Design of an Energy Efficient Residence

1
Design of an Energy Efficient Residence

• Jon Stevens
• HVAC Final Project

2
Background Information

• 2 story residential building, 1000 ft2 footprint
• Bridgeport, Connecticut
• Moderate summers cold winters
• E/3 what is the plan of attack?
• Increase Insulation
• Design for increased use of solar radiation
• Explore using alternative energy sources

3
Changes to Thermal Envelope

• Framing Fraction reduced
• SUPERGREEN FOAM
• R-value of 6.6 (hrft2F/Btu) per inch
• Zero ozone depletion propellant
• Windows
• Increase south facing glass from 40 to 64
• High efficiency windows R-values of 4.5
• Basement insulate around perimeter

4
Natural Gas Consumption

• Reduced from 164MBtu/year to 38 MBtu/year
• 22 MBtu for space heat 16 MBtu for hot water

5
Fuel Cells

• GE Home Gen 7000
• per kWh per MCF X 0.01
• Electricity Generation
• 36 Efficient 1ccf NG 10kwh
• Heat Generation
• 75 Efficiency for Cogeneration
• 47.7 MBtu/year based on 2kW avg. output
• Fuel Types, Natural Gas, Propane
• Supplemental Resistance Heating

6
Energy Comparison

• Typical House
• 164 MBtu HW Heat
• 822/year NG
• 5700 kWh Total Elec.Use
• Assume 0.09/kWh
• 520/year Elec. From Utility
• Total 1342/year

• Efficient House
• 38 MBtu HW Heat
• 0/year due to Cogen
• 6300 kWh Total Elec.Use
• 63.7 MBtu/year _at_5 /MBtu
• 318/year NG for Elec.
• Total 318/year

Theoretical Savings of 76, probably closer to
60
7
Initial Cost

• GE Home Gen 7000
• Retail estimated at 3000 without cogen
• Assuming Cogen will double the price, the simple
  payback would be 6 years.
• Sale of excess power to utility
• Help reduce operating and payback costs

8
Conclusions

• Key Ideas for energy efficient buildings
• Insulate, Insulate, Insulate
• Use as much solar as possible
• Design for the local climate and environment
• Tap the power of alternative energy
• Fuel Cells fresh, hot, and cheap!