Despite the fact that air is supplied at a low temperature (50[degrees]F [10[degrees]C]), and is coming onto the coil at a higher enthalpy than normal, using a direct-expansion coil
with a low face velocity allows this low-temperature air to be generated with a refrigerant saturated suction temperature of 44.2[degrees]F (6.8[degrees]C).
The point labeled "Cooling Coil" on the chart (55[degrees]F [I2.7[degrees]C] dry bulb, 54[degrees]F [I2.2[degrees]C] wet bulb) is the leaving air condition of the direct-expansion coil
. As the air passes through the fan, heat from the fan motor is added.
The direct-expansion coil
design requires a short pump-out period because its normal liquid refrigerant inventory within the unit during cooling mode operation is low.