A condenser coil is one of the principal heat exchangers in air-conditioning and refrigeration
systems. The study of condenser coils is complex by a number of factors. One of the factors is
that the ¯owing refrigerant inside the tube undergoes phase change, i.e. desuperheating,
condensing and subcooling, which results in signi®cant variations in heat transfer and ¯uid
¯ow characteristics along the coil tubes. Another factor is that the complex refrigerant circuitry
of the coils contributes to the uneven heat transfer. To study such a coil, a versatile heat
transfer simulation model and a general performance evaluation criterion that considers all
these variations in the coils is required.