The document discusses ways to minimize power requirements for pumps in the dairy industry. It discusses how pumps account for 20-50% of energy usage in dairy plants and introduces various pump types used. Methods to improve pump efficiency are proposed, including proper sizing of pumps to avoid throttling, use of variable speed drives, impeller trimming, parallel pumping, and regular maintenance. Adopting these strategies can reduce pumping energy usage by 30-50% and lower costs. The document emphasizes the need for dairy plants to invest in more efficient pumping systems and sustainable energy sources.

1. COLLEGE OF DAIRYTECHNOLOGY
RAIPUR,(C.G)
A CREDIT SEMINAR ON (DE – 598)
MINIMISING THE POWER REQUIRMENT FOR PUMPS IN DAIRY INDUSTRY
MAJOR ADVISIOR: Er. C.SAHU
PRESENTED BY : ADARSH M. KALLA
(D.E)

2. INTRODUCTION
• Dairy industries use significant amount of energy, depending on the type of products
manufactured.
• The sources of energy in dairy processing plants are generally electricity and thermal
energy.
• In last 20 years, the dairy industry has improved energy efficiency by wide upgrading of
equipments and closing all small and less efficient plants. (Lunde et al., 2003)
• The awareness of energy consumption in the dairy industry is becoming an issue as the
cost of milk processing is increasing and milk price is decreasing.

3. Cost-wise break-up of fuel being used in the Dairy
industry
Electricity
petroleum products
coal
Other fuels
26%
45%
28%
1%
( ASI database 2007-08 )

4. ELECTRICAL ENERGY
• The cost of electrical energy has increased dramatically in the recent years.
• In India, industrial users pay higher price for electricity relative to domestic and industrial
users.
• For instance, in 2000, industrial users paid 15 times higher price than agricultural users for
electricity. (Abeberese,2012)
• Pumping systems account for nearly 20% of the world’s electrical energy demand and
range from 25-50% of the energy usage in certain industrial plant operations.
(US DOE, 2004)
• It has been estimated that, energy and maintenance costs will account for over 80–95% of
pump ownership costs, with initial costs less than 15% of pump life cycle costs.
(Bower, 1999)

5. CLASSIFICATION OF PUMPS
Pumps
Dynamic
Centrifugal Special effect
Positive
displacement
Reciprocating Rotary
Internal gear External gear Lobe Slide vane
(Bureau of Energy Efficiency, 2004)

6. Positive displacement pumps
• Positive displacement pumps are distinguished by the way they operate: liquid is taken
from one end and positively discharged at the other end for every revolution.
• Positive displacement pumps are widely used for pumping mostly viscous fluids, Such as
cream with high fat content, cultured milk products, curd, whey etc.
• RECIPROCATING PUMPS: If the displacement is by reciprocation of a piston plunger,
then it is called as reciprocating pump. Reciprocating pumps are used only for pumping
viscous liquids and oil in the oil wells.
• ROTARY PUMPS: If the displacement is by rotary action of a gear or vanes in a
chamber of diaphragm in a fixed casing then it is called as rotary pump.
(Ahmad tufail, 1985)

7. 1 2 3
4

8. DYNAMIC PUMPS
Centrifugal pumps:
• Liquid enters the eye of the Impeller & exits the impeller with the help of Centrifugal
Force.
• As water leaves the eye of the impeller a low pressure area is created, causing more
water to flow into the eye (atmospheric pressure & centrifugal force causes this to
happen).
• Velocity is developed by the spinning impeller.
• Water velocity is collected by the diffuser & converted into the pressure by specially
designed pathway.
(Jacobsen, 2003)

9. CENTRIFUGAL PUMP
Centrifugal Pump (Sahdev M)

10. System Characteristics
• A pressure is needed to make the liquid flow at the required rate and this must overcome
head 'losses' in the system.
• Losses are of two types: static and friction head.
• Static Head : Difference between the heights of the Supply & Destination reservoirs. Static
Head is independent of Flow.
• Friction Head : Losses in piping system & equipments. Friction losses are proportional to
the square of the flow rate.
(Bachus and Custodio, 2003)

11. STATIC HEAD
STATIC HEAD STATIC HEAD vs. FLOW

12. FRICTION HEAD
• Friction head is the friction losses
occurred during the flow of liquid through
pipes, values and equipments in the
system.
• Friction tables are available universally
for various pipes, fittings and valves.
These tables show friction losses per 100
feet /meters of a specific pipe size at
various flow rates.
Friction Head vs. Flow ( Bachus and Custodio, 2003)

13. REDUCTION OF HEAD LOSSES
• Static head is a characteristic of the specific installation and reducing this head where
this is possible, generally helps both the cost of the installation and the cost of pumping
the liquid.
• Friction head losses must be minimized to reduce pumping cost, this can be done by:
• Eliminating unnecessary pipe fittings.
• Reducing the length of pipe, and
• Use of larger diameter pipe.

