Double Heat Sink
Sarna News
Double Heat Sinks, often abbreviated DHS and colloquially referred to as "freezers" throughout the Inner Sphere, operate in much the same way and for the same purpose as regular heat sinks. The difference is that a Double Heat Sink offers twice the heat dissipation capacity of a standard heat sink, while being two (Clan version) to three times (Inner Sphere version) as bulky. They can only be mounted on BattleMechs and Aerospace Fighters and are incompatible with standard heat sinks; a given unit must be equipped exclusively with either standard or Double Heat Sinks.
Introduced in 2567 by the Terran Hegemony, Double Heat Sinks were commonly available during the time of the Star League but became Lostech over the course of the Succession Wars. Although the technology was essentially extinct after 2865, it apparently remained in use in some individual cases. Rumours abound that the Bounty Hunter's Marauder and a handful individual BattleMechs from Wolf's Dragoons may have been equipped with Double Heat Sinks.
Following the discovery of the Helm Memory Core and the subsequent dissemination of lost Star League knowledge throughout the Inner Sphere in 3028, Double Heat Sinks have gradually become a staple of 'Mech construction again and were extensively used in retrofits and new designs. The Capellan Confederation already fielded their BJ-3 variant of the Blackjack in the Fourth Succession War, the first regular design sporting Double Heat Sinks in decades if not centuries. The NAIS had Double Heat Sinks ready for serial production in 3041.
The benefits far outweight the risks and by 3058 almost every 'Mech model was equipped or retrofitted with Double Heat Sinks.
Double-strength heat sinks
The secrets behind the production of Double Heat Sinks were already being rediscovered near the end of the Third Succession War by the Federated Suns, who maintained a research department at the Friden AeroSpace Park on Hoff. When the Draconis Combine invaded Hoff in 3022, some 'Mechs among the defenders were equipped with functional prototype heat sinks called "Double-strength heat sinks" that could be combined with regular heat sinks, yet dissipated twice as much heat for the same item mass and size. However, neither the Federated Suns nor the Draconis Combine ever used these again after the battles on Hoff; it must therefore be assumed that either the blueprints were lost over the course of the fighting, or that production later proved impossible or not feasible for other reasons.
In the late 3030s, the nascent Federated Commonwealth deployed more compact experimental Double Heat Sinks which were based on corrosive liquid metal coolants instead of advanced radiators for efficiency, possibly stemming from the research on Hoff. However, it was found that they were too fragile and hard to maintain for more than a few years' worth of effective function.
Associated rules
In game terms, a double heat sink counteracts two points of heat instead of one while retaining its mass of one ton.
The drawbacks of double heat sinks are that they are more expensive than a standard model and that those which are not built into the reactor (i.e. only those that do occupy critical hit slots) occupy more room: Three slots for Star League/Inner Sphere double heat sinks, while a Clan one takes up only two slots (as opposed to a single slot for a standard heat sink). They cannot usually be installed on vehicles, although exceptions are known.
The Double-strength heat sink prototypes fielded by the Federated Suns on Hoff had special rules given in the scenario book, Tales of the Black Widow Company, that applied only for the duration of the Hoff campaign. They could be combined with standard heat sinks and were available as an upgrade or replacement to individual (standard) heat sinks. Like standard heat sinks, they occupied only one critical slot. They were never available outside of that single campaign's scenarios, and circumstancial evidence suggests all Federates Suns 'Mechs so equipped were destroyed.
References
- Tales of the Black Widow Company, pp. 40-42, 47
- Starterbook: Sword and Dragon, p. 57