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Solar
System Size
Sizing a Solar Water and Space System
When sizing a solar heating or cooling system the rule is to
size the total collector area and the
storage volume system to meet 90%–100% of household's energy
needs during the season with the lowest consume (the
summer in cold and temperate climates).
This means that the installed solar system capacity will provide
enough hot water (or other solar energy) during a significant
part of the year, though not during all of it. The installed
solar power will not be sufficient in the coldest (or hottest)
days, but is not practical to size a solar system to provide all
of a home's energetic requirements. The system would be too
large, too costly, and oversized for most of the seasons and
days. It’s preferable to have an auxiliary heating or cooling
system, to compensate the solar system insufficiencies during
worst weather-days.
Collectors Area for solar water heating systems
In the case of solar water heating systems, contractors follow
some rough guidelines:
- around 20 square feet (2 m2) of solar collector area for the
first and the second family members.
For additional family members contractors use to add:
- around 8 square feet (0.7 m2) in the sunny areas
- around 12–14 square feet (1.1 – 1.3m2) in northern areas.
Storage Volume of solar water heating systems
The storage tanks are commonly sized to around 1.5 gallons/5.6
liters of storage for each square foot (0,092 m2) of collector
area. In very warm and sunny climates the value are sometimes
increased to around 2 gallons/7.5 liters of storage for 1 square
foot.
For the simpler solar systems it’s
common to use a small tank of 50- to 60-gallon storage for
households with 1 to 2 people, a medium 80-gallon storage tank
for households of 3-4 people, and a larger one for larger
households.
Sizing a solar swimming pool heating system
The collectors area of the solar swimming pool system varies
according with the uses intended and the climate: see, for
details:
Solar swimming pools sizing
Sizing a solar space heating system
In the case of solar room heaters it’s common to use
around 12–14 square feet (1.1 – 1.3m2)
unglazed solar panels.
The values mentioned for solar water heating systems are
obviously also applicable for space heating systems using heated
water: radiators, radiant floor, etc. Other central systems of
space heating may demand higher collector areas. But all depends
on the system.
Sizing a solar electric system
The number of solar panels you need depends, first of all, on
how much power you need for your home – something you may see in
your electric utility bill (average monthly kilowatt-hours).
Climate is another factor in calculations: if you live in a
sunny place your needs will be lower…
The other factor is, obviously, the solar panel size and
performance, namely their wattage (something that varies a lot
and is closely connected with price...)
For a rough reference on how many panels you will need, take
into account a typical home in Denver, Colorado with a 600
kilowatt-hours monthly electric bill. According with
Vermont Department of Public Service,
that average home will need to use 19 panels of 120 peak watts,
to provide its electrical needs.
See also:
Basics of
solar systems
Domestic Solar Hot Water Systems
Solar Electricity: Photovoltaic PV Systems
Solar Space Heating basics
Solar Space Heating in
radiators, radiant floor and air forced systems
Solar Cooling
Types of solar water
heating systems
Solar Systems Orientation and
Location
Pros and Cons of Solar
Energy Panels
Costs and payback of
Solar Energy
Solar Panels Technology
Quotes and the
buying process
Market and Prices of Solar Hot
Water Systems
Market and Prices of Solar PV
Electricity
Manufacturers of Solar
Power Systems
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