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BASICS OF ENERGY MANAGEMENT

Section A - Energy Basics

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These resource materials were developed by the Kentucky Pollution Prevention Center at the University of Louisville for KEEPS – Kentucky Energy Efficiency Programs for Schools – with support from the U.S. Department of Energy, and the Kentucky Department for Energy Development and Independence.

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Basics of Energy Management

Electricity Units Watt (W)

Electrical unit of power

Kilowatt (kW)Unit of power equivalent to 1,000 watts of electrical

demand

Kilowatt-hour (kWh)Amount of energy consumed when 1,000 watts are used

for one hour

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Basics of Energy Management

Electric Demand Components Demand Period

Time interval during which flow of electricity is measured (usually in 15-, 30- or 60-minute increments depending on rate structure)

Peak DemandHighest average demand over the demand period in the

billing period Electric Load Factor (ELF)

Indicates if peak demand is high for the facility

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Basics of Energy Management

Electric Demand Profile

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Basics of Energy Management

Natural Gas Units Btu: British thermal unit

MMBtu: Million British thermal unit

Btu/hr: British thermal unit per hour

CCF: Hundred cubic feet 10 CCF = 1 MMBtu

Dth: Dekatherm 1 dth = 1 MMBtu or ~10 CCF

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Conversion – Apples to Apples

Horsepower (hp) = 745.6 watts

Motor hp = 2,545 Btu/hr

Boiler hp = 33,475 Btu/hr

Cooling ton = 12,000 Btu/hr

1 kilowatt = 3,412.3 Btu/hr

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Efficiency Work done divided by work put into the system

Efficiency Terms

work outwork in = %

Efficacy Measure of performance using units

• lumens/watt for lighting • kW/ton for chillers

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HVAC Efficiency – COP

Coefficient of Performance (COP)Measurement of how efficiently a heating or cooling system operates at a single outdoor temperature condition

• Temperature condition for heat pumps = 47°F

Heat Pump Chiller

Btu of heat produced (47◦F)Btu of electricity used (47◦F)

3.516kW/ton

Methods to calculate COP

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HVAC Efficiency – EER

Energy Efficiency Ratio (EER)Measurement of how efficiently a cooling system

operates when the outdoor temperature is at a specific level (95°F)

Commonly used when referring to:• air conditioners (window, unitary)• heat pumps (window, unitary, water-source,

geothermal)Btu/hr cooling at 95°F

watts used at 95°F Method to calculate EER

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Conversion - Apples to Apples

Btu of cooling produced

Wh of electricity usedEER =

Energy or heat output (total)

Energy or heat input (external)COP =

EER

3,412 Btu/WhCOP =

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HVAC Efficiency – SEER

Seasonal Energy Efficiency Ratio (SEER)Measurement of how efficiently a residential central

cooling system operates over an entire cooling season• air conditioner or heat pump

Not to be confused with EERSplit cooling system SEER must be greater than 13,

effective 2006

seasonal Btu of cooling

seasonal watt-hours used

Method to calculate SEER

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HVAC Efficiency – HSPF

Heating Seasonal Performance Factor (HSPF)Measurement of how efficiently all residential and some

commercial heat pumps operate in their heating mode over an entire normal heating season

Btu of heat produced over heating season

watt-hours of electricity used over heating season

Method to calculate HSPF

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HVAC Efficiency – AFUE

Annual Fuel Utilization Efficiency (AFUE)Measurement of how efficiently a gas furnace or boiler

operates over an entire heating seasonPercentage of energy consumed by system that is

actually converted to useful heatAFUE for most gas furnaces must be at least 78%

Btu of heat produced over heating season

Btu of natural gas used over heating season

Method to calculate AFUE

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Energy Accounting Terms

Energy Use Index (EUI): Btu/ft2/yearUse when tracking energy savings

Energy Cost Index (ECI): $/ft2/yearUse when comparing within your district

• must be a small district with single utility provider

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Energy and the Environment

1 lb of coal burned produces 1 to 1.25 kWh

*100 lb/yr of coal not burned*

T12 (34W) upgrade to Super-T8 (32W) for 10 fixtures with four lamps per fixture

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Review of Energy Basics

Electric Units – kW, kWh, peak demand, ELF

Natural Gas Units – CCF, MMBtu, dth

HVAC Efficiency – COP, EER, SEER, HSPF, AFUE

Energy Accounting – EUI and ECI

Energy and the Environment1 lb coal burned produces about 1 to 1.25 kWh

Basics of Energy Management