Very High Head per impeller designs     are at risk of generating high operational losses   Select impeller configurations to avoid extreme head per impeller designs (in excess of 3900m)

Maintain Design Simplicity With Optimum Thermodynamics Design compression systems for optimum thermodynamics by selecting a number of intercooled compression stages This will: Minimise Power Requirements Avoid excessive discharge temperatures Avoid high head

	High Performance for new designs can be achieved by correctly defining your design envelope	JIP Population shows that machines operating off design suffer progressively higher losses
	Recommendations: Optimise the map so that the bulk of operating data falls within the peak efficiency operating region A rewheel may be beneficial where machines whose current duties are different from the original design intent Investigate all operating scenarios and verify that the performance map captures them all

	Avoid Extensive Reliance on Recycle Operation to avoid damaging surge conditions

	Avoid Reliance on Maximum Flow Capacity Choke Flow has characteristically low efficiency High Velocities and therefore High Delta P High incidence Losses Don’t over-stretch the choke region Degradation erodes choke first

	JIP Population Operations data shows that High Tip Speed Impeller Designs (in excess of 280m/s), Develop High Operational Losses (in excess of 10%)
		Higher Tip Speeds lead to Higher Gas Velocities, and Higher Diffuser Pressure Loss * Velocity rises with constricted or fouled diffuser passages * Diffuser pressure losses increased with: Choke flows Fouled/constricted diffuser Corrosion

Maximum Losses Head     Efficiency Dehydrated - 10 Wet 30 35

JIP Population Operations data shows that Compressors processing dehydrated gas achieve significantly higher performance Consider processing operations to dehydrate gas prior to compression

Consider future demands when selecting compressor configuration   For Example: Application of a Gearbox Advantage: Achieves higher efficiency for the first and later wheel arrangements

	When designing back-to-back machines, build additional margin to allow for increased wear mechanisms JIP population reveals back-to-back machines suffer increased performance losses due to Balance Piston and Centre Seal wear compared with Straight-Through machines

	Verify that scrubbers designs meet maximum operating demands The JIP Population reveals that: High molecular weight gas applicationssuffer higher losses at high scrubber operating demands Compressors with scrubber operating margins below 15% are exposed to increased risk of degradation

	Machine Deliverability is measured by average Flow per kW. Using the averages derived from the JIP population, this graph can be used to highlight performance losses on existsing machines: