ASHRAE Journal - August 2024 - 47
TECHNICAL FEATURE
large a peak heating load as possible (Figure 2a).
Issues with Conventional Practice
Warming up a building as fast as possible, however,
may not be the most energy effi cient or cost-effective
strategy with modern HVAC systems. Much of the
original research around night setback and optimum
start is decades old, based on studies of buildings with
relatively poor envelopes, prior to the widespread use
of modulating capacity control in HVAC equipment, like
variable speed drives for fans and modulating boilers. In
newer construction, envelope losses are minimized with
high-performance glazing, improved insulation and
sealing. Fans and heating systems generally also operate
more effi ciently at part-load conditions.
Potentially many downsides exist with conventional
morning warm-up practices that may outweigh their
intended benefi ts. These include:
* Brief periods of peak heating demand may drive a
hot water plant to stage on additional equipment, with
negative effi ciency impacts if the lag equipment then
cycles off quickly. In addition to pre- and post-purge
losses for boilers, signifi cant heating energy is required
to warm up the thermal mass and water in a lag boiler,
and that heat is then lost to the environment if the lag
boiler stages back off soon after.5
* Peak heating demand can drive hot water supply
temperature setpoints to reset up to the maximum limit
(e.g., when using demand-based setpoint reset logic
per Guideline 36-2021), resulting in lower equipment
effi ciency for condensing boilers (due to higher boiler
entering water temperatures that prevent or reduce
condensing) or air-to-water heat pumps (due to lower
effi ciencies at higher leaving hot water temperatures).
Data gathered from a broad collection of buildings
with condensing boilers shows that many operate at
temperatures above the condensing region for most or
all of the time.6 Previous research also determined that
losses through hot water distribution piping may make
up a signifi cant fraction of total hot water loop energy
and are greater at higher supply water temperatures.7,8
Depending on where and when these losses occur, they
RELIABLE, STANDARD,
AND CUSTOM SOLUTIONS
AND CUSTOM SOLUTIONS
DATA CENTER SOLUTIONS
The Metrafl ex Company makes a variety of engineered piping products
including energy-effi cient strainers and pump connectors, fl exible
connectors, expansion joints, valves and more.
ASK ABOUT DELEGATED DESIGN SERVICES!
©2024 The Metrafl ex Company
www.Metrafl ex.com
A U G U ST 2 0 2 4 ashrae.org ASHRAE JOURNAL
47
http://www.Metraflex.com
http://www.ashrae.org
ASHRAE Journal - August 2024
Table of Contents for the Digital Edition of ASHRAE Journal - August 2024
Contents
ASHRAE Journal - August 2024 - Intro
ASHRAE Journal - August 2024 - Cover1
ASHRAE Journal - August 2024 - Cover2
ASHRAE Journal - August 2024 - 1
ASHRAE Journal - August 2024 - Contents
ASHRAE Journal - August 2024 - 3
ASHRAE Journal - August 2024 - 4
ASHRAE Journal - August 2024 - 5
ASHRAE Journal - August 2024 - 6
ASHRAE Journal - August 2024 - 7
ASHRAE Journal - August 2024 - 8
ASHRAE Journal - August 2024 - 9
ASHRAE Journal - August 2024 - 10
ASHRAE Journal - August 2024 - 11
ASHRAE Journal - August 2024 - 12
ASHRAE Journal - August 2024 - 13
ASHRAE Journal - August 2024 - 14
ASHRAE Journal - August 2024 - 15
ASHRAE Journal - August 2024 - 16
ASHRAE Journal - August 2024 - 17
ASHRAE Journal - August 2024 - 18
ASHRAE Journal - August 2024 - 19
ASHRAE Journal - August 2024 - 20
ASHRAE Journal - August 2024 - 21
ASHRAE Journal - August 2024 - 22
ASHRAE Journal - August 2024 - 23
ASHRAE Journal - August 2024 - 24
ASHRAE Journal - August 2024 - 25
ASHRAE Journal - August 2024 - 26
ASHRAE Journal - August 2024 - 27
ASHRAE Journal - August 2024 - 28
ASHRAE Journal - August 2024 - 29
ASHRAE Journal - August 2024 - 30
ASHRAE Journal - August 2024 - 31
ASHRAE Journal - August 2024 - 32
ASHRAE Journal - August 2024 - 33
ASHRAE Journal - August 2024 - 34
ASHRAE Journal - August 2024 - 35
ASHRAE Journal - August 2024 - 36
ASHRAE Journal - August 2024 - 37
ASHRAE Journal - August 2024 - 38
ASHRAE Journal - August 2024 - 39
ASHRAE Journal - August 2024 - 40
ASHRAE Journal - August 2024 - 41
ASHRAE Journal - August 2024 - 42
ASHRAE Journal - August 2024 - 43
ASHRAE Journal - August 2024 - 44
ASHRAE Journal - August 2024 - 45
ASHRAE Journal - August 2024 - 46
ASHRAE Journal - August 2024 - 47
ASHRAE Journal - August 2024 - 48
ASHRAE Journal - August 2024 - 49
ASHRAE Journal - August 2024 - 50
ASHRAE Journal - August 2024 - 51
ASHRAE Journal - August 2024 - 52
ASHRAE Journal - August 2024 - 53
ASHRAE Journal - August 2024 - 54
ASHRAE Journal - August 2024 - 55
ASHRAE Journal - August 2024 - 56
ASHRAE Journal - August 2024 - 57
ASHRAE Journal - August 2024 - 58
ASHRAE Journal - August 2024 - 59
ASHRAE Journal - August 2024 - 60
ASHRAE Journal - August 2024 - 61
ASHRAE Journal - August 2024 - 62
ASHRAE Journal - August 2024 - 63
ASHRAE Journal - August 2024 - 64
ASHRAE Journal - August 2024 - 65
ASHRAE Journal - August 2024 - 66
ASHRAE Journal - August 2024 - 67
ASHRAE Journal - August 2024 - 68
ASHRAE Journal - August 2024 - 69
ASHRAE Journal - August 2024 - 70
ASHRAE Journal - August 2024 - 71
ASHRAE Journal - August 2024 - 72
ASHRAE Journal - August 2024 - Cover3
ASHRAE Journal - August 2024 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FYONLJ
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2024november_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2024november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BDMHLG
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WJDGRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ATMAHK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VHQRAW
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