When to use Exchanger++ vs Heat Sinks?

[Astral Projection]

Just wondering, when is it better to use an Exchanger++ vs. 4 tons of Heat Sinks? Also factor in double Heat Sinks.

[Sentient_Toaster]

20% reduction in heat generated from your own weapons (not jumping, or enemies with inferno missiles w/e), stacking multiplicatively, regardless of biome.

4 tons of DHS will take a whopping 12 critical spaces and sink anywhere from 15.6 heat (Martian biome) to... well, standing in a lake on a polar biome should make them sink 57.6, with neutral biomes on land being 24 heat. Halve those for regular heat sinks, but reduce critical spaces req'd to 4 as well.

So if you're firing e.g. 4xMLAS + 4xSRM6 as a classic KGC-0000 loadout, that's 96 heat. .2 * 96 = 19.2. Four DHSs on most biomes would cool more, four regular heat sinks would be worse when not standing in water (even on a polar map).

If you're running the ol' Sleepy Awesome (6x PPC), that's 210 weapon heat. .2 of that is 42; you'd need 7 DHSes (*21* critical spaces) to match that,.

Upshot is the hotter your weapons load, and the more often you're in Martian/Lunar/Desert biomes where heat sinking is penalized, the better exchangers look. Multiple exchangers stack multiplicatively (e.g. heat <= heat * (.8^count), if they're all exchanger++) so there's diminishing returns.


Maximum DHSes assuming a gyro mod is... what, ten -- two per arm, two per torso side, one in each leg, assuming that you're not using the (illegal) SLDF Black Knight which somehow stuffs 4 DHSes in each leg. :D And if you did use ten DHSes in one mech, you're down to -- one CS left per leg, two CS per arm, two per side torso, then just the five left in CT /head of which three goes to a gyro mod and one to a cockpit/comms/rangefinder mod. That's pretty limiting.

[leonzweihander2008]

Lowest Heat Exchanger weighs 2 tons for 10% less weapon heat. This is equal to 2 Double Heat Sinks, or 12 heat. Simplified, your alpha heat has to be 120 or higher to take advantage of heat exchangers.

[Mudpony]

For regular HS, at 5% reduction per ton, the break even point is when you produce 60 points of heat from weapons. That's because at 10 tons of heat sinks, you have 60 heat dissipation, and 5% of that is 3, or 1 HS's worth. Because they're multiplicative rather than additive, well, for the 20% reducers, a second one is worthwhile at 75 (unmodded, of course) weapon heat, as the first will drop you down to 60, and the second by 12 or 4 heat sinks worth.

Double Heat Sinks change the numbers, since now each ton could otherwise dissipate 6 heat, rather than three. Ignoring crits, you'd need 2x the heat for the 5% reduction to match, so 120 heat for the first one, and 150 for the second.

Toaster's numbers for max DHS are slightly off, as the side torsos have 10 slots, so you can hold 3 there, but that would leave you with just 1 slot remaining.

Also, the hot biome benefit isn't all that. You still generate heat, which needs to be sinked by actual heat sinks, which are reduced in effectiveness. At the break even point (that 60 heat for regular HS), your ability to fire weapons without gaining additional heat is the same either way. If you are gaining heat from firing weapons, you will be able to do more before hitting the various threshholds, but conversely, if you aren't firing 60 heat worth of weapons (because you're trying to shed extra heat, the heat comes from JJs, etc), you're worse off. So it pretty much works out the same. Ignoring crits, do you generate 60 (or 120) heat from weapons? If yes, use an Exchanger. If no, don't.

[JC]

ok math guys, can we get an easy answere like.. when is the heat exchanger better? 2,5,6>

[OrbPlaytime]

It is also nuanced by Guts +15 Overheat and then the +30 Overheat trait, because you only alpha certain number of times, allow for running to re-position better, allow for recoil reset, out of combat in X rounds before next lance comes into play/etc.

Depending mech-lance setup, usually better going 10% Exchanger combined with DHS until good assaults and good weapons.
Free tonnage of the mech involved combined with weapons rarity is a big factor on when you can use the 20% Exchanger; mentioning as context in thread the OP makes no comment about mechs used with.

[Ichthyic]

also, if you have the heavy metal DLC, coil weapons only benefit from the base heat with a heat exchanger. what I mean by that is, if your coil weapon has 50 base heat, the exchanger will work on that (so if you are using a 20% exchanger, your base heat is now 40 instead of 50), but each extra evasion pip generates 1.25xbase heat (if you get 4 evasion pips before you fire, that's now 80 heat when you fire the weapon). the extra heat is NOT reduced by a heat exchanger at all. so with the coil weapons, you really need heat sinks and preferably a heat bank to use them effectively.

[Mudpony]

Originally posted by JC:

ok math guys, can we get an easy answere like.. when is the heat exchanger better? 2,5,6>

The simple rule of thumb, purely on the basis of heat dissipation:
Weapon heat you normally generate in a round >= 60? Replace single heat sink(s) with an exchanger.
Weapon heat you normally generate in a round >= 120? Replace DHS witth an exchanger.

There are various nuances, of course, like other posters have mentioned. But purely from a simple heat dissipation standpoint, 60 and 120 are the heat numbers to look for.

