Very good article.

I want to add a thought about the current practice of specifying receivers. When the majority of compressors sold and used were reciprocating compressors, receivers were provided as part of the system to act as a muffler, a point for water separation, and for air storage while the compressor cycled during lulls in plant air usage. A well designed system gave careful consideration to receiver size and placement. The design considerations eventually became rules of thumb, so that the design effort in sizing a receiver was eliminated and design effort reduced.

Today, I would venture that most new compressed air plants use centrifugal oir rotary-screw type compressors, which can more easily throttle from full load to part-load to match plant demand. These machines do not pulsate or require "muffling" to reduce noise and vibration. Since these machines can run at part load, the margin between compressor outlet pressure and plant pressure can be minimized to reduce the horsepower required to generate compressed air.

Based on this premise, I have concluded receivers may not be as important to a compressed air system as in past times. I will agree a receiver is imprtant for reciprocating air compressors, but in future designs for centrifugal and rotary screw systems I plan to reduce or eliminate the installation of air receivers and save the space in the equipment room. If there a receiver is insisted on, I will oversize the main compressed air header for the "stored" volume of air and gain the value of reduced distribution pressure loosses that Roy Stuhlman so well presents in his article.

Thanks for the ideas and potential for savings presented.

Ried Jacobsen