guidelines for conservation of energy on pump irrigation system

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GUIDELINES FOR
CONSERVATION OF ENERGY ON
PUMP IRRIGATION SYSTEM
~ \iR1 3Wlrrr
CENTRAL WATER COMMISSION
NEW DELHI
APRIL 1988

CWC PUBLICATION NO.26/88
CENTRAL WATER· COMMISSION
NAVGAM DESIGN CELL
GUIDELINES FOR
CONSERVATION OF ENERGY' ON
PUMP IRRIGATION SYSTEM
NEW DELHI
WIIRl~~ "-«t~
PU"""

Page No.
1
1
3
5
System 'B' at delivery end and System 'A' at
delivery end
6
7
Method <strong>of</strong> measurement <strong>of</strong> <strong>energy</strong> consumption and
efficiency <strong>of</strong> pumping system
8
9
10
Method <strong>of</strong> discharge measurement from the
trajectory <strong>of</strong> the jet <strong>of</strong> water
11
12

GUIDELINES FOR CONSERVATION OF
ENERGY ON PUMP IRRIGATION SYSTEM
[;.~
In India there are about 64 lakh electric pt~pS and about 56 A diesel
pumps used by farmers <strong>for</strong> irrigation purposeso Such agricultural pumps consume
electricity and diesel worth Rs. 4000 croreJd~,

Find out the gross head on the pumping system by adding the static
head, the losses in the pipes and valves and the exit velocity
head.
STATIC HEAD is the difference in water level in the well and the
level <strong>of</strong> the centre line <strong>of</strong> the exit end <strong>of</strong> the delivery pipeo
Losses in the pipes and valves can be measured by means <strong>of</strong> pressure
and vacuum gauges provided at (i) the top end <strong>of</strong> the suction
pipe near the pump and (ii) the delivery pipe near the pumpo The
total losses in the system can be calculated as per the details
given in Annexure III.
The <strong>energy</strong> consumption and efficiency <strong>of</strong> the pumpi;lg system can be
measured by adopting the method given in Annexure I. The minimum
efficiency <strong>of</strong> the pumping system shall be as specified in th~ relevant
IS Code (I.S. Code No. 6595-1980-Specification <strong>for</strong> horizontal
centrifugal pumps <strong>for</strong> clear, cold, fresh water <strong>for</strong> agricultural
purposes". IS Code No. 9079-1979-"Specification <strong>for</strong> monoset pumps
<strong>for</strong> clear, cold, fresh water <strong>for</strong> agricultural purposes."
Alternately, the actual <strong>energy</strong> consumed as read from the <strong>energy</strong>
meter may be compared with the maximum <strong>energy</strong> that should have
been consumed by the pumping system. If the actual <strong>energy</strong> consumed
is higher than the maximum <strong>energy</strong> that should have been consumed
by the system then remedial measures are necessary to improve the
efficiency <strong>of</strong> the system to save <strong>energy</strong>.
4) Check from the manufacturer's per<strong>for</strong>mance c~art <strong>of</strong> the pump and
motor, the rated discharge <strong>of</strong> the pump <strong>for</strong> the gross head calculated
at Sl.No.2 at the rated voltage. Check the voltage <strong>of</strong> the
power line by a voltmeter to see whether the voltage is the rated
voltage. The discharge <strong>of</strong> the pump shall be measured only when the
voltage is equal to the rated voltage.
The actuaL discharge measured at Sl.No. 1 shall be equal to the
rated discharge <strong>of</strong> the pump. If the actual discharge is less than
the rated discharge then it means that the pumping system is not
working at the optimum efficiency and thus it consumes more <strong>energy</strong>
than required. It plso means that the loss <strong>of</strong> head or <strong>energy</strong> in -
the pipe line and valves and/or the pump is high.

