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SolarDomesticHotWaterHeatingSystems
Design,Installation
and
Maintenance
Presentedby:
ChristopherA.Homola,PE
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A Brief History of Solar Water Heating
Solar water heating has been around for many years because it is theeasiest way to use the sun to save energy and money. One of the earliestdocumented cases of solar energy use involved pioneers moving westafter the Civil War. They would place a cooking pot filled with cold water inthe sun all day to have heated water in the evening.
The first solar water heater that resembles the concept still in use todaywas a metal tank that was painted black and placed on the roof where it
was tilted toward the sun. The concept worked, but it usually took all dayfor the water to heat, then, as soon as the sun went down, it cooled offquickly because the tank was not insulated.
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A Brief History of the American Solar Water Heating Industry
1890 to 1930's - the California Era
The first commercial solar water heater was introduced by Clarence Kemp in the1890's in California. For a $25 investment, people could save about $9 a year in coalcosts. It was a simple batch type solar water heater that combined storage and
collector in one box.
The first thermosyphon systems with the tank on the roof and the collector belowwere invented, patented, and marketed in California in the 1920's by William Bailey.One of the largest commercial systems in California was installed for a resort in
Death Valley.
Natural gas was discovered in Southern California and cheap natural gas,aggressively marketed by utility companies, ended the solar water heating market.Patents were sold to a Florida company, owned by HM Carruthers in 1923 and the
solar hot water industry began in the coastal cities of central Florida and southernFlorida.
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1930's to 1973 - the South Florida Era
Floridians purchased or shipped to the Caribbean more than 100,000thermosyphon water heaters between 1930 and 1954 when the industrycollapsed. During the second World War (1942 to 1945) copper wasreserved for the military and the solar industry was not able to make solar
collectors.
After the war, the Florida industry boomed again for about six years. Half ofMiami homes had solar water heaters with over 80% of new homes having
them installed. In the early 1950's electricity became cheap in Florida andutility companies gave away electric water heaters in an effort to eliminatethe solar water heating industry.
By 1973, there were only two full-time solar water heating companies left inthe United States both operating out of Miami, Florida.
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1973 to 1986 - Oil Embargo and Tax Credits
The oil embargo of 1973 resulted in a rise in fuel prices. A few companiesstarted experimenting with solar water heaters and designing systems but therewere really no national solar collector manufacturers with widespreaddistribution until the late seventies.
The federal government sponsored a few HUD Grants for domestic solar waterheaters in the period just before the start of the 40% Federal tax rebate in 1979.
The tax credit era, 1979 to 1986, started a nationwide boon in solar hot watersystems that resulted in hundreds of manufacturers and thousands ofcontractors and distributors starting new businesses.
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Equipment has improved since the 1980s. Improvements wereprecipitated by both certification design review and experiencedinstallers.
Today, more than 1.2 million buildings have solar water heatingsystems in the United States. Japan has nearly 1.5 million buildings
with solar water heating. In Israel, 30 percent of the buildings use solar-heated water. Greece and Australia are also leading users of solarenergy.
There is still a lot of room for expansion in the solar energy industry.There are no geographical constraints. For colder climates,manufacturers have designed systems that protect components fromfreezing conditions. Wherever the sun shines, solar water heatingsystems can work. The designs may be different from the early solarpioneers, but the concept is the same.
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Environmental
Benefits
Solarwaterheatersdonotpollute.
Solar
water
heaters
help
to
avoid
carbon
dioxide,
nitrogen
oxides,
sulfurdioxide,andtheotherairpollutionandwastescreatedwhen
thelocalutility
generatespowerorfuelisburnedtoheatdomesticwater.
Whenasolarwaterheaterreplacesanelectricwaterheater,theelectricity
displacedover
20
years
represents
more
than
50
tons
of
avoided
carbon
dioxideemissionsalone.
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LongTerm
Benefits
Solarwaterheatersofferlongtermbenefitsthatgobeyondsimple
economics.
Inadditiontohavingfreehotwaterafterthesystemhaspaidforitselfin
reducedutilitybills,ownerscouldbecushionedfromfuture
fuel
shortagesandpriceincreases.
Solarwaterheaterscanassistinreducingthiscountry'sdependenceon
foreignoil.
It is estimated that adding a solar water heater to an existing
home
raises
theresalevalueofthehomebytheentirecostofthesystem.
Homeownersmaybeabletorecouptheirentireinvestmenttheysell
theirhome.
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EconomicBenefits
Many home builders choose electric water heaters because they are easy to
install
and
relatively
inexpensive
to
purchase.
However,
research
shows
that
an
average household with an electric water heater spends about 25%
of its home
energycostsonheatingwater.
Itmakes
economic
sense
to
think
beyond
the
initial
purchase
price
and
consider
lifetimeenergycosts,orhowmuchyouwillspendonenergytousetheappliance
over its lifetime. The Florida Solar Energy Center
studied the potential savings to
Florida homeowners of common waterheating systems compared with electric
water
heaters.
It
found
that
solar
water
heaters
offered
the
largest
potential
savings,withsolarwaterheaterownerssavingasmuchas50%to85%annuallyon
theirutilitybillsoverthecostofelectricwaterheating.
http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/http://www.fsec.ucf.edu/8/13/2019 NOH SolarWtrHtg Pres
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EconomicBenefitsContinued
Asolarhotwaterheaterheatsthesameamountofwaterforafractionofthe
cost.
A
solar
hot
water
heating
systems
performance
is
dependent
on
the
intensityofthesuninitslocation.
Theinitialexpenseofinstallingasolarhot
water heater ($3500 to $5500) tends to be greater than installing an electric
($450
to$650)
or
gas
($750
to
$1000)
water
heater.
Thecostsvaryfromregiontoregion.Dependingonthepriceoffuelsources,the
solarwaterheatercanbemoreeconomicaloverthelifetimeofthesystemthan
heating
water
with
electricity,
fuel
oil,
propane,
or
even
natural
gas
because
thefuel(sunshine)isfree.
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EconomicBenefitsContinued
However,
at
the
current
low
prices
of
natural
gas,
solar
water
heaters
cannot
competewithnaturalgaswaterheatersinmostpartsofthecountryexcept
innewhomeconstruction.Althoughyouwillstillsaveenergycostswitha
solarwaterheaterbecauseyouwon'tbebuyingnaturalgas,itwon'tbe
economicalon
adollar
for
dollar
basis.
