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POLITECHNIKA WROCLAWSKA Design of a Water Network Using EPANET 07-02-2014 Tânia Moreira Dias Faculty of Environmental Engineering Automatics in Environmental Engineering
POLITECHNIKA WROCLAWSKA
Design of a Water Network Using
EPANET
07-02-2014
Tânia Moreira Dias
Faculty of Environmental Engineering
Automatics in Environmental Engineering
Design of a Water Network using EPANET
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Índice
1. Introduction ............................................................................................................... 2
2. General description of water network and hydraulic model ..................................... 3
2.1 Water network .................................................................................................... 3
2.2 Water Demand ................................................................................................... 8
2.3 Pumping Station ............................................................................................... 10
2.3.1 Controls applied to the pumping station .......................................................... 12
2.4 Water Tank ...................................................................................................... 13
3. Result of preliminary design of water network ....................................................... 14
3.1 Pressure distribution in the whole system and put screenshot ............................ 14
3.2 Velocity in the Pipes ........................................................................................ 16
3.3 Operational state of the pumping station ......................................................... 18
4. Cost reduction analysis............................................................................................ 19
4.1 Description of proposed system optimization ..................................................... 19
4.2 Cost reduction analysis ........................................................................................ 21
5. Conclusion ............................................................................................................... 22
Design of a Water Network using EPANET
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1. Introduction
In order to ensure the availability of sufficient quantity of good quality of water, it
becomes imperative in a modern society to plan and build suitable water supply schemes,
which provides potable water to the community, which includes households and industry,
according to their demand.
This report consists on the description of the process of creation of a water network for a
fictional city using for that purpose the EPANET Software.
This report is divided in three main steps, the first one was to design a water network to
provide water to a fictional city. This city includes regular customers, people living in
households, and a high water demand factory that is responsible for the manufacture of
Jeans. This water network includes a tank, a pumping station and a reservoir.
The second step was to test the hydraulic model that was built in the first place and try to
make it functional.
The third and last step was to take the hydraulic model produced and try different
scenarios always aiming the cost reduction of the building of this water network.
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2. General description of water network and hydraulic
model
2.1 Water network
Within this project was provided a scanned version of the map of the city, FIG X, that as
one can see consists on the representation of the demand points and their elevation, the
pipes that make the connection between the junctions, the tank and the reservoir.
Figure 1- Topographic Map of the City
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In order to create the water supply system in EPANET Software, first map was vectored
using the AutoCad Software. The AutoCad drawing included only the isolines and the
pipes that connect the nodes of water demand. There was also the need to scale the map
to ‘real life’ measures, for that the length of the pipes were measured in the paper and
then re-sized with 1:5000 scale.
The drawing was after transferred to EPANET using the EPACAD, with this software is
possible to export the file in format .dxf and select only the layer containing the pipes of
the hydraulic model to start building your network.
It was also provided the total demand of water and the percentage of water demand at
each junction. With this data was possible to calculate the average water demand in each
node as one can see in the Table 1.
Table 1- %total water demand at each node
% total water demand
average water demand @ node, dm3/s
1 15,0% 20,34 2 15,5% 21,018 3 11,0% 14,916 4 16,0% 21,696 5 3,0% 4,068 6 10,5% 14,238 7 16,5% 22,374
8 12,5% 16,95 sum 100,0% 135,6
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The Figure2 represents the water network after the input of all initial provided data, which
includes the elevation of the nodes, the length of the pipes, the location of the tank and
the Jeans Factory.
Figure 2- Components of the network for the city
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The figure 2 represents the non-optimized water network that was modeled. Here it is
possible to see the location of the tank, the nodes and the pipes that connect them and a
pumping station. It is also possible to see the identification of the junctions and pipes
which are characterized in the tables below.
Table 2- Characterization of the Pipes
Length Diameter Roughness
Link ID m mm mm Pipe 1 344.85 176.2 0.05 Pipe 2 192.11 315 0.05 Pipe 3 290.71 220.4 0.05 Pipe 4 344.85 600 0.05 Pipe 5 286.27 312.8 0.05
Pipe 6 526.19 220.4 0.05 Pipe 7 258.06 312.8 0.05 Pipe 8 380.29 277.6 0.05 Pipe 9 268.52 396.6 0.05 Pipe 10 390.29 396.6 0.05 Pipe 11 219.03 396.6 0.05 Pipe 12 288.12 396.6 0.05 Pipe 13 50 396.6 0.05 Pipe 14 1 220.4 0.05 Pipe 15 2 220.4 0.05 Pipe 16 5 220.4 0.05 Pipe 17 7 220.4 0.05 Pipe 18 100 220.4 0.05
Pipe 19 7 220.4 0.05 Pipe 20 5 220.4 0.05
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The water network is constituted by 20 HDPE pipe PN10, each one with different lengths
and diameter, as is described in Tab2. In this table are marked the maximum and
minimum diameter of the pipes, in red and green, respectively. The diameters of the pipes
were chosen using a manufacturer table below.
