Quality Products & Services Since 1985
 
Energy Savings Analysis
How to select efficient pumps for low operating cost and low life cycle cost?
Look at our example below that compares Pump A vs Pump B for the same application design conditions of service (DCOS):
DCOS:
GPM = 3000 Pump A Efficiency at DCOS = 86%
TDH = 150 Pump B Efficiency at DCOS = 81%
 
Assumptions:
  • DCOS: 3000 GPM @ 150 TDH
  • Constant speed pump operation
  • Pump A is 86% Efficient at DCOS
  • Pump B is 81% Efficient at DCOS
  • Pump system motor efficiency is set at 95%
  • Power Cost is $.06/KwH
  • Pumping Water with 1.0 Specific Gravity
  • 8000 hours/yr annual pump operation
 
Brake Horse Power =

GPM x TDH x SG

3960 x Pump Efficiency

 
Pump A

Req. BHP

=

3000 x 150 x 1.0

=

132.1

3960 x 86% Pump Eff

         
Pump B

Req. BHP

=

3000 x 150 x 1.0

=

140.3

3960 x 81% Pump Eff

Difference in Pump A and Pump B BHP

=

( 140.3 - 132.1 )

=

8.2

NOTE: Pump B requires 8.2 BHP more than Pump A
     
Energy Savings =

BHP diff x .746 Kw/BHP x 8000 hrs/yr

motor efficiency
       
Therefore Energy Savings = 8.2 BHP x .746 KW/BHP x 8000 hrs/yr

=

51,240

KwH/yr
95% Motor Efficiency
         
Operating Cost Savings =

51,240 KwH/year

x

$0.06 per KwH

=

$3,074

per year
             
Assuming 20 year pump life, the total operating cost savings for selecting
the higher efficiency pump is

=

$61,487

   
   
For assistance in calculating the cost of pumping and life cyle cost, please call SPE
at (800) 890-0935 or email us at sales@southeastpump.com.
 
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