1. Ductless Heat Pumps Determining Cost Savings Example Gary Nordeen Bill Kingrey, P.E. 11/5/08 AFE Webinar

2. Introduction This presentation will help you to determine potential cost savings using ductless heat pumps

3. Step 1: Determine Fuel Costs Real Fuel Costs Include: Taxes Demand charges for electricity Meter charge, minimum payments Fuel consumption charges

4. Calculate Fuel Costs Divide total bill for each fuel type by # of units of fuel Use a winter month bill for heating supplement and a summer month bill for cooling supplement Electricity = total bill / #kWh used Gas = total bill / # therms used Oil = total bill / # gallons used

5. Step 2: Estimate Existing System Efficiency Cooling Mode: divide seasonal energy efficiency ratio (SEER) of chosen heat pump by 3.413 SEER / 3.413 = Efficiency in cooling mode Heating Mode: divide heating seasonal performance factor (HSPF) by 3.413 HSPF / 3.413 = Efficiency in heating mode

6. Step 3: Calculate Cost of Energy Use the following table OR the Fuel Cost Calculators at www.nwBuildings.org/dhp.aspx

7. Fuel Cost Table Cost Approx. FUEL UnitsFactor Efficiency #2 Fuel Oil$/gal.1396.82 #6 Bunker $/gal.1524.82 Coal$/ton23.77 Cord Wood$/Cord18.60 Electricity$/kWh.003417 1.00 Heat Pump$/kWh.003417 2.50 Natural Gas$/therm.1.80 Propane$/gal.0915.80 Wood Pellets $/ton 16.77 Cost / mmBTU = Fuel cost / (Cost Factor x Efficiency) Alternative: Use handy spreadsheet at: www.nwbuildings.org/dhp.aspx

8. Sample Calculations Follow The sample uses Fuel oil and Electricity prices to calculate the delivered cost of heating and cooling in a large building, then compares it with the cost of supplying heating and cooling with a ductless heat pump.

9. Step 1: Calculating Fuel Costs Fuel Oil #2 Fuel oil @ $3.00/gal burned at 82% efficiency = $3.00 / (.1396 x.82) = $26.21 / mmBTU Electricity Electricity @ $.112 / kWh at 100% efficiency =.112 / (.003417 x 1.0)=$32.78 / mmBTU

10. Step 2: Estimate Large Cooling System Efficiency To calculate savings in a system to supplement cooling you need to know the efficiency of the existing system Estimate the EER (8 to 18) of the chiller system – including cooling tower and pumps and divide by.03413 to obtain the efficiency Or use efficiency of 250% for air– cooled units, 250 to 330% for water cooled units

11. Gather the Information Assume the building is newer and the water-cooled chiller runs at 300% efficiency Assume the “real” cost of electricity is $ 0.12 / kWh Cooling costs = $11.71 / mmBTU

12. Determine Energy Costs for Ductless Heat Pump SEER = 19 COP = 19 / 3.413 = 5.57 = 557% Efficiency Fuel Cost is $ 6.30 / mmBTU Fuel Cost Savings is $ 11.71 - $ 6.30 = 5.41 / mmBTU

13. What Did We Learn? The existing HVAC system is providing cooling at about twice the cost of the DHP We can justify the DHP on cost savings for cooling-only Can we justify the DHP on heating performance or improved comfort? Repeat the analysis using the heat pump efficiency of HSPF/3.413 and the appropriate fuel cost and efficiency for the building heating system.

14. More Information Northwest Building Efficiency Center www.nwBuildings.org/ Info@nwBuildings.org 866-929-6232