Which formula is used to calculate Super Heat?

The formula for calculating superheat is based on the measurement of the suction line temperature and the saturation temperature of the refrigerant at the corresponding pressure in the evaporator. Superheat represents the amount of heat added to the refrigerant vapor beyond its saturation point.

In this context, superheat is determined by taking the suction line temperature, which is the actual temperature of the vapor returning to the compressor, and subtracting the suction saturation temperature, which is the temperature at which the refrigerant would begin to condense back into a liquid at the existing pressure. This measurement allows HVAC technicians to assess the performance of the system, ensuring that it operates efficiently and that there is sufficient refrigerant in the evaporator to absorb heat.

If the superheat is too low, it may indicate that the system is overcharged or that there is insufficient airflow over the evaporator coil. Conversely, if the superheat is too high, it may mean that the system is undercharged or that there is a restriction in the system.

The other formulas presented do not accurately characterize the superheat calculation, as they either involve incorrect relationships or measurements that do not pertain to the superheat concept.