ASHRAE Journal - January 2021 - 37

TECHNICAL FEATURE

92% of losses could be attributed to
catastrophic leaks, in which systems
lost 50% or more of their initial
charge.
The climate impacts of these losses
are significant. Atmospheric concentrations of refrigerants, including both HFCs and older, ozonedepleting compounds phased out
under the 1987 Montreal Protocol, are
continuing to increase. The impacts
are so large that the nonprofit Project
Drawdown ranks refrigerant management among the most impactful
solutions for climate change.4
HFCs will eventually be replaced by
compounds with lower GWP; some
promising alternatives, including
CO2, R-32 and R-466a, are currently
in limited use. In addition, air-towater and ground-source systems
may gain market share versus directexchange ASHPs. In these systems,
water or an antifreeze solution is
used to transfer heat in and out of
the building, and the entire refrigerant circuit is contained within a single, factory-made unit. Compared to
a direct-exchange heat pump, these
systems contain less total refrigerant,
and all refrigerant connections are
made under factory conditions.
While new refrigerants and
technologies may reduce future
climate impacts, direct-exchange,
HFC-based heat pumps dominate
the present market, and reducing
losses from these systems is a critical short-term goal. Beyond climate
change, there are other reasons to be
concerned about refrigerant leaks.
Systems that are low on refrigerant
will run less efficiently and may be
unable to maintain comfort. Low
charge may lead to premature failure of system components, particularly compressors.

Left unaddressed, these problems
will reduce customer satisfaction and impede adoption of heat
pumps. Anecdotally, we know one
progressive developer who found
that 30% of the heat pumps in his
new multifamily building leaked
refrigerant. The issue was so bad, he
reported, that he was considering
electric baseboard heat instead of
heat pumps for future projects.
Our objectives in this article are to
provide technicians, engineers and
energy-efficiency programs with
best practices for reducing refrigerant leaks from ASHPs. We draw on
our experience as an installer and
an HVAC engineer, along with manufacturer's instructions and applicable standards and regulations.
We note areas in which existing
guidelines are vague, inconsistent or
impractical, and recommend standardizing both testing methods and
" pass/fail " criteria.

FIGURE 1 Air-source heat pumps.

FIGURE 2 Tightening a flare nut with a torque

wrench.

Installation
Refrigerant connections for small
inverter-driven ASHPs are typically
made using flare joints. The flaring
process begins with cutting tubing, leaving a few inches of slack in
case a flare is defective and must be
remade. Use a good quality cutter,
work gradually to avoid deforming the tubing and inspect to make
sure that the cut is square. Debur to
remove the thin lip of copper inside
the tubing, but be careful not to
gouge or otherwise damage the tubing wall.
Some line sets come shipped from
the factory pre-flared, but these
flares are often damaged in transport; we recommend making new
ones.
Flaring itself involves site-forging

the end of the copper tubing into a
female cone, which fits over a brass
male cone to form a mechanical
seal. To seal tightly, the flare must be
of the correct dimensions. The flare
angle, specified in the installation
instructions, is 45°; the size of the
cone varies with tubing diameter.
The flaring tool grips the tubing
and rotates a steel cone around
the inside surface until it is fully
expanded.
Good-quality manual flaring tools
have the following features:
¥ A gauge or stop that ensures
that tubing is positioned at the correct depth;

