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7/29/2019 Calculating Pump Head
1/9
CalculatingPumpHeadHowtocalculatethePumpHeadforOpenandClosedSystems
6/27/2012Vemco,Inc.
7/29/2019 Calculating Pump Head
2/9
c
I
t
c
s
c
eforewecan
ydronicsyste
alculationdenaclosedsys
pensystem,
hesameplac
ommonopen
ystemoccurs
ollectsinthe
iagram(ther
pensystems
igure1:CloshatisPump Units
"feet"
Pumpo
o
o
discusspum
m.Itisimpor
endsonthetem,thefluid
tis.
In
aclose
thereisn
systemisth
wherethew
coolingtowe
ightside)iscl
dontrequire
dandOpenHead?
ofMeasure:).
Headisthet
StaticHeaappliesonl
onone
sid
tooverco
FrictionHfrictionres
piping,hea
isusuallye
footofstaPressureHpressureh
Condensat
head,wem
tanttoknow
ypeofsysteisnotexpos
dsystem,
the
breakinthe
coolingtow
terexitsthe
sumpbefore
osed.Becaus
expansionta
ydronicSyst
ntheU.S.sys
otalresistanc
:Statichead
yinopensyst
of
the
syste
eanyelevati
ad:Thisisals
ults.Thiscau
texchangers,
xpressedinu
icheight.ead:Whenlieadexists.Co
epumpsofte
stunderstan
whetherthe
thatthepudtoabreaki
fluid
travels
pipingloop.
rportionofa
spraynozzles
beingpump
itisclosed,
nks,astheflu
ems
tem,headis
ethatapum
representsth
ems.Noteth
pushes
the
on.
ocalledpress
esalossinp
coils,valves,
nitscalled"fe
uidispumpe
mmonapplic
deliverwat
Ca
dthedifferen
umpserves
pserves.nthepipings
hroughacon
hevastmajo
chilledwate
,andisexpos
daroundthe
nexpansion
idisnaturall
easuredeit
mustoverco
enetchange
atinaclosed
fluidup
the
o
uredrop.Whessure.Com
andfittings.
etofhead."
dfromavess
tionsinclude
rfromanat
lculati
cebetween
nopenorac
ystemthatin
tinuousclose
rityofhydro
system,asd
edtoairinth
loopagain.
tankabsorbs
freetounde
erinPSIori
me.Itconsist
inheight,in
loopsystem,
therside
of
t
enfluidflows
onentscausi
hepumpmufootoffrictielatonepre
condensate
osphericrec
gPump
nopenhydro
losedsystem,
terruptsforc
dpiping
syste
icpipingsyst
epictedbelo
efillsectiono
otethatthe
anythermal
rgothermale
"feetofhea
softhefollo
eet,thatthe
thestatichea
esystem,
so
throughany
ngfrictioninc
stovercomet
nheadiseqsuretoaves
umpsandb
eivertoadea
Head
nicsystemabecausethe
dflowatany
mthat
starts
emsareclose
.Abreakint
fthetower.
hilledwater
xpansionoft
xpansion.
"(usuallyab
ingcompon
pumpmusto
diszerobeca
thepump
do
systemcomp
ludeboilers,
hisfriction.F
altoliftingtelatanother
ilerfeedpu
eratoroperat
daclosed
umphead
point.Inan
andends
in
d.Themost
hepiping
hewater
sideofthis
hefluid.
breviatedto
nts:
ercome.It
usethefluid
esnot
need
onent,
hillers,
rictionhead
efluidonepressure,
ps.
ingat5
7/29/2019 Calculating Pump Head
3/9
t
o
o,forhydron1. Forcl
Wher
Fricti
valve2. Foro
head.
*ThetepsinCalcuasically,
we
n
tep1:Layouerminalunittep2:Selecthegraphsbe
oo
herePisthe
PSIG,mea
OnePSIG
isaconsid
VelocityHvelocityat
endingpoi
considerat
velocities
velocityhe
thegravita
isafractio
insignifica
icapplicatiosedsystems:
npressuredpressuredroensystems:
"sourceunit"latingthePueed
to
plug
v
tthepipingsanditsGPM.pipesizesforlowarefrom
PipeSizesPipeSizesmaximum
headloss(al
ingthatinad
quals2.31fe
rationonlyi
ad:Accelera
anendingpoi
nt.Therefore
ion.Inanope
sedinhydro
adisdefined
tionalconsta
ofafoot.Si
t).
s,wecansa:Pumphead
op=pipingp+accessorieumphead=
isdefinedaspHeadalues
into
the
ystemusingl
eachsegmetheASHRAEF
f2"andUnfover2":.7
ocalledfricti
ditiontothe
t,sothediff
someopen
ingwaterfro
ntrequirese
thebeginnin
nsystem,the
icsaresolo
bytheformul
t32feet/sec
ceheadloss
that:
thesumof
ressuredropspressuredrthesumofal
theboiler,chi
proper
form
ogicalroutin
t,basedonpundamentals
er:2fpsminft.ofP/100
onlossorpre
Ca
otherheads,
rentialhead
ystems.
