Topic #2: refrigerant gas is superheated when it enters condenser shell side. the superheated refrigerant gas is cooled first to saturated gas and then eventually to saturated liquid refrigerant when it leaves the condenser (shell side). thus, when the condenser tubes are clean, i. e., mineral fouling free, the temperature of the liquid refrigerant leaving condenser is almost equal to the water temperature leaving condenser. the difference between the two temperatures is called “condenser approach.” in other words, when a condenser is perfectly managed, the condenser approach is zero or one-two deg c. with severe mineral fouling inside condenser tube, the condenser approach temperature can be over 10 degc. explain why the condenser approach temperature increases over 10 degc using mathematical equations from heat transfer and thermodynamic theories