A project is approved to replace 50, 1,000-watt mercury lamps with 50,
Project cost is $10,500 with discounted
400-watt sodium lamps in a hangar.
Determine if a meter can be
benefits of $34,969 (project information).
included in this project within the quidelines of paraqraph 1 (b).
C o m p u t e SIR, b o t h w i t h a n d w i t h o u t a m e t e r , a n d e v a l u a t e r e s u l t s .
Calculate cost for the completed project and ensure meter costs are
equal to or less than 10% of this value.
If preceding step is unsuccessful, reevaluate, c o m b i n i n g a d d i t i o n a l
Cost of installed meter is $2,000.
SIR must be greater than 2.5.
SIR = D i s c o u n t e d B e n e f i t s / P r o j e c t C o s t ;
Procedure A: SIR Test:
SIR (No meter) = $34,969/$10,500 = 3.33
SIR of 3.33
SIR of 2,80
SIR (With meter) = $34,969/$12,500 = 2.80
SIR remains greater than 1; project will not be jeopardized by meter.
Calculation of 10% Criteria:
Since the meter cost ($2,000) is greater than 10% of the project cost
$1,050) a meter can not be included in this p r o j e c t ,
Meter Justification for Entire H a n g a r :
Excluding electric costs for the lamps, the daily energy load is
determined to be 60kW for 8 hours and 35 kW for the remaining 16 hours.
Costs per y e a r :
1,040 kWh/day x 260 days x 0.06/kWh = $16,224
$16.224 + $4,992 = $21,216
10% x $21,216 = $2,121
$2,121 is greater than $2,000 (meter c o s t ) ; t h e r e f o r e , one meter for the
entire hanqar is justified as it meets both the SIR and 10% criteria,
Application of 10 Percent and SIR Criteria to Meter Projects