Final Project

  LEED Certification  

Points Achieved: 71                                                   

Certification: Gold Certified

Estimated Cost: $212900 ($22900 more for LEED home)

Main Strategies Used:

(1)   Innovation/Design - Followed a quality and durability management process throughout to allow us to make sure things were getting done as planned and as a checklist, and used a automated energy management system throughout house to control lightning and geothermal HVAC system

(2)   Increased overall water efficiency/usage - Installed low flow rate toilets and showers, drought-tolerant plants that require minimal irrigation and no chemicals, ENERGY STAR washing machine that uses 40% less water, and connected a rainwater harvesting tank to the roof.

(3)   Reduced energy need – Installed a geothermal heating/cooling system, increased insulation throughout house including around hot water pipes, ENERGY STAR refrigerator which is 20% more energy efficient than normal refrigerator.

(4)   Waste Reduction – Contributed to the most of the LEED home increased cost, used FSC-certified doors and reclaimed hardwood floors, and implemented waste reduction program during construction.

Meeting the LEED Gold certification required special green appliances, lights, building materials, and energy systems. LEED homes are typically more expensive than standard homes because the products used are normally more specialized. Using these practices and standards allowed us to obtain LEED Gold certification.

Energy Needs of the Home

            A standard home with 2 bedrooms, no basement, and 1000 sq. ft. of area was started with.  R-values of building materials were calculated and assumed; these results can be seen in Table 1 below.  

 

Table 1: R-values for a 1000 Sq. Ft. House.

Parameter
	Siding	4
	Insulation	20
	Wood Studs	7
Plaster inside		1
Roof		15

As can be seen, the insulation and roof account for most of the resistance of the house, which makes sense.  These R-values were then used to calculate the overall thermal conductance of the house.  This value was found to be .315966 BTU/hF.  After doing a little research, properties of the house needed to calculate the heating and cooling degree days were assumed to be the contents of Table 2.

Table 2: Air Properties for 1000 Sq. Ft. House

Cpair	0.239706	Btu (therm.)/lb-°F
Air volume	9000	ft^3
Rate	18000	ft^3/hour
Q	5	ft^3/s
Mdot	0.01185	lbm/s

Heating and cooling degree days could then be obtained through degreedays.net; this website produced an excel file showing the heating and cooling degree days by month in Boulder, Co.   These heating and cooling degree days could then be used to calculate the heating and cooling needed for the house; the results of these calculations can be seen in Table 3.

Table 3: Heating and Cooling Degree Days Results

HDD	7600
Qheat	17618.5	kWh/Year
CDD	356
Qcooling	825.2	kWh/Year

Heating uses almost three times as much energy per year as cooling; this would make sense because the average temperature is quite low throughout the year in Boulder.  After calculating the heating and cooling needs, other sources of energy usage were estimated using manufacturer estimates of normal, everyday appliances and fixtures; these values can be seen in Table 4.

Table 4: Estimates of KWh/Year of Everyday Appliances and Fixtures

Appliance	Energy use(kWh/Year)
Refrig	411
TV*2	358
Lighting	1552.8
Dish Washer	422
Microwave	131.4
Washer	267
Dryer	413
Water heating	1424
Internet	84
Qheat	17618.5
Qcooling	825.2
Total	28570.1

To better visually represent this data, a pie chart was created to see where the most energy usage was taking place; this can be seen in Figure 1.  

Figure 1: Calculated Energy Usage of the House.

Economic Feasibility Assessment:

• Boulder, CO has a climate that required analysis for only the heating season

• Indoor temperature of 67-72 degrees F

• Horizontal loops 12 feet underground  (20% propylene glycol solution)

• Pump and Compressor in a single unit (ClimateMaster Tranquility 27-038)

•  Pump COP = 3.5

• Compressor COP = 5

• Results

o   Pipe length = 660 feet

o   Geothermal Start-up costs = $6500

o   Furnace Start-up costs = $3000

o   Yearly savings using Geo = $140

o   Payback time = 25 years (best case)

•  Not exactly feasible for home size/location

• Wind energy could potentially aid geothermal on this site