Designed for use in space, a radiator heat sink is for all intents and purposes identical to a standard Btech Single Heat Sink. It dissapates 1 pt of heat regardless of what environment it is in, though it is affected by water in the exact same way a standard Btech SHS is affected.
A much more efficient, but physically larger heat sink, an Air-Cooled Heat Sink draws in and expells air to rid itself of heat. (This is the large vent-like intake seen on the chests of many Mobile Suits.) For all intents and purposes, it is identical to a Btech Double Heat Sink, though it does not function in space.
An Air-Cooled Heat
Sink may not function under water, though there is a variant of
the Air-Cooled Heat Sink (with the same dimentions, but
dissipating 3pts of heat), that may function under water only.
An unusual but very effective heat sinking system, a Fin-Radiator Heat Sink operates exactly like a Radiator HS during normal operations. Should the pilot activate it (declaring its use) or the mech exceed +13 on the heat scale, fins deploy from the heat sink location, providing a much greater surface area for heat dissapation. In this mode, the Fin-Radiator is capable of dumping 3pts of heat per turn in space (or 4pts in atmosphere).
The folding fins of this Radiator system, though compact and efficient, are necessarily fragile. Any weapons hit on the carrier mech while the Fins are engaged, in a location where the critical slots for the Fin-Radiators are located, automatically destroys the fins, reverting the Radiator to its normal operating mode (1pt of heat dissipation).
A one-shot system, the Coolant Gas system consists of a 1 crit-sized cannister of compressed gas. When released, the gas sprays along the outside of the mech and through all heat-sinking vents, absorbing up to 20pts of heat (any environment except water.)
A critical hit on a Coolant Gas location results in the detonation of the cannister, releasing the gas uncontrollably, and reducing the heat of the carrier mech by 10pts.
A variant of this system is used to help Mobile Suits reenter the atmosphere of a planet.