Air Lubrication Saving

Air-layer or micro-bubble systems inject compressed air under the hull to reduce frictional resistance. Net saving is the frictional reduction MINUS the compressor power cost. EEDI Category C innovative-tech credit.

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\Delta P_\text{gross} = P_\text{ME} \cdot f_\text{fric} \cdot f_\text{cov} \cdot r

Symbol	Meaning	Unit
$\Delta P_\text{gross}$	Gross ME power saved from reduced hull friction	kW
$\Delta P_\text{net}$	Net saving after compressor cost	kW
$P_\text{ME}$	Main-engine delivered power at reference load	kW
$f_\text{fric}$	Share of total resistance that is frictional	fraction
$f_\text{cov}$	Wetted-surface fraction covered by air layer	fraction
$r$	Drag reduction on the covered area	fraction
$P_\text{comp}$	Compressor power demand	kW

Source: Mitsubishi Heavy Industries - *MALS Air Lubrication System*; Silverstream Technologies - *Air Lubrication System*; IMO Resolution MEPC.1/Circ.815 - innovative energy-efficient technologies

In short

Net fuel and CO₂ saving from an air-lubrication system - frictional reduction on the covered wetted surface minus compressor power cost.

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