Presenting a Case Study in Pumping Efficiency Improvements

for Irrigation Applications

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

Traditional Flow/Pressure Control Methods:

Discharge or ‘Throttle’ Valve

Pump Speed = 100% Pump Energy Consumption = 80 to100%*

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

Traditional Flow/Pressure Control Methods

Bypass Control Valve

Pump Speed = 100% Pump Energy Consumption =100%

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

Energy Efficient Pump Flow/Pressure Control

Pump Speed Control (by VSD)

Pump Speed = 50% to 100% Pump Energy Consumption = 20% to 100%

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

VSD Control of an Irrigation Pump is usually the most efficient option

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

100% Speed (50Hz) = 100% Energy consumption (100kW)

How Does a Variable Speed Drive (VSD) Improve Pumping Efficiency ?

A 20% reduction in speed (40 Hz) results in a 50% reduction in energy (50kW)

What are the Additional Benefits of Fitting a VSD to an Irrigation Pump?

The resulting lower operating speed will increase the life of the pump.

They eliminate the inrush current on start up. Soft starting reduces the stress on the motor, pump, coupling and the supply network.

They eliminate the control valve (and associated losses), start-up and by-pass priming piping. They are easy to retrofit.

They can provide system control logic, fault protection and diagnostics, and can simplify the operation of a pumping system

Case Study #1Pozzebon Farm - Dimbulah

45kW Pump with Discharge Valve @ 45psi 2x Centre Pivots, Fertigation for Mango Sprinklers 850 Hours Average Irrigation P/A 850 h x 45 kW = 38,250 kW/h 38,250 kW/h x $0.14 = $5400 Pumping Costs P/A

Existing Pump prior to VSD Installation

Calculations in simple terms

Case Study #1Pozzebon Farm – Dimbulah

Existing Pump After VSD Installation

45kW Pump and Danfoss Aqua VSD 45psi = 19.5 kW Average Power Consumption 850 h x 19.5 kW = 16,575kWh 16,575 kWh x $0.14 = $2,300 Pumping Costs P/A $5400 - $2300 = $3100 Cost Savings P/A Installed Cost of VSD $12,500 $12,500 / $3,100 = 4 Years ROI 6 Years x $3100 = $18,600 Expected Energy Cost

Savings over design life of VSD after ROI...

Pozzebon Farm - Dimbulah

Centrifugal Pump Set-up

Pozzebon Farm - Dimbulah

Discharge Valve now 100% Open

Pozzebon Farm - Dimbulah

Simple Installation with IP56 VSD

Pozzebon Farm - Dimbulah

Simplified Controls – Easily Incorporated in Existing Control Systems, eg. WISA

Pozzebon Farm - Dimbulah

Pressure transmitter connected directly to, and powered from the VSD – pressure feedback and over and under pressure protection - LED Display of system pressure.

Case Study #2De Lai Farm - Kirai

90kW Pump with Discharge Valve @ 170psi Movable Trolley to compensate for Dam Level 1x Linear Hose, 1x Hard Hose 985 Hours Average Irrigation P/A 985 h x 90 kW = 88,650 kW/h 88,650 kW/h x $0.18 = $16,000 Pumping Costs P/A

Existing Pump prior to VSD Installation

Calculations in simple terms

Case Study #2De Lai Farm – Kirai

Existing Pump After VSD Installation

90kW Pump and Danfoss Aqua VSD 170 psi = 60 kW Average Power Consumption 985 h x 60 kW = 59,100 kW/h 59,100 kW/h x $0.18 = $10,600 Pumping Costs P/A $16,000 - $10,600 = $5,400 Cost Savings P/A Installed Cost of VSD $17,000 $17,000 / $5,400 = 3 Years ROI 7 Years x $5,400 = $37,800 Expected Energy Cost

Savings over Design Life of VSD after ROI...

De Lai Farm - Kirai

Before VSD Installation

De Lai Farm - Kirai

After VSD Installation, on-site at dam

De Lai Farm - Kirai

IP55 Enclosure simplifies installation – weather and vermin proof