Chapter 5 part 2

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Chapter 5 part 2
Heat Pumps Refrigerators Air Conditioners Ground
Source Geothermal Systems Efficiency of Heat
Pumps Energy Efficient Buildings Countering Sick
Building Syndrome
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Air Conditioner Layout
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Home Heat Pump
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Heat Pump Efficiency
Efficiency 100 Thigh/(Thigh-Tlow) Where
Thigh is the temperature of the high Temperature
reservior in degrees Kelvin Tlow is the
temperature of the low temperature Reservoir in
degrees Kelvin As the temperature difference
decreases, does A heat pump become more or less
efficient? Can a heat pump efficiency exceed
100?
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Coefficient of Performance
COP heat transferred/electricty used useful
work/energy input why does COP change with the
outdoor temperature?
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Seasonal Performance Factor
SPF total energy output/total energy used How
does SPF relate to the theoretical efficiency of
a heat pump?
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Relative Costs of Heating Methods
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Ground Source Geothermal Pump
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Tradeoffs of Ground Source
More efficient (why?) Less peak power use (peak
shaving) Why? BUT High initial cost for
boreholes or trenches More than conventional
heating/cooling Needs a superinsulated building
to be economical In NY winters
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Energy Efficient Office Building
A-Interior Windows Funnel Light B-Fluorescent Ligh
ts C-Task Lighting D-Occupancy Sensors Low E
Film Low Toxicity Materials Atrium More
Insulation
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Energy Efficient Office 2
1-Solar Panel 2-Hot Air Duct 3-Air
Filter 4-Heater 5-Air Supply Pump 6-Circulation
Duct 7-Outflow Duct 8-Exhaust Fan 9-Heat
Exchanger
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Energy Efficient Refrigerator(Vestfrost/Sunfrost)
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Features of Vest Frost
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Energy Efficiency of Typical Refrigerator
We use about 500 KWH per month. Fridge is 15 of
costs Our refrigerator uses 75 kWH per month or
2.25 kWH Per day or almost 3 times the usage of a
vestfrost. Why?
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Total Energy Usage
Q/t 1/R Adelta T Where Q is heat loss per
unit time t, R is average R value, A is surface
area, And delta T is temperature
difference. Qtotal sum (A/R)24DD Where DD
are the annual degree days R is the average R
value, A is surface area Of house. Infiltration
losses must be added to this.
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Prevention of Sick Building Syndrome
House plants can dramatically reduce the
levels Of formaldehyde, benzene and
trichloroethylene Within a home. Air inside a
well insulated home Often 2 to 5 times more
polluted than outdoor air. Some good ones Aloe
vera (also good for burns) Bamboo palm Spider
plant English ivy Janet Craig Warnecki dracaena
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Chrysanthemum
Same as the outdoor plants, Will also grow
well indoors
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Devils Ivy
Grows well in Hanging pots Will tolerate neglect
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African Daisy
Needs to be started In a professional
Greenhouse. Prefers warmer Climates.
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Peace Lily
One of the easiest Of large houseplants Grows
well in low light Survives well at average House
temperatures And humidity levels.