Atlas Copco ER S-1, Instruction Book, Page: 29 / 40

20/06/2011 PM 9845 0512 02 Page 27 of 36
9.6. Recoverable energy
The recoverable energy is calculated using the following formula:
RECOVERED ENERGY (kW) = 4.2 x water flow (l/s) x water temperature rise (°C)
The maximum recoverable energy is approx. 70-80% of the shaft power of the compressor.
Compared to the electrical input power the percentage will be lower for air cooled compressors, because the fan also
requires some power that is not recoverable.
In VSD compressors the recoverable energy is also a little lower because the drive also requires some power that is not
recoverable.
Formula:
Q [l/s] = Recovered energy [kW]
4,2*T[°C]
9.7. Data for low temperature rise/high water flow systems
In the tables below, typical values are provided for the above mentioned type of water flow system.
11
+
-30 kW range & VSD (ER S-1)
Parameters Units 11+ kW 15+ kW 18+ kW 22+ kW 26+ kW 30 kW
Recoverable energy kW 8.3 11.3 13.5 16.5 19.5 22.5
Water flow l/min 11.8 16.1 19.3 23.6 27.9 32.2
Temperature at inlet ºC 50 50 50 50 50 50
Temperature at outlet ºC 60 60 60 60 60 60
Pressure drop bar 0.008 0.014 0.019 0.027 0.037 0.048
30
+
-45 kW range (ER S-2)
Parameters Units 30+ kW 37 kW 45 kW
Recoverable energy kW 22.5 27.8 33.8
Water flow l/Min 32.2 39.7 48.3
Temperature at inlet °C 50 50 50
Temperature at outlet °C 60 60 60
Pressure drop bar 0.129 0.192 0.278
37
+
-75 kW & VSD range (ER S-2)
Parameters Units 37
+
kW
(VSD)
45
+
kW
(VSD)
55 kW
(VSD)
75 kW
Recoverable energy kW 27.8 33.8 41.3 56.3
Water flow l/Min 39.7 48.3 59.0 80.4
Temperature at inlet °C 50 50 50 50
Temperature at outlet °C 60 60 60 60
Pressure drop bar 0.192 0.278 0.405 0.727