1. Energy Conserving Alternatives HVAC 15a CNST 305 Environmental Systems 1 Dr. Berryman

2. Formulas Note: These calculations do not include the cost of fan operation…add 10% for residential and 20% for commercial applications

3. Estimate Annual Energy

4. Energy Sources

5. Annual Costing Office – Example I Office – Example II Given: 1500 hrs heating and cooling Contributing lighting load (10 hrs) – 220,320 BH Peak Heat Loss – 406,850 BH Peak Heat Gain – 630,172 BH

6. Energy Alternatives Improved Heat Pumps Given: Current Heat Pump – COP 2; SEER 9 New Heat Pump – COP 2.8; SEER 13 Annual Full Load heating hrs = 1500 Annual Full Load cooling hrs = 1500 Electricity $0.08 per kWh Annual Heat Loss 389,680,000 BTU/yr Annual Heat Gain 945,000,000 BTU/yr Cost $10,000 1 st year return on investment: 47%

7. Energy Alternatives Less Ventilation Given: Original Design – 2,970 CFM winter 2,400 summer New Design – 2000 CFM winter/summer Winter TD is 60 o F; Summer CLTD 20 o F GD (grain difference) = 40 Annual Full Load heating hrs = 1600 Annual Full Load cooling hrs = 1400 Heat w/ an 75% efficient oil fired boiler Oil $0.90 per gallon Cool w/ SEER 8 electric chiller Electricity $0.07 per kWh Cost $2,500 1 st year return on investment: 53%

8. Energy Alternatives More Roof Insulation Given: Roof area 10,800 SF Current U value = 0.05 New U value = 0.04 Winter TD is 60 o F; Summer CLTD 36 o F Annual Full Load heating hrs = 1600 Annual Full Load cooling hrs = 1400 Heat w/ an 80% efficient gas furnace Natural Gas $0.75 per therm Cool w/ SEER 10 air conditioner Electricity $0.09 per kWh Cost $3,000 1 st year return on investment: 5.8%

9. Efficient Designs - Opportunities Solar Designs Thermal Mass Evaporation Air movement Ventilation/Infiltration Mechanical Systems Zoning

10. Summary Calculated values for heat loss and gain may be used to estimate annual energy consumption and evaluate energy conserving alternatives. Indoor fan energy is not usually included in equipment efficiency ratings – Allow 10% residential and 20% for commercial