> What is the operating fluid that will evaporate at -28C?
remember that its operating at a much higher pressure than normal plus there is a pressure differential between the "hot" side and the "cold" side.
my refrigerant is propane, which is a gas until -48c at atmospheric pressure.
The main issue is not the refrigerant, but ice build up on the condenser coil. this (I assume) stops the airflow over the coils and generally stops the condenser from absorbing heat(ice might also be less conductive).
