When determining the quantity of refrigerants emitted from a piece of equipment, it is generally considered that the amount of refrigerant emitted is equal to the amount that was added to the equipment after a period of time to return the equipment back to a full charge.
- For example, if you recharge the refrigerant in a Chiller unit to a full charge, then after one year of operation you need to add 0.5kg to fully recharge the unit, then it is assumed that the 0.5kg was emitted due to leaks or servicing throughout the year.
When tracking refrigerant emissions, a facility can directly measure and record the amount of refrigerant added to a piece of equipment in the reporting year or a leakage rate can be determined and used to estimate emissions.
The leakage rate is typically expressed as the percentage of a full charge that would be lost in a 12-month period. The example below is one way to calculate a leak rate.
- Take the kilograms (kg) of refrigerant you added to recharge the system to a full charge and divide it by the kg of refrigerant in the normal full charge for the system.
- Determine the number of days that have passed between charges (e.g., how many days between the last time refrigerant was added and this time refrigerant was added), then divide by 365 (the number of days in a year).
- Take the kg of refrigerant determined in step 1 and divide it by the number of days determined in step 2.
- Lastly, multiply it by 100% (to determine a percentage).
For example:
Chiller #1
- Refrigerant Added = 1kg
- Full charge = 5kg
- Days between charges = 275
Leakage rate = (1kg / 5kg) / (275 / 365) x 100% = 26.5%
Therefore, this Chiller unit loses/emits 1.33kg (26.5% of a full charge) of refrigerant in a year.
Note: Leakage rates may also be used to determine preventative maintenance schedules or when equipment may need additional service or replacement.