Lecture 4

Tank Volume

The Tank Volume:To get the tank volume, we have to get the

total hourly demand and the hourly pumping.

T

o

t

a

l

H

o

u

r

l

y

D

e

m

a

n

d

Hourly Pump Flow

Tank Volume

The Pump:The pump will operate 18 hours/ day

The pump flow:Let Qtotal in our network = 6392.035 m3/day, then

Qpump = Qtotal / #of pumping hours

= 6392.035 / 18 = 355.11307 m3/hr Where : Qtotal = ∑ Q for all types of demand at all nodes in

the network (m3/day)

Choose (6) consecutive hours to shut off the

pump in the day.

You have to choose hours which has

minimum demand to get minimum tank

volume.

The hourly Pumping

We have to find the demands per hour in the network using the pattern factors for every type of demand.

Q domestic at a given hour = domestic hour factor*Qavg_domestic

Q public at a given hour = public hour factor*Qavg_public

….. etc

Find the total demand required at every hour Qtotal at a given hour = Q domestic + Q Public + Q mosque

…etc , at the given hour

The total hourly demand:

Time ( hr )Domestic Pattern

QdomesticSchool Pattern

Qschool Public

Pattern

Qpublicmosque Pattern

Qmosque Qtotal

m3/h m3/h m3/h m3/h m3/h

1 0.55 132.6270 0

0.0645 1.548 00 134.175

2 0.4 96.4560 0

0.0645 1.548 00 98.004

3 0.3 72.342 0 0 0.579 13.896 0.6 0.702 86.9404 0.4 96.456 0 0 0.579 13.896 2.08 2.4336 112.7865 0.35 84.399 0 0 1.287 30.888 0.6 0.702 115.9896 0.53 127.804 0 0 1.287 30.888 0.89 1.0413 159.734

7 0.85 204.9691.32 0.5148

0.8045 19.308 0.30.351 225.143

8 1.1 265.2542.43 0.9477

0.8045 19.308 0.60.702 286.212

9 1.3 313.4821.59 0.6201

2.2525 54.06 00 368.162

10 1.575 379.7964.86 1.8954

2.2525 54.06 00 435.751

11 1.575 379.796 1.48 0.5772 0.994 23.856 0 0 404.22912 1.5 361.710 1.37 0.5343 0.994 23.856 0.3 0.351 386.451

If (Qtotal – Qpump) > 0 , then water from tank is

need.

If (Qtotal – Qpump) < 0 , then water goes to tank.

∑ Q From tank = ∑ Q To tank

Tank Volume

Time ( hr )Qtotal Qpump Qtotal - Qpump

From tank To tank

m3/h m3/h m3/h

1134.175

0 134.175 134.175 0

2 98.004 0 98.004 98.004 0

3 86.940 0 86.940 86.94 0

4112.786

0 112.786 112.7856 0

5 115.989 355.11 -239.121 0 239.121

6 159.734 355.11 -195.377 0 195.3765

7 225.143 355.11 -129.967 0 129.9672

8 286.212 355.11 -68.898 0 68.8983

9 368.162 355.11 13.052 13.0521 0

10 435.751 355.11 80.641 80.6409 0

11 404.229 355.11 49.119 49.1187 0

12 386.451 355.11 31.341 31.3413 0

Tank Volume:

24

Tank Volume:Many trials should be made. Choose the most

economical tank which has the minimum volume.

An additional volume has to be added to the total volume as a provision for fire or repair. This volume has its own pipes; it means that it is not available for common use.

Vi=∑ Q From tank = ∑ Q To tankSo, Tank Volume = 1.05 * Vi +240

Tank Dimensions:Assume a tank with 6-15 m base diameter,

then find its height.Height of tank 5-10 m.Max. Height of tank= 10m

Questions