Originally Posted by
US Iceman
The Evaporator capacity is based on capacity (btuh or equivalent) per degree of Temperature Difference (TD). The TD is based on room temp. minus evap. temp. If the room temp is 4.4°C (40°F) with an evaporating temperature of -1.1°C (30°F), then the coil TD is only 3.3°K (or 10°F).
With a saturated evaporating temperature of -1.1°C, you can only obtain a superheat of 3.3°k maximum. There is no other heat to use to increase the gas temperature in the superheated region. In fact, I doubt you will be able to obtain that much.
In other words, if the room temperature is only 4.4°C (40°F), you can't raise the superheat any higher.