Very often in an industry, different types, capacities and makes of compressors are connected to a common distribution network. In such situations, proper selection of a right combination of compressors and optimal modulation of different compressors can conserve energy.
Where more than one compressor feeds a common header, compressors have to be operated in such a way that the cost of compressed air generation is minimal.
If all compressors are similar, the pressure setting can be adjusted such that only one compressor handles the load variation, whereas the others operate more or less at full load.
If compressors are of different sizes, the pressure switch should be set such that only the smallest compressor is allowed to modulate (vary in flow rate).
If different types of compressors are operated together, unload power consumptions are significant. The compressor with lowest no load power must be modulated.
In general, the compressor with lower part load power consumption should be modulated.
Compressors can be graded according to their specific energy consumption, at different pressures and energy efficient ones must be made to meet most of the demand.