mastandstill
ergy.Inclos
velocity
equ
velocityhea
thatthisheaV
2/2gwher
ond2.Theref
calculationsa
llfrictionpre
+terminalup.
lfrictionloss
ller,orheate
laabove.
asdetermin
ropervelocitBook.Recom
mumto4fpequivalentfe
ssuredrop).
lculati
hepumpmu
inthisapplic
orlowveloci
dsystemsth
alsthe
final
v
istheoretica
disnegligibleVistheflui
reattypical
rereallyesti
ssuredrops
itpressured
splusthest
changer,wh
edbythebui
andpressurmendedvelo
maximumetminimum
gPump
stovercome
tionis5X2.3
tyatthestart
estartingpoi
elocity,so
vel
llyaconsider
,andisignorvelocityinf
velocitiesof2
ates,thissm
op+source
ticliftofthe
ichcreatesth
ldingrequire
edrop.citiesare:
o4ft.ofP/1
Head
pressurehe1=11.6.Pre
ingpointtoa
tisthesame
ocityhead
is
ation,butthe
ed.(Notethaetpersecon
6fps,theve
allfigurebec
nitpressure
fluidplusthe
ehotorchille
ents.Note
00equivalen
adof5PSIG.
ssurehead
higher
asthe
ota
pipeline
the
andgis
locityhead
mes
rop*+
pressure
dwater.
ach
feet
7/29/2019 Calculating Pump Head
4/9
Calculati gPumpHead
7/29/2019 Calculating Pump Head
5/9
r
S
t
t
I
t
herecomme
easonablyec
elocitieswill
ncethelayo
tep3:Deterooo
xample:Ava
pecialConsiometimespr
xample:Apl
hepumpfor
nswer:Feeti
tep4:Deterhestatichea
hatthestatic
nthedrawin
owersumpis
dedranges
nomicaltoi
allowairtoc
tandpipesi
ineFrictionSourcean
Accessory
significant
Todeterm
havearesi
rate,uset
PDInFeetlvehasaCvo
PDinFeeteration:Presssuredrops
PDinfeetteandfram
hisitem?
nHead=8.5
inetheStatidissimplyth
headisthed
below,show
28aboveth
nsurethatth
stall.Noteth
llectathigh
eforeachse
DuetoSourcterminalEqu
itemsinclude
pressuredro
inevalveDP
stanceof1P
efollowingf
=(FlowRatef10.Flowthr
=(21/10)2XsureDropsInillbegiveni
=PDinPSIXheatexchan
PSIX2.31ft./
cHead(Opetotalheight
ifferenceinhingacooling
pump,soth
epipingsyste
attheminim
oints,withth
ctionhasbee
,Terminalaipment:Cons
filters,strain
thatwould
efertocurve
IG(2.31feet)
rmulatocal
RatedCv)2Xoughthevalv
.31=10.2PSIandConPSIunitsins
.31
erprintouts
SI=19.64ft.
SystemsOnlhatthepum
ightthatthe
ower,thesta
epumpmust
Ca
mwillbequi
mvelocities
epossiblere
ndetermined
dAccessoryultmanufact
rs,checkval
otbecovere
sorCvrating
.Sincethepr
ulatethepre
2.31eis21GPM.
ertingPSItoteadoffeeto
owsapress
y)
mustliftthe
pumpwillbe
ticheightmi
onlyprovide
lculati
t,consumer
arerecomme
ultofairbin
followthese
EquipmentInrerscatalog
esormultip
underthee
.ACvisdefi
essuredropi
ssuredropth
hatisthev
Head
fhead.Toco
redropof8.
fluid.Itappli
requiredtop
htappearto
anetliftof1
gPump
easonablepu
ndedbasedo
ing.
steps:
cluding:
sorcompute
urposevalves
quivalentfeet
edastheflo
proportional
roughtheval
lveDPinfee
nvertPSIunit
PSI.WhatP
esonlyinop
rovide.
be40.Howe
.Therefore,
Head
mphorsepow
nthefacttha
selections.
thatcouldha
ofpipingrul
atwhichth
tothesquar
eforanyflo
tofhead?
stofeetofh
infeetmust
nsystems.R
ver,thewate
thestatichea
er,andbe
tlower
vea
ofthumb.
valvewill
oftheflow
rate:
ad:
eaddedto
member
rlevelinthe
dis12.
7/29/2019 Calculating Pump Head
6/9
I
i
igure2,Statitep5:Deterthesystemi
nPSIX2.31/
tep6:Detereet"
ecausefittin
quivalentlen
alves,etc.).
