Minimum system water volume calculations, Deltachill ™ chillers, Design features & information – Airedale DeltaChill FreeCool 110kW - 1080kW User Manual
Page 22
DELTACHILL
™
Chillers
22
Chillers
Technical Manual : 7022932_V1.9_11/2013
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
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/minute) x Minimum Compressor Run
Time (mins) x Chiller Loading Factor
Where
V
min
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
Example:
Chiller at 35°C Ambient, 7/12°C Water, Model DCC033DR-08BMM0 with a
permanent load of 129.6kW
Unit capacity at design conditions
= 326 kW
Permanent Heat Load
= 129.6kW
Minimum Turndown
= 27%
V
min =
326 x 60
x 2 x
(326 x 0.27)
x 1.2 = 1522 Litres
4.19 x 5
129.6
METHOD 2
Where the system permanent heat load is unknown:
V
min
=
Water Flow Rate (litres/hour) x Minimum Turndown Ratio x
1.2
Maximum number of compressor starts (per hour)
Example:
Chiller at 35°C Ambient, 7/12°C Water, Model DCC033DR-08BMM0
Unit capacity at design conditions
= 326 kW
Minimum Turndown
= 27% (0.27)
V
min =
326 x 3600
x 0.27 x 1.2
= 1512.5 Litres
4.19 x 5
12