Even if the actual discharge is equal to the rated discharge in a pumping
system containing G.I. pipes and ordinary footvalve , the system
efficiency can be improved by following method~
1) If the foot valve is covered by plastic sheet or gunny cloth, remove
the same. Cover the footvalve by suitable strainer, if necessary,
to prevent leaves and weeds entering the valve. Do not allow
silt to accumulate near the foot valve. Periodical checking is
necessary <strong>for</strong> the same.
2) a) If the footvalve is not a frictionless footvalve, replace the
same by a frictionless or minus friction footvalve, <strong>of</strong> standard
make con<strong>for</strong>ming to the r.S •.Code, No. 10805-1986. Kirloskar'
Minus Friction footvalves, Pant Nagar footvalves or equivalent
available in the market can be used.
b) As the diameter <strong>of</strong> the minus friction footvalve increases, it
is found that the head loss through the footvalve decreases.
There<strong>for</strong>e, a footvalve <strong>of</strong> bigger, diameter than the diameter
<strong>of</strong> the suction pipe may b~ used alongwith a taper piece.
3) Check whether proper size <strong>of</strong> pipe <strong>for</strong> suction & delivery as recommended
by the I.S. Code No. 9694 (Part I) - 1980. Code <strong>of</strong> practice
<strong>for</strong> the selection, installation, operation and maintenance <strong>of</strong> horizontal
centrifugal pumps <strong>for</strong> agricultural applications - Part I -
Selection, is used in the pumping system.
Table No. 4 <strong>for</strong> Nominal pipe size <strong>for</strong> suction and delivery lines
as given in the I.S. Code is reproduced in Annexure II.
4) Check the G.I. pipe line with Rigid PVC pipes <strong>of</strong> proper size which
gives less friction loss in turn reducing the <strong>energy</strong> consumption.
HOPE pipes can also be used but they are costlier than RPVC pipes.
The fC' valve fo~ G.I. pipe is 100 against 150 <strong>for</strong> Rigid PVC or
HOPE pipes.
5) Check whether proper size <strong>of</strong> footvalve and sluice valve has been
provided as shown in the table given in Annexure II. Otherwise
change the same alongwith the pipes.
6) Suction head should not be more than 4.5m. Otherwise the pump will
operate at low efficiency and the discharge will be less. Long
time operation with high suction lift will result in damage to the
impeller <strong>of</strong> pump. There<strong>for</strong>e the pump shall be installed in such
a manner that the suction head is lesp than 4.5m. Suction head
should be measured from time to time to check whether the same is
within 4.5m and suitable meaSures as discussed under Sl.No. 1,2,3
and 4 should be taken necessary, to keep the suction head within
4.5m.
7) In the suction side <strong>of</strong> a pumping system, if the G.I. pipe and ordinary
footvalve are replaced by R. P.V.C. pipe and frictioi,less

footvalve, then it is observed that the saving in <strong>energy</strong> can be
nearly 32% <strong>for</strong> a discharge <strong>of</strong> 11.7 litres/sec. and a lift <strong>of</strong> 3.5m
(See Figure 3).
8) a) A horizontal delivery pipe provided at about 1.5 M above the
water level in the channel or sump as shown in Fig.1 causes
unnecessary loss <strong>of</strong> <strong>energy</strong>. This system can be improved by
providing 2 Nos. <strong>of</strong> 45 0 bends and a horizontal pipe at a lower
level just about 15 em above the water level as shown i.nFig. 2
will save head loss by 97.5% on delivery side and save <strong>energy</strong>
consumption.
b) A diffuser provided at the delivery end can further reduce the
loss <strong>of</strong> head due to exit velocity by about 50% in a 63 mm diameter
pipe and above 87% in a 110 mm diameter pipe.
The improved system as
saving in <strong>energy</strong>. For
<strong>energy</strong> can be saved in
<strong>of</strong> a motor-pump giving
110 mm dia RPVC pipes •.
or 0.47 H .P.
shown in Fig. 2 will give substantial
example, nearly 260 units <strong>of</strong> electrical
800 hours <strong>of</strong> pumping per annum in case
a discharge <strong>of</strong> 12.5 l/sec. through
The saving in power is nearly 0.350 Kw
d) If the conventional pumping system as shown In Fig. 3 having
G.I. pipes and ordinary foot valve is improv€d by providing
RPVC pipes diffuser and frictionless footval~es and the delivery
end <strong>of</strong> pipe is bent down to have the exit end <strong>of</strong> pipe
to be in the same line as the centre line <strong>of</strong> the pump, then
saving in <strong>energy</strong> to the extent <strong>of</strong> 47% can be obtained, when
the discharge is 11.7 l/sec. and the static lift <strong>of</strong> water is
3.5 m.
9) Check whether the pump and motor are made as per relevant I.S.
standards. Mono-block pumpsets having combined efficiency not
less than 60-65% should be used. Replace the pump and motor if it
is found to give less efficiency. "Also check whether the motor
is <strong>of</strong> proper size. Oversized motor with higher H.P. rating than
r~quired will operate at lower efficiency and consume more <strong>energy</strong>.
There<strong>for</strong>e correct size <strong>of</strong> motor should be determined <strong>for</strong> the given
discharge and gross head from the per<strong>for</strong>mance chart <strong>of</strong> the manufacturer
and the same should be installed. A good guide can be had
from the "Guidelines <strong>for</strong> selection <strong>of</strong> agricultural pumpsets -
Field staff and farmers guide" prepared by the National Bank <strong>for</strong>
Agriculture and Rural Development, Bombay (Page 12, 13 and Table
VIII) <strong>for</strong> the selection <strong>of</strong> motor.
10) A capacitor fitted to the motor reduce <strong>energy</strong> consumption. There<strong>for</strong>e,
capacitor should be got connected to the motor, if it is not
already provided with the motor.
11) Power meters may be got checked frequently <strong>for</strong> its proper functioning.
12) If it is not possible to replace the pump and motor, due to high
cost, at least the valves and pipes must be changed. It is found

