ASHRAE Journal - ACMA Supplement - Fall 2013 - 19

rectangular equivalents (often requiring 25% less metal by
weight) and demand less fan energy.
Smart deSign uSing total preSSure, avoid and
account for SyStem effectS

AMCA recommends that ducted fans be selected based on the
total pressure (static pressure + velocity pressure) and required
airflow. System designers often estimate the pressure drop in
ducted HVAC systems using well-established tools and techniques.
The resulting pressure drop represents the total energy per unit
volume of airflow, and this should be matched to the fan total
pressure. However, common practice is to match the pressure
drop of the system to the fan static pressure. This is incorrect
because it ignores energy available in the fan velocity pressure
that can be utilized by the system to meet the pressure drop
requirement. This common design error is usually more than offset
by system effects that are not accounted for in the system design
process. Uneven air distribution at the fan inlet or outlet and the
effect of fan-to-duct transition fittings are examples, as are fitting
transitions placed too close together downstream. Most commercial
building duct systems exhibit more pressure drop than estimated
in the design because of these system effects.
When fans are selected on the basis of fan static pressure to meet
a total pressure requirement, the resulting selection will likely

consume more power than necessary to meet flow requirements.
System effects (unaccounted pressure drop) generally offset this
oversight. But good design practice requires proper estimation of
duct pressure losses, including system effects, and fan selection
based on fan total pressure. High-performance air systems need
to be well designed to take advantage of energy saving benefits.
reduce refrigerant riSk

Minimize refrigerant volumes. Refrigerant is expensive, and
prone to escape. Refrigerant leak detectors are expensive. The
last few decades have forced CFCs and now most HCFCs off
the market, rendering obsolete some equipment that used them.
The future of refrigerants is uncertain—change in the refrigerants we use is certain. Keeping refrigerant in the equipment
room and reducing your exposure to change is smart. Packaged
rooftops and chillers minimize this risk.
Systems using expansive refrigerant piping must also be considered against the refrigerant concentration limits described in
ASHRAE Standard 15. Since the entire building’s refrigerant
charge can escape into the smallest room served, the design
professional must calculate this worst-case refrigerant concentration level and compare it to the limits described in ASHRAE
Standard 15. Multi-evaporator systems increase the number of
potential refrigerant leak points, and the concentration levels

www.info.hotims.com/44636-13
w w w. a m c a . o r g

a m c a I n t e r nat I o na l

inmotion

Fall 2013

19


http://www.aerovent.com http://www.aerovent.com http://www.info.hotims.com/44636-13 http://WWW.AMCA.ORG

ASHRAE Journal - ACMA Supplement - Fall 2013

Table of Contents for the Digital Edition of ASHRAE Journal - ACMA Supplement - Fall 2013

Contents
ASHRAE Journal - ACMA Supplement - Fall 2013 - Cover1
ASHRAE Journal - ACMA Supplement - Fall 2013 - Cover2
ASHRAE Journal - ACMA Supplement - Fall 2013 - Contents
ASHRAE Journal - ACMA Supplement - Fall 2013 - 2
ASHRAE Journal - ACMA Supplement - Fall 2013 - 3
ASHRAE Journal - ACMA Supplement - Fall 2013 - 4
ASHRAE Journal - ACMA Supplement - Fall 2013 - 5
ASHRAE Journal - ACMA Supplement - Fall 2013 - 6
ASHRAE Journal - ACMA Supplement - Fall 2013 - 7
ASHRAE Journal - ACMA Supplement - Fall 2013 - 8
ASHRAE Journal - ACMA Supplement - Fall 2013 - 9
ASHRAE Journal - ACMA Supplement - Fall 2013 - 10
ASHRAE Journal - ACMA Supplement - Fall 2013 - 11
ASHRAE Journal - ACMA Supplement - Fall 2013 - 12
ASHRAE Journal - ACMA Supplement - Fall 2013 - 13
ASHRAE Journal - ACMA Supplement - Fall 2013 - 14
ASHRAE Journal - ACMA Supplement - Fall 2013 - 15
ASHRAE Journal - ACMA Supplement - Fall 2013 - 16
ASHRAE Journal - ACMA Supplement - Fall 2013 - 17
ASHRAE Journal - ACMA Supplement - Fall 2013 - 18
ASHRAE Journal - ACMA Supplement - Fall 2013 - 19
ASHRAE Journal - ACMA Supplement - Fall 2013 - 20
ASHRAE Journal - ACMA Supplement - Fall 2013 - 21
ASHRAE Journal - ACMA Supplement - Fall 2013 - 22
ASHRAE Journal - ACMA Supplement - Fall 2013 - 23
ASHRAE Journal - ACMA Supplement - Fall 2013 - 24
ASHRAE Journal - ACMA Supplement - Fall 2013 - 25
ASHRAE Journal - ACMA Supplement - Fall 2013 - 26
ASHRAE Journal - ACMA Supplement - Fall 2013 - 27
ASHRAE Journal - ACMA Supplement - Fall 2013 - 28
ASHRAE Journal - ACMA Supplement - Fall 2013 - Cover3
ASHRAE Journal - ACMA Supplement - Fall 2013 - Cover4
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