EPANETFOR 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

IT HAS USDA CCE CERTIFICATION

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).

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 gpmand the pressure requirement at the turnout is 60 psi. The locationof the pump and pipeline have already been surveyed. PVC pipe willbe 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

1 802.2700 1458.6700 100.0343 stream 2 815.1200 1467.9300 110.0037 pump intake 3 824.7000 1467.9400 110.2987 pump discharge 4 1058.0700 1524.3300 113.2476 gs 5 1161.3700 1589.3400 115.3981 gs 6 1216.9900 1665.9100 117.2178 gs 7 1555.9200 1880.0600 119.3127 gs 8 1928.6900 2009.7200 120.4318 gs 9 2293.3500 2066.4500 125.2222 gs 10 2682.3300 2123.1800 130.3264 gs 11 2933.5500 2252.8400 150.5632 Smith TO base 5000.0000 5000.0000 500.0000 base

[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 1458.67 2 815.12 1467.93 3 824.7 1467.94 4 1058.07 1524.33 5 1161.37 1589.34 6 1216.99 1665.91 7 1555.92 1880.06 8 1928.69 2009.72 9 2293.35 2066.45 10 2682.33 2123.18 11 2933.55 2252.84

EPANET NETWORK INPUT FILE (*.inp)

Import file

PU

MP

PUM P M OTOR

W ATER TO W IRE EFFICIENCY

DESIGN PARAMETERSTDH = 200 ftQ = 400 gpm

VFDMeter

60-8

0 %

eff

.

80-9

0 %

eff

.

95-9

8 %

eff

.

Exam ple:

TDH = 200 ftQ = 400 gpmPum p E ffic iency (from curve)= 75%Pum p M otor E ffic ieny (assum ed) = 85%NO VFD drive to pum p (set m otor rpm = 3600)

W HP = (200 x 400)/ 3960 = 20.20 hpBHP = 20.2 / 75% = 26.94 hpEHP = 26.94/ 85% = 31.69 hp

W ater to w ire E ffic iency (pum ping p lant eff.) = 75% x 85% = 64%

Assum e you draw through the m eter 30 hp (22.38 Kw) for 1 day. Assum e the cost o f e lectric ity = $0.05 /Kw -hr

To run the pum p for 24 hours:

22.38 Kw x 24 hours x $0.05/Kw -hr = $26.86

BH PEH P

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 frequencyand 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 = PowerN= Speed (rpm)

Initially we have a 10 hp pump running at 3600 rpm to meet demand andpressure requirements in our piping system. Demand declines and theVFD lowers the pump speed to 3200 rpm. What are the power savings?

P1 = 10 hpN1 = 3600 rpm N2 = 3200 rpmP2 = 7 hp

An 11.1% speed decrease results in a 30% decrease in powerConsumption! Small speed decreases result in large energy savings.

The Real Cost of Electricity-Whats On Your Bill!

**Demand Charge is based on the highest average 15 minute power usage forthe billing period. Demand charge kicks in at > 15 kw usage. (pacific power)

Example Bill

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 intoThe 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 rateC = discharge coefficientp = pressurey = 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 theSprinkler/nozzle.

Questions ?