Evaporator Core: Description and Operation
A/C Evaporator CoreThe A/C evaporator core is functionally a heat exchanger in which the refrigerant absorbs heat from the surrounding air as it passes over the outer surface of the core. The refrigerant, when it is delivered through the circuit to the A/C evaporator core, is in a low-pressure liquid form. Then, as a result of the evaporation process, the liquid is converted to a low-pressure vapor and simultaneously the metal surfaces of the core are cooled.
The A/C evaporator core is a "flooded type" (plate-fin) similar to those used in passenger cars. The condenser to evaporator tube connects to the bottom of the A/C evaporator core and suction accumulator / drier assembly connects to the top of the A/C evaporator core. The evaporator inlet tube is fitted with an A/C evaporator core orifice to control refrigerant flow. This A/C evaporator core orifice can be removed from the inlet tube for replacement if it becomes necessary. However, a special tool, Orifice Tube Remover and Installer D80L-19990-A or equivalent, is necessary to prevent breakage when removing the A/C evaporator core orifice.