14. H-Q CURVES
• SYSTEM CURVE: The system curve is a plot
of system resistance to be overcome by the
pump versus various flow rates.
• System curve changes with physical
configuration of the system, such as
• Height or elevation.
• Diameter and length of pipe.
• Number and types of fittings.
• And, pressure drop across various equipments.
(Bloch and Budris, 2004.)
SYSTEM CURVE

15. PUMP CURVE
• The performance of a pump can be
expressed graphically as head against
flow rate.
• The pump where the head falls gradually
with increasing flow, is called the pump
characteristic curve.
• This is because as flow rate increases
frictional losses increase and head falls
gradually.
HEAD
FLOW
(Jacobsen, 2003)

16. PUMP OPERATING POINT
• When a pump is installed in a system the effect can be illustrated graphically by
superimposing pump and system curves. The operating point will always be where the
two curves intersect.

17. PUMP OPERATING POINT
• The pump operating point is also called as best efficiency point at which the efficiency of
the pump is highest or it is the pumping capacity at maximum impeller diameter.
• An error in the system curve calculation leads to the wrong selection of pump, which is less
than optimal for the actual system head losses.
• Adding safety margins people, will select a sufficiently large pump which results in an
oversized pump, which will operate at an excessive flow rate or in a throttled condition,
which increases energy usage and reduces pump life.
(Bureau of Energy Efficiency, 2004)

18. EFFECT OF OVERSIZED PUMP ON ENERGY
USAGE
• Pumps that are oversized for a particular application, consume more energy than is truly
necessary. Replacing oversized pumps with pumps that are properly sized can often reduce the
electricity use of a pumping system by 15% to 25% (U.S DOE, 2011).
• A pump is selected based on how well the pump curve and system head-flow curves match.
• In the system under consideration, liquid has to be first lifted to a height – this represents the
static head. Then, we make a system curve, considering the friction and pressure drops in the
system.

19. EFFECT OF OVERSIZED PUMP

20. • The best efficiency point has shifted from 82% to 77% efficiency.
• The actually operating point is at C, which is 300 m3/hr on the original system
curve. The head required at this point is only 42 meters.
• The incorrect calculation of system curve leads selection of oversized pump,
which has reduced efficiency and increased power consumption.
• Hence, a new pump is needed which will operate with its best efficiency point
at C.

21. ENERGY LOSS IN THROTTLING
• Throttling valves are indications of
oversized pumps as well as the
inability of the pump system design
to accommodate load variations
efficiently, and should always be
avoided (Tutterow et al. 2000).
• Consider a case, where we need to
pump 68 m3/hr of water at 47 m
head. The pump characteristic curves
(A…E) for a range of pumps are
given in the Figure.

22. If we select E, then the
pump efficiency is 60%
Hydraulic Power = Q (m³/s) x Total
head, hd-hs(m) x ρ(kg/m³) x g (m²/s)
1000
= (68/3600) x 47 x 1000 x 9.81
1000
=8.7Kw
•Shaft Power -8.7 / 0.60 = 14.5 Kw
•Motor Power -14.5 / 0.9 = 16.1Kw
(considering a motor efficiency
of 90%)
Hydraulic Power = Q (m³/s) x Total head,
hd-hs (m) x ρ(kg/m³) x g (m²/s)
1000
(68/3600) x 76 x 1000 x 9.81
1000
=14kw
Shaft Power -14 / 0.50 = 28 KW
Motor Power -28 / 0.9 = 31
KW(considering a motor efficiency of
90%)
If we select A, then the
pump efficiency is 50%

23. ADDITIONAL POWER
• Hence the additional power= 31-16.1
= 14.9 KW
• Energy used= total hrs per year × 14.9 KW
8760hrs/ year × 14.9 KW
1,30,524 KW.
• Total extra money spent = Rs 6,05,631
• In this example, the extra cost of the electricity is more than the
cost of purchasing a new pump.