Paybacksvarywidely,butyoucanexpectasimplepaybackof4to8years
on
awell
designed
and
properly
installed
solar
water
heater.
You
can
expect
shorterpaybacksinareaswithhigherenergycosts.Afterthepayback
period, you accrue the savings over the life of the system, which ranges
from
15to40years,dependingonthesystemandhowwellitismaintained.
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EconomicBenefitsContinued
You
can
determine
the
simple
payback
of
a
solar
water
heater
by
firstdeterminingthenetcostofthesystem.Netcostsincludethetotalinstalled
costlessanytaxincentivesorutilityrebates. Afteryoucalculatethenet
costofthesystem,calculatetheannualfuelsavingsanddividethenet
investmentbythisnumbertodeterminethesimplepayback.
Anexample:Yourtotalutilitybillaverages$160permonthandyourwater
heatingcostsareaverage(25%ofyourtotalutilitycosts)at$40permonth.
Ifyoupurchaseasolarwaterheaterfor$2,000thatprovidesanaverageof
60%of
your
hot
water
each
year,
that
system
will
save
you
$24
per
month
($40x0.60=$24)or$288peryear(12x$24=$288).Thissystemhasa
simplepaybackoflessthan7years($2,000
$288=6.9).
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For the remainder of the life of the solar water heater, 60% of the hot
water
will
be
free,
saving
$288
each
year.
You
will
need
to
account
for
someoperationandmaintenancecosts,whichareestimatedat$25
to$30
ayear.Thisisprimarilytohavethesystemcheckedevery3years.
Ifyou
are
building
anew
home
or
refinancing
your
present
home
to
do
amajor renovation, the economics are even more attractive. The cost of
including thepriceofasolarwater heater in anew 30year mortgage is
usually between $13 and $20 per month. The portion of the federal
income tax deduction for mortgage interest attributable to the solar
system reduces that amount by about $3 to $5 per month. If your fuelsavingsaremorethan$15permonth,the investment inthesolar
water
heaterisprofitableimmediately.
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Peak Power Benefit
A typical residential solar water heating system (SWHS) for a family offour delivers 4 kilowatts of electrical equivalent thermal power whenunder full sun and when the temperature of the water in the storagetank is about the same as the air temperature. Such a systemtypically has about 64 square feet of solar collector surface area andproduces approximately the same peak power as 400 square feet ofphotovoltaic panels.
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Production Capacity Benefit
Ratings of collectors and systems, along with other informationspecific to the local area, can be used to calculate the specificreduction in a utilitys peak demand. On average, for every solar
water heating system that is installed, 0.5 kilowatts of peakdemand is deferred from a utilitys load.
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Energy Production Benefit
Because peak performance occurs infrequently, a more realisticindication of solar thermal system performance is the rated dailyenergy output of the collectors or system.
Using this method, a typical solar water heating system contributes7 to 10 kilowatt-hours per day, depending on the solar resource andtype of collector.
Electric water heating for residential applications typically
consumes about 12 kilowatt-hours per day, depending on groundwater temperature.
Annual site-specific energy savings for domestic water heating
systems are available at www.solar-rating.org for all systemscertified by the Solar Rating and Certification Corporation (SRCC).
Using this data, a typical solar water heating system producesabout 3,400 kilowatt-hours per year, depending on local conditionsand type of collector.
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Atmosphere
AngleofIncidence
Geography
LatitudeandSeason
AirPollutionandNaturalHaze
What
Influences
the
Amount
of
Solar
Radiation?
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Atmosphere
The atmosphere absorbs certain wavelengths of light more than others. The exact spectraldistribution of light reaching the earth's surface depends on how much atmosphere the lightpasses through, as well as the humidity of the atmosphere. In the morning and evening, thesun is low in the sky and light waves pass through more atmosphere than at noon. Thewinter sunlight also passes through more atmosphere versus summer. In addition, differentlatitudes on the earth have different average thicknesses of atmosphere that sunlight must
penetrate. The figure below illustrates the atmospheric effects on solar energy reaching theearth. Clouds, smoke and dust reflect some solar insolation back up into the atmosphere,allowing less solar energy to fall on a terrestrial object. These conditions also diffuse orscatter the amount of solar energy that does pass through.
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Angle of Incidence
The suns electromagnetic energy travels in a straight line. The angle
at which these rays fall on an object is called the angle of incidence. Aflat surface receives more solar energy when the angle of incidence iscloser to zero (i.e. perpendicular) and therefore receives significantlyless in early morning and late evening. Because the angle of incidenceis so large in the morning and evening on earth, about six hours ofusable solar energy is available daily. This is called the solarwindow.
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Absorptance vs. Reflectance
Certain materials absorb more insolation than others. More absorptivematerials are generally dark with a matte finish, while more-reflectivematerials are generally lighter colored with a smooth or shiny finish.
The materials used to absorb the sun's energy are selected for theirability to absorb a high percentage of energy and to reflect a minimumamount of energy. The solar collector's absorber and absorber coatingefficiency are determined by the rate of absorption versus the rate of
reflectance. This in turn, affects the absorber and absorber coating'sability to retain heat and minimize emissivity and reradiation. Highabsorptivity and low reflectivity improves the potential for collectingsolar energy.
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Collecting and Converting Solar Energy
Solar collectors capture the suns electromagnetic energy andconvert it to heat energy. The efficiency of a solar collectordepends not only on its materials and design but also on its
size, orientation and tilt.
Available solar energy is at its maximum at noon, when the sunis at its highest point in its daily arc across the sky. The sun's
daily motion across the sky has an impact on any solarcollector's efficiency and performance in the following ways.
1.Since the angle of incidence of the solar energy measuredfrom the normal (right angle) surface of the receiving surface
changes throughout the day, solar power is lower at dawn anddusk. In reality, there are only about 6 hours of maximumenergy available daily.2.The total energy received by a fixed surface during a given
period depends on its orientation and tilt and varies with weatherconditions, time of day and season.
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Insolation
Insolation is the amount of the suns electromagnetic energy thatfalls on any given object.
Simply put, when we are talking about solar radiation, we arereferring to insolation.
In Florida (at about sea level), an object will receive a maximum ofaround 300 Btu/ft2hr (about 90 watts/ft2 or 950 watts/meter2) at highnoon on a horizontal surface under clear skies on June 21 (the dayof the summer equinox).
