High quality Plate Type Evaporator is very efficient and the coil usually made up of copper or aluminum is embedded in the plate so as so to form a flat looking surface. Externally the evaporator looks like a single plate, but inside it there are several turns of the metal tubing through which the refrigerant flows. The evaporator version chillers with most rapidly gaining popularity are a relic of plate and frame heat exchanger. The Plate Type Evaporator is very efficient.