Helical Coil Heat Exchanger has many advantages over other heat exchangers : Where space is limited, so that not enough straight pipe can be laid. Where flow rates are low, other heat exchangers would become uneconomical. Helical coils can be installed inside tanks or vessels. Typical applications are : Heating Grease / Oil in a tank using internal helical coil Heating medium can be steam or hot thermic oil Indirect bath heater