Comfort-Aire HWW120 - Manual (Page 11)

10
Heat Controller, Inc. WATER-TO-WATER (HWW) SERIES Installation & Operation
Ground-Water Heat Pump Applications
Typical open loop piping is shown in Figure 3 [See Page 11].
Shut off valves should be included in case of servicing. Boiler
drains or other valves should be ‘tee’d’ into the line to allow acid
flushing of just the heat exchanger. Pressure temperature plugs
should be used so that flow and temperature can be measured.
Piping materials should be limited to PVC SCH80 or copper.
Due to the pressure and temperature extremes, PVC SCH40
is not recommended. Water quantity should be plentiful and of
good quality. Consult Table 1 for water quality guidelines.
The unit can be ordered with either a copper or cupro-nickel
water heat exchanger. Copper is recommended for closed
loop systems and open loop ground water systems that are
not high in mineral content or corrosiveness. In conditions an-
ticipating heavy scale formation or in brackish water, a cupro-
nickel heat exchanger is recommended.
In ground water situations where scaling could be heavy or
where biological growth such as iron bacteria will be present,
a closed loop system is recommended. It is recommended to
install an intermediate heat exchanger to isolate an open loop
from the heat pump loop on open well systems. Heat exchang-
ers may over time lose heat exchange capabilities due to a
build up of mineral deposits inside. These can be cleaned only
by a qualified service mechanic as acid and special pumping
equipment are required.
Table 1: Water Quality Standards
WaterÊQuality
Parameter
HX
Material
Closed
Recirculating
OpenÊLoopÊandÊRecirculatingÊWell
ScalingÊPotentialÊ-ÊPrimaryÊMeasurement
pH/CalciumÊHardness
All
-
pHÊ<Ê7.5ÊandÊCaÊHardnessÊ<100ppm
Method
IndexÊLimitsÊforÊProbableÊScalingÊSituationsÊ-Ê (OperationÊoutsideÊtheseÊlimitsÊisÊnotÊrecommended)
Ryznar
All
- 6.0К-К7.5
StabilityÊIndex IfÊ>7.5ÊminimizeÊsteelÊpipeÊuse.
Langelier All
- -0.5ÊtoÊ+0.5
SaturationÊIndex
IfÊ<-0.5ÊminimizeÊsteelÊpipeÊuse.ÊBasedÊuponÊ150¡FÊ[66¡C]ÊHWGÊand
DirectÊwell,Ê85¡FÊ[29¡C]ÊIndirectÊWellÊHX
IronÊFouling
IronÊFe 2+ (Ferrous)
All
-
<0.2ÊppmÊ(Ferrous)
(BacterialÊIronÊpotential) IfÊFe 2+ Ê(ferrous)>0.2ÊppmÊwithÊpHÊ6К-К8,КO2<5ÊppmÊcheckÊforÊironÊbacteria
IronÊFouling All
- <0.5ÊppmÊofÊOxygen
AboveÊthisÊlevelÊdepositionÊwillÊoccur.
CorrosionÊPrevention
pH All
6К-К8.5 6К-К8.5
Monitor/treatÊas
needed
MinimizeÊsteelÊpipeÊbelowÊ7ÊandÊnoÊopenÊtanksÊwithÊpHÊ<8
HydrogenÊSulfideÊ(H 2 S) All
- <0.5Êppm
AtÊH
2
S>0.2Êppm,ÊavoidÊuseÊofÊcopperÊandÊcopperÊnickelÊpipingÊorÊHX's.
RottenÊeggÊsmellÊappearsÊatÊ0.5ÊppmÊlevel.
CopperÊalloyÊ(bronzeÊorÊbrass)ÊcastÊcomponentsÊareÊOKÊtoÊ<0.5Êppm.
AmmoniaÊionÊasÊhydroxide,Êchloride,Ê
nitrateÊandÊsulfateÊcompounds
All
- <0.5Êppm
Maximum
MaximumÊAllowableÊatÊmaximumÊwaterÊtemperature.
ChlorideÊLevels
50¡FÊ(10¡C) 75¡FÊ(24¡C) 100ϒF (38ϒC)
Copper - <20ppm NR NR
CuproNickel - <150Êppm NR NR
304ÊSS - <400Êppm <250Êppm <150 ppm
316ÊSS - <1000Êppm <550Êppm < 375 ppm
Titanium - >1000Êppm >550Êppm >375 ppm
ErosionÊandÊClogging
ParticulateÊSizeÊand
Erosion
All
<10ÊppmÊofÊparticles
andÊaÊmaximum
velocityÊofÊ6ÊfpsÊ[1.8Êm/s].
FilteredÊforÊmaximum
800ÊmicronÊ[800mm,
20Êmesh]Êsize.
<10ÊppmÊ(<1ÊppmÊ"sandfree"ÊforÊreinjection)ÊofÊparticlesandÊaÊmaximum
velocityÊofÊ6ÊfpsÊ[1.8Êm/s].ÊFilteredÊforÊmaximumÊ800ÊmicronÊ[800mm,
20Êmesh]Êsize.AnyÊparticulateÊthatÊisÊnotÊremovedÊcanÊpotentially
clogÊcomponents.
Notes: Rev.: 01/21/09B
• NR - Application not recommended.
• "-" No design Maximum.
• Closed Recirculating system is identified by a closed pressurized piping system.
• Recirculating open wells should observe the open recirculating design considerations.
AboveÊtheÊgivenÊlimits,ÊscalingÊisÊlikelyÊtoÊoccur.ÊÊScalingÊindexesÊshouldÊbeÊcalculatedÊusingÊtheÊlimitsÊbelow
ScalingÊindexesÊshouldÊbeÊcalculatedÊatÊ150¡FÊ[66¡C]ÊforÊdirectÊuseÊandÊHWGÊapplications,ÊandÊatÊ90¡FÊ[32¡C]ÊforÊindirectÊHXÊuse.Ê
AÊmonitoringÊplanÊshouldÊbeÊimplemented.