Daikin VRV-WIII Service Manual download pdf (Page 16)

• Water-cooled design guide

• VRV Systems • Water-cooled design guide

3 Water piping elements

3 - 3 Water pipes

3 - 3 - 4 Example of dimensioning the water pipes:

RECOMMENDATION

1 in VRV-WIII capacity tables 4 water flows are mentioned for each model/connection ratio: 50, 60, 96, 120 l/min

2 water flows of either 60 or 96 l/min are advisable in order to maintain a balance between pipe diameter and pressure losses. As water flow

increases, pipe diameter reduces whereas pressure losses increase with increased water flow.

Procedure for pipe selection:

• reverse return piping was chosen

• the water flow should be determined for each section of the water circuit

• by means of the using the friction loss diagram (fig.1), the diameter should be determined based on following input:

- water flow

- recommended domain of water velocities

- recommended domain of linear pressure losses (100-400 Pa/m)

• the total linear friction losses should be determined by multiplying the pressure drop (Pa/m) obtained from the diagram, with the pipe length.

• local pressure losses should be calculated for special fittings like elbows, T-connections, reducers, etc. The values can be obtained from pipe

manufacturers' catalogues. The following table can be also used: the equivalent length should be multiplied with the pressure drop (Pa/m)

determined before.

Equivalent length of local friction loss (m)

• total friction loss in pipes should be calculated by adding the linear and local friction losses.

The total friction loss in pipes will serve further when selecting the circulating pump.

Nominal pipe size

mm 15 20 25 32 40 50 65 80

in 1/2 3/4 1 1 1/4 1 1/2 2 2 1/2 3

Elbow

0.5 0.6 0.9 1.1 1.3 1.6 2.1 2.6

T-connection straight through

0.3 0.4 0.6 0.8 0.9 1.1 1.4 1.7

T-connection through branch

1.0 1.3 1.8 2.3 2.8 3.5 4.2 5.7

Gate valve

0.1 0.15 0.2 0.3 0.35 0.4 0.5 0.6

Reducer (3/4)

0.1 0.15 0.2 0.3 0.35 0.4 0.5 0.6

Globe valve

4.56.59.01116212630

1.0 m/s

15 mm

80 mm

100 mm

125 mm

150 mm

200 mm

250 mm

300 mm

350 mm

65 mm

50 mm

40 mm

32 mm

25 mm

20 mm

1.6 m/s

2.5 m/s

4.0 m/s

0.63 m/s

0.4 m/s

600

400

300

200

100

0.2

2346810 20304060

0.3 0.4 0.6 0.8 1

100 20080

0.03 0.04 0.06 0.08 0.1

PRESSURE DROP, Pa/m

Fig. 1 VOLUMETRIC FLOW RATE, L/s

Black Steel Pipe

Friction Loss for Water in Commercial Steel Pipe

nominal pipe sizes

1 2 ... 11 12 13 14 15 16 17 18 19 20 21 ... 42 43

Comments to this Manuals

No comments

Daikin VRV-WIII Service Manual Page 16

Comments to this Manuals

Related products and manuals for Split-system air conditioners Daikin VRV-WIII