# What is the amount of bleed air required for de-icing? What is the power impact of this bleed air?

I was wondering if anybody has any rough equations/figures that answer the following questions.

What is the mass/flow rate of bleed air required for de-icing based on temperature of the air intake?

Essentially if there is ice present and the ambient temperature is T_a then how does this effect the mass flow rate of bleed air required to de ice.

Also, how does the amount of bleed air used (mass flow) relate to the decrease in power output?

** I'm aware this likely depends on many things, but I'm fine with the most simplistic answer with many assumptions.

• This is like asking how much energy does it take to run an air conditioner.
– Jim
Commented Nov 20, 2022 at 14:29
• Too many variables. Is it an evaporative anti-ice system that takes late stage high temp bleed to heat the wing LEs above the boiling point, or a conventional non-evaporative system that can take air from earlier stages? In any case, the bleed demand is enough to impact take-off performance, requiring TO perf charts for the Anti-Ice On and Anti-Ice Off case, possibly in the range of 3-5%. If you had a perf chart for a particular type for WAI on/off, you could interpolate the effect. Commented Nov 20, 2022 at 14:59
• @Jim Yep, and wouldn't that be a perfectly valid question too? Commented Nov 20, 2022 at 18:34