Airedale TurboChill FreeCool 200kW - 1830kW - Manual (Page 36)

36 Chiller Technical Manual 7525355 V1.1.0_03_2013
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Chillers TurboChill™ Air Cooled and FreeCool
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.
Minimum System Water Volume Calculations
METHOD 1
(Preferred Method)
Where the system permanent heat load is known, the minimum water volume in litres Vmin is:
Vmin = 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 = 1 compressor – 30%
2 compressors – 15%
Example:
750kW output at 35°C Ambient and 7/12°C Water
Permanent Heat Load = 300kW
Minimum Turndown = 15% (2 compressors)
METHOD 2
Where the system permanent heat load is unknown:
Vmin = Water Flow Rate (litres/hour) x Minimum turndown ratio x 1.2
Maximum number of compressor starts (per hour)
Minimum Turndown = 1 compressor – 30%
2 compressor – 15%
Example: 750kW output at 35°C Ambient and 7/12°C Water
Minimum Turndown = 0.15 (15% 2 compressors)
= Vmin = 750 x 60 x 2 x (750 x 0.15) x 1.2 = 1935 Litres
4.19 x 5 300
Vmin = 750 x 3600 x 0.15 x 1.2
4.19 x 5
12
1935 Litres =