Capillary forces are by far the most common form of condensate return employed, but a number of rotating air conditioning heat pipes are used for cooling of electric motors and other rotating machinery.

In some applications a mechanical pump is used to return condensate in two-phase run-around coil heat recovery systems. While this may be regarded as a retrograde step, it is a much more effective method for condensate return than reliance on capillary forces.

Applications are related to five principal functions of the air conditioning heat pipe: separation of heat source and sink,temperature flattening, heat flux transformation, temperature control, and action as a thermal diode or switch.

The two major applications, cooling of electronic components and heat exchange, can involve all of these features. In the case of electronics cooling and temperature control, all features can be important.

In heat exchangers employing air conditioning  heat pipes, the separation of heat source and sink, and the action as a thermal diode or switch, are most significant.