The fluid is warmed as it passes through the cooling coil, which warmer temperature serves to reheat the air passing over the heat transfer coil.

This charge transfer is due to the mechanical release or closure of the contacts, the contact-to-coil capacitance, and the stray capacitance between signal and relay drive lines.

HIMOD flagship series USES interactive "type v" coil, the internal thread copper tube and punched slotted fin, and heat transfer efficiency is higher than the traditional coil unit.