P-4. Design for lowest life cycle cost

Design drive system for variable speed operation of the centrifugal pump in water supply system so that the system has lowest life cycle cost (LCC).

Given parameters:

• Rated flow 50 l/s, head 200 m, pump efficiency 81%
• Speed range 0 - 1450 rpm
• Grid voltage – 400 V
• Clean electric room for FC with abundant heat removal capabilities
• Distance from the electric room to the pump - 30 m
• Conditions at the place of the pump installation - wet
• Pump's mechanical configuration – horizontal
• Load profile is given (table)

Assume the pump works 24 hours a day. Energy price - 0,2 Euro/kWh Design for 3 different lifetimes: 1, 5 and 10 years.