Bleedless Anti Ice vs Pneumatic Anti Ice

[Reverb_SR71]

bleedless anti ice vs Pneumatic Anti ice when compared to the load and power draw from the engine.

In a normal bleed based anti ice system there is an increase in fuel consumption as the system is turned on as some of the mass flow is used up ( energy is being tapped from the engine to power it) , this is shown in the cruise performance tables etc .


My question is does the 787s bleed system have any similar effects ? cause normal electrical loads run off the IDG dont have any such problems i think ? . or does it have a similar effect ? .

My understanding is there will be similar effects as the power put on the IDG will demand extra torque from the driving shaft and will cause similar increase in fuel flow and consumption.

Thanks

[awblain]

Electrical heating on the 787 should be more efficient - all the electrical energy taken from the 787 heats the wing, whereas some of the hot bleed air in a conventional system flies off into the wake without heating the wing.

The electrical power required by the heaters still has to come from the engines, requiring more fuel for the same thrust when the heaters are on.

[bucks_raj]

I am too small and slow for an electrical system but have seen a pneumatic for sure.

Atr 72's 2400 shp at Cruise.

On a certain day flying with the Left bleed off resulted in a 5~6% power differential b/w the E1 and E2.

THe fuel flow on the Bleed off engine showed a marked increase which was clearly visible on the NAVLOG as well as the FF counter.