The finned pack coil allows the exchange of energy between the two fluids that pass through it: one inside and the other outside the tubes that make up its core. The latter are connected to each other by metal bends which are welded following a pattern designed from time to time to optimize the circulation of fluids inside the circuits. To increase the heat exchange surface, the tubes are inserted one by one in a series of fins, i.e. cut and punched plates that make up the finned pack.

To maximize the transfer of energy, the tube assembly is made integral with the finned pack by rolling, a mechanical expansion operation.

The supply and discharge of the fluid inside the tubes takes place thanks to two elements which are normally welded cylindrical manifolds, while the containment frame of the tube-finned pack body is crossed by the air which is generally to be considered as the treated fluid .

The choice of materials and thicknesses are evaluated by the technical office in relation to the compatibility with the fluids used and with the process for which the coil is intended: copper, pre-galvanized steel, stainless steel and cupronickel are foreseen for the pipes; for the fins, the materials available are copper, aluminum alloy in several variants and stainless steel.

Water, glycol water, superheated water, steam, refrigerant gases, oils, air and fumes are the fluids that can be treated by the finned pack coil each of which, after the pressure seal test, is provided with a special label which certifies materials, weight, fluids and limits of use.