Refrigerant charge is a term used for the type and mass of refrigerant a refrigeration plant will hold to perform under the given conditions.
The type of refrigerant must be applicable for the application and the ambient conditions. For example, the ASHRAE standards are general recommendations regarding local ambient conditions for inside and outside temperatures in both summer and winter in any country.
Any refrigerant must be suitable for the application and the ambient conditions so the performance is energy efficient and reliable. Poorly-chosen refrigerant can lead to instability, inefficient heat exchange, and high power consumption by the compressor, among other undesired effects.
It is important to know the charge on a refrigeration plant, since refrigerant in almost all countries are subject to environmental control. Almost any refrigeration plant will lose an amount of its refrigerant charge through sealings, stuffing boxes, valves, etc. over time.
It is important to service and overhaul the refrigeration plant. Loss of refrigerant charge will affect the performance, running hours and the reliability of operation.