EPANET
FOR PRESSURIZED PIPE SYSTEMS
WHAT IS IT?
“EPANET is a Windows computer program
that performs extended period simulation
of hydraulic and water-quality behavior
within pressurized pipe networks. A
network can consist of pipes, nodes (pipe
junctions), pumps, valves and storage
tanks or reservoirs.”
WHO DEVELOPED IT?
Water Supply & Water Resources Section of the
Environmental Protection Agency (Lewis Rossman)
WHERE CAN I GET IT?
EPANET AND MANUAL CAN BE DOWNLOADED AT
http://servicecenter.kcc.usda.gov/sfw_e_l.htm
ADVANTAGES OF USING EPANET:
• SURVEY DATA CAN BE READ INTO PROGRAM (A LITTLE EDITING IN EXCEL)
• ALL CALCULATIONS ARE DONE INTERNALLY AND QUICKLY
• GRAPHICS, SUMMARY OUTPUT TABLES
• EASY TO CHECK OTHER PERSONS WORK
• CHANGES ARE QUICK AND EASY
• UNLIMITED NETWORK SIZE AND COMPLEXITY (LOOPED SYSTEMS, ETC.)
• ERROR CHECKING AND WARNINGS
DISADVANTAGES OF USING EPANET:
• HAVING TO LEARN THE PROGRAM (CAN TAKE SOME TIME).
IT HAS USDA CCE CERTIFICATION
Program components
• Lets check out the various components
with a simple example.
• A gravity pipe running from a diversion to a
pond
EXAMPLE PUMPED SYSTEM PROBLEM
We are installing a pump in a stream to pump water to an on-farm
irrigation system. After analyzing the on farm system,
we have determined that the peak crop water requirement is 350 gpm
and the pressure requirement at the turnout is 60 psi. The location
of the pump and pipeline have already been surveyed. PVC pipe will
be used. Pump site elevation = 3500 ft
Determine the:
1. Pump selection to deliver the flow and pressure to the turnout
2. Pressure rating of the pipe
3. Daily electrical costs to run the pump
GPS Survey Pro Exported Text File
1
2
3
4
5
6
7
8
9
10
11
base
802.2700
815.1200
824.7000
1058.0700
1161.3700
1216.9900
1555.9200
1928.6900
2293.3500
2682.3300
2933.5500
5000.0000
1458.6700
1467.9300
1467.9400
1524.3300
1589.3400
1665.9100
1880.0600
2009.7200
2066.4500
2123.1800
2252.8400
5000.0000
100.0343
110.0037
110.2987
113.2476
115.3981
117.2178
119.3127
120.4318
125.2222
130.3264
150.5632
500.0000
stream
pump intake
pump discharge
gs
gs
gs
gs
gs
gs
gs
Smith TO
base
EPANET NETWORK INPUT FILE (*.inp)
[TITLE]
EXAMPLE PUMPED SYSTEM EPANET-ENGINEERS MEETING 2005
[JUNCTIONS]
1
100.0343
2
110.0037
3
110.0037
4
113.2476
5
115.3981
6
117.2178
7
119.3127
8
120.4318
9
125.2222
10
130.3264
11
150.5632
[COORDINATES]
1
802.27
2
815.12
3
824.7
4
1058.07
5
1161.37
6
1216.99
7
1555.92
8
1928.69
9
2293.35
10
2682.33
11
2933.55
1458.67
1467.93
1467.94
1524.33
1589.34
1665.91
1880.06
2009.72
2066.45
2123.18
2252.84
Import file
Example:
TDH= 200 ft
Q = 400 gpm
Pump Efficiency (from curve)= 75%
Pump Motor Efficieny (assumed) = 85%
NO VFD drive to pump (set motor rpm = 3600)
WHP = (200 x 400)/ 3960 = 20.20 hp
BHP = 20.2 / 75% = 26.94 hp
EHP = 26.94/ 85% = 31.69 hp
Water to wire Efficiency (pumping plant eff.) = 75% x 85% = 64%
Assume you draw through the meter 30 hp (22.38 Kw) for 1 day.
Assume the cost of electricity = $0.05 /Kw-hr
DESIGN PARAMETERS
TDH = 200 ft
Q = 400 gpm
To run the pump for 24 hours:
22.38 Kw x 24 hours x $0.05/Kw-hr = $26.86
BHP
Meter
W
EHP
60-80 % eff.
80-90 % eff.
PUMP MOTOR
PUMP
VFD
95-98 % eff.
WATER TO WIRE EFFICIENCY
HP
To
i
I rr
tio
ga
n
Sy
em
st
From Berkeley Pump Selection Software, Q = 350 gpm, TDH = 215 ft
Power, hydraulic (water) : 18.97 hp
Power, brake : 26.90 hp
Minimum recommended driver rating set @ : 30.00 hp / 22.37 kW
Electronic Variable Frequency Drives (VFD’s)
“control the speed and torque of an AC electric motor by varying the frequency
and voltage of the electricity supplied to the motor. They replace inefficient,
energy robbing controls such as control valves, pressure reducing valves, etc.”
Why Use VFD’s?
From Pump Affinity Laws (constant impeller diameter):
P1/P2= (N1/N2)3
P = Power
N= Speed (rpm)
Initially we have a 10 hp pump running at 3600 rpm to meet demand and
pressure requirements in our piping system. Demand declines and the
VFD lowers the pump speed to 3200 rpm. What are the power savings?
P1 = 10 hp
N1 = 3600 rpm
N2 = 3200 rpm
P2 = 7 hp
An 11.1% speed decrease results in a 30% decrease in power
Consumption! Small speed decreases result in large energy savings.
The Real Cost of Electricity-Whats On Your Bill!
Example Bill
**Demand Charge is based on the highest average 15 minute power usage for
the billing period. Demand charge kicks in at > 15 kw usage. (pacific power)
Pump Example
Summary of Pipeline/Irrigation Projects
Using GIS Survey--EPANET
1) Conduct the GPS survey of water levels, pumps, pipelines,
sprinkler locations, etc.
2) Export the data from Survey Pro to a text format.
3) Read the exported text file into Excel and manipulate it into
The EPANET input format.
4) Import the nodes into EPANET
5) Draw the pipe network and begin the simulation
Sprinkler Simulation EPANET
Emitter-Sprinkler Orifice Equation
q = C py
q = emitter flow rate
C = discharge coefficient
p = pressure
y = pressure exponent
y
= 0.5 for sprinklers/nozzles
Calculate the Emitter Coeficients for the Varying Nozzles
For the rainbird 30H (SBN-3) with plug @ 50 psi:
9/64” nozzle, C = q/p0.5 = 4.1 gpm/ 500.5 = 0.580
5/32” nozzle, C = 0.707
11/64” nozzle, C = 0.863
3/16” nozzle, C = 1.018
Change the emitter coefficient in EPANET to change the
Sprinkler/nozzle.
Questions ?