Finned Tube Heat Exchangers consist of a shell & finned tubes assembly. Fins are used to increase the effective surface area of heat exchanger tubing. Finned tubes are used when the heat transfer coefficient on the outside of the tubes is appreciably lower than that on the inside; as in heat transfer from a liquid to a gas, vapor to a gas, such as steam to air heat exchanger, thermic fluid to air heat exchanger. When an extended surface is needed on only one fluid side (such as in a gas to liquid exchanger) or when the operating pressure needs to be contained on one fluid side, a finned tube heat exchanger may be selected. 

Applications of finned tube heat exchangers include Steam air heater / steam radiator, Thermic fluid air heater / thermic fluid radiator, Hot water air heater / hot water radiator, Air heater for fluid bed dryers, Air heater for spray dryers, Air heater for flash dryers and Air heater for dryers.

Marine heat exchangers are the most common way to cool a boat's/ship engine, using the lake, river or Sea water in which the boat floats. Direct cooling of the cylinders and heads by sea-water is unsatisfactory because sea water will eventually ruin the cylinder block and heads. Since this water may be corrosive the engine may be cooled by a sealed mixture of distilled/Fresh water and antifreeze.

Heat from the water-antifreeze mixture is then transferred to the Sea (or lake or river) water which flows into a heat exchanger. The water-antifreeze mixture runs through the heat exchanger dumping heat, but remaining separate from corrosive salts and chemicals found in the water the boat is floating in. If the Sea water eventually corrodes and ruins the heat exchanger it can be replaced at a fraction of the cost of replacing the engine.