp. cutter : 490
Fed. corvette : 500

Someone else getting 550 for the corvette is curious, could there be other things at play?

Edit: DBS with G5 dirty drives : 518
The extra thermal load isn't a factor (as expected, it should only apply when on the move)
 
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Heres a handful i've run

Imp. courier : 345
FDL : 335
Imp. cutter : 490
Fed. corvette : 500

Someone else getting 550 for the corvette is curious, could there be other things at play?
Were you particularly close to a star? What were your calculated powerplant heat efficiency and thruster power draw numbers? May want to double check the numbers, and re-run the test. Since your number was lower than the other, it could be that there was something else unaccounted for adding heat into the system. Maybe some other small module turned on? Your courier value lines up with mine, but that number for the FDL seems low.
 
Did a test to double check. Turned every module off in the courier. Engaged silent running. Turned on the heatsink launcher, fired a heatsink, then turned it off again. Sat there in space for 5 minutes, and saw no change in heat. It's possible that when you conducted your test you were near a star, or forgot to turn off a module. The powerplant definitely doesn't generate heat on its own, and if it does, the amount is so low as to be negligible. Incidentally, I've added the heat capacities of the courier and keelback.
What's about silent running? :D
5 minutes isn't enough, i used to go for a smoke, cook some coffee and than when i came back heat already was about 60%.
Of course this can only be tested with A-classed life support. With D you have only 7:30 min
 
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What's about silent running? :D
5 minutes isn't enough, i used to go for a smoke, cook some coffee and than when i came back heat already was about 60%.
Of course this can only be tested with A-classed life support. With D you have only 7:30 min
I was in silent running that entire time, which meant any heat being generated would be staying in my ship. If the heat didn't move at all in 5 minutes of silent running will all modules off, then it's not going to move in another 10- certainly not by 60%-90%.
 
Were you particularly close to a star? What were your calculated powerplant heat efficiency and thruster power draw numbers? May want to double check the numbers, and re-run the test. Since your number was lower than the other, it could be that there was something else unaccounted for adding heat into the system. Maybe some other small module turned on? Your courier value lines up with mine, but that number for the FDL seems low.
Just repeated, got the same result.

The efficiency value there comes to 0.4 * (1 - 0.016) = 0.3936 therms/mj


Time to overheat was 118 seconds
0.3936 * 118 * 10.72 = 497.88
Rounded up to 500

I was ~400ls from the star (1ls from station), so there shouldn't be any outside environmental factors.
 
Well, maybe I did it wrong. I'll redo it later and provide a documentation video. Sorry if I misled anyone.
 
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