to improve the efficiency <strong>of</strong> the system, by about 15% to
2~.
~
13) The pump and motor should be installed on firm foundation with
anchor belts etc. to avoid vibration <strong>of</strong> the pump.
~le farmer will require the services <strong>of</strong> a consulting agency or an
Engineer to check the efficiency <strong>of</strong> the pumping system and to suggest remedial
measures to be adopted to improve the efficiency. If the above said measures
are taken, the resultant saving in <strong>energy</strong> will go a long way in helping the
progress <strong>of</strong> the nation. The saving in <strong>energy</strong> will more than compensate the
capital cost invested in a very short time. After that it is all pr<strong>of</strong>it <strong>for</strong>
the farmer.

•
00 lEND
~ __ 2.5M
{M
II.'~EL/VERY
PIPE (RPVCl
FiG.1 SYSTEM 'B' AT DELIVERY END
DELIVERY PIPE _'_M-+ IM. ---1
(RPVCl
I
90·BE~O ~5 REND
1MI
MOTOR
PUMP
I O~M.I
------T~~~~MI
CHANNEL

FIG.3
I
---1I
_.._....- _.1'-
.-...:...__--.All: _ _ _
-
- - -- --
SKETCH FOR ORIGINAL PUMPING SYSTEM
SKETCH FOR NEW IMPROVED
PUMPING SYSTE M
(NOT TO SCALE)

METHOD OF MEASUREMENT OF ENERGY CONSUMPTION
AND EFFICIENCY OF PUMPING SYSTEM
a~ Input power to the pumping system can be measured by means <strong>of</strong> a watt meter
in the power lines connected to the motor. For 3 phase A.C. motor two watt
meters have to be connected to the terminals <strong>of</strong> the motor and the total <strong>of</strong>
the two watt meter readings will give the total power.
b) Alternatively input power can be calculated by measuring the number <strong>of</strong> units
consumed by the motor in the <strong>energy</strong> meter <strong>for</strong> a particular amount <strong>of</strong> time.
The power input to the motor
Energy in Kwh
Time in hours
c) Output power <strong>of</strong> the pumping system can be determined by measurement <strong>of</strong> discharge
by provision <strong>of</strong> a V-notch in the irrigation channel carrying water
to the fields from the pump delivery. The gross head on the pumping system
can be calculated by adding the static head, .the losses in the pipes and
valves and exit velocity head.
Static head is the difference in w-ater level in the well and the level <strong>of</strong>
the centre line <strong>of</strong> the delivery pipe. Losses in the pipes and valves can
be calculated as per the,I.S. Code No. 9694 (Part I) - 1980 - (Code <strong>of</strong>
Practice <strong>for</strong> the selection, installation, operation and maintenance <strong>of</strong>
horizontal centrifugal pumps <strong>for</strong> Agricultural Applications - Part I Se.1ection).
The output power can be calculated by using the following <strong>for</strong>mula:
WQH
Power output = 75 - x 746 watts.
3
where w - 1000 Kg/m Unit weight <strong>of</strong> water
Output power <strong>of</strong> pumps
(in watts)
Input to motor
(in watts)
WQHt
75 M x
0.746 kwh
P
Minimum efficiency <strong>of</strong> the pumping system as per
1.S. Code.