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PV Solar Radiation (Flat Plate, Facing South,Latitude Tilt)Static Maps
These maps provide monthly average daily totalsolar resource information on grid cells ofapproximately 40 km by 40 km in size. Theinsolation values represent the resource availableto a flat plate collector, such as a photovoltaicpanel, oriented due south at an angle from
horizontal to equal to the latitude of the collectorlocation.
Resource:
National Renewable Energy Laboratory
www.nrel.gov/gis/solar.html
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OptimumPerformanceConsiderations
OptimumTilt:
Tolatitude
for
greatest
performance
or
up
to
latitude
minus
5 degrees.
OptimumSummerLoad: Latitudeminus15degrees(e.g.solarairconditioning).
OptimumWinterLoad: Latitudeplus15degrees(e.g.solarspaceheating).
OptimumAzimuth:
Towardtheequator(e.g.Facingsouthinnorthernhemisphere).
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Figure 1. Sun Path Diagrams for 28 N. Latitude
Seasonal Variations
The dome of the sky and the suns path at various times ofthe year are shown in Figure 1.
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Figure 2a And 2b. Collected Energy Varies with Time of Year And Tilt
For many solar applications, we want maximum annual energy harvest. For others, maximum
winter energy (or summer energy) collection is important. To orient the flat-plate collectorproperly, the application must be considered, since different angles will be best for eachdifferent application.
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Actual Collector Orientation Possibilities
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Collector Orientation
Collectors work best when facing due south. If roof lines or other factors dictate
different orientations, a small penalty will be paid, as shown in Figure 3. As anexample: for an orientation 20 degrees east or west of due south, we must increasethe collector area to 1.06 times the size needed with due south orientation (dashedline on Figure 3) to achieve the same energy output. The orientation angle awayfrom due south is called the azimuth and, in the Northern Hemisphere, is plus if thecollector faces toward the east and minus if toward the west.
Figure 3. Glazed Collector Orientations
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Tilt Angle
The best tilt angle will vary not only with the collectorsgeographical location but also with seasonal function. Solarwater heating systems are designed to provide heat year-round.
In general:
A)Mounting at an angle equal to the latitude works best for year-round energy use.
B)Latitude minus 15 degrees mounting is best for summer energycollection.
C)Latitude plus 15 degrees mounting is best for winter energy
collection.
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Various Collector Tilt Angles
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Solarwaterheatingsystemsincludestoragetanksandsolar
collectors.
Therearetwotypesofsolarwaterheatingsystems:Active,which
havecirculating
pumps
and
controls,
and
Passive,
which
dont.
Mostsolarwaterheatersrequireawellinsulatedstoragetank.
Solarstorage
tanks
have
an
additional
outlet
and
inlet
connected
toandfromthesolarcollector.
Intwotanksystems,thesolarwaterheaterpreheatswater
beforeitenterstheconventionalwaterheater.
Inonetanksystems,thebackupheateriscombinedwiththe
solarstorageinonetank.
Solar Water Heating System Basics
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Electric Back-Up
Solar systems with single tanks are designed to encouragetemperature stratification so that when water is drawn for service, it is
supplied from the hottest stratum in the tank (i.e. top of tank).
While a solar system tank in the United States normally contains aheating element, the element is deliberately located in the upper third
of the tank.
The electric element functions as back-up when solar energy is notavailable or when hot water demand exceeds the solar-heated supply.
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Natural Gas Back-Up
Natural gas back-up systems may use passive (thermosyphon orintegral collector system) solar preheating plumbed in series forproper operation.
Or two separate tanks may be used for active solar systems withnatural gas back-up heating systems.
The solar storage tank is piped in series to the auxiliary tank sending
the hottest solar preheated water to the gas back-up tank.
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SolarCollectors
Fourtypesofsolarcollectorsareusedforresidential
applications:
Flatplatecollector
Integralcollectorstoragesystems
Batchsystem
Evacuatedtubesolarcollectors
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FlatPlateCollector
Flatplatecollectorsaredesignedtoheatwatertomedium
temperatures(approximately140degreesFahrenheit).
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Flat plate collectors typically include the following components:
1.Enclosure: A box or frame that holds all the components together.
2.Glazing: A transparent cover over the enclosure that allows the suns rays topass through to the absorber. Most glazing is glass but some designs use clear
plastic.
3.Glazing Frame: Attaches the glazing to the enclosure. Glazing gaskets preventleakage around the glazing frame and allow for contraction and expansion.
4.Insulation: Material between the absorber and the surfaces it touches that
blocks heat loss by conduction thereby reducing the heat loss from the collectorenclosure.
5.Absorber: A flat, usually metal surface inside the enclosure that, because of itsphysical properties, can absorb and transfer high levels of solar energy.
6.Flow Tubes: Highly conductive metal tubes across the absorber through whichfluid flows, transferring heat from the absorber to the fluid.
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IntegralCollectorStorage(ICS)Systems
In other solar water heating systems the collector and storagetank are separate components. In an integral collector storage(ICS) system, both collection and solar storage are combined
within a single unit. Most ICS systems store potable waterinside several tanks within the collector unit. The entire unit isexposed to solar energy throughout the day. The resultingwater is drawn off either directly to the service location or as
replacement hot water to an auxiliary storage tank as water isdrawn for use.
Cutaway of an ICS system
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Batch solar water heater
Batch System
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The simplest of all solar water heating systems is a
batch system.
It is simply one or several storage tanks coated withblack, solar-absorbing material in an enclosure withglazing across the top and insulation around the other
sides.
It is the simplest solar system to make. When exposedto sun during the day, the tank transfers the heat it
absorbs to the water it holds.
The heated water can be drawn directly from the tankor it can replace hot water that is drawn from an interiortank inside the building.
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EvacuatedTubeSolarCollectors
Thistypeofsystemfeaturesparallelrowsoftransparentglasstubes.
Eachtubecontainsaglassoutertubeandmetalabsorbertubeattached
toafin. Thefinscoatingabsorbssolarenergybutinhibitsradiativeheat
loss.
Thesecollectors
are
used
more
frequently
for
commercial
applications.
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Evacuated-tube collectors generally have a smaller solar collecting surfacebecause this surface must be encased by an evacuated glass tube. They
are designed to deliver higher temperatures (approximately 300 degreesFahrenheit). The tubes themselves comprise the following elements:
1.Highly tempered glass vacuum tubes, which function as both glazing and
insulation.
2.An absorber surface inside the vacuum tube. The absorber is surroundedby a vacuum that greatly reduces the heat loss.
