ASHRAE Journal - March 2012 - 46

Total Energy Wheel Control In a Dedicated OA System
By John Murphy, Member ASHRAE

W

ith increased focus on reducing energy consumption in buildings, the use of exhaust-air energy recovery in HVAC systems

is becoming more common, somewhat prompted by the requirements of ASHRAE Standards 90.1 and 189.1. Proper control of the energyrecovery device is critical to realize the expected energy savings. Al-

wheel pre-cools and “pre-dries” (pre-dehumidifies) the outdoor air by transferring both sensible heat and water vapor to the cooler, drier exhaust airstream. During the heating season, when it is cold and dry outside, this same device pre-heats and pre-humidifies the outdoor air by removing both sensible heat and water vapor from the exhaust air and transferring it to the entering outdoor airstream.

though there are several other types of energy-recovery devices, and Importance of Proper Wheel Control Many proponents explain the benefits exhaust-air energy recovery is also applied in mixed-air systems, the focus of this article is on proper control of a total energy wheel (or enthalpy wheel) when applied in a dedicated outdoor air system (DOAS).
Exhaust-Air Energy Recovery
Exhaust-air energy recovery refers to the transfer of energy between the outdoor and exhaust airstreams. For the configuration discussed in this article, a total energy wheel is arranged to pre46 ASHRAE Journal

condition the entering outdoor air (OA) by exchanging sensible heat and water vapor (latent heat) with the exhaust air (EA) stream (Figure 1). During the cooling season, when it is hot and humid outside, the total energy
ashrae.org

of exhaust-air energy recovery by focusing on the hottest and coldest days of the year. The more extreme the outdoor conditions, the greater the energy savings and the more that cooling and heating plants can be downsized. However, during less-severe outdoor conditions, improper operation of the About the Author
John Murphy is an applications engineer with Trane, a business of Ingersoll Rand in La Crosse, Wis.