Volume Rate <strong>of</strong> Nominal Pipe Size <strong>of</strong> Nominal Pipe Size <strong>of</strong>
Flow Suction Pipe Delivery Pipe
~ rom rom
1 2 3
0.50 20 20
1.00 30 25
1.25 40 32
1.60 40 40
2.00 40 40
2.50 50 40
3.20 65 50
4.00 65 50
5.00 65 65
8.00 80 80
10.00 100 80
12.50 100 100
16.00 125 100
20.00 125 125
25.00 150 125
32.00 150 150
40.00 200 150
50.00 200 200
60.00 250 200
80.00 250 250
100.00 300 250
125.00 350 300
Note -- The above values have been calculated on the basis <strong>of</strong>
velocity <strong>of</strong> flow <strong>of</strong> 1.5 Mis (approx) and 2.0 mls (approx)
in the suction and delivery pipes respe~tively.

Pressure at the top end <strong>of</strong> the suction
pipe near the pump.
P1
Kg/em
2
Pressure in the deli.very pipe near the
pump.
P2 Kg/em
2
Difference in level between the gauges
at inlet and outlet <strong>of</strong> the pumps.
Total head loss in the pumping system
(in ems) (P2 )
-P1 - ~50 em + hg
w

i
Horizontal and vertical co-ordinates <strong>of</strong> any point on
the jet <strong>of</strong> water leaving out <strong>of</strong> the delivery pipe in
Metres.
Velocity <strong>of</strong> water at the exit point <strong>of</strong> delivery pipe
in rn/sec.
. 1 . d .. / 2
Acce erat~on ue to grav~ty ~n rn see •

1. Selection <strong>of</strong> Agricultural Pumpsets - Field Staff and Farmers Guide by
National Bank <strong>for</strong> Agriculture and Rural Development Bombay.
Guidance to Farmers - Selecting, Operating and Maintaining Centrifugal
Pump by Dr. Sakthi Vadivel, Anna University, Madras - 25.
3. Techno-Economic Aspects <strong>of</strong> Different Types <strong>of</strong> Pump Rectification Measur~s
by Dr. S.M. Patel, Director, Institute <strong>of</strong> Co-operative Management
prep.ared <strong>for</strong> Gujarat Energy Development Agency.
4. Proceedings <strong>of</strong> the National Seminar on Use <strong>of</strong> Plastics in Agriculture
held at Vigyan Bhavan, Feb. 6, 1987, organised by the Directorate <strong>of</strong>
Extension (Ministry <strong>of</strong> Agriculture Govt. <strong>of</strong> India).
5. 1.S. Code No. 6595-1980 "specification <strong>for</strong> horizontal centrifugal pumps
<strong>for</strong> clear, cold, fresh water <strong>for</strong> Agricultural Purposes".
6. I.S. Code No.9079-1979 - "Specification <strong>for</strong> monoset pumps <strong>for</strong> clear,
cole, fresh wat€:r <strong>of</strong> Agricultural purposes".
7. 1.S. Code No.9694 (Part I) - 1980 "Code <strong>of</strong> practice <strong>for</strong> the Selection,
Installation, Operation and Maintenance <strong>of</strong> Horizontal Centrifugal
Pumps <strong>for</strong> Agricultural Applications - Part I - Selection".
8. 1.5. Code No.10805-1986 "Specification <strong>for</strong> Footvalves" Reflux Valves or
Non-Return valves and Bore Valves to be used in Suction lines <strong>of</strong> Agricultural
Pumping System".
,
9. I.S. Code No. 2951 (Part I & II) - 1965 "Recommendation <strong>for</strong> Estimation
<strong>of</strong> Flow <strong>of</strong> Liquids in closed conduit".

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