What does “Approach” mean in heat exchangers?
This term refers to the difference between the leaving process fluid temperature and the change of state temperature of the refrigerant. For evaporators, if water is cooled from 12°C to 6°C and evaporating temperature is 1°C, the approach is 5K. For condensers, if water is warmed from 30°C to 35°C and condensing temperature is 40°C, the approach is 5K.