The refrigerant enters the evaporator intermittently through a
expansion, generally of the thermostatic type, being completely vaporized and superheated by gaining heat in its flow through the interior of the tubes.
Thus, in one part of the evaporator there is saturated refrigerant fluid (liquid + steam) and in the other part, superheated fluid. This type of evaporator is widely used with halogenated refrigerants, especially in small capacity installations.
Its main drawback is related to its relatively low overall heat transfer coefficient resulting from the difficulty of maintaining the surface of the wetted tubes with refrigerant and the surface needed to promote overheating.
