How a heat pipe works
A heat pipe uses a two-phase working fluid to move heat between separated finned sections with no moving parts and no direct stream contact - ideal when the two air streams must stay completely isolated.
Why specify it
For contaminated or uneven exhaust, a heat pipe gives indirect, contamination-free recovery and can bridge streams that cannot share a common core. It is often used as a supplementary (about 30 percent) dehumidification or heat-recovery boost.
Watch-outs
Heat pipes are orientation-sensitive and best for sensible recovery; they complement rather than replace plate or wheel cores in most systems.