March 2012



ASHRAE Journal - March 2012

Table of Contents for the Digital Edition of ASHRAE Journal - March 2012

ASHRAE Journal - March 2012
Contents
Commentary
Show Coverage
Meetings and Shows
Feature Articles
ASHRAE’s Best: 2012 Technology Awards
Total Energy Wheel Control in a Dedicated OA System
Optimizing Design & Control of Chilled Water Plants Part 4: Chiller & Cooling Tower Selection
Improving DHW System Performance
Technology Award Case Studies:
Ice Rink Uses CO2 System
Standing Columns
Building Sciences
Emerging Technologies
Refrigeration
Special Products
IAQ Applications
People
Products
Classified Advertising
Advertisers Index
ASHRAE Journal - March 2012 - Intro
ASHRAE Journal - March 2012 - ASHRAE Journal - March 2012
ASHRAE Journal - March 2012 - Cover2
ASHRAE Journal - March 2012 - 1
ASHRAE Journal - March 2012 - 2
ASHRAE Journal - March 2012 - Contents
ASHRAE Journal - March 2012 - Commentary
ASHRAE Journal - March 2012 - 5
ASHRAE Journal - March 2012 - Show Coverage
ASHRAE Journal - March 2012 - 7
ASHRAE Journal - March 2012 - 8
ASHRAE Journal - March 2012 - 9
ASHRAE Journal - March 2012 - 10
ASHRAE Journal - March 2012 - 11
ASHRAE Journal - March 2012 - 12
ASHRAE Journal - March 2012 - 13
ASHRAE Journal - March 2012 - 14
ASHRAE Journal - March 2012 - 15
ASHRAE Journal - March 2012 - 16
ASHRAE Journal - March 2012 - 17
ASHRAE Journal - March 2012 - 18
ASHRAE Journal - March 2012 - 19
ASHRAE Journal - March 2012 - 20
ASHRAE Journal - March 2012 - 21
ASHRAE Journal - March 2012 - 22
ASHRAE Journal - March 2012 - 23
ASHRAE Journal - March 2012 - 24
ASHRAE Journal - March 2012 - 25
ASHRAE Journal - March 2012 - Meetings and Shows
ASHRAE Journal - March 2012 - 27
ASHRAE Journal - March 2012 - ASHRAE’s Best: 2012 Technology Awards
ASHRAE Journal - March 2012 - 29
ASHRAE Journal - March 2012 - 30
ASHRAE Journal - March 2012 - 31
ASHRAE Journal - March 2012 - 32
ASHRAE Journal - March 2012 - 33
ASHRAE Journal - March 2012 - 34
ASHRAE Journal - March 2012 - 35
ASHRAE Journal - March 2012 - 36
ASHRAE Journal - March 2012 - 37
ASHRAE Journal - March 2012 - Ice Rink Uses CO2 System
ASHRAE Journal - March 2012 - 39
ASHRAE Journal - March 2012 - 40
ASHRAE Journal - March 2012 - 41
ASHRAE Journal - March 2012 - 42
ASHRAE Journal - March 2012 - 43
ASHRAE Journal - March 2012 - 44
ASHRAE Journal - March 2012 - 45
ASHRAE Journal - March 2012 - Total Energy Wheel Control in a Dedicated OA System
ASHRAE Journal - March 2012 - 47
ASHRAE Journal - March 2012 - 48
ASHRAE Journal - March 2012 - 49
ASHRAE Journal - March 2012 - 50
ASHRAE Journal - March 2012 - 51
ASHRAE Journal - March 2012 - 52
ASHRAE Journal - March 2012 - 53
ASHRAE Journal - March 2012 - 54
ASHRAE Journal - March 2012 - 55
ASHRAE Journal - March 2012 - 56
ASHRAE Journal - March 2012 - 57
ASHRAE Journal - March 2012 - 58
ASHRAE Journal - March 2012 - 59
ASHRAE Journal - March 2012 - Optimizing Design & Control of Chilled Water Plants Part 4: Chiller & Cooling Tower Selection
ASHRAE Journal - March 2012 - 61
ASHRAE Journal - March 2012 - 62
ASHRAE Journal - March 2012 - 63
ASHRAE Journal - March 2012 - 64
ASHRAE Journal - March 2012 - 65
ASHRAE Journal - March 2012 - 66
ASHRAE Journal - March 2012 - 67
ASHRAE Journal - March 2012 - 68
ASHRAE Journal - March 2012 - 69
ASHRAE Journal - March 2012 - 70
ASHRAE Journal - March 2012 - 71
ASHRAE Journal - March 2012 - Improving DHW System Performance
ASHRAE Journal - March 2012 - 73
ASHRAE Journal - March 2012 - 74
ASHRAE Journal - March 2012 - 75
ASHRAE Journal - March 2012 - 76
ASHRAE Journal - March 2012 - 77
ASHRAE Journal - March 2012 - 78
ASHRAE Journal - March 2012 - 79
ASHRAE Journal - March 2012 - Building Sciences
ASHRAE Journal - March 2012 - 81
ASHRAE Journal - March 2012 - 82
ASHRAE Journal - March 2012 - 83
ASHRAE Journal - March 2012 - 84
ASHRAE Journal - March 2012 - 85
ASHRAE Journal - March 2012 - 86
ASHRAE Journal - March 2012 - 87
ASHRAE Journal - March 2012 - Emerging Technologies
ASHRAE Journal - March 2012 - 89
ASHRAE Journal - March 2012 - 90
ASHRAE Journal - March 2012 - 91
ASHRAE Journal - March 2012 - 92
ASHRAE Journal - March 2012 - 93
ASHRAE Journal - March 2012 - Refrigeration
ASHRAE Journal - March 2012 - 95
ASHRAE Journal - March 2012 - Special Products
ASHRAE Journal - March 2012 - 97
ASHRAE Journal - March 2012 - IAQ Applications
ASHRAE Journal - March 2012 - 99
ASHRAE Journal - March 2012 - People
ASHRAE Journal - March 2012 - 101
ASHRAE Journal - March 2012 - Products
ASHRAE Journal - March 2012 - 103
ASHRAE Journal - March 2012 - 104
ASHRAE Journal - March 2012 - 105
ASHRAE Journal - March 2012 - 106
ASHRAE Journal - March 2012 - 107
ASHRAE Journal - March 2012 - 108
ASHRAE Journal - March 2012 - 109
ASHRAE Journal - March 2012 - Classified Advertising
ASHRAE Journal - March 2012 - 111
ASHRAE Journal - March 2012 - Advertisers Index
ASHRAE Journal - March 2012 - Cover3
ASHRAE Journal - March 2012 - 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