Ultima Compact™
Chillers
19
Ultima Compact 30-150kW Technical Manual 9690553 V1.2.0_10_2019
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.
Only use the SHC data when calculating fluid volume. Use figure for 0% concentration (100%
water). When calculating volumes of glycol solutions, refer to glycol data correction factors and
convert the water volume.
CAUTION
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 (CLF)
Example: 150kW Cooling Duty at 35°C Ambient and 7/12°C Water
Minimum Turndown =
0.25 (25% : 4 Compressors)
150 x 3600
x 0.25 x 1.2
= 773.3 Litres
4.19 x 5
10
Where
V
min
is the minimum water volume in litres
Minimum Compressor Run Time is
6 minutes
CLF = Minimum Turndown x Cooling Duty x 1.2
Permanent Heat Load
METHOD 2
Where the system permanent heat load is unknown:
V
min
=
Cooling Duty x 3600
Cp x
Δt
x Min Turndown
x 1.2
Maximum number of Compressor starts(per hour)
V
min
=
Water Flow Rate (litres/hour) x Min. Turndown x 1.2
Maximum number of Compressor starts(per hour)
Please refer to Mechanical Data for information for Minimum Turndown for each model.
V
min
=
150 x 60
x 6
x
0.25 x 150 x 1.2
=
1546.5 Litres
4.19 x 5
75
Example: 150kW Cooling Duty at 35°C Ambient and 7/12°C Water
Permanent Heat Load:
75kW
Minimum Turndown =
0.25 (4 Compressors = 25%)
Ins
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