Airedale OptiChill FreeCool 500kW - 1365kW - Manual (Page 21)

Chillers OPTICHILL
™
Chillers
21
Technical Manual : 6530166 V1.6.0 02_2013
Design Features & Information
SPECIFIC HEAT CAPACITY (SHC)
% Ethylene Glycol Concentration 0% 10% 20% 30% 40%
Specific Heat Capacity (kJ/kgK) (1) 4.190 4.115 3.901 3.686 3.474
% Propylene Glycol Concentration 0% 10% 20% 30% 40%
Specific Heat Capacity (kJ/kgK) (1) 4.190 4.139 4.033 3.903 3.749
(1) Data quoted for water/glycol solutions at a nominal temperature of 10°C.
CAUTION Only use the SHC data when calculating fluid VOLUME. USE figure for 0% concentration
(100% water) when applying Glycol Correction Factors, refer to
Glycol data , on page 32.
MINIMUM SYSTEM WATER VOLUME CALCULATIONS
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 = 20%
Example: 600kW Chiller at 35°C Ambient, 7/12°C Water, Model OPC600HED10 with a
permanent load of 360kW
Permanent Heat Load = 360kW
Minimum Turndown = 20%
V
min =
605.1 x 60
x 5 x
121
x 1.2 = 3495 Litres
4.19 x 5 360
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)
Minimum Turndown = 20%
Example: 600kW Chiller at 35°C Ambient, 7/12°C Water, Model OPC600HED10
Minimum Turndown = 0.20 (20%)
V
min =
605.1 x 3600
0.20 x 1.2 x
5
= 2079 Litres
4.19 x 5 60