Post on 21-Dec-2015
SIMDEUM: water demand in distribution network modelling Mirjam Blokker
20 November 2009 – Colloquium TU Delft
2Watercycle Research Institute
From transport model …
3Watercycle Research Institute
… to a more detailed model …
4Watercycle Research Institute
… to an all-pipes model
5
Demand allocation: top-down or bottom-up?
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:000
1000
2000
3000
4000
tij d
Q (
m3/h
)
Sat
Sun
Mon
Tue
Wed
Thu
Fri
0:00 6:00 12:00 18:00 24:000
1
2
3
4
5
6
Q (
m3/h
)
Tue 13 J une
Wed 14 J une
0:00 6:00 12:00 18:00 24:000
0.05
0.1
0.15
0.2
0.25
Q (
l/s)
6Watercycle Research Institute
Is a bottom-up demand allocation the future?
Practical considerations
Is it necessary for specific purposes?• Hydraulics influence WQ processes• Choice in spatial and temporal aggregation influences
hydraulic model results• Effect of Bottom-Up or Top-Down demand
allocation in real network
7Watercycle Research Institute
Pulse Pulse IntensityIntensity
FlowFlowIntensityIntensity
TimeTime
TimeTime
),,( DIBQ
elsewhere
DTI
DIB
0
),,(
Basic principle of stochastic demand model
Source: Buchberger, 2007
8Watercycle Research Institute
SIMDEUM: parameters follow from surveys and information on appliances
0 6 12 18 240
2
4
6
time (h)
multiplier
0 6 12 18 240
0.2
0.4
0.6
0.8
1
time (h)
cdf
0 5 10 150
0.05
0.1
0.15
0.2
Ftoilet flush
cdf
0 20 400
0.02
0.04
0.06
Fkitchen tap
cdf
0 0.5 10
0.1
0.2
0.3
0.4
0.5
IPRP
(l/s)
cdf
0 0.1 0.20
2
4
6
8
10
Ikitchen tap
(l/s)
cdf
0 1 20
0.02
0.04
0.06
0.08
0.1
time (min)
Q (l/s)
0 30 60 90 1200
0.05
0.1
0.15
0.2
time (min)
Q (l/s)
0 100 2000
0.5
1
1.5
2
2.5
DPRP
(s)
cdf
0 10 20 300
0.02
0.04
0.06
0.08
0.1
Dshower
(min)
cdf
0 50 1000
0.01
0.02
0.03
Dkitchen tap
(s)
cdf
0 30 60 90 1200
0.05
0.1
0.15
0.2
time (min)
Q (l/s)
pdfArray
cdfArray
WC w/o saving
WC w/ saving
washing m achine
dishwasher
Duration
Intensity
When
PRP SIMDEUM
How often did you flush the
toilet?
How long did you take a
shower for?
When did you get up, leave the house, go
to bed?
Siemens typical
patterns
I
D
No flow measurements
9Watercycle Research Institute
Compare: flows
43 homes
Zandvoort, 1000 homes
office
10Watercycle Research Institute
wat
er a
ge (
h)
0
2
4
6
8
10
0
2
4
6
8
10
12
14
16
wat
er a
ge (
h)
00:00 06:00 12:00 18:00 00:000
5
10
15
20
25
00:00 06:00 12:00 18:00 00:000
10
20
30
40
50
measurements
a b
c d
compare: travel timesw
ater
age
(h)
0
2
4
6
8
10
0
2
4
6
8
10
12
14
16
wat
er a
ge (
h)
00:00 06:00 12:00 18:00 00:000
5
10
15
20
25
00:00 06:00 12:00 18:00 00:000
10
20
30
40
50
ModelTD
measurements
a b
c d
wat
er a
ge (
h)
0
2
4
6
8
10
0
2
4
6
8
10
12
14
16
wat
er a
ge (
h)
00:00 06:00 12:00 18:00 00:000
5
10
15
20
25
00:00 06:00 12:00 18:00 00:000
10
20
30
40
50
ModelBU
(95% c.i.)
