ULTIMA
™ REMOTE AIR COOLED
Chillers
12
Chillers
Technical Manual : Part No 6259485 V1.15.0_08_2018
Design Features & Information
MINIMUM SYSTEM WATER VOLUME CALCULATIONS
METHOD 1
Where the system permanent heat load is known:
Vm =
Water Flow Rate (litres/minute) x Minimum Compressor Run Time
(mins) x Chiller Loading Factor
Where
Vm is the minimum water volume in litres
Minimum Compressor Run Time is 2 minutes
Chiller Loading Factor =
Minimum Turndown (kW) x 1.2
Permanent Heat Load
The Chiller Loading Factor limits:
Max
1.00
Min
0.25
Example
250 kW Chiller, 7/12°C Water, Model URAC250DQ with a permanent load of 95 kW
litres
1085
95
1.2
60
2
5
4.19
60
250
Vm
METHOD 2
Where the system permanent heat load is unknown:
Vm =
Water Flow Rate (litres/hour) x Minimum Turndown Ratio x 1.2
Maximum Compressor Starts Per Hour
Where
Minimum Turndown Ratio = Minimum Stage Capacity (kW)
Chiller Full Capacity (kW)
Example
250 kW Chiller, 7/12°C Water, Model URAC250DQ permanent load unknown.
litres
1031
12
1
x
1.2
x
250
60
x
5
x
4.19
3600
x
250
Vm
Method 1 is always preferred.