Power / EnergyManagement

Background        USA has 6% of worlds population - Uses 33% of energy consumed        In 1946 we used 30*1015 BTU

        In 1980 we used 90*1015 BTU (Industry used 36% of this)

        In 1990 we used 120*1015 BTU

        Since the 1970's Companies have associated Energy Conservation with Cost Reductions1.     Lucent - Since 1980 9% per year growth with -2% per year energy costs (savings)2.     TRW - Between 1972-78, Energy cost down 19%

Basic Building and Occupancy Data(Overall Sizes, Occupation Time, etc.)

Zone DataObtained From

Drawings?

Check Drawingwith VisualInspection

Carry Out SiteSurvey

Collect Bills fromPrevious years

Can Bills beallocated to

Zones?

Complete BulidingZone Size Data

Estimate forRough Guide

Install Metersto Collect Data

Yes No

Yes No

Compile Utility Costs for Each Zone from Previous Years

Compile List of Utility Systems Installed for Each Zone

Above = Zones---------------

Below = Systems

Check Drawing Specfor System Design

Data

Install Meters for EachSystem

Detail Energy Consumption Components for Each System

Do Zone and PlantEnergy Audit

Do An Energy Audit on Plant to Determine Areas to Save Energy

Energy AuditCompile Energy Data About Each Building Zone

Basic Building and Occupancy Data(Overall Sizes, Occupation Time, etc.)

Zone DataObtained From

Drawings?

Check Drawingwith VisualInspection

Carry Out SiteSurvey

Collect Bills fromPrevious years

Can Bills beallocated to

Zones?

Complete BulidingZone Size Data

Estimate forRough Guide

Install Metersto Collect Data

Yes No

Yes No

Compile Utility Costs for Each Zone from Previous Years

Start Energy Savings Actions in Highest Cost Zone

Compile List of Utility Systems Installed for Each Zone

Check Drawing Specfor System Design

Data

Install Meters for EachSystem

Detail Energy Consumption Components for Each System

Take Action onHighest Cost System

From Highest Cost Zones First

See Below For Types of Action StepsSee Below For Types of Action Steps

Utility Rates        Commercial - usually highest

        Residential

        Government - usually lowest

Rates Consist of:1.      Energy Charge2.      Fuel Adjustment Charge3.      Taxes4.      Demand Charge5.      Power Factor Penalty

Customer Type

Meter Reading KWH Used

Energy Charge (- Demand)

Dem

and

Ch

arge

Power Factor

Fuel Adj.

Tax

Energy Charge

Rate is dependent on:        Commercial, residential Government

        Time of Day (Peak Demand Periods)

        Total Amount Used (get break after use a predetermined amount)

 

Ways to reduce these costs:        Run on off peak times        Energy storage in off peak times        Energy Audit

        Computer controlled "Alternative load-control"* Computer control systems or zones help to eliminate peak use and optimize power use thus reducing costs.

Sense Control

Peak demand time

Zone temperatures

Condition of machines

Snow melting

Etc.

Heating

Air conditioning

Lighting

Etc.

Control Diagram on Next Slide

1Demand Charges (Item "a" on the bill)This is a payment to the utility for their ability to supply customer's peak

requirements. This can be as much as 40-45% of the bill. They measure the highest use during some period (usually a 1/2 hour period) then bill upon this highest use.

Demand Charges Ways to reduce these costs:        Make peak loads during "off-peak-load hours"        Shed peak loads        Balance power loading (with computer control)        Produce your own power during peak 

Ref: C. F. Paxton, "Solving Resistance Welding Problems with Mini- and Micro-Computers" Welding Journal, August 1979.

Balanced Load

Unbalanced Load

. Power Factor Penalty (Item "b" on the bill)Power factor is the ratio of real power to apparent power or kW/kVA, where

kW or kilowatts are measured with a wattmeter and kVA or kilovolt-amperes are measured with a voltmeter and ammeter. A power factor of one or unity is ideal. A power factor of less than one means that a portion of the current being drawn through the power lines is not actually being used by the machinery to produce work.

Ways to reduce these costs        Decrease reactance in secondarya)      Smaller loop in secondaryb)      Less magnetic material within loop

        Install series capacitors on machines or shunt capacitors in plant

        Use 3 phase machines wherever practicable