ASHRAE Journal - April 2014 - 59

Column EnginEEr's notEbook

Cascading laboratory makeup air directly from non-laboratory spaces.

Lab
Ventilation
System

Office
Heat Recovery Options
* Runaround Coil (Shown)
* Evaporative Assisted Coil
* Enthalpy Heat Wheel
COuRtesy WsP usA

maintain the building at a slight positive
Figure 1
pressure with respect to the outdoor, in
order to minimize drafts at entrances, and
to reduce outdoor air infiltration in inconvenient locations.
These two strategies do not address the
issue of balancing required ventilation airflow against sensible heat gains in the space,
nor do they address issues of differential
outdoor air ventilation requirements among
the various non-lab occupancies in the
building. Raising the supply air temperature
can minimize reheat in low sensible load,
exhaust driven spaces, but supply air dewpoint control and the cooling requirements
of other lab spaces may limit that reset.
The first step in reducing reheat in laboratory spaces is to disconnect provision
of ventilation and dehumidification from
provision of sensible cooling, by supplying
air that has the required low dew-point
temperature but a substantially higher
dry-bulb temperature. In-space cooling
using passive chilled beams or recirculating fan coils can then supply supplemental
local cooling, where required, while reheat
is reduced for ventilation-driven spaces.
Arguably, the cost of a passive chilled beam
in a load-driven lab space is of the same
order of magnitude as a reheat coil in a
ventilation-driven lab space.
In humid climates, however, the apparatus dew-point required for space humidity
control may limit the ability to separate sensible cooling and ventilation. Several strategies are available to
enable delivery of higher temperature dehumidified air
in these climates, without wasting the sensible cooling
that accompanied condensing excess humidity out of
the air.
The first of these is the simple runaround coil.
Two additional coils sandwich the cooling coil of
the laboratory air-handling unit. Warm outdoor air
flows through the first coil, heating the water flowing
within, then flows through the cooling coil, where it is
cooled to the required dew-point temperature (usually 54°F [12°C] or less), then flows through the downstream coil, where it is warmed by the circulating

Typical HVAC System

water that was heated by the air when it flowed across
the most upstream coil. In this way, sensible cooling
is transferred from the cooling coil discharge air into
the cooling coil input air with little or no loss. The only
energy implication of this strategy is the increased pressure drop across the three coil assembly and the small
energy consumption of the pump that circulates water
between the two coils.
This technique is highly effective at peak outdoor
design conditions, but is almost ineffective when the
outdoor dry-bulb temperature is 64°F (18°C) with a
dense fog or heavy rain. The air onto the outer coil is
insufficiently warm to give much reheat benefit to the
air downstream of the cooling coil. Ventilation-driven
Apri l 2014

