ASHRAE Journal - May 2014 - 50
Technical FeaTure
when comparing different energy recovery exchangers, both effectiveness and RER need to be considered.
An exchanger with a higher effectiveness may have a
lower RER, but the higher effectiveness results in less
work to be done by the less-efficient mechanical heating or cooling system. Which exchanger will result in
higher overall system efficiency is a balance between
effectiveness and RER, and depends on the efficiency of
the mechanical conditioning system. AHRI Guideline
V, Calculating the Efficiency of Energy Recovery Ventilation and
Its Effect on Efficiency and Sizing of Building HVAC Systems, is a
good resource that includes several examples on calculating this combined efficiency.
Energy Recovery Exchanger Placement vs. Performance
The application of the device within the system also will
affect the fan power added with energy recovery. Figure 6
will give a good approximation of what to expect for a
100% outdoor air system. However, in some cases, adding exhaust air recovery may not add supply fan power
at design and may actually lower it. The air-handling
equipment arrangement can make a difference. This is
especially true for mixed air systems, those that use airhandling equipment to cool and heat both the ventilation
air and recirculated air to condition the building.
For example, let's look at a variable air volume air handler with ducted return air. This example system (shown
as System A in the tables) at design has a 1.25 in. w.g.
(311 Pa) external static pressure on the return path, with
a supply airflow of 10,000 cfm (4719 L/s) and outdoor
airflow of 5,000 cfm (2360 L/s) and exhaust airflow of
4,500 cfm (2124 L/s). The alternative proposed system
with energy recovery (System B) adds an energy wheel
with a 0.90 in. w.g. (224 Pa) supply pressure drop and
0.80 in. w.g. (199 Pa) exhaust pressure drop having an
exchanger effectiveness of 80% that reduces the outdoor
air enthalpy 71% with respect to the exhaust.
The prescriptive fan power limit in Standard 90.1
allows for an additional 2.44 bhp (1.82 kW) to the
allowed system design fan power limit (see sidebar,
"Example Fan Power Limitation"). When considering
this system one may divide this credit between the
exhaust and supply fans. More often many assume
that including recovery will add the 0.90 in. w.g. (224
Pa) to both the exhaust and supply fan total static
pressure, and use this as the basis for the building
energy model for System B. This assumption will
www.info.hotims.com/49804-49
50
ASHRAE JouRnAl
ashrae.org
M ay 2 0 1 4
ASHRAE Journal - May 2014
Table of Contents for the Digital Edition of ASHRAE Journal - May 2014
Contents
ASHRAE Journal - May 2014 - BB1
ASHRAE Journal - May 2014 - BB2
ASHRAE Journal - May 2014 - Cover1
ASHRAE Journal - May 2014 - Cover2
ASHRAE Journal - May 2014 - 1
ASHRAE Journal - May 2014 - 2
ASHRAE Journal - May 2014 - Contents
ASHRAE Journal - May 2014 - 4
ASHRAE Journal - May 2014 - 5
ASHRAE Journal - May 2014 - 6
ASHRAE Journal - May 2014 - 7
ASHRAE Journal - May 2014 - 8
ASHRAE Journal - May 2014 - 9
ASHRAE Journal - May 2014 - 10
ASHRAE Journal - May 2014 - 11
ASHRAE Journal - May 2014 - 12
ASHRAE Journal - May 2014 - 13
ASHRAE Journal - May 2014 - 14
ASHRAE Journal - May 2014 - 15
ASHRAE Journal - May 2014 - 16
ASHRAE Journal - May 2014 - 17
ASHRAE Journal - May 2014 - 18
ASHRAE Journal - May 2014 - 19
ASHRAE Journal - May 2014 - 20
ASHRAE Journal - May 2014 - 21
ASHRAE Journal - May 2014 - 22
ASHRAE Journal - May 2014 - 23
ASHRAE Journal - May 2014 - 24
ASHRAE Journal - May 2014 - 25
ASHRAE Journal - May 2014 - 26
ASHRAE Journal - May 2014 - 27
ASHRAE Journal - May 2014 - 28
ASHRAE Journal - May 2014 - 29
ASHRAE Journal - May 2014 - 30
ASHRAE Journal - May 2014 - 31
ASHRAE Journal - May 2014 - 32
ASHRAE Journal - May 2014 - 33
ASHRAE Journal - May 2014 - 34
ASHRAE Journal - May 2014 - 35
ASHRAE Journal - May 2014 - 36
ASHRAE Journal - May 2014 - 37
ASHRAE Journal - May 2014 - 38
ASHRAE Journal - May 2014 - 39
ASHRAE Journal - May 2014 - 40
ASHRAE Journal - May 2014 - 41
ASHRAE Journal - May 2014 - 42
ASHRAE Journal - May 2014 - 43
ASHRAE Journal - May 2014 - 44
ASHRAE Journal - May 2014 - 45
ASHRAE Journal - May 2014 - 46
ASHRAE Journal - May 2014 - 47
ASHRAE Journal - May 2014 - 48
ASHRAE Journal - May 2014 - 49
ASHRAE Journal - May 2014 - 50
ASHRAE Journal - May 2014 - 51