24. Effect of speed variation
• The pump with fixed impeller diameter and so varying the rotational speed has a direct effect
on the performance of the pump.
• By reducing pump speed, less energy is imparted to the fluid and less energy needs to be
throttled or bypassed.
• If speed is varied all the parameters will change like head, power, flow rate and net positive
suction head.
• The equations relating rotodynamic pump performance parameters of flow, head and power
absorbed, to speed are known as the Affinity Laws:
• Q α N
• H α N²
• P α N³
(Mackey, 2004)

25. EFFECT OF SPEED VARIATION ON POWER
CONSUMPTION
• Power(kW): Power is proportional to the cube of speed
• P₁ / P₂ = (N₁)³ / (N₂)³
• Example: 5kw/ P₂ = 1750³ / 3500³
• P₂ = 40 Kw
• As can be seen from the above laws, doubling the speed of the centrifugal pump will
increase the power consumption by 8 times. Conversely a small reduction in speed
will result in drastic reduction in power consumption.
• This forms the basis for energy conservation in pumps with varying flow
requirements.

26. EFFICIENCY IS INDEPENDENT OF SPEED VARIATION
• From fig it is clear that Points of
equal efficiency on the curves for
the 3 different speeds are joined to
make the iso-efficiency lines.
• It shows that efficiency remains
constant over small changes of
speed providing the pump continues
to operate at the same position
related to its best efficiency point
(BEP).

27. SPEED CONTROLLERS
• The pump speed adjustments provide the most efficient means of controlling pump flow.
 There are two primary methods of reducing pump speed:
• multiple-speed pump motors and
• variable speed drives (VSDs)
(EUHI, 2004)

28. MULITIPLE SPEED MOTORS
• Multiple speed motors are designed to operate at two, three, or four separate designated
speeds.
• The speed of an induction motor depends on the frequency of the electrical power supply.
• SPEED (R/MIN) = 120 X SUPPLY FREQUENCY (HZ).
• Multiple-speed motors contain a different set of windings for each motor speed;
consequently, they are more expensive and less efficient than single speed motors.
• Multiple speed motors also lack subtle speed changing capabilities within discrete speeds.
(EUHI, 2004)

29. VARIABLE SPEED DRIVES
• VSDs allow pump speed adjustments over a continuous range, avoiding the need to jump
from speed to speed as with multiple-speed pumps.
• VSDs control pump speed using several different types of mechanical and electrical
systems. Mechanical VSDs include fluid couplings, and adjustable belts and pulleys.
• Electrical VSDs include eddy current clutches and variable frequency drives (VFDs).
• VFDs adjust the electrical frequency of the power supplied to a motor to change the motor's
rotational speed. VFDs are by far the most popular type of VSD.
(EUHI, 2004)

30. Benefits of VSDs
• Energy Savings
Energy savings of between 30% and 50% have been achieved in many installations by
installing VSDs.
• Improved Process Control
By matching pump output flow or pressure directly to the process requirements, small
variations can be corrected more rapidly by a VSD than by other control forms, which
improves process performance.
• Improved System Reliability
Any reduction in speed achieved by using a VSD has major benefits in reducing pump
wear, particularly in bearings and seals.
(U.S DOE, 2004).

31. IMPELLER TRIMMING
• Impeller trimming refers to the process of matching the diameter of an impeller to reduce
the energy added to the system fluid.
• According to the (U.S. DOE, 2006), one should consider trimming an impeller when any
of the following conditions occur:
• When many system bypass valves are open.
• When pump is working under Excessive throttled condition .
• High levels of noise or vibration indicate excessive flow.
• A pump is operating far from its design point.

32. IMPELLER TRIMMING
Considerations:
• The impeller should not be trimmed
more than 25%,otherwise it leads to
vibration due to cavitation and
therefore decrease the pump
efficiency.
• The balance of the pump has to be
maintained, i.e. the impeller
trimming should be same on all
sides.
(http://www.ecosmartelectricians.com.)

33. IMPELLER TRIMMING
( http://flickriver.com.) (http://www.whatisall.com.)

34. ELEMINATING BY-PASS CONTROL
• The flow can also be reduced by installing a by-pass control system, it consist of two pipe
lines.
• One of the pipelines delivers the fluid to the delivery point, while the second pipeline
returns the fluid to the source.
• In other words, part of the fluid is pumped around for no reason, and thus is an energy
wastage. This option should therefore be avoided.
• The elimination of bypass loops and other unnecessary flows can also lead to energy savings
of 10% to 20%. (U.S. DOE, 2011)
• But in some cases small by-pass line is required to prevent a pump running at zero flow
required for safe operation of pump.

