Session 1, Energy 101
Foundational Energy Building Blocks
Dan Howett, P.E.
Oak Ridge National Laboratory
August 9, 2016
Rhode Island Convention Center • Providence, Rhode Island
Agenda
What is a “BTU”?
What is a “kilowatt”?
What is a “kilowatt‐hour”?
How to read an electric bill.
What is a “demand charge”?
How to use, or not use, the Levelized Cost of Electricity.
• What does “efficiency” really mean?
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Energy Exchange: Federal Sustainability for the Next Decade
What is a “BTU”?
• British Thermal Unit (BTU).
• Unit of heat energy required to raise one pound of water by 1°F.
Grande coffee = one pound water
1BTU in
121°F
120°F
119°F
1BTU out
Energy Exchange: Federal Sustainability for the Next Decade
BTUs Applied to Air Flow
• Heat energy needed to raise 54 cubic feet of air by 1°F
1BTU in
86°F
85°F
84°F
1BTU out
Energy Exchange: Federal Sustainability for the Next Decade
What is a “ton” of cooling?
• It is not a “quantity” of heat energy. Rather, it is a “rate” of how fast energy is moving out of a space.
• One HVAC “ton” = 12,000 BTU/HR moving out of a space.
• Equals the heat rate required to melt one ton of ice in 24 hours.
Energy Exchange: Federal Sustainability for the Next Decade
What is a “ton” of cooling? (cont.)
• Look at a typical one bedroom apartment…
Sun (3,000btu/hr)
Conduction (5,000btu/hr)
1 person (500btu/hr)
Television
(500btu/hr)
A/C
Bedroom
1 ton A/C
(12,000btu/hr)
Lighting
Kitchen
(600btu/hr) (2,400btu/hr)
Living Room
Kitchen
Energy Exchange: Federal Sustainability for the Next Decade
What is a “kilowatt”?
• Electric Power, the Watt (W).
– 1 watt = 1 Joule/second. It is a term from the metric system.
– 1 watt = Power required to move 1 amp of current with 1 volt of potential difference.
Energy Exchange: Federal Sustainability for the Next Decade
What is a “kilowatt”?
• 1 W = 3.412 BTU/hr.
– A watt really isn’t that big of a unit. – A normal incandescent bulb consumes 40‐100 watts.
• The kilowatt (KW) is much more common.
– 1 KW = 1000 watts.
– A 200 ton chiller might consume 150KW of electrical power at peak.
• Utility power is often measured in megawatts (MW)
– 1 MW = 1000 KW = 1,000,000 W.
– W.H. Zimmer Station produces 1300 net MW of power.
Energy Exchange: Federal Sustainability for the Next Decade
What is a “kilowatt‐hour”?
• Electric Energy, the Kilowatt‐Hour (KWH)
– 1 KWH = 1KW of power that is consumed or produced for 1 hour.
– It is the common unit for measuring electrical energy consumption.
– Examples
• A 1000 watt electric heater operating for one hour consumes 1 KWH of electricity.
• A 100 watt light bulb operating for ten hours consumes 1 KWH of electricity.
• A 1 megawatt generating station operating for one hour produced 1000 KWH of electricity.
– Converting BTUs to KWH
• 1 KWH = 3,412 BTUs
Energy Exchange: Federal Sustainability for the Next Decade
Reading a Residential Electric Bill
Monthly consumption (KWH)
Energy cost adjustments
Fixed monthly service charge
Rate schedule $/kwh for each kwh
Taxes and “other” delivery fees
Total Monthly Cost ($)
Energy Exchange: Federal Sustainability for the Next Decade
What is a “Demand Charge”? The highest power consumption rate in the billing cycle.
Monthly consumption (kwh)
Fixed monthly service charge
Energy cost adjustments
Rate schedule $/kwh for each kwh
Taxes and “other” delivery fees
$175.58
Peak Demand (9/14 @ 1420hrs): Demand Charge: 2.4kw @ $10.50ea
Total Monthly Cost ($)
2.4kw
$25.20
Energy Exchange: Federal Sustainability for the Next Decade
Levelized Cost of Electricity (LCE)
Total Cost ($) / Total Consumption (kwh) = $/kwh
Total Consumption (kwh)
670kwh
$150.38
• Dr. Tamm’s LCE: $.224/kwh
• Mr. Howett’s LCE: $1.459/kwh
16kwh
$23.34
Total Cost ($)
Energy Exchange: Federal Sustainability for the Next Decade
LCE vs Actual Savings For Each kwh
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LCE is $0.224/kwh.
Refrigerator uses 100kwh/month.
Salesman says new model uses 50% less energy.
100kwh/month x 50% x $0.224/kwh = $11.20/month in savings.
• 100kwh/month x 50% x
$0.182/kwh = $9.10/month in
savings.
$.182/kwh
Energy Exchange: Federal Sustainability for the Next Decade
What “efficiency” really means?
(Useful work by of a process) (Work input required by the process)
Useful Work = Heat Energy into the Cooking Oil
Natural Gas
1000 BTUs input
800 BTUs heat into the oil
800 / 1000 = 80% effcy
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Electricity 1000 BTUs input (293 watts)
1000 BTUs heat into the oil
1000 / 1000 = 100% effcy
Energy Exchange: Federal Sustainability for the Next Decade
Other ways to view “efficiency”?
(Useful work by of a process) (Work input required by the process)
‐ Useful Work = 12,000 BTU/hr of heat removed from the room ‐ Work Input = 1,000 watts electricity
1,000 W x 3.412 BTU/hr/W = 3,412 BTU/hr
‐ Efficiency = 12,000 BTU/hr / 3,412 BTU/hr = 350% efficient! ‐ Coefficient of Performance (COP): Unit‐less measure of “efficiency”, used when “efficiency” exceeds 100%.
Efficiency = 350% COP = 3.5
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Energy Exchange: Federal Sustainability for the Next Decade
Other ways to view “efficiency”?
(Useful work by of a process) (Work input required by the process)
Useful Work = 12,000 BTU/hr of heat removed from the room Work Input = 1,000 watts electricity
1,000 W x 3.412 BTU/hr/W = 3,412 BTU/hr
‐ EER (Energy Efficiency Ratio): Cooling Cap (BTU/hr) / Power Input (W)
EER = 12,000 BTU/hr / 1,000 W = 12.0
‐ SEER (Seasonal Energy Efficiency Ratio): Total Cooling (BTU) / Total Input(W‐hr)
‐ HSPF (Heating Seasonal Perf. Factor): Total Heating (BTU) / Total Input(W‐hr)
‐ Chiller Rating in KW/Ton: Total Input (KW) / Total Cooling (tons)
KW/Ton = 1,000 W / 12,000 BTU/hr = 1.0 KW / 1.0 Ton Cooling = 1.0 KW/Ton
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Energy Exchange: Federal Sustainability for the Next Decade
Questions?
Energy Exchange: Federal Sustainability for the Next Decade