ASHRAE Journal - May 2014 - 52
ASHRAE Journal - May 2014 - 53
ASHRAE Journal - May 2014 - 54
ASHRAE Journal - May 2014 - 55
ASHRAE Journal - May 2014 - 56
ASHRAE Journal - May 2014 - 57
ASHRAE Journal - May 2014 - 58
ASHRAE Journal - May 2014 - 59
ASHRAE Journal - May 2014 - 60
ASHRAE Journal - May 2014 - 61
ASHRAE Journal - May 2014 - 62
ASHRAE Journal - May 2014 - 63
ASHRAE Journal - May 2014 - 64
ASHRAE Journal - May 2014 - 65
ASHRAE Journal - May 2014 - 66
ASHRAE Journal - May 2014 - 67
ASHRAE Journal - May 2014 - 68
ASHRAE Journal - May 2014 - 69
ASHRAE Journal - May 2014 - 70
ASHRAE Journal - May 2014 - 71
ASHRAE Journal - May 2014 - 72
ASHRAE Journal - May 2014 - 73
ASHRAE Journal - May 2014 - 74
ASHRAE Journal - May 2014 - 75
ASHRAE Journal - May 2014 - 76
ASHRAE Journal - May 2014 - 77
ASHRAE Journal - May 2014 - 78
ASHRAE Journal - May 2014 - 79
ASHRAE Journal - May 2014 - 80
ASHRAE Journal - May 2014 - 81
ASHRAE Journal - May 2014 - 82
ASHRAE Journal - May 2014 - 83
ASHRAE Journal - May 2014 - 84
ASHRAE Journal - May 2014 - 85
ASHRAE Journal - May 2014 - 86
ASHRAE Journal - May 2014 - 87
ASHRAE Journal - May 2014 - 88
ASHRAE Journal - May 2014 - 89
ASHRAE Journal - May 2014 - 90
ASHRAE Journal - May 2014 - 91
ASHRAE Journal - May 2014 - 92
ASHRAE Journal - May 2014 - 93
ASHRAE Journal - May 2014 - 94
ASHRAE Journal - May 2014 - 95
ASHRAE Journal - May 2014 - 96
ASHRAE Journal - May 2014 - 97
ASHRAE Journal - May 2014 - 98
ASHRAE Journal - May 2014 - 99
ASHRAE Journal - May 2014 - 100
ASHRAE Journal - May 2014 - 101
ASHRAE Journal - May 2014 - 102
ASHRAE Journal - May 2014 - 103
ASHRAE Journal - May 2014 - 104
ASHRAE Journal - May 2014 - Cover3
ASHRAE Journal - May 2014 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_MCDEBX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WNYSQY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XATVOD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FJSHSS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CCBZDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XDEFVG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2023november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHGNBL
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WPKBNJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_UUVCDE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTGDEW
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2023
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LKRFXS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AZSOFG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ERCDBH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QWDFRV
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JHGVDF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPUYHG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SREIBM
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LRTGLK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OKRFGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2022november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TZSERA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_LVRUIX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RPTVYZ
https://www.nxtbook.com/nxtbooks/ashrae/mini_pub_catalog
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XIYTGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2022
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RFGDOB
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PABXNU
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_REMKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PICVBT
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_AOYTVW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JQOPLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IOYTBC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SGAJJF
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_IGHYER
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_PDRKLS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2021november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XCODFR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QSLFGO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ILKVNM
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2021
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPDJKD
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