Atlas Copco GA 110 VSD+ Instruction Book page 26

Calculation examples
Text on figure
(1)
(2)
Example point X
High temperature rise, low water flow application, e.g. pre-heating of boiler feed water in open
circuit:
• Compressor unit: GA 160 VSD+ - 50 Hz
• Working pressure: 8 bar / 116 psi
• Water flow: 0.6 l/s / 1.27 cfm
• Water inlet temperature: 31 °C / 88 °F
• Water outlet temperature: 85 °C / 185 °F
The formula to calculate the amount of recovered energy results in (2):
• 4.2 x 0.6 x (85 - 31) = 136 kW ( ± as indicated on the curve)
The outlet temperature for a water flow of 0.6 l/s can be calculated backwards from formula (2):
• Toutlet = 31 + (136 / (4.2 x 0.6)) = 85 °C (185 °F)
Total pressure drop on waterside is (1):
• pd = (4.23 x 0.6²) + (1.62 x 0.6) = 2.5 kPa = 25 mbar (0.36 psi)
Example point Y
Low temperature rise, high water flow application, e.g. central heating in closed circuit:
• Compressor unit: GA 160 VSD+ - 50 Hz
• Working pressure: 8 bar / 116 psi
• Water flow: 4 l/s / 0.87 cfm
• Water inlet temperature: 47.5 °C / 117.5 °F
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Water outlet temperature (°C)
Water inlet temperature (°C)
Instruction book
9829 3178 63