Table 3- Manufacturer Table of Pipe diameters
outside diameter (mm)
thickness of the wall (mm)
internal diameter (mm)
OD e ID 125 7,4 110,2 140 8,3 123,4 160 9,5 141 180 10,7 158,6 200 11,9 176,2 225 13,4 198,2 250 14,8 220,4 280 16,6 246,8 315 18,7 277,6 355 21,1 312,8 400 23,7 352,6 450 26,7 396,6
500 29,7 440,6 560 33,2 493,6 630 37,4 555,2
710 42,1 625,8 800 47,4 705,2 900 53,3 793,4
1000 59,3 881,4 1200 70,6 1058,8
𝐼𝑛𝑡𝑒𝑟𝑛𝑎𝑙 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 = 𝑂𝑢𝑡𝑠𝑖𝑑𝑒 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 − 2 × 𝑇ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 𝑡ℎ𝑒 𝑤𝑎𝑙𝑙
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Table 4- Characterization of the Junctions
Elevation Base Demand Head Pressure
Node ID m LPS m m Junc 7 107.34 22.374 166.69 59.35 Junc 8 106.41 20.34 166.70 60.29 Junc 9 108.65 20.34 166.69 58.04 Junc 10 107.35 16.95 166.65 59.30 Junc 11 105.32 14.238 166.45 61.13 Junc 12 103.73 21.696 166.60 62.87 Junc 13 102.47 14.916 166.89 64.42 Junc 14 104.42 21.018 166.80 62.38 Junc 15 102.375 4.068 167.22 64.85
Junc 16 102.723 4.068 167.41 64.69 Junc j2 105.32 75 166.41 61.09 Junc j14 102.7 0 167.43 64.73 Junc j15 102.7 0 167.43 64.73 Junc j16 102.7 0 103.22 0.52 Junc j17 102.7 0 103.22 0.52 Junc j19 102.7 0 167.43 64.73 Junc j20 102.7 0 167.43 64.73 Junc j21 102.7 0 103.11 0.41 Junc j22 102.7 0 167.54 64.84 Junc j23 102.7 0 167.46 64.76 Junc j1 102.7 0 167.43 64.73 Junc j3 102.7 0 167.43 64.73
Junc j4 102.7 0 103.22 0.52
2.2 Water Demand
First, it was considered the Average Water Demand for the population of 135, 6 LPS and
later it was created the pattern in the Graph 1 according to their needs.
In this graph is possible to notice a smaller water demand during the night, because most
of the population is sleeping and the highest peaks registered in the morning, when people
are getting ready to leave the house and at the beginning of the night, when they arrive
home.
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Graph 1- Water Demand Population
The manufacture of Jeans has a high demand for water, so it was established the average
water demand of 75 LPS and was created a pattern for the demand during the 24 hours of
the day.
This factory is operating 24 hours a day but the demand is not constant during these hours.
As one can see in the pattern, the highest demand occurs in the morning period, drops a
little bit during the lunch hours and is reestablished at 15:00 to the morning values. After
19:00 the demand drops because part of the employees is not working and there is less
production during the night.
Graph 2- % average water demand jeans factory
0
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
%WD
%WD
0,000
0,500
1,000
1,500
2,000
2,500
3,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
% average water demand
% average water demand
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2.3 Pumping Station
If gravity is insufficient to supply water at an adequate pressure, then pumps need to be
installed to boost the pressure. Pumps can be either permanently operational or
intermittent. They can be controlled by a time-switch, pressure or a water level in a tank
or reservoir.
Pumping Stations are facilities that include pumps and other equipment for pumping the
water from the reservoir to the network, allowing the supply of water to the population.
Because of the demand of water by the city and industry, first it was designed a pumping
station with four pumps, three big pumps (from these three, two are active and one is in
the reserve) and a smaller active pump.
It was chosen Wilo as the pump manufacturer and the selection of the pumps. This process
take into account the duty points, flow and total head in the system and the characteristics
of the water.
Duty Points Water , Pure
Flow Total Head
Temperature (ºC)
Density (kg/m3)
Viscosity (mm2/s)
Pump5,6 and7 140 66 10 1 1,36 Pump1 70 66 10 1 1,36
After the selection of the pump that best fits the system, it was created in EPANET their
hydraulic curve and the efficiency curve, using the performance curve of the pump,
supplied by wilo-select.com
Figure 3- Performance Curve of Pump5, Pump6 and Pump7
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Figure 6- Cross Section of Pumping Station
Figure 4- Performance Curve of Pump1
Figure 5- Plan View of the Pumping Station
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2.3.1 Controls applied to the pumping station
;Automation for pump1
LINK pump1 CLOSED AT TIME 0
LINK pump1 OPEN AT TIME 9
LINK pump1 CLOSED AT TIME 12
;Automation for pump5
LINK pump5 CLOSED AT TIME 0
LINK pump5 OPEN AT TIME 15
LINK pump5 CLOSED AT TIME 19
These controls were applied to the system and they mean that from 0h to 8h, only the
pump6 works because the demand is not that big during the night. From 9h to 12, the
pump6 and the pump1 work together. From 12h to 15, only the pump6 works. At 15h the
pump5 works together with pump6 until 18h. And finally, from 18h to 24h, only the
pump6 works.