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ActiveSolarWaterHeatingSystems
TherearetwoSolarWaterHeatingSystemtypes:ActiveandPassiveTherearetwotypesofActiveSolarWaterHeatingSystems:
DirectCirculationSystems
IndirectCirculationSystems
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DirectCirculationSystems
Pump circulates domestic water through the collector(s) and into
the
building. This type of system works well in climates where it rarely
freezes.
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DirectPumpedSystem
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DirectSystemwithPhotovoltaicPoweredPump
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Direct System with Automatic Drain-down system configuration
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Thedirectpumpedsystemhasoneormoresolarenergycollectors
installedontheroofanda
storage tank located somewhere within the building. A pump circulates the water from the
tank
up
to
the
collector
and
back
again.
This
is
called
a
direct
(or
open
loop)
system
because
thesunsheatistransferreddirectlytothepotablewatercirculatingthroughthecollectorand
storagetank. Neitheranantifreezenorheatexchangerisinvolved.
This system has a differential controller that senses temperature differences between water
leavingthe
solar
collector
and
the
coldest
water
in
the
storage
tank.
When
the
water
in
the
collectorisabout1520Fwarmerthanthewaterinthestoragetank,thepumpisturnedonby
thecontroller. Whenthetemperaturedifferencedropstoabout35F,thepumpisturnedoff.
Inthisway,thewateralwaysgainsheatfromthecollectorwhen
thepumpoperates.
A flushtype freeze protection valve installed near the collector provides freeze protection.
Whenever temperatures approach freezing, thevalveopens to letwarmwater flow through
thecollector.
Thecollector
should
always
allow
for
manual
draining
by
closing
the
isolation
valves
(located
abovethestoragetank)andopeningthedrainvalves.
Automaticrecirculationisanothermeansoffreezeprotection. Whenthewaterinthecollector
reachesatemperaturenear freezing, thecontroller turns thepumpon fora fewminutes to
warmthe
collector
with
water
from
the
storage
tank.
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DirectSystem
Advantages
Servicewateruseddirectlyfromcollectorloop.
Noheatexchanger moreefficientheattransfertostorage.
Circulationpump(ifneeded)needsonlytoovercomefriction
losses system
pressurized.
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DirectSystem
Disadvantages
Qualityofservicewatermustbegoodtopreventcorrosion,scaleordepositsincomponents.
Freezeprotectiondependsonmechanicalvalves.
Recommendedin
climates
with
minimal/no
freeze
potential,
andgoodwaterquality.
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IndirectCirculationSystems
Pumpcirculatesanonfreezing,heattransferfluidthroughthecollector(s)
andaheatexchanger.
Thisheats
the
water
that
then
flows
into
the
home.
Thistypeofsystemworkswellinclimatespronetofreezingtemperatures.
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IndirectPumpedSystemUsingAntiFreezeSolution
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This system design is common in northern climates, where freezing weather
occursmorefrequently. Anantifreezesolutioncirculatesthroughthecollector,
and
a
heat
exchanger
transfers
the
heat
from
the
antifreeze
solution
to
the
storagetankwater. Whentoxicheatexchangerfluidsareused,adoublewalled
exchanger is required. Generally, if the heat exchanger is installed in the
storagetank,itshouldbelocatedinthelowerhalfofthetank.
Aheattransfersolution ispumpedthroughthecollector inaclosed loop. The
loopincludesthecollector,connectingpiping,thepump,anexpansiontankand
aheatexchanger. Aheatexchangercoil inthe lowerhalfof thestorage tank
transfersheatfromtheheattransfersolutiontothepotablewaterinthesolar
storagetank. Analternativeofthisdesignistowraptheheat
exchangeraround
thetank. Thiskeepsitfromcontactwiththepotablewater.
The differential controller, in conjunction with the collector and tank sensors,
determineswhen
the
pump
should
be
activated
to
direct
the
heat
transfer
fluid
throughthecollector. Thephotovoltaicpanel locatedontheroofsuppliesthe
powertooperatethecirculatingpump.
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IndirectPumpedSystemUsingAntiFreezeSolution
andWrapAroundHeatExchanger
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Afailsafemethodofensuringthatcollectorsandcollectorlooppipingneverfreeze
istoremoveallthewaterfromthecollectorsandpipingwhenthesystemisnot
collectingheat.
This
is
amajor
feature
of
the
drain
back
system.
Freeze
protection
isprovidedwhenthesystemisinthedrainmode. Waterinthe
collectorsand
exposedpipingdrainsintotheinsulateddrainbackreservoirtankeachtimethe
circulatingpumpshutsoff. Aslighttiltofthecollectorsisrequiredinordertoallow
completedrainage. Asightglassattachedtothedrainbackreservoirtankshows
whenthereservoirtankisfullandthecollectorhasbeendrained.
Inthisparticularsystem,distilledwaterisrecommendedtobeusedasthecollector
loopfluidtransfersolution. Usingdistilledwaterincreasestheheattransfer
characteristicsand
prevents
possible
mineral
buildup
of
the
transfer
solution.
Whenthesunshinesagain,thecirculatingpumpisactivatedbyadifferential
controller. Waterispumpedfromthereservoirtothecollectors,allowingheatto
becollected.
The
water
stored
in
the
reservoir
tank
circulates inaclosedloopthroughthecollectorsandaheatexchangeratthebottomofthe
storagetank.
Theheatexchangertransfersheatfromthecollectorloopfluidtothepotablewater
locatedinthestoragetank.
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IndirectSystem
Advantages
Freezeprotectionprovidedbyantifreezefluidordrainback.
Collector/pipingprotectedfromaggressivewater.
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IndirectSystem
Disadvantages
Mustaccountforreducedheattransferefficiencythroughheat
exchanger.
Addedmaterials=addedcost.
Ifnotusingwater,fluidsrequiremaintenance.
Mostdesignsrequireaddedpumpingcost.
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Passive Solar Water Heaters
Passive solar water heaters rely on gravity and the tendency for waterto naturally circulate as it is heated.
Passive solar water heater systems contain no electrical components,
are generally more reliable, easier to maintain, and possibly have alonger work life than active solar water heater systems.
The two most popular types of passive solar water heater systems
are: Integral-Collector Storage (ICS) andThermosyphon systems.
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IntegralCollectorStorageSystem
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Inanintegralcollectorstoragesystem,thehotwaterstoragesystemisthecollector.
Coldwaterflowsprogressivelythroughthecollectorwhereitis
heatedbythesun.