35. BY-PASS CONTROL VALVE
(httpwww.wassertech.netcontentview1629lang,thai)

36. OPERATING PUMPS IN PARALLEL
• Operating two pumps in parallel and
turning one off when the demand is lower,
can result in significant energy savings.
• Parallel pumps are an option when the
static head is more than fifty percent of the
total head.
• The system curve normally does not change
by running pumps in parallel.
• The flow rate will be lower than the sum of
the flow rates of the different pumps.
(Anonymous, 2005)

37. PUMP SYSTEM MAINTENANCE
• Poor maintenance can lower pump efficiency, and drastically increase pumping energy costs.
• Improved pump system maintenance can lead to energy savings from 2% to 7%.(U.S. DOT,1998)
 pump system maintenance program generally include the following tasks :
• Replacement of worn impellers, especially in caustic or semi-solid applications.
• Bearing inspection and repair.
• Replacement of lubricants, on an annual or semiannual basis.
• Inspection and replacement of mechanical seals.
• Checking of pump/motor alignment.
• Inspection of motor condition, including the motor winding insulation.
(Sullivan et al., 2010)

38. AVOID CAVITATION
• CAVITATION: Cavitation may be defined, as a
hydrodynamic phenomenon resulting in the
formation of vapour bubbles or pockets in a liquid
when it is subjected to reduced pressure at
constant ambient temperatures.
• The pressure reaches up to 1,00,000 bar causing
damage to impeller.
• Effects
• Cavitation causes a great deal of noise, damage
to components, vibrations, and a loss of
efficiency.
• Cavitation reduces efficiency and increases power
consumption.
(Ahmad tufail, 1985) ( http://yamahajetboaters.com.)

39. RECOMMENDATIONS
• A system approach can be effective in assessing system performance.
• Follow proper operating and maintenance practices.
• Analyze Life-Cycle Costs before making a decision.
• Facility manager should be able to convince financial personal that investment in pumping is
worth making.
• The dairy industry should show interest in energy conservation programmes and invest in
energy efficient pumping system.
• The dairy should plan for use of sustainable energy like solar energy, wind energy and
biomass energy.

40. CONCLUSION
• The greed of humans has lead to unfair exploitation of the natural
resources and a bad impact on the environment. which has lead to
think about efficient use of these resources and increase interest in
renewable resources.
• Newer technologies and methods have to be developed until a new
source of energy is invented.

41. REFERENCE
• Abeberese.B.A., 2012. Electricity Cost and Firm Performance: Evidence from India. JOB MARKET PAPER: PP.1
• Ahmad tufail, 1985; Dairy plant engineering and management, kitab mahal. 5th edition, Allahabad.
• Anonymous, 2005. Parallel pump can provide multiple benefits. 20 (1):pp 1-2
• Bachus,L. and Custodio, A. 2003. Know and Understand Centrifugal Pumps. 1st edition, Elsevier Ltd. The
Boulevard, Langford Lane, Kidlington, Oxford , UK. pp 92-97
• Bloch,P.B and Budris,R.A. 2004. Pump user’s hand book: life extension.2nd edition Ferimont ltd, Lilburn,
Georgia , U.S. pp76-77
• Bower, John. 1999. “Reducing Life Cycle Cost by Energy Saving in Pump Systems.” In Proceedings from 1999
Industrial Energy Technology Conference. May. Houston, Tex.: Texas A&M University.
• Euro pump and The hydraulic institute, kidlington, U.K. 2004. Variable speed drives: A guide to successful
applications. Elsevier ltd. pp 59-64.
• http://flickriver.com
• http://www.ecosmartelectricians.com.
• http://www.whatisall.com.

42. • http://yamahajetboaters.com.
• httpwww.wassertech.netcontentview1629lang,thai.
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energy consumption database, 2007–08.
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Energy Efficiency in Electrical Utilities, 2004.Report New Delhi, manager of publication chapter 6.
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performance of the Australian dairy processing industry using life cycle assessment. Dairy Research
Development Corporation.pp.43
• Mackey, R. 2004. The practical pumping handbook. Elsevier Ltd. Kidlington, U.K. pp.22-25
• Sahdev, M. Centrifugal Pumps: Basic concepts of operation, maintenance and trouble shooting, Part I.
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43. • Sullivan, P.G., Pugh, R., Melendez, R., Hunt, D.W.P.A. (2010). Operation and maintenance best
practices- A Guide to achieving operational efficiency. Pacific Northwest National Laboratory. Pp.224-
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