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2.4 Water Tank
The water tank is located north of the system, it has 50 m of diameter, the initial and
maximum level of 4,5m and minimum level of 0,5 m.
In this figure it’s possible to see that the tank is located 20 meters above the last node
elevation.
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Graph 3- Price of Electricity
3. Result of preliminary design of water network
3.1 Pressure distribution in the whole system and put screenshot
Figure 7- Minimum Pressure Distribution
This figure represents the minimum values of pressure distribution in the system. As
expected, the pressure near the pumping station is higher than in the rest of the network.
0
0,05
0,1
0,15
0,2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
€ kWh
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Figure 8- Maximum Pressure Distribution
In Figure8 is possible to see that the maximum pressure is high in the all system and
decreases, gradually, upstream of the pumping station.
Figure 9- Average Pressure Distribution
In Figure9, one can see that by the time when pressure values are average, they are higher
in the low areas of the city and lower in the higher areas of the city
With high pressures, there are more leakage problems and higher energy and maintenance
costs.
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3.2 Velocity in the Pipes
Graph 4- Velocity in the Pipes
In Graph4 are represented the maximum, minimum and average velocity in the system
pipes. It is possible to see that the highest velocities are registered on the pipes that are
part of the pumping station and the highest value is about 5 m/s.
0
1
2
3
4
5
Velocity in the Pipes
Minimum
Maximum
Average
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Figure 10- Average Velocity Distribution
The figure10 represents the velocity registered in the pipes during the most time of the
day, time statistics average. It’s possible to notice that the velocity in higher in the pipes
that connect the reservoir to the most functional pump, in the pipes that connect the
pumping station to the rest of the network and also the pipe that supplies water from the
network to the Jeans Factory. In the most parts of the network, the velocity in the pipes is
between 0,1 and 1 m/s.
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3.3 Operational state of the pumping station
By the end of the creation of the pumping station, the graph shows that the system flow
balance is good, since the flow that is produced is equal to the one that is consumed.
Table 5 - Pumping Costs
Percent Average Kw-hr Average Peak Cost
Pump Utilization Efficiency /m3 Kwatts Kwatts /day
pump5 16.67 67.96 0.25 89.76 89.83 11.50
pump6 100.00 68.76 0.25 95.15 116.35 64.16
pump7 0.00 0.00 0.00 0.00 0.00 0.00
pump1 12.50 66.83 0.26 88.67 88.70 8.52
Total Cost 84.18
Demand Charge
0.00
In this state, the pumps average efficiency was set to at 75% and, according to the energy
report on EPANET, the cost of energy per day, to pump water to the system is 84,18€.
Graph 5- System Flow Balance
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4. Cost reduction analysis
4.1 Description of proposed system optimization
Figure 11-Improved Water Network
In this part of the report, the aim was to create a more economically efficient water
network by reducing the pumping costs. In this improved system, represented in
Figure11, there are only two pumps, which performance curves are shown below. Only
the pump6 works during the 24 hours of the day and the pump1 is installed just as a
reserve.
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Figure 12- Performance Curve Pump6
Figure 13-Performance Curve Pump1
For cost reduction reasons, the Pump6 was controlled to perform at 0.9 relative speed at
0 hours into the simulation. This change in the speed alone is responsible saves about 20
€ per day, without affecting the balance of the system.
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Figure 14- System Flow Improved System
From the Figure14, one can see that the system is well balanced even though there’s only
one functional pump.
4.2 Cost reduction analysis
Table 6- Pumping Costs Improved System
Percent Average Kw-hr Average Peak Cost
Pump Utilization Efficiency /m3 Kwatts Kwatts /day
pump6 100,00 71,32 0,18 81,43 92,43 55,41
pump1 0,00 0,00 0,00 0,00 0,00 0,00
Total
Cost
55,41 €
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Graph 6- Comparison of pumping costs
With the improved system, the pumping costs were reduced in 34%. Since the minimum
of reduction of costs was settled in 25%, it is possible to say that the changes applied on
the pumping station were successful.
5. Conclusion
In a water distribution system, the components sharing capital costs are pumps and
pumping stations, pipes of various commercially available sizes and materials, storage
reservoir; and recurring costs such as energy usage.
In this simulation, for the reduction of costs, the only changes occur in the design of the
pumping station, it was reduced the number of pumps from 4 to 2 and changing the
relative speed of the pump in the improved system. In the comparison of pumping costs
was only take into account the costs of the energy used by the pumps but the comparison
should also include the prices of the pumps that were installed in each of the simulated
systems. So, there were obviously more ways to make the system more efficient such as
using the water from the tank to supply water in times were the demand is lower.
84,18
55,41
0
10
20
30
40
50
60
70
80
90P
rice
per
day
(€
)
Cost of Pumping
First Design Improved Design
