The idea would be a utility item for the purpose of improving heat loss with out the cost impact of a heat sink launcher and limited ammunition.
Pro's -
no ammo cost
reduces heat loss
good for fuel scooping heat gains
static gains through increased heat sink utilities. The more you have, the more you are pulling heat away from the system and moving it to the outside of the ship. (good for explorers)
Con's -
heat reduction is no where as near as the heat sink launcher. Even fully decked out with passive heat sinks would not counter a shield cell bank's heat gain.
increases your own heat signature the more heat you have. The trade off for improved heat loss is by moving it externally to the utility slot's. (be especially neat if they looked like big heat sinks that go from silver to dull red all the way up to a bright orange based on your heat levels)
game play uses -
standard management of heat trade off would fight against subtle heat gains.
Fuel scooping would be improved by the trade off. At a similar distance a ship would gain heat from the sun with out them. But with passive heat sinks your system would improve the rate of temperature drop and lower your top end point.
a cold running ship could potentially run with a full kit of passive heat sinks and a heat sink launcher and remain under 19% for a longer duration before climbing back over the threshold for signature. Maybe if a ship can run cold enough actually run under 19% heat with engineering to run cold. Thus making a true sneak in and out ship.
I would say you need to be careful not to confuse a heat sink with a radiator.
I myself consider additional radiator modules one of those things that has me going 'where is optional radiator system add-ons?' myself.
To be clear, a heat sink is usually a combination of good heat conduction, as well as high heat capacity. The material is like a tank, but for heat energy. Water is a good example of a heat sink. It conducts thermal energy really easily, and stores a LOT of it.
Now, I know it's used in active cooling systems (known as the working fluid), but that's because a good heat sink material is an equally good heat transfer material.
Anyway, the simplest heat 'sink', is a container of water. Run some cooling pipes around it at a heat exchanger, the water builds up heat.
With the heat-sink launchers, there's actually kind of a silly thing FD has been doing with the Sinks. That is, ejecting them. It's the wrong way to utilize a heat sink. Dump a bunch of heat into a thermal 'tank' and kick the tank off the ship SEEMS like a good idea. But considering you have both a fixed number of heat sinks, and cannot replace them until you reach a resupply facility of some kind, what you're really doing is filling one heat capacity unit up, and then removing that excess capacity from your ship.
Consider it this way:
Let's start with some simple numbers and a definition:
CALORIE: "The energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules)."
Assume your ship can hold 100 calories of thermal energy before it begins to bleed into systems and cause damage. (This makes it easy to visualize).
If you add a heatsink launcher, let's assume you get 10 'shots'. Each shot can hold a large chunk of thermal energy to dump from your ship. For number's sake, let's take a small number, like 10. I never use them, so I don't know what their actual value is.
Between all ten heat sinks stored in the launcher, you have an additional 100 calories of thermal storage.
The way the game treats it, you're at 95 calories from thermally dangerous activity, about to overheat. You fire the launcher. The ship dumps 10 calories into a sink, and ejects it. You're dropped to 85, and down a sink.
WHY would you do this?
Confused?
Consider the sinks if the game used them properly. You have 10 sinks, totaling 100 calories of additional heat capacity. Instead of your ship hitting the overheat limit at 100 calories, the extra 100 calories of heatsink storage takes your total thermal capcity to 200. You don't overheat until the heat sinks are 'saturated' AND the ship itself reaches temp level 100. You may still argue that you can eject the sinks, but WHY? If you dump your heat sinks, you aren't increasing the heat capacity of your ship, you're DECREASING it.
Thus, a heat sink, if the game used it properly, would be a module that INCREASES the total heat your ship can absorb before it reaches critical temperature.
What people REALLY want for advanced heat management, are realistic heatsinks, and radiator modules.
If heat sinks increase the buffer of your ship, then a radiator is the 'get that heat out of here' system.