ModelBU
()
ModelTD
measurements
a b
c d
11Watercycle Research Institute
Practical considerations – automatic linking
data
SIMDEUM0 6 12 18 24
0
0.1
0.2
0.3
0.4
time (hr)
flow
(l/
s)
total fl ow
fl ow hot water
Censusdata
Landregister
Pipe informationsystem connections
Customerinformation
12Watercycle Research Institute
Skeletonize and aggregation
13Watercycle Research Institute
Hydraulics influence water quality processes
High flows can re-suspend particles or slough biofilm
Dissolved substances move with the water; may also disperse in case of laminar flows
Non-conservative substances (chlorine) decrease under influence of contact time and e.g. temperature
…
14Watercycle Research Institute
(AOC and dissolved solids)
Suspended solids
© J.H.G. Vreeburg
Regulardeposition &resuspension
Biofilmformation &sloughing
Corrosion
Precipitation &flocculation
Suspended solids
incidental
resuspension(AOC and
dissolved solids)
WQ processes in the distribution network
15Watercycle Research Institute
Suspended solids
© J.H.G. Vreeburg
Regulardeposition &resuspension
Biofilmformation &sloughing
Suspended solids
incidental
resuspension
hydraulic processes in the distribution networkparticles / wall interaction
Maximum shear stress or velocity
16Watercycle Research Institute
(AOC and dissolved solids)
© J.H.G. Vreeburg
Biofilmformation
Corrosion
(AOC and dissolved solids)
hydraulic processes in the distribution networkdissolved substances / wall interaction
Residual chlorine is related to• Contact time (travel time)• Temperature• Biostability (incoming water quality)
17Watercycle Research Institute
(AOC and dissolved solids)
(AOC and dissolved solids)
hydraulic processes in the distribution networkdissolved substances / dispersion
vmax
v
Stagnant flow, v = 0 m/sLaminar flow, vmax = 2 * vmean = 0,04 m/sTurbulent flow, vmax = 1.2 * vmean = 1,0 m/s
vmax
v
18Watercycle Research Institute
SIMDEUM: SIMulation of Demand, an End-UseModel
SIMDEUM was developed and validated with flows and travel times
Conclusion: SIMDEUM generates realistic demand patterns, and thus a proper BU model can be constructed.
Next step:Determine difference between current (TD) method and new (BU) method
19Watercycle Research Institute
Choice in spatial and temporal aggregation influences hydraulic model results
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:000
0.05
0.1
0.15
0.2
v [m
/s]
time step 5 min
time step 15 min
time step 1 h
20Watercycle Research Institute
00:00 06:00 12:00 18:00 00:000
1
2
3
4
5
Q [
103 m
3/h
]
Wednesday 25-J ul-2007
Thursday 26-J ul-2007
Correlation – level pumping station
0 1 2 3 4 50
1
2
3
4
5
pattern 1
patt
ern
2
R = 0.99
Auto correlation (5 min)R = 1R = 1
21Watercycle Research Institute
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:000
2
4
6
Q [
m3/h
]
Tuesday 13-J un-2006
Wednesday 14-J un-2006
Correlation – level 150 homes
0 1 2 3 4 50
1
2
3
4
5
pattern 1
patt
ern
2
R = 0.68
Auto correlation (5 min)R = 0.84R = 0.80
22Watercycle Research Institute
00:00 06:00 12:00 18:00 00:000
200
400
600
800
1000
Q [
l/h]
Tue-19-Apr-2005
Wed-20-Apr-2005
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
pattern 1
patt
ern
2
R = 0.26
Auto correlation (5 min)R = 0.66R = 0.44
Correlation – level single home
23Watercycle Research Institute
Effect of Bottom-Up or Top-Down demand allocation in real network (Purmerend)
Two network models:• BU: model + SIMDEUM demand patterns
• Each connection has unique demand pattern• Time step is 0.01 h (36 s)
• TD: model + sum demand pattern• Sum pattern is the total flow of BU model• Time step is 5 min