Hotwaterisdrawnfromthetop,whichisthehottest,andreplacementwaterflows
into the bottom. This system is simple because pumps and controllers are not
required.
On demand, cold water from the building flows into the collector
and hot water
fromthecollectorflowstoastandardhotwaterauxiliarytankwithinthebuilding.
Aflushtypefreezeprotectionvalveisinstalledinthetoppipingnear
thecollector.
As temperatures near freezing, this valve opens to allow relativelywarmwater to
flowthroughthecollecttopreventfreezing.
In
areas
of
the
country,
the
thermal
mass
of
the
large
water
volume
within
theintegralcollectorstoragecollectorprovidesameansoffreezeprotection.
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ThermosyphonSystem
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As thesun shineson the collector, the water inside the collector flow
tubes is heated. As it heats, this water expands slightly and becomeslighterthanthecoldwaterinthesolarstoragetankmountedabovethecollector. Gravitythenpullsheavier,coldwaterdownfromthe
tankand
intothecollectorinlet. Thecoldwaterpushestheheatedwaterthrough
thecollectoroutletandintothetopofthetank,thusheatingthewater
inthe
tank.
In a thermosiphon system there is no need for a circulating pump
and
controller. Potablewater flowsdirectly to the tankon the roof. Solar
heatedwater
flows
from
the
rooftop
tank
to
the
auxiliary
tank
installed
atgroundlevelwheneverwaterisusedwiththebuilding.
The thermosiphon system features a thermally operated valve that
protects the collector from freezing. It also includes isolation valves,whichallowthesolarsystemtobemanuallydrained incaseoffreezingconditions,ortobebypassedcompletely.
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Typical Components of a Direct Flat Plate Collector System
AIR VENT
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Allows air that has entered the system to escape, and in turn prevents air locks that wouldrestrict flow of the heat-transfer fluid. An air vent must be positioned vertically and is usually
installed at the uppermost part of the system. In active direct systems supplied by pressurizedwater, an air vent should be installed anywhere air could be trapped in pipes or collectors.Indirect systems that use glycol as the heat-transfer fluid use air vents to remove any dissolvedair left in the system after it has been pressurized or charged with the heat-transfer fluid. Oncethe air has been purged in these indirect systems, the air vent mechanism is manually closed.
TEMPERATURE-PRESSURE RELIEF VALVE
Protects system components from excessive pressures and temperatures. A pressure-temperature relief valve is always plumbed to the solar storage (as well as auxiliary) tank. Inthermosiphon and ICS systems, where the solar tanks are located on a roof, these tanks may
also be equipped with a temperature-pressure relief valve since they are in some jurisdictionsconsidered storage vessels. These valves are usually set by the manufacturer at 150 psi and210 F. Since temperature pressure relief valves open at temperatures below typical collectorloop operating conditions, they are not commonly installed in collector loops.
PRESSURE RELIEF VALVE
Protects components from excessive pressures that may build up in system plumbing. In anysystem where the collector loop can be isolated from the storage tank, a pressure relief valvemust be installed on the collector loop. The pressure rating of the valve (typically 125 psi) mustbe lower than the pressure rating of all other system components, which it is installed to protect.The pressure relief valve is usually installed at the collector.
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PRESSURE GAUGE
Is used in indirect systems to monitor pressure within the fluid loop. In both direct and
indirect systems, such gauges can readily indicate if a leak has occurred in the systemplumbing.
VACUUM BREAKER
Admits atmospheric pressure into system piping, which allows the system to drain. Thisvalve is usually located at the collector outlet plumbing but also may be installed anywhereon the collector return line. The vacuum breaker ensures proper drainage of the collectorloop plumbing when it is either manually or automatically drained. A valve that incorporatesboth air vent and vacuum breaker capabilities is also available.
ISOLATION VALVES
These valves are used to manually isolate various subsystems. Their primary use is toisolate the collectors or other components before servicing.
DRAIN VALVES
Used to drain the collector loop, the storage tank and, in some systems, the heat exchangeror drain-back reservoir. In indirect systems, they are also used as fill valves. The mostcommon drain valve is the standard boiler drain or hose bib.
CHECK VALVES
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CHECK VALVES
Allow fluid to flow in only one direction. In solar systems, these valves preventthermosiphoning action in the system plumbing. Without a check valve, water that cools in theelevated (roof-mounted) collector at night will fall by gravity to the storage tank, displacinglighter, warmer water out of the storage tank and up to the collector. Once begun, thisthermosiphoning action can continue all night, continuously cooling all the water in the tank. Inmany cases, it may lead to the activation of the back-up-heating element, thereby causing thesystem to lose even more energy.
FREEZE-PROTECTION VALVES
Are set to open at near freezing temperatures, and are installed on the collector return line ina location close to where the line penetrates the roof.
Warm water bleeds through the collector and out this valve to protect the collector and pipesfrom freezing. A spring-loaded thermostat or a bimetallic switch may control the valve.
TEMPERATURE GAUGES
Provide an indication of system fluid temperatures.
A temperature gauge at the top of the storage tank indicates the temperature of the hottestwater available for use.
Temperature wells installed at several points in the system will allow the use of a single
gauge in evaluating system operation.
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SelectingaSolarWaterHeatingSystem
Investigatelocalcodes,covenants,andregulations.
Considertheeconomicsofasolarwaterheatingsystem.
Evaluatethesitessolarresource.
Determinethecorrectsystemsize.
Estimateandcomparesystemcosts.
Building Codes, Covenants, and Regulations for
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Building Codes, Covenants, and Regulations for
Solar Water Heating Systems
Before installing a solar water heating system, you should investigate local building
codes, zoning ordinances, and subdivision covenants, as well as any special regulationspertaining to the site. A building permit will probably be required to install a solar energysystem onto an existing building.
Not every community or municipality initially welcomes renewable energy installations.
Although this is often due to ignorance or the comparative novelty of renewable energysystems, compliance with existing building and permit procedures to install a system isunavoidable.
The matter of building code and zoning compliance for a solar system installation is
typically a local issue. Even if a statewide building code is in effect, it's usually enforcedlocally by the city, county, or parish. Common problems owners have encountered withbuilding codes include the following:
Exceeding roof loadUnacceptable heat exchangersImproper wiringUnlawful tampering with potable water supplies.
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Potential zoning issues include the following:
Obstructing sideyardsErecting unlawful protrusions on roofsSiting the system too close to streets or lot boundaries.