Longhetablebelo
cHeightExainethePressopen,deter
SI.
inethe"Wosresultinm
gthofapipin
ethodfordwliststhenu
ple
sureHead(Sinethepres
rstPressurerepressured
gcircuitisthe
eterminingemberofequi
meOpenSysuredifferent
ropLoop"aropthanplai
actualmeas
uivalentlenalentfeetof
Ca
temsOnly)ialrequired,i
dEstimatetnpipe,weac
redlengthpl
th:pipingforvar
lculati
fany.Dontf
eFrictionLoountforthe
usanallowa
iousfittingsa
gPump
orgettomulti
ssforthatLobyusing"e
ceforallthe
ndaccessorie
Head
plypressure
opbyUsinguivalentleng
fittings(elbo
s:
ifferentials
quivalentth."The
s,tees,
7/29/2019 Calculating Pump Head
7/9
t
l
t
ousethism
otalequivale Short
esignersofte
quivalentlenithanyrule
ipingsystem
owmultiplyoptogetthhereisadou
thod,addth
tfeetofpipicutmethodfnskiptheab
gth.Thisprovfthumb,ho
withanextre
thefrictionltotalpipingt.Thefrictio
equivalentleg.
rdetermininvemethoda
idesspeedan
ever,watch
menumbero
ssper100ofrictionloss.
inthewors
ngthofeach
gequivalentndsimplymu
dareasonab
utforoddba
ffittings,etc)
pipingfromSelectthewoloopisused
Ca
iteminthefl
length:ltiplytheactulyaccuratees
llsituations(t
.Insuchsitua
theASHRAErstloopbyin
asthefrictio
lculati
idspathtot
alpipinglengtimationfor"
heboilerroo
tions,thelon
hartstimestpection,ifphead.
gPump
heactuallen
thtimes1.5ttypical"hydr
mis2blocks
gmethodpro
heequivalenssible.Calcul
Head
thofpipingt
o1.75togetnicpipingsy
wayfromth
videsbetter
lengthinthateseveralbr
ogetthe
thetems.As
building,a
ccuracy.
"worst"anchesif
7/29/2019 Calculating Pump Head
8/9
f
t
c
i
S
igure3,Worotethatthe
romotherpahanthepress
ase"totalfric
nblack.
otes
1. Thosebalan
2. Ifthepress
drop
afetyfactorsoumaywish
Jobsitresult
Theimake
reco
wateralrea
pump
ressureDroomesystems
eadsthando
ww.vemcoin
tPressureDworstloopis
allelloops.Inuredropthro
tionlossloop
circuitswith
cingvalves(n
earediffere
redrop/foot
er100.Itsi
toaddasafe
econditions
inaddedfric
teriorpipew
upbringsina
mendtotals
,
which
resultyhaveasafimpellerstha
Correctionsutilizeeither
eswater.For
c.com
opCircuitsimplythatth
thedrawing
ughCoils1a
isshowninli
lesspressure
otshownabo
tpipesizeso
mayvary
by
plifiestheca
yfactortoth
aynotallow
ion.
allsbecomer
steadysuppl
afetyallowan
s
in
more
frictymarginoftcausewast
orGlycol.ethyleneorp
discussionso
eloopthatr
above,assum
d2.Assumin
ghtblue.Itw
dropthanth
e).
nthecircuit,
ection.This
i
lculationsco
ecalculatedh
directroutin
ughovertim
ofcorrosion
cesof1525%
ion
than
hot
around12%.denergy!
ropyleneglyc
theeffectso
Ca
sultsinthela
ethatthepr
gthatthebra
ouldbeerron
"worst"circ
hecircuitma
sone
good
re
siderably.
eadfortwor
ofpipingas
eduetocorr
causingoxyg
forfrictionc
water.
ThereBecarefulof
olmixturesin
fglycol,cont
lculati
rgesttotalpr
ssuredropt
nchpipingfo
eoustoaddt
itwillbebal
yhavetobe
asonfor
sele
easons:
shownonth
osion,especi
en.Thisincre
alculations.N
ore,if
you
arexcessivesaf
lieuofwater
ctyourlocal
gPump
essuredrop.roughCoil3
rallthreecirc
hepressured
ncedinthefi
nalyzedinse
tingall
pipin
plan.Extral
llyinopensy
asesfriction.
otethatthef
edesigning
aetyfactors.T
.Thesefluids
Vemco,Inc.o
Head
onotaddprnditsvalvea
uitsissimilar
ropsofthepi
eldbypartial
ctions,becau
at
the
same
ngthandext
stems,where
arioussourc
rictiontables
hotwater
syeyresultino
resultinhigh
ffice
essuredropsrehigher
,the"worst
pingshown
lyclosing
sethe
pressure
raelbows
freshwater
es
assumecold
stem,you
versized
erpump
7/29/2019 Calculating Pump Head
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Calculati gPumpHead