3. Introduction
What is pumping system?
A pump is a device that moves fluids (liquids or gases) by mechanical action.
Pumps operate by some mechanism (reciprocating or rotary), and
consume energy to perform mechanical work by moving the fluid. Pumps
operate via many energy sources, including manual
operation, electricity, engines, or wind power
Used for
• Domestic, commercial, industrial and
agricultural services
• Municipal water and wastewater services
4. Objective of pumping system
• Transfer liquid
from source to
destination
• Circulate liquid
around a system
Main pump component
• Pump
• Prime mover(electric motor, diesel engines, air system)
• Piping to carry fluid
• Valve to control in system
End use equipment
• Heat exchanger, tanks, hydraulic machine
5. Pumping system characteristics
Head
• two types: static and friction
Static head
• difference in height between
source and destination
Static head consists of
• Static suction head (hS): lifting liquid relative to
pump center line
• Static discharge head (hD) vertical distance
between centerline and liquid surface in
destination tank
6. Static head at certain pressure
head(meter)= pressure (pascal)/specific gravity
Friction head
• Resistance to flow in pipe and fittings
• Depends on size, pipes, pipe fittings,
flow rate, nature of liquid
• Proportional to square of flow rate
• Closed loop system only has
friction head(no static head)
7. In most cases:
Total head = Static head + friction head
8. Solar pumping system
• The operation of solar powered pumps is more economical mainly due to the lower operation and
maintenance cost
• less environmental impact than pumps powered by an internal combustion engine (ICE).
• Solar pumps are useful where grid electricity is unavailable and alternative sources (in particular wind) do
not provide sufficient energy.
Components
• solar panels.
• the controller
• the pump
• The solar panels make up most (up to 80%) of the systems cost
• The size of the PV-system is directly dependent on the size of the pump, the amount of water that is
required (m³/d) and the solar irradiance available.
9. The purpose of the controller
• output power that the pump receives with the input power available from the solar panels.
• provides a low voltage protection, whereby the system is switched off, if the voltage is too low or too high.
11. Positive Displacement Pumps
• For each pump revolution
• Fixed amount of liquid taken from one end
• Positively discharged at other end
• If pipe blocked
• Pressure rises
• Can damage pump
• Used for pumping fluids other than water
Reciprocating pump
• Displacement by reciprocation of piston plunger
• Used only for viscous fluids and oil wells
Rotary pump
• Displacement by rotary action of gear, cam or vanes
• Several sub-types
• Used for special services in industry
12. Dynamic pumps
• Mode of operation
• Rotating impeller converts kinetic energy into
pressure or velocity to pump the fluid
• Two types
• Centrifugal pumps: pumping water in
industry – 75% of pumps installed
• Special effect pumps: specialized conditions
13. Centrifugal Pumps
• Liquid forced into impeller
• Vanes pass kinetic energy to liquid:
liquid rotates and leaves impeller
• Volute casing converts kinetic energy
into pressure energy
14. Impeller
• Main rotating part that provides centrifugal
acceleration to the fluid
• Number of impellers = number of pump
stages
• Impeller classification: direction of flow,
suction type and shape/mechanical
construction
Shaft
• Transfers torque from motor to impeller
during pump start up and operation
15. Casings
• Functions
• Enclose impeller as “pressure vessel”
• Support and bearing for shaft and impeller
Volute case
• Impellers inside casings
• Balances hydraulic pressure on pump shaft
Circular casing
• Vanes surrounds impeller
• Used for multi-stage pumps
Volute casing
16. Assessment of pumps
How to Calculate Pump Performance
• Pump shaft power (Ps) is actual horsepower delivered to the pump shaft
Pump shaft power (Ps):
Ps = Hydraulic power Hp / pump efficiency ηPump
Pump Efficiency (ηPump):
ηPump = Hydraulic Power / Pump Shaft Power
• Pump output/Hydraulic/Water horsepower (Hp) is the liquid horsepower delivered
by the pump
Hydraulic power (Hp):
Hp = Q (m3/s) x Total head, hd - hs (m) x ρ (kg/m3) x g (m/s2) / 1000
17. Energy Efficiency Opportunities
1. Maintenance
2. Monitoring
3. Controls
4. More efficient pump
5. Proper pump sizing
6. Multiple pumps for varying loads
7. Impeller trimming
8. Adjustable speed drives(ASD)
9. Avoiding throttling valves
10. Proper pipe sizing
11. Replacement of belt drives
12. Precision casting, surface coating or
polishing
13. Improvement of sealing
18. Maintenance
Typical energy savings for operations and maintenance are
estimated to be between 2% and 7% of pumping electricity
• Replacement of worn impellers, especially in caustic or semi-solid
applications.
• Bearing inspection and repair.
• Bearing lubrication replacement, once annually or semiannually.
• Inspection and replacement of packing seals.
• Inspection and replacement of mechanical seals.
• Wear ring and impeller replacement.
• Pump/motor alignment check.
• The largest opportunity is usually to avoid throttling losses.
19. Monitoring
Monitoring should include:
•Wear monitoring
•Vibration analyses
•Pressure and flow monitoring
•Current or power monitoring
•Differential head and temperature rise across the pump (also known as
thermodynamic monitoring)
•Distribution system inspection for scaling or contaminant build-up
20. Control
The objective of any control strategy is to shut
off unneeded pumps or to reduce the load of
individual pumps. Remote controls enable
pumping systems to be started and stopped
relatively quickly and accurately
21. More efficient pumps
• Pump efficiency may degrade 10% to 25% in its lifetime.
• A number of pumps are available for specific pressure
head and flow rate capacity requirements. Choosing
the right pump often saves both in operating costs and
in capital costs (of purchasing another pump).
• Replacing a pump with a new efficient one reduces
energy use by 2% to 10%. Higher efficiency motors have
been shown to increase the efficiency of the pump
system 2% to 5%.
22. Multiple pumps for varying loads
The use of multiple pumps is often the most cost-effective
and most energy-efficient solution for varying loads,
particularly in a static head-dominated system. Alternatively,
adjustable speed drives could be considered for dynamic
systems.
The installation of parallel systems for highly variable loads
on average would save 10% to 50% of the electricity
consumption for pumping
23. Impeller trimming
• Trimming reduces the impeller’s tip speed, which in turn
reduces the amount of energy imparted to the pumped
fluid; as a result, the pump’s flow rate and pressure both
decrease.
• A smaller or trimmed impeller can thus be used efficiently
in applications in which the current impeller is producing
excessive heat. In the food processing, paper and
petrochemical industries, trimming impellers or lowering
gear ratios is estimated to save as much as 75% of the
electricity consumption for specific pump applications.
24. Adjustable speed drives(ASDs)
• ASDs better match speed to load requirements for
pumps. As for motors, energy use of pumps is
approximately proportional to the cube of the flow rate
and relatively small reductions in flow may yield
significant energy savings
• the installation of ASDs improves overall productivity,
control and product quality, and reduces wear on
equipment, thereby reducing future maintenance costs.
25. Proper pipe sizing
Energy may be saved by reducing losses due to friction
through the optimization of pipe diameters. The frictional
power required depends on flow, pipe size (diameter),
overall pipe length, pipe characteristics (surface roughness,
material, etc.), and properties of the fluid being pumped.
26. Improvement of sealing
Seal failure accounts for up to 70% of pump
failures in many applications. The sealing
arrangements on pumps will contribute to the
power absorbed. Often the use of gas barrier
seals, balanced seals can help to optimize
pump efficiency.
