1. Factors
   1. 4 CFM = 1 Motor HP
   2. 1HP = 0.829 kW
   3. 1 CFM= 0.207kW
2. Energy
   1. Losses
      1. Heat of Compression 80%
      2. Desciccant Dryer 6%
      3. Filter and Leaks ~ 6%
      4. Pneumatic to Mechanical Conversion ~2%
      5. Useful Energy Output ~ 9%
      6. measures
   2. 90% of energy to produce air is lost
   3. Use of Variable Speed Drive (VSD)
      1. saves energy
   4. Measures
      1. Compressor sizing
      2. System pressure to a minimum
      3. Leaks
      4. Heat recovery
      5. Inappropriate use of air
      6. Optimise air use
      7. Use cooler inlet air
3. Compressor
   1. Positive Displacement
      1. Reciprocating and Rotary
         1. Single or double acting
            1. single compresses air in one direction of its stroke
            2. double compresses air in both strokes/more efficient
         2. Single or multi stage
            1. compresses air from inlet to discharge pressure in one operation
            2. compresses from inlet to discharge in two or more operations/more efficient
   2. Dynamic
      1. Centrifugal and Axial
   3. Duty Cycle
      1. % time running under load
4. Cooling
   1. Air
   2. Water
   3. Oil
      1. holds internal temp -discharge oil relatively cool
      2. discharge air is clean & free from burned oil or carbon
5. Coolers
   1. Intercoolers
      1. removes heat of compression between stages
         1. cools air less volume
            1. more efficiency
   2. After-cooler
      1. heat exchanger
         1. removes heat from compressor lubricant/ heat of compression
      2. located between compressor and air dryer
6. Types
   1. Rotary Air Compressors
      1. Oil cooled rotary helical screw compressor
         1. holds internal temp -discharge oil relatively cool
         2. discharge air is clean & free from burned oil or carbon
      2. Non lubricating rotary screw and lobe compressor
      3. Sliding vane rotary compressor
   2. Centrifugal Air Compressors
      1. Oil free
      2. If provides load <80% it blows off/inefficient
      3. Should be used for base load running 100% at all times
   3. Reciprocating Air Compressors
7. Dryers
   1. Refrigerated
   2. Desiccant
   3. Membrane