Sunday, December 11, 2011

LEED Certification: Gold

Rating Achieved: Gold
Home Size Adjustment: -8
Number of points: 67
Total Cost: $8,360.13 (Rough estimate, not including tax or shipping)

Biggest point contributions:

(1) Sustainable Site -Taking steps to minimize the constructions impact on the site gained 18 points.  This includes planting non-invasive plants, installing a light colored, high albedo permeable driveway, and having a compact development.

(2) Location and Linkage - Choosing the right site gained a lot of LEED points for little cost.  The site had to be on previously developed land, near a water line, near community resources, and near but not on to of a park.  By assuming the house was built on this kind of site, the project gained approximately 11 virtually free points.

(3) Reduced Water Need - Drought tolerant plants (ground cover - carpobrutus edulis), low flow rate toilet and shower, and reduced irrigation need accounted for 12 points.

(4) Environmental Quality - Reducing exposure to pollutants by not having a fireplace, using MERV 13 filters, carbon monoxide detectors, and not building a garage added 12 more points to the total.

(5) LEED Education - Educating the team, the public and home owners through manuals, newspaper articles, workshops, and open houses got 6 points.





LEED Certification Cost Sheet

Calculations

Friday, December 9, 2011

Geothermal System In Phoenix Arizona

GeoComfort GCT036 Geothermal Heat Pump
  • 38,900 Btu/hr Cooling Capacity
  • 28,500 Btu/hr Heating Capacity
  • Desuperheater for Hot Water Heating
  • 1000 CFM Airflow Rate
  • 2.68 kW at Full Load
  • 6000 Btu/hr, 24 GPH Water Heating Capacity
  • 4 Feet Head Loss


Vertical Ground Loop
  • 1200 Feet HDPE 1.25" Piping
  • 6 - 100 Foot Deep Bore Holes
  • 7 GPM Flow Rate
  • 73 Degree Fahrenheit Ground Temperature
  • At Full Load, Loop Temperature
    • 108 deg F Incoming Temp
    • 97 deg F Outgoing Temp
  • 45,000 Btu/hr Heat Dissipated in Loop
  • 10 Feet Head Loss
 
 Wilo-Stratos ECO 16 F Pump
  • 120 Watts
  • At 7 GPM, 24 Ft of Head Loss



Energy Use
  • Heat Pump -- 2.68 kW
  • Pump -------- 0.12 kW
  • Total --------- 2.80 kW


Economics
  •  Heat Pump Price -------- $10000
  • Ground Loop Price
    • at $15 per foot ---- $9175
  • Pump ---------------------- $500
  • Total Cost ----------------- $19675
  • Cost With 30% Rebate -- $13773
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  • Annual Costs with Geothermal ------------- $350 
  • Annual Costs with AC and Water Heater- $ 1502
    ----------------------------------------------------------------------
    • Payback Time --- 9.4 Years