ASHRAE Journal - October 2022 - 52

TECHNICAL FEATURE
period (4.22 years) resulting in an average of 139 kg
(306 lb) of R-22 annually and 19.4 kg (42.8 lb) of R-410A
annually. These numbers are divided by the total charge
of all systems for annual estimated refrigerant replacement
(i.e., emissions) of 2.8% of the systems' R-22 charge
and 0.7% of the systems' R-410A charge.
Refrigerant Use Analysis-Emission Causes
The information from the service ticket database determined
that 78 of 94 instances of reported refrigerant use
were associated with a leak, while the remainder were
generally associated with replacement of a refrigeration
system component. In the case where a leak was suspected
or confirmed, 51 times the technician noted only
adding refrigerant (65%) and did not specifically describe
a leak repair (Table 4). In some cases a leak repair (e.g.,
quick tightening of a Schrader valve) may have been performed
but not noted. In other cases refrigerant may have
been added with no additional actions taken. When a leak
repair was noted, the most common location was at a service
port Schrader valve (n = 10).
The 78 instances of refrigerant use associated with
leaks were categorized by the number of times a leak was
reported in the same piece of equipment (Table 5). Most
of the time (n = 68, 87%) the leak was an isolated event,
and the problem did not resurface within the study
period. In 10 cases the same piece of equipment had
two to four records of refrigerant leaking, meaning that
either no repair was attempted initially (i.e., only refrigerant
was added) or the repair failed. Refrigerant use for
reasons other than leaks was recorded 16 times in the
service ticket database, where the most common repair
was compressor replacement (n = 10) (Table 6).
Repair of and replacement of components in the
refrigeration systems does not necessarily result in
refrigerant emissions. In these cases the refrigerant
is generally recovered and either reused or recycled.
However, some emissions of refrigerant may occur with
these repairs.
Conclusion
The total annual refrigerant emissions from air-conditioning
equipment at a school district were estimated
for the entire inventory, which consisted of 1,199 pieces
of R-22 equipment and 654 pieces of R-410A equipment
on May 20, 2020. Based on the net refrigerant use over
the analysis period from March 1, 2016, through May 20,
52
ASHRAE JOURNAL ashrae.o rg O CTO B E R 2022
TABLE 3 Summary of refrigerant purchased and recovered at the school district
over the study period based on receipts from suppliers and service contractors.
DESCRIPTION
Assumed District Refrigerant Inventory March 1, 2016
Refrigerant Purchases, Supplier 1
Refrigerant Purchases, Supplier 2
Refrigerant Recovery, Supplier 3
Refrigerant Purchases, Service Contractor 1
Refrigerant Recovery, Service Contractor 1
Refrigerant Purchases, Service Contractor 2
Refrigerant Purchases, Service Contractor 2
Refrigerant Purchases, Service Contractor 3
Reported District Refrigerant Inventory May 20, 2020
NET REFRIGERANT USED FOR MAINTENANCE AND OPERATIONS
MARCH 1, 2016, TO MAY 20, 2020
AVERAGE REFRIGERANT USE PER YEAR (OVER 4.22 YEARS)
AVERAGE REFRIGERANT CHARGE OF DISTRICT HVAC SYSTEMS
AVERAGE CALCULATED PERCENT OF TOTAL REFRIGERANT CHARGE
CONSUMED FOR MAINTENANCE AND OPERATIONS
R-22 (kg)
545.5
109.1
(16.8)
109.5
(13.2)
2.3
(150)
586.4
139.0
5039
2.8%
R-410A
(kg)
11.4
22.7
1.4*
13.1
28.6*
4.5
80.3
19.4
2813
0.7%
*Service ticket database documented refrigerant used but no receipt was
found; amount was estimated from equipment information and service notes.
TABLE 4 Number of service tickets reported by description of the action taken by
the service technician for refrigerant use associated with leaks.
DESCRIPTION OF ACTION
Added Refrigerant
Leak Repair-Service Port
Leak Repair-Unknown
Leak Repair-Damage or Vandalism
Leak Repair-Evaporator Coil
Leak Repair-Distributor and Service Port
Leak Repair-Flare Fitting
Leak Repair-Suction Filter Shell Housing
Leak Repair-TXV Capillary Tube
TOTAL
1
1
1
1
58
20
R-22
40
9
6
R-410A
11
1
3
2
2
TOTAL
51
10
9
2
2
1
1
1
1
78
TABLE 5 Number of times a leak was reported in the same piece of equipment.
R-22
1 REPORT
2 REPORTS
3 REPORTS
4 REPORTS
TOTAL
51
4
1
2
58
R-410A
17
2
1
20
TOTAL
68
6
2
2
78
2020, the annual estimated refrigerant emissions were
2.8% for R-22 equipment and 0.7% for R-410A equipment.
An analysis of the district's service ticket database
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ASHRAE Journal - October 2022

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