ASHRAE Journal - April 2022 - 8
LETTERS
Chilled-Water VAV System Configuration and Design
I found February's " Air-Cooled
Chillers: Chilled-Water VAV System
Configuration and Design " by
Nabil Nassif, Ph.D., P.E., Member
ASHRAE, interesting because it
reminded me of a design I would
occasionally come across in my early
days in the HVAC industry in New
York City some 50-plus years ago.
The design was a combination
heating-cooling coil in air-handling
units, usually in office buildings.
Of course properly zoned two-pipe
(or three-pipe) secondary fan coil
systems were more common for the
perimeter of office buildings (the
premier design being four-pipe
fan coils). With the advent of VAV,
it became a more cost-effective
option, especially with the reduction
in percent glazing of a building,
replacing perimeter fan coils.
I have some questions and points
about other design bases indicated
from the February article.
1. Why are proposed Option 1 and
Option 3 limited to an air-cooled
chiller plant? Why not apply them
to a water-cooled chiller plant?
2. The cooling and heating plant
consists of two 500 ton chillers and
two 5 MBtu/h boilers. The article
did not state if this is an N + 1 design.
Or is each chiller size for 50% of
the building cooling load and each
boiler size for 65%/75% of the building
heating load? The difference is
the implied size of the building with
an N + 1 design, implying a smaller
building. And perhaps that's why
the author specified this design for
an air-cooled chiller plant.
3. The hot water circulating tem®
peratures
shown seems to preclude
specifying condensing boilers. The
higher temperatures shown in an
AHU coil would be warranted in a
winter climate similar to New York
and other northeast states.
4. In terms of control valve location
at the coil, one finds varying
opinions. Some prefer the chilled
water control valve on the return
side, i.e., outlet side, and the hot
water control valve on the supply,
8
ASHRAE JOURNAL ashrae.o rg A P R I L 2 0 2 2
http://ww.berner.com
http://www.ashrae.org
ASHRAE Journal - April 2022
Table of Contents for the Digital Edition of ASHRAE Journal - April 2022
Contents
ASHRAE Journal - April 2022 - Intro
ASHRAE Journal - April 2022 - Cover1
ASHRAE Journal - April 2022 - Cover2
ASHRAE Journal - April 2022 - 1
ASHRAE Journal - April 2022 - Contents
ASHRAE Journal - April 2022 - 3
ASHRAE Journal - April 2022 - 4
ASHRAE Journal - April 2022 - 5
ASHRAE Journal - April 2022 - 6
ASHRAE Journal - April 2022 - 7
ASHRAE Journal - April 2022 - 8
ASHRAE Journal - April 2022 - 9
ASHRAE Journal - April 2022 - 10
ASHRAE Journal - April 2022 - 11
ASHRAE Journal - April 2022 - 12
ASHRAE Journal - April 2022 - 13
ASHRAE Journal - April 2022 - 14
ASHRAE Journal - April 2022 - 15
ASHRAE Journal - April 2022 - 16
ASHRAE Journal - April 2022 - 17
ASHRAE Journal - April 2022 - 18
ASHRAE Journal - April 2022 - 19
ASHRAE Journal - April 2022 - 20
ASHRAE Journal - April 2022 - 21
ASHRAE Journal - April 2022 - 22
ASHRAE Journal - April 2022 - 23
ASHRAE Journal - April 2022 - 24
ASHRAE Journal - April 2022 - 25
ASHRAE Journal - April 2022 - 26
ASHRAE Journal - April 2022 - 27
ASHRAE Journal - April 2022 - 28
ASHRAE Journal - April 2022 - 29
ASHRAE Journal - April 2022 - 30
ASHRAE Journal - April 2022 - 31
ASHRAE Journal - April 2022 - 32
ASHRAE Journal - April 2022 - 33
ASHRAE Journal - April 2022 - 34
ASHRAE Journal - April 2022 - 35
ASHRAE Journal - April 2022 - 36
ASHRAE Journal - April 2022 - 37
ASHRAE Journal - April 2022 - 38
ASHRAE Journal - April 2022 - 39
ASHRAE Journal - April 2022 - 40
ASHRAE Journal - April 2022 - 41
ASHRAE Journal - April 2022 - 42
ASHRAE Journal - April 2022 - 43
ASHRAE Journal - April 2022 - 44
ASHRAE Journal - April 2022 - 45
ASHRAE Journal - April 2022 - 46
ASHRAE Journal - April 2022 - 47
ASHRAE Journal - April 2022 - 48
ASHRAE Journal - April 2022 - 49
ASHRAE Journal - April 2022 - 50
ASHRAE Journal - April 2022 - 51
ASHRAE Journal - April 2022 - 52
ASHRAE Journal - April 2022 - 53
ASHRAE Journal - April 2022 - 54
ASHRAE Journal - April 2022 - 55
ASHRAE Journal - April 2022 - 56
ASHRAE Journal - April 2022 - 57
ASHRAE Journal - April 2022 - 58
ASHRAE Journal - April 2022 - 59
ASHRAE Journal - April 2022 - 60
ASHRAE Journal - April 2022 - 61
ASHRAE Journal - April 2022 - 62
ASHRAE Journal - April 2022 - 63
ASHRAE Journal - April 2022 - 64
ASHRAE Journal - April 2022 - 65
ASHRAE Journal - April 2022 - 66
ASHRAE Journal - April 2022 - 67
ASHRAE Journal - April 2022 - 68
ASHRAE Journal - April 2022 - 69
ASHRAE Journal - April 2022 - 70
ASHRAE Journal - April 2022 - 71
ASHRAE Journal - April 2022 - 72
ASHRAE Journal - April 2022 - Cover3
ASHRAE Journal - April 2022 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XGMDXI
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_YELQLJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QJLWMC
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