ashrae.org

ASHRAE JouRnAl

59



ASHRAE Journal - April 2014

Table of Contents for the Digital Edition of ASHRAE Journal - April 2014

ASHRAE Journal - April 2014
Contents
Commentary
Industry News
Letters
Meetings and Shows
Feature Articles
Lessons Learned from ASHRAE HQ Renovation
Current Trends for Health-Care Ventilation
Technical vs. Process Commissioning: Pre-Functional Testing
Building Sciences
Engineer's Notebook
Technology Award Case Study: Crime Lab Deconstruction
Refrigeration Applications
Technology Award Case Study: Designing for Sustainability
Data Centers
HVAC Applications
Energy Modeling
IAQ Applications
People
Special Products
Classified Advertising
Advertisers Index
ASHRAE Journal - April 2014 - ASHRAE Journal - April 2014
ASHRAE Journal - April 2014 - Cover2
ASHRAE Journal - April 2014 - 1
ASHRAE Journal - April 2014 - 2
ASHRAE Journal - April 2014 - Contents
ASHRAE Journal - April 2014 - Commentary
ASHRAE Journal - April 2014 - 5
ASHRAE Journal - April 2014 - Industry News
ASHRAE Journal - April 2014 - 7
ASHRAE Journal - April 2014 - Letters
ASHRAE Journal - April 2014 - 9
ASHRAE Journal - April 2014 - 10
ASHRAE Journal - April 2014 - 11
ASHRAE Journal - April 2014 - Meetings and Shows
ASHRAE Journal - April 2014 - 13
ASHRAE Journal - April 2014 - Lessons Learned from ASHRAE HQ Renovation
ASHRAE Journal - April 2014 - 15
ASHRAE Journal - April 2014 - 16
ASHRAE Journal - April 2014 - 17
ASHRAE Journal - April 2014 - 18
ASHRAE Journal - April 2014 - 19
ASHRAE Journal - April 2014 - 20
ASHRAE Journal - April 2014 - 21
ASHRAE Journal - April 2014 - 22
ASHRAE Journal - April 2014 - 23
ASHRAE Journal - April 2014 - 24
ASHRAE Journal - April 2014 - 25
ASHRAE Journal - April 2014 - 26
ASHRAE Journal - April 2014 - 27
ASHRAE Journal - April 2014 - 28
ASHRAE Journal - April 2014 - 29
ASHRAE Journal - April 2014 - 30
ASHRAE Journal - April 2014 - 31
ASHRAE Journal - April 2014 - Current Trends for Health-Care Ventilation
ASHRAE Journal - April 2014 - 33
ASHRAE Journal - April 2014 - 34
ASHRAE Journal - April 2014 - 35
ASHRAE Journal - April 2014 - 36
ASHRAE Journal - April 2014 - 37
ASHRAE Journal - April 2014 - 38
ASHRAE Journal - April 2014 - 39
ASHRAE Journal - April 2014 - 40
ASHRAE Journal - April 2014 - 41
ASHRAE Journal - April 2014 - 42
ASHRAE Journal - April 2014 - 43
ASHRAE Journal - April 2014 - Technical vs. Process Commissioning: Pre-Functional Testing
ASHRAE Journal - April 2014 - 45
ASHRAE Journal - April 2014 - 46
ASHRAE Journal - April 2014 - 47
ASHRAE Journal - April 2014 - 48
ASHRAE Journal - April 2014 - 49
ASHRAE Journal - April 2014 - 50
ASHRAE Journal - April 2014 - 51
ASHRAE Journal - April 2014 - Building Sciences
ASHRAE Journal - April 2014 - 53
ASHRAE Journal - April 2014 - 54
ASHRAE Journal - April 2014 - 55
ASHRAE Journal - April 2014 - 56
ASHRAE Journal - April 2014 - 57
ASHRAE Journal - April 2014 - Engineer's Notebook
ASHRAE Journal - April 2014 - 59
ASHRAE Journal - April 2014 - 60
ASHRAE Journal - April 2014 - 61
ASHRAE Journal - April 2014 - 62
ASHRAE Journal - April 2014 - 63
ASHRAE Journal - April 2014 - 64
ASHRAE Journal - April 2014 - 65
ASHRAE Journal - April 2014 - Technology Award Case Study: Crime Lab Deconstruction
ASHRAE Journal - April 2014 - 67
ASHRAE Journal - April 2014 - 68
ASHRAE Journal - April 2014 - 69
ASHRAE Journal - April 2014 - 70
ASHRAE Journal - April 2014 - 71
ASHRAE Journal - April 2014 - 72
ASHRAE Journal - April 2014 - 73
ASHRAE Journal - April 2014 - Refrigeration Applications
ASHRAE Journal - April 2014 - 75
ASHRAE Journal - April 2014 - Technology Award Case Study: Designing for Sustainability
ASHRAE Journal - April 2014 - 77
ASHRAE Journal - April 2014 - 78
ASHRAE Journal - April 2014 - 79
ASHRAE Journal - April 2014 - 80
ASHRAE Journal - April 2014 - 81
ASHRAE Journal - April 2014 - 82
ASHRAE Journal - April 2014 - 83
ASHRAE Journal - April 2014 - Data Centers
ASHRAE Journal - April 2014 - 85
ASHRAE Journal - April 2014 - 86
ASHRAE Journal - April 2014 - 87
ASHRAE Journal - April 2014 - 88
ASHRAE Journal - April 2014 - 89
ASHRAE Journal - April 2014 - HVAC Applications
ASHRAE Journal - April 2014 - 91
ASHRAE Journal - April 2014 - 92
ASHRAE Journal - April 2014 - Energy Modeling
ASHRAE Journal - April 2014 - IAQ Applications
ASHRAE Journal - April 2014 - 95
ASHRAE Journal - April 2014 - 96
ASHRAE Journal - April 2014 - 97
ASHRAE Journal - April 2014 - People
ASHRAE Journal - April 2014 - 99
ASHRAE Journal - April 2014 - 100
ASHRAE Journal - April 2014 - Special Products
ASHRAE Journal - April 2014 - 102
ASHRAE Journal - April 2014 - Classified Advertising
ASHRAE Journal - April 2014 - Advertisers Index
ASHRAE Journal - April 2014 - Cover3
ASHRAE Journal - April 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