Intercooler

An intercooler is a component of technology commonly found in the construction of starships. 23rd century Federation ships commonly were fitted with vital intercooler assemblies. In particular, such systems included plasma intercoolers, and when operated as a network, were referred to as an intercooler matrix.

Examples
On the warp nacelles of class I starships in Starfleet service, a pair of intercoolers were fitted in protrusions near the aft end of the nacelle assembly. This particular intercooler was known as the final stage intercooler. 

Intercooler matrix technology is a feature of Jem'Hadar attack ships. In the year 2375, the Cardassian Rebellion set a bomb in such a Jem'Hadar ship's intercooler, even though Kira Nerys had instructed them to rig the secondary plasma relay instead.