Power Consumption and Efficiency

We have to distinguish two levels of power consumption:

• The power consumption of the blower P producing compressed air.

• The total power demand PT = P/(r|b ■ r|m ■ r|g), with r|b = 0.8 for the blower (newer equipment), r|m = 0.95 for the motor and r|g = 0.95 for the transmission (Mueller et al. 2002).

The power demanded for compression is:

pout

where k = 0.2857 for dry air, pinis the pressure before compression, poutis the pressure after compression, T is the temperature (K), R = 8.314 J (mol K)-1 is the gas constant and QGp is the mass flow rate of air (kg h-1).

Considering: 1

h 3600 s s we obtain:

3600 3.6

pout kW

Now we calculate the efficiencies using Eqs. (5.77) and (5.80): SOTR

and for the total efficiency:

0 0

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