Look at condensation process. In condenser refrigerant gas becomes liquid. This liquid have saturated temperature. Outlet or bottom of the condenser is flooded. In this flooded area liquid refrigerant will be cooled below saturated temperature. Subcooling is temperature difference between saturated temperature and outlet temperature. Outlet or bottom of evaporative condensers are not flooded and outlet liquid has saturated temperature. R22 condensing pressure is 300 psig. Saturated temperature is 55C. If you cool liquid refrigerant to 50C, subcooling will be 55-50=5C. At air temperature of 0C you can get condensing pressure of 300 psig if condenser operate at reduced capacity. Assume that air condenser has 20 fans but you run only 1 located at outlet of the condenser. Condensing pressure will be 300 psig but you will be able to get subcooling 30-40C.