Solar Space Heating in Western Washington

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Solar Space Heating in Western Washington

• Jack Hardy
• Solar Design and Construction
• www.sdc-homes.com
• jack_at_sdc-homes.com
• 360-319-6273

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Its possible to resist an invasion of an army,
but not an idea whose time has come.Victor
Hugo
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Has the time come for solar energy?

• 1973
• Arab Oil Embargo
• U.S. gas rose from 39 to 55 cents per gallon
• Stock Exchange lost 97 billion in 6 weeks

• Today
• Fuel costs increasing
• Peak oil approaching

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Topics

• Passive Solar Space Heating
• Active Solar Space Heating
• Economics of Solar Space Heating

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The Greenhouse Effect
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Passive Solar Heating

• The simplest and most economical approach
• No fans, pumps, or active circulation of heat

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Passive Solar Heatingdirect gain
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Passive Solar Heating

• Lets design a passive solar home (shall we?)
• Eight steps

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Passive Solar Heating1) Select a building site
with a mostly unobstructed southern exposure
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Passive Solar Heating2) Place a large percentage
of the windows on the south side of the house to
maximize heat gain
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Passive Solar Heating3) Use tight construction
and good insulation to reduce heat loss
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Passive Solar Heating4) Place thermal mass
within the house to store heat
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Passive Solar Heating5) Design roof overhangs
plantings for winter sun and summer shade
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Passive Solar Heating6) Estimate glass to mass
ratio

• Assume a 2240 sq ft home, with 1700 sq ft of
  floor exposed to direct sun 400 sq ft of
  thermal mass wall
• Initially plan 7 of floor space as south windows
  157 sq ft
• Add an additional 1 sq ft of south glass for
  every
• 5.5 sq ft of sunlit floor mass 309 sq ft
• 40 sq ft of floor not in direct sun 14 sq ft
• 8.3 sq ft of thermal mass wall 48 sq ft
• Total south glass 528 sq ft or 23.6 of total
  floor space

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Passive Solar Heating 7) Model the Monthly Heat
Budget
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Passive Solar Heating8) Adjust design based on
modeling and construct home
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Solar Design Construction 2005-B
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Solar Design Construction 2005-B
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Passive Solar Heatingindirect gain
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Active Solar Heating

• Air or liquid collectors concentrate solar heat
  gain
• Heated air or liquid is circulated through pipes
  or ducts using pumps or fans
• Heat is transferred directly to interior space or
  to storage for later use
• Differential thermostats are used to control heat
  flow

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Active Solar Heatingair collectors - plates
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Active Solar Heatingair collectors - plates
Enermodel Engineering Panel
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Active Solar Heatingair collectors attic to
rock bed
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Active Solar Heatingair collectors sun space
to rock bed
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Active Solar Heatingair collectors to plenums
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Active Solar Heatingliquid collectors
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Active Solar Heatingliquid collectors
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Does it work?
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Does it work?
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Economics of Solar Heating
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Economics of Solar HeatingHow much does it cost?

• Added costs of construction
• Passive - glazing
• Active - collectors
• Thermal mass
• Extra insulation
• For example
• add about 5 per sq ft or 10 K for a 2000 sq ft
  home
• For a 300,000 home 3.3 percent

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Economics of Solar HeatingDoes it pay?

• Winter heating costs expected to soar up 50
  percent nationwide
• By H. Josef Hebert, Associated Press Writer   
  October 11, 2005
• WASHINGTON --Heating bills are headed through the
  roof, expected to average 50 percent higher this
  winter for homes that use natural gas. People in
  parts of the Midwest are likely to pay even more
  -- as much as 1,600 for the winter months if the
  weather is especially bad.

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Economics of Solar HeatingDoes it pay?

• Heating bills
• With good design, heating costs (gas) for a 2000
  sq ft home in western Washington can be reduced
  from 852 to 148 per year, an initial savings of
  704 per year
• Natural gas costs are predicted to increase about
  14 per year
• Over a 15 year period a solar home will save more
  than 35,000 in heating costs
• Incentives (for active systems)
• Federal Tax Credit 30 up to 2000 (years 2006
  2007)
• Mortgage advantages
• Energy efficient mortgages may receive up to 4
  additional borrowing limit and discounts on
  closing costs and fees
• Increased home value
• selling price of homes increases 20.73 for every
  1 decrease in annual fuel bills (The Appraisal
  Journal, Oct 1998)
• Using the above example, a solar home would have
  an added value of 14,593 compared to a
  traditional home

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Summary Solar Space Heating

• Western Washington is an ideal location
• Its time has come
• It is not complicated
• It will pay you
• It will reduce greenhouse gas emissions

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Solar Space Heating Information

• Jack Hardy
• Solar Design and Construction
• www.sdc-homes.com
• jack_at_sdc-homes.com
• 360-319-6273
• http//www.eere.energy.gov/solar/
• Chiras, D.D. 2002. The Solar House. 274 pp.
  Chelsea Green Publishing. White River Junction,
  Vermont 05001
• Kachadorian, J. 1997. The Passive Solar House.
  210 pp. Chelsea Green Publishing. White River
  Junction, Vermont 05001
• Watson, D. 1977. Designing and building a solar
  house. 282 pp. Garden Way Publishing,
  Charlotte, Vermont 05445
• Watson, D. and Labs, K. 1983. Climatic
  building design. 288 pp. McGraw Hill, New York.