Daikin UWL040B5 - Page 27

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Water Storage Tank Volume Calculating
Calculating volume of expansion water tank
Vmin is referred to the below table:
An expansion water tank with a proper volume must be installed to adapt to water volume changes as the
temperature changes and avoid freezing burst and pressure instability at the water pump inlet.
The expansion water tank can also be used to supplement water and discharge air.
Calculating volume of expansion water tank.
V
p
: effective volume of the expansion water tank (volume of water between the signal pipe and the
overow pipe). m
3
α: volume expansion coefcient of water (α =0.0006/°C)
t: max. water temperature variation °C.
V
s
: water volume in the system (total water volume in the system and pipes) m
3
Model UWL030B5 UWL040B5
Setting EWT (ºC) Vmin. (L)
20 127 117
19 137 126
18 149 137
17 164 150
16 181 165
15 203 184
14 231 208
13 267 239
12 317 280
11 390 339
10 507 430
Note:
1. The total water volume of the entire hydraulic system includes the water in main pipe, water tank
and terminal equipments, in which the 2-way valve is open.
2. If the water volume (V) while the unit is running is less than Vmin, it's recommended to install a
water tank of (Vmin-V)L, or it will cause the unit frequent ON/OFF.
3. The Vmin in the table is calculated based on nominal cooling water ow and 5ºC anti-freeze. If the
water ow and anti-freeze temperature change, related Vmin will change.
4. The table is applied for the water volume selection of normal chiller, not for the chiller under low
leaving water temperature with glycol.
sP
VtV ×∆×= α