24Watercycle Research Institute
Purmerend network
Diameter
60.00
150.00
200.00
250.00
mm
Area A (12.3 km)
Ø63 PVC 5.5% Ø90 PVC < 2.0% Ø100 AC 57.0% Ø110 PVC 8.7% Ø150 AC < 2.0% Ø160 PVC 4.8% Ø200 AC 14.0% Ø250 AC 3.8% Ø300 AC < 2.0% rest 4.7%
25Watercycle Research Institute
Effect of Bottom-Up or Top-Down demand allocation in real network (Purmerend)
1. Cross correlation with respect to incoming flow
2. Flow direction reversals
3. Flow regime: stagnant, laminar, turbulent flow
4. Travel time
5. Maximum velocity
26Watercycle Research Institute
cross correlation to incoming flow
cross correlation to incoming flow
0.0-0.2
0.2-0.4
0.4-0.60.6-0.8
0.8-1.0
1. Cross correlation
BU TD=1
27Watercycle Research Institute
flow direction reversals
flow direction reversals
uni-directional flow
15%
25%35%
45%
2. Flow direction reversals
BU TD
Q
QQFDR
=0: no reversals=1: 50% reversals
28Watercycle Research Institute
% stagnant flow
% stagnant flow
0.0-0.2
0.2-0.4
0.4-0.60.6-0.8
0.8-1.0
3.a Stagnant flow
BU TD
Mainly at connection lines
29Watercycle Research Institute
% laminar flow
% laminar flow
0.0-0.2
0.2-0.4
0.4-0.60.6-0.8
0.8-1.0
3.b Laminar flow
BU TD
Also at connection lines
30Watercycle Research Institute
% turbulent flow
% turbulent flow
0.0-0.2
0.2-0.4
0.4-0.60.6-0.8
0.8-1.0
3.c Turbulent flow
BU TD
31Watercycle Research Institute
travel time [h]
travel time [h]
0-6
6-12
12-1818-24
>24
4. Travel times
BU TD
At 0:00 h (simulation run 48 h)
32Watercycle Research Institute
Travel times, average or accounting?
…the longer water is in contact with the fabric of the distribution system, the higher the propensity for water quality problems to occur, and it is feasible that a small volume of poor quality water could conceivably harbor enough bacteria to cause failed regulatory samples and pose a public health risk.
33Watercycle Research Institute
maximum velocity [m/s]
maximum velocity [m/s]
0
0.0-0.1
0.1-0.20.2-0.3
> 0.3
5. Max flow velocities
BU TD
0 0.05 0.1 0.15 0.2 0.25 0.30
0.05
0.1
0.15
0.2
0.25
0.3
0.35
vmax
[m/ s], standard model
v max
[m
/s],
SIM
DEU
M m
odel
connection lines
100 mm
150 mm
200 mm
300 mm
400 mm
500 mm
34Watercycle Research Institute
Quantifying effect of Bottom-Up or Top-Down demand allocation in real network
1. Cross correlation
2. Flow direction reversals
3. Flow regime:
a. Stagnant flow
b. Laminar flow
c. Turbulent flow
4. Travel time
5. Maximum velocity
1. Large effect on diameter < 200 mm
2. Large effect
3.
a. Effect in branch ends
b. Effect in branch ends
c. Limited effect
4. Limited effect on average travel times, more effect on variation
5. Effect especially noticeable on smaller pipe diameters and in branch ends
35Watercycle Research Institute
When is a BU model required?
Tracing contaminants: when is the water save again, including for customers at the outskirts of the network?
Id. for residual chlorine
Hydraulics and water quality in branched networks
DispersionFlow direction reversals
Maximum velocitiesNetwork fouling
36Watercycle Research Institute
Is a bottom-up demand allocation the future?
Practical considerations• Yes – automatic demand generation and allocation• Possibly followed by skeletonization / aggregation step
Is it necessary for specific WQ purposes?• Self-cleaning network design: yes, in simplified form
(uni-directional only)• Tracing dissolved substances: yes in the outskirts
(dispersion, flow direction reversals); yes in case maximum travel time is important (non-conservative substances)
SIMDEUM: water demand in distribution network modelling Mirjam Blokker
20 November 2009 – Colloquium