[danko9696]

Some things to consider in addition to many others said before:

- The heat reduction is applied per weapon, not over the total, and then it is rounded down. Which means 4xML will generate 4 x 12 = 48 heat in principle but with a Regular TEX will generate 4 x roundeddown(12*0.9) = 40 heat. In practice you can have a 16.7% of actual heat reduction with some weapons like MLs for a two tons TEX. This also means that TEX+ often offer no advantage at all depending on the weapon, while weighting one ton more than regular TEX, and the same for TEX++ vs TEX+. In other words, regular TEX are the most useful type of TEX by far, followed by TEX++ and the lest useful are the TEX+.

- This may be obvious but is good to keep it in mind: if you don't alpha then TEX become less efficient when compared to regular heatsinks. If for example you fire just three of six weapons because you only need a small amount of damage to finish a mech then that's wasting TEX potential. In that case you could have cooled more with heatsinks. And of course, if you don't fire at all, because you can't then TEX don't do anything for you. In practice this means that DHS are always better than TEX, and you only use TEX when you don't have enough DHS or you run out of crit slots.


What I do is using a spreadsheet like this[i.imgur.com] where I can get some sort estimation for the optimal number of TEX. In this case using HS the optimal number of TEX 10% would be around 3xTEX and using DHS only 1xTEX. But this estimation doesn't take into account jump heat or that you may not alpha, so unless there is a huge difference (which may be if you have only regular HS) or I don't have enough room (most likely when using DHS) then I always take the heatsinks.

So this is only kind of a fast rough reference.

Originally posted by Ichthyic:

also, if you have the heavy metal DLC, coil weapons only benefit from the base heat with a heat exchanger. what I mean by that is, if your coil weapon has 50 base heat, the exchanger will work on that (so if you are using a 20% exchanger, your base heat is now 40 instead of 50), but each extra evasion pip generates 1.25xbase heat (if you get 4 evasion pips before you fire, that's now 80 heat when you fire the weapon). the extra heat is NOT reduced by a heat exchanger at all. so with the coil weapons, you really need heat sinks and preferably a heat bank to use them effectively.

That's incorrect and it is much more simple than that. With Coils there is no base heat or extra heat. The damage is calculated first, and then heat is damage/2. And that's why TEX don't work at all with them. With 3xTEX++, if you fire 1xCOIL-L @ 2 CHEVS, you'll do 70 dmg and you'll generate 35 heat, while a SNPPC fired in the same salvo will generate 17 heat instead of 35.

Heat banks are also not exactly good, because for them to be useful you need to be very close to overheating when you fire. If you wouldn't without them, then they'll be counterproductive. If you don't care about overheating but only about not shutting down then they become much better, because now you have a +30 to max heat instead of the +15 to overheat threshold.

[Mudpony]

Originally posted by danko9696:

- The heat reduction is applied per weapon, not over the total, and then it is rounded down. Which means 4xML will generate 4 x 12 = 48 heat in principle but with a Regular TEX will generate 4 x roundeddown(12*0.9) = 40 heat.

This is incorrect. A TEX, 10%, will reduce 4x12 to a shown 43, a 5 drop, not to 40. A TEX+ will drop it to 40.

Now, if you only do a single ML (or AC/10, in my case), both will show the 12 heat reduced to 10. That's because, like with damage and most everything else, the game doesn't show the partials, only the whole number part of it, but it does use floats to keep track of all these numbers. So in the case of a single ML, 12 gets reduced to 10.8, which is shown as 10. But if you have 4, your heat generated is 10.8 x4, or 43.2 (that 5 drop from up above is actually a 4.8), and is therefore shown as 43. And with a 15% reduction, it winds up being 40.8, which is shows as 40. So the 15% does provide an additional 2.4 reduction, or 50% more than the 10% offers.

Well, unless the UI in the mech bay is wrong ;)

[danko9696]

Originally posted by Mudpony:

This is incorrect. A TEX, 10%, will reduce 4x12 to 43, a 5 drop, not to 40. A TEX+ will drop it to 40.

Now, if you only do a single ML (or AC/10, in my case), both will show the 12 heat reduced to 10. That's because, like with damage and most everything else, the game doesn't show the partials, only the whole number part of it, but it does use floats to keep track of all these numbers. So in the case of a single ML, 12 gets reduced to 10.8, which is shown as 10. But if you have 4, your heat generated is 10.8 x4, or 43.2, and is therefore shown as 43. And with a 15% reduction, it winds up being 40.8, which is shows as 40. So the 15% does provide an additional 2.4 reduction, or 50% more than the 10% offers.

You're wrong with this issue. I'm not using the UI as a reference but the log files from the debug mode, and the AIM mod when it worked pre 1.8. Damage is fractional, heat isn't, and heat is rounded down after TEX are applied per weapon.

And yes, the UI in the mech bay is wrong when TEX are considered, although depending on the setup the difference may be very small (if you have very few weapons generating a lot of heat each one). A very long time since I don't trust it and part of the reason why I made my own planner.

[Astral Projection]

Thanks all. I have 2 Atlas now and the one with Heat Exchanger++ is ridiculously more efficient.