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TIPS FOR PUMPING SYSTEM ENERGY ASSESSMNET

DO NOT HARM

SYSTEM NEEDS MUST BE MET AFTER OPTIMIZATION IS IMPLEMENTED

  • DISTANT USERS

  • MAXIMUM AND MINIMUM CONDITIONS

  • EMERGENCY SITUATIONS

  • FUTURE DEMANDS 

GI GO

GARBAGE IN  GARBAGE OUT

  • MEASUREMENTS ACCURACY

  • INFORMATION ABOUT A PUMPING SYSTEM 

ESTABLISH SYSTEM BOUNDARIES. THE SYSTEM APPROACH
System_approach_sch.png

The system approach is the most powerful method of increasing the pumping system efficiency. When we concentrate not only on a pump or an electric motor we consider the whole system.

Pump and driver, including power supply system (motor and VFD, if used)Piping, valves, fittings, tanks, heat exchangers, boilers, etc.

We will consider the System approach in a special presentation. System boundaries encompass:

MEASURED PARAMETERS 

HYDRAULIC PARAMETERS 

  • FLOW

  • INLET PRESSURE

  • DISCHARGE PRESSURE

ELECTRIC  PARAMETERS 

  • POWER

  • CURRENT

  • VOLTAGE

  • POWER FACTOR

System_approach_Formula.png
SET A BASELINE

The assessment considers the overall efficiency by comparing the power needed to fulfill system requirements to the input power. To calculate overall efficiency we need to measure hydraulic parameters and electric parameters (input power). Then more information we get about the pumping system then more reliable analysis we can do and energy-saving measures. Set a baseline means that the current situation should be recorded and used for the comparison variants of the upgraded system.

WHAT INFORMATION IS NECESSARY TO HAVE BEFORE PSA

P&ID  to capture the critical elements of the system.
Walk the system down with P&ID.
Develop a simplified flow diagram

PID.jpg
SIMPLE.png

P&ID is highly recommended to have before assessment. Review P&ID and piping isometrics 
Walk the system down (nice to have a P&ID when you do)
Talk with operators.

Develope the simplified scheme. 

IS IT POSSIBLE TO MEASUARE PARAMETERS FROM  THE LIST ABOVE ?

What instruments are installed?

  • Flowmeter.

  • Pressure gauges on the inlet and outlet pipelines.

  • Power meter?

IF NOT?

More information we have about pump More reliable results we will get. The list of information about the pump is presented here. There are different sources where we can get it. 
Nameplate,  test report or catalog, manual, 

INFORMATION ABOUT PUMP 

What instruments are installed?

  • Type of pump, 

  • Number of stages, 

  • Speed, 

  • Flow and head at the design point, 

  • Impeller diameter,

  • Manufacturer

  • Serial number 

  • Date of manufacturing. 

  • Pump curve, 

  • Maintenance records, 

  • Presence of cavitation.

  • Presence of manometers. 

NAMEPLATE
PUMP NAMEPLATE.jpg
PUMP CURVES
Pump_curves.png

Validation during measurements.

Analysis of changes.

The chart shows the efficiency curves for impeller trimming. It can be used during field measurements for validation. You can immediately define that the values of flow or head are far from the real values. 
During the analysis superimposing a system curve, will show the impact of making changes to the pump. The operating efficiency after a change will be dependent on the system the pump is attached to. 

TYPES OF PUMP CURVES

  • Curve for pump model - usually from a manufacturer's catalog.

  • Factory curve. Test report from the factory.

  • Field-tested curve. Test report after commissioning.

RECOMMENDATIONS:

  • Getting a factory test curve should be standard practice for pumps above 50 kW; 

  • A field certified curve should be obligatory for pumps above 130 kW.

RECOMMENDATIONS:

  • Type, 

  • Voltage, 

  • Frequency, 

  • Full load amps, 

  • Rated power, 

  • Speed, 

  • Efficiency, 

  • Power factor, 

  • Service factor.

NAMEPLATE
Motor_nameplate.jpg
INFORMATION ABOUT SYSTEM
ALGORITM.png

Parameters changes in time

  • Normal operating conditions, minimum and maximum conditions must be considered.

  • The system needs to be evaluated over a longer period of time

  • Historical process control data is available.

Load profile.png
ADDITIONAL SYSTEM DATA

Static head in the system.
Operating hours.
Pump control method.

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Curv_fric.png
MANDATORY CONDITIONS
PRESSURE MEASUREMENTS 

Should be taken with calibrated, reliable gauges or sensors.

FLOW MEASUREMENTS

Should be taken with properly installed, calibrated meters.
If using portable flow meters, confirm measurement at alternative locations
The pressure drop across a component and component curve.

MOTOR INPUT POWER

Preferably measure power directly with a power meter

Can calculate motor input power using measured voltage and current, and estimating the power factor

CROSS-VALIDATION 

Flow rate, pressure, and power measurements may not be available but can be determined using cross-validation

  • Use pump differential pressure (total head) and pump curve to estimate the flow rate

  • Use motor input power and efficiency to calculate shaft horsepower, then use a pump curve to estimate a flow rate

  • Use valve position, flow rate, and Cv data to estimate dP

  • Measure drawdown and fill times to estimate the flow rate

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