HEATING SYSTEMS

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HEATING SYSTEMS
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Questions

• Why do we need heating systems?
• What was the first heating system?
• Which types of energy do you need to operate
  todays heating systems?

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How is the human body like a heating system?

• Purpose of a heating system
• Comparison of components in a radiant heat system
  vs. the human body
• Seasonal heat flow associated with your house and
  your body
• Purpose of insulation

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Desert Cottontailhow does the rabbit shed excess
thermal energy?
Ears serve as heat radiators (see blood vessels)
Fur keeps the rabbit warm at night
http//k43.pbase.com/o6/50/493350/1/81965672.V6e9S
MLr.DesertCottontail7907web.jpg
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Function of a heating system

• 1. Burn a fuel
• 2. Heat a fluid (air or water)
• 3. Circulate a heated fluid
• 4. Transfer thermal energy into a space
• By convection, conduction and radiation

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Heating System

• Any device or process that transfers energy to a
  substance to raise the temperature of the
  substance.

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The problem HEAT FLOW FROM HOUSE
During cold days
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Three thermal energy transfer methods in action.
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Different types of heating systems

• Radiant heating system
• Forced-air heating system
• Wood stove
• Fireplace
• Heat Pump
• Circulation of geothermal fluids

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Radiant Heat System
Where does the thermal energy go?
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Forced-air Heating System
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Solar Heating System
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Wood Stoves
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Geothermal Heating Systems
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Do you see where thermal energy is added to a
fluid and can you find the exhaust?
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• http//www.hometips.com/hyhw/comfort/38comf.html

http//www.woodfloorsonline.com/techtalk/woodwater
7.html
http//www.greenenergy.org.uk/sta/solarenergy/howw
ork.htm
http//www.totalcomfortnc.com/geo.htm
http//www.diydata.com/projects/centralheating/bal
ancing/balancing.htm
http//www.northridgevillehistoricalsociety.org/im
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http//www.igshpa.okstate.edu/geothermal/geotherma
l.htm
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Heating Systems

• 2nd law of thermodynamicsheat always flows from
  a hotter to a colder substance

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Explain why the heat flow for a home is different
in the winter vs. the summer.
Summer outdoor air temperature is greater than
indoor air temperature (flow is from outside
in) Winterindoor temperature is greater than
outdoor temperature (flow is from inside out)
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Commom Fuel Sources for Heating

• Wood
• Coal
• Oil
• Natural Gas (methane)

Methane CH4
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Mid-1700s to 1800s

• Fireplace with brick
• Franklin iron wood stove
• Fuel Source wood

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1885-1900

• Coal Boiler
• Natural convection (no electricity for pumps)
• Fuel Source coal

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1900-1930s

• Coal Boiler
• Circulated water or steam to radiators
• Fuel Source coal

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1930s -

• Radiant Heat and Forced Air Heating Systems
• Circulated heated water or steam to radiators
  and heated air through ducts to registers
• Fuel Source natural gas and oil

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1950s --

• Trend towards forced air heating systems to
  accommodate central air conditioning
• Fuel Source forced air heating(natural gas)
• Air conditioning (electricity from coal)

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Radiant Heating System
radiator
Radiant energy
Water-filled pipes
90 F
150 F
Heat a fluid
Circulate a heated fluid
Burn a fuel
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Forced-air Heating System (can be adapted to
central whole-house air conditioning)
convection
Circulate a heated fluid
Heat a fluid
Burn a fuel
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Convection, Conduction or Radiation?

• Stick in campfire
• Hot air balloon rising
• Hot concrete surface at pool
• Lizard sunning itself on a rock
• Pan of soup warming on the stove
• Foot on cold tile floor

• Conduction
• Convection
• Radiation
• Radiation
• Convection
• Conduction