Special area regulationssuch as local community, subdivision, or
homeowner's association covenantsalso demand compliance. Thesecovenants, historic district regulations, and flood-plain provisions caneasily be overlooked.
Building Codes, Covenants, and Regulations for
Solar Water Heating Systems Continued
Renewable Energy Funding Sources
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The Database of State Incentives for Renewables & Efficiency (DSIRE) isa comprehensive source of information on state, local, utility, and federalincentives that promote renewable energy and energy efficiency. Thewebsite is http://www.dsireusa.org.
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Federal Level Funding
Federal Incentives for Renewable Energy
U.S. Department of Treasury - Renewable Energy Grants
Eligible Renewable Technologies:
Solar Water Heating, Solar Space Heating, & Photovoltaic Systems
Energy Efficient Mortgages
Federal Housing Authority (FHA) & Veterans Affairs (VA) programs
Eligible Renewable Technologies:
Solar Water Heating, Solar Space Heating, & Photovoltaic Systems
State Level Funding
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State of Ohio Incentives for Renewable Energy
Ohio Department of Development - Advanced Energy Program Grants- Multi-Family Residential Solar Thermal Incentive
Eligible Renewable Technologies:
Solar Water Heating & Solar Space Heating Systems
Applicable Sectors: Multi-Family Residential, Low-Income Residential
Ohio Department of Development - Advanced Energy Program Grants- Non-Residential Renewable Energy
Eligible Renewable Technologies:
Solar Water Heating, Wind, & Photovoltaic Systems
Applicable Sectors: Commercial, Industrial, Nonprofit, Schools, LocalGovernment, State Government, Agricultural, Institutional
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SiteAssessment
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SolarPathFinder
http://www.solarpathfinder.com
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Collector PositioningFlat-plate collectors for solar water heating are generally mounted on a building or the ground in a fixedposition at prescribed angles. The angle will vary according to geographic location, collector type and use ofthe absorbed heat.Since residential hot water demand is generally greater in the winter than in the summer, the collectorideally should be positioned to maximize wintertime energy collection, receiving sunshine during the middlesix to eight daylight hours of each day. Minimize shading from other buildings, trees or other collectors. Planfor lengthening winter shadows, as the sun's path changes significantly with the seasons.
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Ideally, the collector should face directly south in the northernhemisphere and directly north in the southern hemisphere.
However, facing the collector within 30 to 45 either east or west of duesouth or north reduces performance by only about 10 percent.
A compass may be used to determine true south or north.
The closer to the equator, the less the need to maintain the orientationand direction of the collector, but be aware of the seasonal position ofthe sun in the sky and how it may affect the seasonal performance ofthe system.
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The optimum tilt angle for the collector is about the same as the site'slatitude plus or minus 15. An inexpensive inclinometer will aid indetermining tilt angles. If collectors will be mounted on a sloped roof,check the roof's inclination to determine whether the collectors should bemounted parallel to the roof or at a different tilt. In general, collectorsshould be mounted parallel to the plane of a sloped roof unless the
performance penalty is more than 30 percent. The mounted collectorshould not detract from the appearance of the roof.
Total length of piping from collector to storage should not exceed 100
feet. The longer the pipe run, the greater the heat loss. If a greater lengthis necessary, an increase in piping diameter or pump size may berequired.
If the collectors will be roof-mounted, they should not block drainage or
keep the roof surface from properly shedding rain. Water should notgather or pool around roof penetrations. Roof curbs may be require.
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To Estimate Shading of a Rooftop/Pole Mount on the Future Site
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To Estimate Needed Pole Height to Avoid Shading
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To Estimate How Much to Crop Tree to Avoid Shading
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SiteAssessmentBenefits
Arenewableenergysiteassessmentconductedbyacertified
assessorprovidesanopportunitytodiscusswithanexperienced,
objectivethirdpartyaboutthecharacteristicsofthepropertyandlearn
about
avariety
of
equipment
and
options.
Asiteassessmentisessentialwhenconsideringasolarproject.
The
site
assessors
report
can
be
used
to
present
a
summary
of
informationandoptionstodecisionmakersfortheirapproval.
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Costof
aRenewable
Energy
Site
Assessment
Certifiedassessorsestablishtheirownfeesfortheirservices.
On average, the full cost of an assessment is between $300 and
$500. Thecostvariesdependingon thenumberof technologies
being assessed and the complexity of the system, as well as the
assessorstravelcosts.
When arranging for a site assessment, discuss with the assessor
your expectations so that you can receive an accurate cost
estimate.
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SizingtheSolarHotWaterHeatingSystem
Justas
you
have
to
choose
a30
,40
,or
50
gallon
conventional
water
heater,
you
need to determine the rightsizesolar waterheater to install. Sizingasolar water
heater involves determining the total collector area and the storage volume
requiredtoprovide100%ofyourhousehold'shotwaterduringthesummer.Solar
equipment experts use worksheets or special computer programs to assist
you
in
determininghowlargeasystemyouneed.
Solarstoragetanksareusually50,60,80,or120galloncapacity.Asmall(50to60
gallon) system is sufficient for 1 to 3 people, a medium (80gallon) system is
adequate
for
a
3
or
4person
household,
and
a
large
(120gallon)
system
is
appropriatefor4to6people.
Aruleofthumbforsizingcollectors:allowabout20squarefeetofcollectorareafor
eachof
the
first
two
family
members
and
8square
feet
for
each
additional
family
memberifyouliveintheSunBelt.Allow12to14additionalsquarefeetperperson
ifyouliveinthenorthernUnitedStates.
i i h l i i d
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SizingtheSolarHotWaterHeatingSystem
Continued
Aratio
of
at
least
1.5
gallons
of
storage
capacity
to
1square
foot
of
collector
area
preventsthesystemfromoverheatingwhenthedemandforhotwaterislow.
In very warm, sunny climates, experts suggest that the ratio should be at least 2
gallons
of
storage
to
1
square
foot
of
collector
area.
Forexample,afamilyoffourinanorthernclimatewouldneedbetween64and68
squarefeetofcollectorareaanda96
to102gallonstoragetank.
(Thisassumes
20
square
feet
of
collector
area
for
the
first
person,
20
for
the
second
person,12to14forthethirdperson,and12to14forthefourthperson.
Thisequals64to68squarefeet,multipliedby1.5gallonsofstoragecapacity,which
equals96
to
102
gallons
of
storage.)
Becauseyoumightnotbeabletofinda96gallontank,youmaywanttogeta120
gallontanktobesuretomeetyourhotwaterneeds.
