Airedale OptiChill FreeCool 500kW - 1365kW - Manual (Page 51)

Chillers OptiChill Freecool
Chillers
51
Technical Manual : 7197700 v1.2.0 02_2013
Minimum system water volume
METHOD 1
(Preferred Method)
Where the system permanent heat load is known, the minimum water volume in litres V
min
is:
V
min
= Water Flow Rate (litres/min)
x Minimum Compressor Run Time (min)
x Chiller Loading Factor
Chiller Loading Factor = Minimum Turndown (kW) x 1.2
Permanent Heat Load
Minimum Turndown = 17.5%
Example: 922.4kW Chiller at 35°C Ambient, 7/12°C Water, Model OFC095R20-87MS6 with a
permanent load of 553kW
Permanent Heat Load = 553kW
Minimum Turndown = 17.5%
V
min =
922.4 x 60
x 5 x
922.4 x 0.175
x 1.2 = 4631 Litres
4.186 x 5 553
METHOD 2 Where the system permanent heat load is unknown:
V
min
= Water Flow Rate (litres/hour)
x Minimum Turndown
x 1.2
x Minimum Compressor Run Time (Hours)
+ Unit water volume
Minimum Turndown = 17.5%
Example: 922.4kW Chiller at 35°C Ambient, 7/12°C Water, Model OFC095R20-87MS6
Minimum Turndown = 0.175 (17.5%)
V
min =
922.4 x 3600
0.175 x 1.2 x
5
+ 1657= 4433 Litres
4.186 x 5 60