ASHRAE Journal - December 2019 - 30

TECHNICAL FEATURE

Lifetime GHG Emissions Metric Tons
CO2e/ton·R (Capacity)

of which can provide an economic
TABLE 2 Fugitive emissions of refrigerants.
benefit to the building owner. The
TYPE OF EQUIPMENT REFRIGERANT INSTALLATION
OPERATION REFRIGERANT REMAINING
RECOVERY
WEIGHT
AT END OF LIFE
EFFICIENCY
worst-case scenario is when all
Percentage of
Percentage of Percentage Of
Kilogram Percentage
refrigerant is lost from an HVAC
Of Refrigerant Refrigerant Per Year
Refrigerant
Remaining
system and the compressor is damDomestic Refrigeration 0.05 - 0.5
1
0.1 - 0.5
80
70
aged, effectively ending the life
Stand-Alone
0.2 - 6
3
1 - 15
80
70
Commercial Applications
of the HVAC system. Catastrophic
Medium and Large 50 - 2,000
3
10 - 35
100
70
failures with complete emission of
Commercial
refrigerant cost the building owner
Refrigeration
Transport Refrigeration
3-8
1
15 - 50
50
70
financially for emergency repair of
the system as well as the lost opporIndustrial Refrigeration, 10 - 10,000
3
7 - 25
100
90
Including Food
tunity for capturing and reselling
Processing and
or reusing the refrigerant.
Cold Storage
Chillers 10 - 2,000
1
2 - 15
100
95
A life cycle assessment of air-conResidential and Com0.5 - 100
1
1 - 10
80
80
ditioning systems shows the relative
mercial Air
impacts of refrigerant leaks (direct)
Conditioning, Including
Heat Pumps
and energy consumption (indirect)
Mobile Air Conditioning
0.5 - 1.5
0.5
10 - 20
50
50
on total greenhouse gas emissions.
FIGURE 2 Life-cycle emissions per ton of cooling for residential and commercial units.
An assessment was completed for: (1) standard efficiency units with a 15-year lifetime, (2) conservative
14
A.
Indirect
Direct
Residential
estimates for refrigerant emissions from Table 2 and a 1%
12
loss during refrigerant manufacturing,8 (3) 2.5 lbs/ton
10
of R-410A, and (5) annual energy consumption of 920
kWh per ton for a residential system and 1,800 kWh per
8
ton for a commercial unit. The environmental impact
6
per ton (capacity) of residential and commercial HVAC
4
systems was estimated for three end-of-life refrigerant
recovery loss rates, as shown in Figure 2.
2
The emissions related to energy consumption dur0
1
20
100
ing the use phase is the largest impact for this scenario.
EOL Recovery Loss Rate (%)
High-efficiency equipment with optimal controls and
proper maintenance would significantly reduce this
B.
Indirect
Direct
Commercial
25
impact. An important assumption in these calculations
is the CO2e emission factor for electricity. The national
20
average value of 1.52 lb CO2e/kWh from ASHRAE
Standard 105-2014 was used for these calculations.9
15
The impact from energy consumption will obviously
reduce with a cleaner grid. For example, California's
10
emission rate of 0.81 is nearly half the national value.
5
If high-efficiency equipment and clean energy sources
are used, then the refrigerant management becomes the
0
1
20
100
dominant climate impact, which is why best refrigerant
EOL = End of Life
EOL Recovery Loss Rate (%)
GHG = Greenhouse Gas
management practices are important.

Waste Streams for Residential and Commercial Equipment
Residential and commercial HVAC systems go through
similar steps to enter the recycle streams or end up as
30

ASHRAE JOURNAL

ashrae.org

D E C E M B E R 2 0 19

municipal solid waste.
Removal of Equipment. For residential equipment,
it is common for equipment to be removed only after

https://www.ashrae.org/

ASHRAE Journal - December 2019

Table of Contents for the Digital Edition of ASHRAE Journal - December 2019