Resources
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AnalysisTools
Preliminary Screening:
To determine if a project is a possible
candidateforsolarhotwaterheating,tryusingtheFederalRenewable
EnergyScreeningAssistant(FRESA)software. Thisisawindowsbased
softwaretool
which
screens
projects
for
economic
feasibility.
It
is
able
to evaluate many renewable technologies including solar hot water,
photovoltaics,andwind.
Another
and
somewhat
more
detailed
screening
tool,
Retscreen,
is provided by Natural Resources Canada. Go tohttp://www.retscreen.net/
todownloadthesimulationsoftware.
http://www.retscreen.net/http://www.retscreen.net/http://www.retscreen.net/http://www.retscreen.net/http://www.retscreen.net/http://www.retscreen.net/8/13/2019 NOH SolarWtrHtg Pres
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ResourcesContinued
AnalysisTools
Detailed Performance:
Once preliminary viability has been established, it will
eventually be necessary to evaluate system performance to generate more precise
engineeringdataandeconomicanalysis. Thiscanbeaccomplishedbaseduponhourlysimulation software or by hand correlation methods based on the results of hourly
simulations. Twosoftwareprogramswhichareavailableinclude:
FCHART,
acorrelation
method
available
from
the
University
of
Wisconsin.
Go
to
http://www.fchart.com/
todownloadthesimulationsoftware.
TRNSYS,
softwareavailablefromtheUniversityofWisconsin. Goto
http://sel.me.wisc.edu/trnsys/ to
download
the
simulation
software.
FCHART can be used with the following:
http://www.fchart.com/http://www.fchart.com/http://www.fchart.com/http://www.fchart.com/http://www.fchart.com/http://www.fchart.com/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://sel.me.wisc.edu/trnsys/http://www.fchart.com/8/13/2019 NOH SolarWtrHtg Pres
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Collector Types
Flat-Plates
Evacuated TypesIntegral Collectors
System Types
Water Storage Heating
Building Storage HeatingDomestic Water HeatingIntegral Collector-Storage DHWIndoor and Outdoor Pool Heating
Features
Life-cycle economics with cash flowWeather data for over 300 locationsWeather data can be addedMonthly parameter variation2-D incidence angle modifiers
English and SI unitsApproved for use in CaliforniaVersions for Mac, DOS, and Windows
F-Chart
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Example Input
Parameter Input Screen for Flat-Plate Collector
F-ChartExample Input
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Example InputParameter Input Screen for General Solar Heating System
F Chart
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F-ChartExample Output
F-Chart
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F ChartExample Output
Graphical Output Screen showing Solar vs. Month
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Installation
ll i f h l
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InstallationoftheSolarHotWaterSystem
Theproper
installation
of
solar
water
heating
systems
depends
on
many
factors.
Thesefactorsincludesolarresource,climate,localbuildingcoderequirements,
andsafety
issues.
Wind Loading
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A mounted collector is exposed not only to sunlight and the rigors of ultraviolet lightbut also to wind forces. For example, in parts of the world that are vulnerable tohurricanes or extreme wind storms, the collector and its mounting structure need tobe able to withstand intermittent wind loads up to 146 miles per hour. Thiscorresponds to a pressure of about 75 pounds per square foot. Winds, and thermalcontraction and expansion may cause improperly installed bolts and roof seals toloosen over time. As always, follow local code requirements for wind loading.
Roof Mounting Considerations
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Example of a Collector mounted down from
roof ridge to reduce wind loading and heat losses
Do not mount collectors near the ridge of a roof or other places where the wind
load may be unusually high. The figure below shows a desirable location for aroof-mounted collector. Mounting collectors parallel to the roof plane helpsreduce wind loads and heat loss.
Ground Mounting
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In an alternative to roof mounting, the collector for a solar water
heating system may be mounted at ground level. The lower edge ofthe collector should be at least one foot above the ground so it willnot be obstructed by vegetation or soaked by standing water.
Roof Mounted Collectors
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Example of a Rack-mounted collector
There are four ways to mount flat-plate collectors on roofs:
1. Rack Mounting. This method is used on homes with flat roofs. Collectors aremounted at the prescribed angle on a structural frame. The structural connectionbetween the collector and frame and between the frame and building, or site mustbe adequate to resist maximum potential wind loads.
2. Standoff Mounting. Standoffs separate the collector from the finished roofsurface; they allow air and rainwater to pass under the collector and minimize
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Example of a Standoff-mounted collector
surface; they allow air and rainwater to pass under the collector and minimizeproblems of mildew and water retention. Standoffs must have adequate
structural properties. They are sometimes used to support collectors at slopesthat differ from that of the roof angle. This is the most common mountingmethod used.
3. Direct Mounting. Collectors can be mounted directly on the roofsurface Generally they are placed on a waterproof membrane covering
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Example of a Direct- or flush-mounted collector
surface. Generally, they are placed on a waterproof membrane coveringthe roof sheathing. Then the finished roof surface, the collector's structural
attachments, and waterproof flashing are built up around the collector. Aweatherproof seal must be maintained between the collector and the roofto avoid leaks, mildew and rotting.
4. Integral Mounting. Integral mounting places the collector within the roofconstruction itself. The collector is attached to and supported by the structural
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Example of an Integral-mounted collector
construction itself. The collector is attached to and supported by the structuralframing members. The top of the collector serves as the finished roof surface.
Weather tightness is crucial in avoiding water damage and mildew. Only collectorsdesigned by the manufacturer to be integrated into the roof should be installed as thewater/moisture barrier of buildings. The roofing materials and solar collectors expandand contract at different rates and have the potential for leaks. A well sealed flashingmaterial allows the expansion and contraction of the materials to maintain a water
seal.
Roof Work Considerations
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Roof Work Considerations
The most demanding aspects of installing roof-mounted collectors arethe actual mounting and roof penetrations. Standards and codes aresometimes ambiguous about what can and cannot be done to a roof.
Always follow accepted roofing practices, be familiar with local building
codes, and communicate with the local building inspector. These areprime roof work considerations:
1. Perform the installation in a safe manner.
2. Take precautions to avoid (or minimize) damage to the roof area.3. Position collectors for the maximum performance compatible withacceptable mounting practices.
4. Seal and flash pipe and sensor penetrations in accordance with goodroofing practices. Use permanent sealants such as silicone, urethane orbutyl rubber.
