Hi Tec
So they have these two large electrically driven compressors that require 270V DC power.
Make that four. Two per air con system.
After an aircraft lands from a flight, as engine bleed is still available, it is used to start APU as in B777.
B777 is the only type I can think of with a pneumatic starter (in addition to electric).
Are there others? A380 perhaps?
Let me give an emergency situations where there is a total power failure on B777 and B787 at cruise altitude of 40,000 ft.
On a Boeing 777 the bleed air from the engines is still available, (Bleed valves stay open when power is removed), and this is used to automatically start the APU through a pneumatic starter. This source is unlimited unlike a battery with a fixed charge. Bleed air is also available for pressurization of aircraft, so the crew, if they are 40,000 ft, need not worry about pressurization, and when APU starts, power is also restored. Crew have to deal with only the electrical failure during this critical period.
Have there been many (any?) total electrical power failures that haven't been caused by loss of the engines too? I can't think of any.
Point being, the 787 has the same redundancy in regard to engine failure but increased redundancy with regard to electrical power-by a long way.
Four main generators instead of two.
Two auxiliary generators instead of one.
These power conversions generate heat and these panels that are located in the middle of the aircraft (Approximately below the first row of economy seats on ANA), are cooled using 2 large refrigeration units.
Not quite. There are two independent liquid cooling systems. Not refridgeration units. The power conversion units, ATRUs and CSMUs use this cooling fluid in a closed circuit.
Otherwise you're spot on.