JAN UARY 2021

ashrae.org

ASHRAE JOURNAL

37


http://www.ashrae.org

ASHRAE Journal - January 2021

Table of Contents for the Digital Edition of ASHRAE Journal - January 2021

Contents
ASHRAE Journal - January 2021 - Intro
ASHRAE Journal - January 2021 - Cover1
ASHRAE Journal - January 2021 - Cover2
ASHRAE Journal - January 2021 - 1
ASHRAE Journal - January 2021 - 1a
ASHRAE Journal - January 2021 - 1b
ASHRAE Journal - January 2021 - Contents
ASHRAE Journal - January 2021 - 3
ASHRAE Journal - January 2021 - 4
ASHRAE Journal - January 2021 - 5
ASHRAE Journal - January 2021 - 6
ASHRAE Journal - January 2021 - 7
ASHRAE Journal - January 2021 - 8
ASHRAE Journal - January 2021 - 9
ASHRAE Journal - January 2021 - 10
ASHRAE Journal - January 2021 - 11
ASHRAE Journal - January 2021 - 12
ASHRAE Journal - January 2021 - 13
ASHRAE Journal - January 2021 - 14
ASHRAE Journal - January 2021 - 15
ASHRAE Journal - January 2021 - 16
ASHRAE Journal - January 2021 - 17
ASHRAE Journal - January 2021 - 18
ASHRAE Journal - January 2021 - 19
ASHRAE Journal - January 2021 - 20
ASHRAE Journal - January 2021 - 21
ASHRAE Journal - January 2021 - 22
ASHRAE Journal - January 2021 - 23
ASHRAE Journal - January 2021 - 24
ASHRAE Journal - January 2021 - 25
ASHRAE Journal - January 2021 - 26
ASHRAE Journal - January 2021 - 27
ASHRAE Journal - January 2021 - 28
ASHRAE Journal - January 2021 - 29
ASHRAE Journal - January 2021 - 30
ASHRAE Journal - January 2021 - 31
ASHRAE Journal - January 2021 - 32
ASHRAE Journal - January 2021 - 33
ASHRAE Journal - January 2021 - 34
ASHRAE Journal - January 2021 - 35
ASHRAE Journal - January 2021 - 36
ASHRAE Journal - January 2021 - 37
ASHRAE Journal - January 2021 - 38
ASHRAE Journal - January 2021 - 39
ASHRAE Journal - January 2021 - 40
ASHRAE Journal - January 2021 - 41
ASHRAE Journal - January 2021 - 42
ASHRAE Journal - January 2021 - 43
ASHRAE Journal - January 2021 - 44
ASHRAE Journal - January 2021 - 45
ASHRAE Journal - January 2021 - 46
ASHRAE Journal - January 2021 - 47
ASHRAE Journal - January 2021 - 48
ASHRAE Journal - January 2021 - 49
ASHRAE Journal - January 2021 - 50
ASHRAE Journal - January 2021 - 51
ASHRAE Journal - January 2021 - 52
ASHRAE Journal - January 2021 - 53
ASHRAE Journal - January 2021 - 54
ASHRAE Journal - January 2021 - 55
ASHRAE Journal - January 2021 - 56
ASHRAE Journal - January 2021 - 57
ASHRAE Journal - January 2021 - 58
ASHRAE Journal - January 2021 - 59
ASHRAE Journal - January 2021 - 60
ASHRAE Journal - January 2021 - 61
ASHRAE Journal - January 2021 - 62
ASHRAE Journal - January 2021 - 63
ASHRAE Journal - January 2021 - 64
ASHRAE Journal - January 2021 - 65
ASHRAE Journal - January 2021 - 66
ASHRAE Journal - January 2021 - 67
ASHRAE Journal - January 2021 - 68
ASHRAE Journal - January 2021 - 69
ASHRAE Journal - January 2021 - 70
ASHRAE Journal - January 2021 - 71
ASHRAE Journal - January 2021 - 72
ASHRAE Journal - January 2021 - 73
ASHRAE Journal - January 2021 - 74
ASHRAE Journal - January 2021 - 75
ASHRAE Journal - January 2021 - 76
ASHRAE Journal - January 2021 - 77
ASHRAE Journal - January 2021 - 78
ASHRAE Journal - January 2021 - 79
ASHRAE Journal - January 2021 - 80
ASHRAE Journal - January 2021 - 81
ASHRAE Journal - January 2021 - 82
ASHRAE Journal - January 2021 - 83
ASHRAE Journal - January 2021 - 84
ASHRAE Journal - January 2021 - 85
ASHRAE Journal - January 2021 - 86
ASHRAE Journal - January 2021 - 87
ASHRAE Journal - January 2021 - 88
ASHRAE Journal - January 2021 - 89
ASHRAE Journal - January 2021 - 90
ASHRAE Journal - January 2021 - 91
ASHRAE Journal - January 2021 - 92
ASHRAE Journal - January 2021 - 93
ASHRAE Journal - January 2021 - 94
ASHRAE Journal - January 2021 - 95
ASHRAE Journal - January 2021 - 96
ASHRAE Journal - January 2021 - 97
ASHRAE Journal - January 2021 - 98
ASHRAE Journal - January 2021 - 99
ASHRAE Journal - January 2021 - 100
ASHRAE Journal - January 2021 - 101
ASHRAE Journal - January 2021 - 102
ASHRAE Journal - January 2021 - 103
ASHRAE Journal - January 2021 - 104
ASHRAE Journal - January 2021 - 105
ASHRAE Journal - January 2021 - 106
ASHRAE Journal - January 2021 - 107
ASHRAE Journal - January 2021 - 108
ASHRAE Journal - January 2021 - 109
ASHRAE Journal - January 2021 - 110
ASHRAE Journal - January 2021 - 111
ASHRAE Journal - January 2021 - 112
ASHRAE Journal - January 2021 - Cover3
ASHRAE Journal - January 2021 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VJKSRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDHUTC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JPPKRR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDLTTH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CKLLES
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SLDOX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_HJETUK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OLUHGE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ZERDGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QVMNEO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BBATRE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_STUBMW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TPEMPE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JNMKDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FBTTPA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WQMMNE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TVBRYN
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2020
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
https://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
https://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
https://www.nxtbook.com/nxtbooks/amca/2014summer2
https://www.nxtbook.com/nxtbooks/amca/2014summer
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
https://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
https://www.nxtbookmedia.com