Appendix B — Alternative methods of calculating emissions from refrigerants and medical gas

This appendix outlines two screening methods (Methods B and C) to estimate emissions from refrigerant leakage when top-up information is not available. Method C is the same as Method B except that it allows the use of default refrigerant quantities as well as default leakage rates.

B.1 Method B – Default annual leakage rate

\[ \begin{aligned} E &= OE \times \mathrm{GWP} \end{aligned} \]

Where:

  • E = emissions from equipment in kg CO2-e
  • OE = operation emissions, kg by gas type
  • GWP = the 100-year global warming potential of the refrigerant used in equipment (Table 4.2).

\[ \begin{aligned} OE &= C \times ALR \end{aligned} \]

Where:

  • C = original full refrigerant charge in equipment (kg)
  • ALR = the default annual leakage emission factor for equipment (%).

The type and quantity of HFC in the equipment will often be shown on the compliance plate. If not, this method requires service agents’ advice for refrigerant type and full refrigerant charge of each piece of equipment.

B.2 Method C – Default annual leakage rate and default refrigerant charge

\[ \begin{aligned} E &= ( IE + DE + (C \times ALR )) \times \mathrm{GWP} \end{aligned} \]

Where:

  • E = emissions from equipment in kg CO2-e
  • IE = installation emissions
  • C = default refrigerant charge in each piece of equipment (kg)
  • ALR = default annual leakage emission factor for equipment (%)
  • DE = disposal emissions (as per method B)
  • GWP = the 100-year global warming potential of the refrigerant used in equipment (Table 4.2), where GWP is shown in kg CO2-e.

Table B.1 contains default refrigerant charge amounts for the New Zealand refrigeration and air-conditioning equipment stock.

Table B.1: Default refrigerant charges for refrigeration and air-conditioning equipment
Refrigeration unit type Default refrigerant charge (kg) Default leakage rate (operating- ALR) Default leakage rate (installation- AEF) Method B Method C
Small refrigerator or freezer (<150 litres) 0.07 3% n/a Recommended Acceptable
Medium refrigerator or freezer (150-300 litres) 0.11 3% n/a Recommended Acceptable
Large refrigerator or freezer (>300 litres) 0.15 3% n/a Recommended Acceptable
Small commercial standalone chiller (<300 litres) 0.25 8% n/a Acceptable Screening method only
Medium commercial stand-alone chiller (300-500 litres) 0.45 8% n/a Acceptable Screening method only
Large commercial stand-alone chiller (>500 litres) 0.65 8% n/a Acceptable Screening method only
Small commercial standalone freezer (<300 litres) 0.2 8% n/a Acceptable Screening method only
Medium commercial stand-alone freezer (300-500 litres) 0.3 8% n/a Acceptable Screening method only
Large commercial stand-alone freezer (>500 litres) 0.45 8% n/a Acceptable Screening method only
Water coolers 0.04 3% n/a Recommended Acceptable
Dehumidifiers 0.17 3% n/a Recommended Acceptable
Small self-contained air conditioners (window mounted or through the-wall) 0.2 kg per kW cooling capacity 1% 0.50% Acceptable Screening method only
Non-ducted and ducted split commercial air conditioners (<20 kW) 0.25 kg per kW cooling capacity 3% 0.50% Acceptable Screening method only
Commercial air conditioning (>20kW) Wide range Wide range Wide range Unacceptable Unacceptable
Cars/vans 0.7 10% n/a Recommended Acceptable
Trucks 1.2 10% n/a Acceptable Screening method only
Buses 2.5 (but up to 10) 10% n/a Acceptable Screening method only
Refrigerated truck trailer units 10 25% 0.50% Acceptable Unacceptable
Self-powered or 'cabover' refrigerated trucks 6 25% 0.50% Acceptable Unacceptable
'Off-engine' or 'direct drive' refrigerated vans and trucks 2.5 25% 0.50% Acceptable Unacceptable
Three-phase refrigerated containers 5.5 25% 0.50% Acceptable Unacceptable
Single-phase refrigerated containers 3 25% 0.50% Acceptable Unacceptable
Centralised commercial refrigeration eg, supermarkets Wide range Wide range Wide range Unacceptable Unacceptable
Industrial and commercial cool stores Wide range Wide range Wide range Unacceptable Unacceptable

Note1: In the absence of consistent information for New Zealand, the default assumption for the assembly (installation) emissions rate is the rounded-off IPCC 2006 mid-range value. It is not applicable (relevant) for many pre-charged units.

Note2: Internal dimensions up to 100x50x30cm for 150 litres; 150x50x40cm for 300 litres; 200x50x50cm for 500 litres.

Table B.2: Detailed 100-year GWPs for various refrigerant mixtures
Refrigerant type (trade name) HFC-23 HFC-32 HFC-125 HFC-134a HFC-143a HFC-152a PFC-218 Other Total GWP
GWP100 (IPCC Fifth Report, AR5) 12,400 677 3,170 1,300 4,800 138 8,900 0
R-22 100% 1,760
R-23 100% 12,400
R-134a 100% 1,300
R403B 39% 61% 4,457
R404A 44% 4% 52% 3,943
R406A 100% 1,780
R407C 23% 25% 52% 1,624
R407F 30% 30% 40% 1,674
R408A 7% 46% 47% 3,257
R409A 100% 1,485
R409B 100% 1,474
R410A 50% 50% 1,924
R413A 88% 9% 3% 1,945
R416A 59% 41% 975
R417A 46.6 % 50% 3.4 % 2,127
R422A 85.1 % 11.5 % 3.4 % 2,847
R436A 100% 1
R436B 100% 1
R502 100% 4,786
R507A 50% 50% 3,985

Note: values might differ from those reported in Table 4.2 due to rounding.

B.3 Assumptions

The default factors in methods B and C for operating refrigerant equipment are derived from a report by CRL Energy Ltd to the Ministry for the Environment on the Assessment of HFC Emission Factors for GHG Reporting Guidelines (2008). These are based on data for New Zealand refrigeration and air-conditioning equipment stock.

In the absence of consistent information for New Zealand, the default assumption for the assembly emissions rate is the rounded-off IPCC 2006 mid-range value. This will not apply to many ‘pre-charged’ units as these are sealed to prevent leakage.

For simplicity, the default operating emission factor does not take account of the variability associated with equipment age.