5. Locate collectors so they are accessible for needed maintenance.
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Maintenance
M i
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Maintenance
Regular maintenance on simple systems can be as infrequent as every 35years,preferablybyaqualifiedcontractorwithexperienceandknowledgeof
solarhotwaterheatingsystems. Systemswithelectricalcomponentsusually
requireareplacementpartortwoafter10years.
Corrosion and Scaling in Solar Water Heating Systems
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CorrosionandScalinginSolarWaterHeatingSystems
Thetwo
major
factors
affecting
the
performance
of
properly
sited
and
installed
solar
waterheatingsystemsincludescalingandcorrosion.
Corrosion
Most
welldesigned
solar
systems
experience
minimal
corrosion.
When
they
do,
it
is
usually galvanic corrosion, an electrolytic process caused by two dissimilar metalscomingintocontactwitheachother.Onemetalhasastrongerpositiveelectricalcharge
andpullselectronsfromtheother,causingoneofthemetalsto
corrode.
The
heattransfer
fluid
in
some
solar
energy
systems
sometimes
provides
the
bridge
overwhichthisexchangeofelectronsoccurs.
Oxygen entering into an open loop solar system will cause rust in any iron or steel
component.
Such
systems
should
have
copper,
bronze,
brass,
stainless
steel,
plastic,
rubbercomponentsintheplumbingloop,andplasticorglasslinedstoragetanks.
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Scaling
Domesticwater
that
is
high
in
mineral
content
("hard
water")
may
cause
the
buildup
or
scaling of mineral (calcium) deposits in solar heating systems. Scale buildup reduces
systemperformanceinanumberofways.Ifthesystemusesdomesticwaterastheheat
transferfluid,scalingcanoccurinthecollector,distribution
piping,andheatexchanger.
Insystems
that
use
other
types
of
heat
transfer
fluids
(such
as
glycol),
scaling
can
occur
onthesurfaceoftheheatexchangerthattransfersheatfromthesolarcollectortothe
domesticwater.Scalingmayalsocausevalveandpumpfailuresonthedomesticwater
loop.
Scaling can be avoided by using a water softener(s) or by circulating a mild acidic
solution(suchasvinegar)throughthecollectorordomesticwaterloopevery35years,
orasnecessarydependingonwaterconditions.
There maybe theneed to carefullyclean heat exchanger surfaces
with mediumgrain
sandpaper. A "wraparound" external heat exchanger is an alternative to a heat
exchangerlocatedinsideastoragetank.
PeriodicInspectionList
Thefollowingaresomesuggestedinspectionsofsolarsystemcomponents.
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Collectorshading
Visuallycheckforshadingofthecollectorsduringtheday(midmorning,noon,
and midafternoon) on an annual basis. Shading can greatly affect the
performance of solar collectors. Vegetation growth over time or new
construction on the building or adjacent property may produce shading that
wasn'tthere
when
the
collector(s)
were
installed.
Collectorsoiling
Dusty or soiled collectors will perform poorly. Periodic cleaning may be
necessaryin
dry,
dusty
climates.
Collectorglazingandseals
Look for cracks in the collector glazing, and check to see if seals are in good
condition.
Plastic
glazing,
if
excessively
yellowed,
may
need
to be
replaced.
Pipingandwiringconnections
Lookforfluidleaksatpipeconnections.Allwiringconnections
shouldbetight.
Pipingand
wiring
insulation
Lookfordamageordegradationofinsulationcoveringpipesandwiring.
Roofpenetrations
Flashingandsealantaroundroofpenetrationsshouldbe ingoodcondition.
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g p g
Supportstructures
Checkallnutsandboltsattachingthecollectorstoanysupport
structuresfor
tightness.
Pressure
relief
valve
(on
liquid
solar
heating
collectors)Makesurethevalveisnotstuckopenorclosed.
Pumps
Verifythatdistributionpump(s)areoperating.Checktoseeiftheycomeon
whenthe
sun
is
shining
on
the
collectors
after
mid
morning.
If
the
pump
is
notoperating,theneitherthecontrollerorpumphasmalfunctioned.
Heattransferfluids
Antifreeze
solutions
in
solar
heating
collectors
need
to
be
replacedperiodically. If water with a high mineral content (i.e., hard water) is
circulated in the collectors, mineral buildup in the piping may need to be
removed by adding a descaling or mild acidic solution to the water every
fewyears.
Storagesystems
Checkstoragetanks,etc.,forcracks,leaks,rust,orothersignsofcorrosion.
Manufacturers
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ACRSolar
International
Corporation
http://www.solarroofs.com
FAFCO,Inc.
http://www.fafco.com
VeluxAmerica
http://www.veluxusa.com
Heliodyne,Inc.
http://www.heliodyne.com
SiliconSolarInc.
http://sunmaxxsolar.com
Solarhart
http://www.solarhart.com
SunEarth,Inc.
http://www.sunearthinc.com
Solene,LLC
http://www.soleneusa.com
ThermoTechnologies
http://www.thermomax.com
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TradeAssociations
AmericanSolarEnergySociety(ASES)
http://www.ases.org
FloridaSolarEnergyCenter(FSEC) http://www.fsec.ucf.edu
SolarEnergyIndustriesAssociation(SEIA)
http://www.seia.org
SolarRating&CertificationCorporation(SRCC)http://www.solarrating.org
About the American Solar Energy Society
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About the American Solar Energy Society
Established in 1954, the American Solar Energy Society (ASES)is the nonprofit organization dedicated to increasing the use ofsolar energy, energy efficiency, and other sustainabletechnologies in the United States
Ab t th Fl id S l E C t
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About the Florida Solar Energy Center
The Florida Solar Energy Center (FSEC) was created by the FloridaLegislature in 1975 to serve as the states energy research institute.The main responsibilities of the center are to conduct research, testand certify solar systems and develop education programs.
About the Solar Energy Industries Association
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About the Solar Energy Industries Association
Founded in 1974, the Solar Energy Industries Association (SEIA) isthe leading national trade association for the solar energy industry.The mission of the Solar Energy Industries Association is to expandmarkets, strengthen research and development, remove market
barriers and improve education and outreach for solar energyprofessionals.
Ab t th S l R ti d C tifi ti C ti
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About the Solar Rating and Certification Corporation
In 1980 the Solar Rating and Certification Corporation(SRCC) was incorporated as a non-profit organizationwhose primary purpose is the development andimplementation of certification programs and national ratingstandards for solar energy equipment.
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The End