Transcript Document

Power / Energy
Management
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 Reductions
1. Lucent - Since 1980 9% per year growth with -2% per
year energy costs (savings)
2. TRW - Between 1972-78, Energy cost down 19%
Do An Energy Audit on Plant to
Determine Areas to Save Energy
Bas ic Building and Oc c upanc y D at a
(Ov erall Sizes , Oc c upat ion Tim e, et c . )
C ollec t Bills f rom
Prev ious y ears
Z one D at a
Obt ained F rom
D rawings ?
Yes
C hec k D rawing
wit h Vis ual
I ns pec t ion
No
C an Bills be
alloc at ed t o
Z ones ?
C arry Out Sit e
Surv ey
Yes
No
Es t im at e f or
R ough Guide
C om plet e Buliding
Z one Size D at a
I ns t all Met ers
t o C ollec t D at a
C om pile U t ilit y C os t s f or Eac h Z one f rom Prev ious Y ears
Above = Zones
--------------Below = Sys tems
C om pile Lis t of U t ilit y Sy s t em s I ns t alled f or Eac h Z one
C hec k D rawing Spec
f or Sy s t em D es ign
D at a
I ns t all Met ers f or Eac h
Sy s t em
D et ail Energy C ons um pt ion C om ponent s f or Eac h Sy s t em
D o Z one and Plant
Energy Audit
Energy Audit
Compile Energy Data About Each Building Zone
Basic Building and Occupancy Data
(Ov erall Sizes, Occupation Time, etc.)
Collect Bills f rom
Prev ious y ears
Zone Data
Obtained From
Drawings?
Yes
Check Drawing
with Visual
Inspection
No
Can Bills be
allocated to
Zones?
Carry Out Site
Surv ey
Yes
Complete Buliding
Zone Size Data
Estimate f or
Rough Guide
No
Install Meters
to Collect Data
Compile Utility Costs f or Each Zone f rom Prev ious Y ears
Start Energy Savings Actions in Highest Cost Zone
From Highest Cost Zones First
Compile List of Utility Sy stems Installed f or Each Zone
Check Drawing Spec
f or Sy stem Design
Data
Install Meters f or Each
Sy stem
Detail Energy Consumption Components f or Each Sy stem
Take Action on
Highest Cost Sy stem
See Below For Types of Action Steps
Utility Rates
 Commercial - usually highest
 Residential
 Government - usually lowest
Rates Consist of:
1.
2.
3.
4.
5.
Energy Charge
Fuel Adjustment Charge
Taxes
Demand Charge
Power Factor Penalty
Customer Type
KWH Used
Meter Reading
Power Factor
Fuel Adj.
Energy Charge
(- Demand)
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 loadcontrol"
* Computer control systems or zones help to
eliminate peak use and optimize power use
thus reducing costs.
Sense
Control
Peak demand time
Heating
Zone temperatures
Air conditioning
Condition of machines
Lighting
Snow melting
Etc.
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-peakload hours"
 Shed peak loads
 Balance power loading (with
computer control)
 Produce your own power during peak
Unbalanced
Load
Balanced
Load
Ref: C. F. Paxton, "Solving Resistance Welding Problems with
Mini- and Micro-Computers" Welding Journal, August 1979.
. 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 secondary
a) Smaller loop in secondary
b) Less magnetic material within loop
 Install series capacitors on machines or
shunt capacitors in plant
 Use 3 phase machines wherever practicable