Each ship already comes with designed-in radiators. Those are the orange glowing bits that have cover panels on them that open when you're charging your FSD. Interesting fact on the glowing. The hotter something is, the more efficient a radiator it becomes. That's why they glow ALL the time and can dump the heat of a star baking you with its corona. Your thermal energy is SHOVED with brute force into the radiator coils. I say shoved, but energy cannot really be forced anywhere. It always flows from point of highest energy density, to point of lowest energy density. So it's likely that the reactor cooling system and main radiator array are running on some seriously vicious thermal conducting chemical and a refrigerant cycle similar to an AC unit or fridge, but at industrial temperatures.
If you're going to make heat management more customizable in-game, then what should be considered along side more realistic heat sinks, is additional radiator modules to increase a ship's ability to dump the heat into space.
Honestly, looking at the way ships are designed, auxiliary radiators would have to go in Utility slots. Because they HAVE to have radiator coils on the surface of the ship.
So here's what
I would do:
1: Heat Sink launcher goes away. That's not how heat sinks work. And dumping any fluid that isn't used PROPULSION FUEL is dumping 'storage' capacity for heat.
2: Heat sinks become an optional module. It is effectively a tank full of water, and weighs in tons the volume it takes up (Water at standard temperature and pressure weighing one metric ton, occupies a space of one cubic meter). This module is unpowered and only costs weight. It's just... heavy. As it's like a cargo rack that is ALWAYS full.
3: What used to be the heat-sink launcher becomes the auxiliary radiator module. This module is an active radiator, increasing the ability for a ship to remove excess heat. As the refrigerant cycle that runs them will require powerful industrial pumps, this module requires power to operate. The A.R.M. goes in external utility slots, as it MUST have surface access. Or it's worthless.
Mind you, because the ARMs are 'bolt on' instead of integrated with the ship's central power system, their efficiency as a heat dump is a lot lower than the main. So to balance the bolt-on ability to manage heat, you need to take up multiple utility slots to get REALLY GOOD heat control.
Couple the ARM with onboard heat sink tanks, and you can both increase your heat capacity, and heat dumping abilities, making ships that can loiter in the coronas of hot stars.
4: Something I pointed out in the suggestions threat for stellar hazards, different star classes put out different heat levels. I would definitely make that a thing, and heat management options would be a LOT more important for route selection and fuel scoop activites.
5: If I could find a way to make it viable, the angle and direction of a ship would also affect heat absorption. When close to a star, you'd be a FOOL to have your radiators FACING the star. You can't dump heat out of the ship if the radiator is ABSORBING the heat of a stellar inferno. So keeping the ship 'belly down' or 'sideways' (wing on) to a star would be CRITICAL at close ranges. If you put the star above you, or face your radiators (wherever they are) towards the heat source, you cook.
FAST.
6: If 5 became a thing, a heat source proximity marker would be added to the HUD. It would show the location of heat sinks around your ship in a clock-face like arrangement, and have an arrow pointing at the major heat source. Keep the heat sinks from lining up with it, or at least SHALLOW, so they don't back thermal energy up into your ship.
This would likely change up a lot of old gameplay styles, as active heat management just got more complicated. But it SHOULD still be a simple-enough concept for players to take in stride.
7: If we STILL wanted a 'heat sink launcher', I would change it into an emergency coolant dump port. What is emergency coolant?
Fuel.
See, in vehicles like the SR-71 blackbird and with many rocket nozzles, engineers actually use fuel lines near the hottest points to both act as a coolant for that hot point, and to pre-heat the fuel for easier ignition (and higher efficiency since it's a bit pre-expanded). In an elite ship, a heat-sink 'launcher' would simply be injecting your own fuel into an emergency cooling line, and using the Helium 3 to absorb heat, before dumping it out the port, or into the engines. (If we went the Engine route, the module would be internalized, instead of an exterior utility module). Instead of spending money on some set of random parts. Emergency heat dumping would take from your fuel supply. For balance purposes, this method of heat dispersal would NOT work well during fuel scooping. You're fuel is going to be HOT freshly scooped from a star. Why dump cold fuel while taking in hot? Don't emergency dump while scooping.
