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> In addition, a new galley air cooling system will also be certified, which features lighter and more efficient refrigeration units for very long flights. I w

> In addition, a new galley air cooling system will also be certified, which features lighter and more efficient refrigeration units for very long flights. I wonder how they work.. considering outside air is way below freezing ar cruising altitude, I guess radiators? Could the refrigerant be brought close to the plane's skin to cool it?

lazide 2mo ago
Or just… computer controlled air vents?
- Scoundreller 2mo ago
  may not be worth the aero hit. Kinda like running a/c in a car at high speeds instead of opening the windows. Not sure where the crossover point is. In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one.
  - schiffern 2mo ago
    >In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one. Or use those triangular vent windows / wing windows, as seen on old trucks and classic cars. https://www.fastlanecars.com/blog/wing-windows-history-and-classic-car-design https://www.fastlanecars.com/blog/wing-windows-history-and-c... https://www.ccjdigital.com/trucks/article/15749837/the-story-of-truck-wing-windows-the-end-of-the-traditional-truck https://www.ccjdigital.com/trucks/article/15749837/the-story... You could quickly flip it open with a servo when braking, controlled by a differential thermostat so it only pulls in air when the outside isn't too much hotter than inside. I think you actually want a negative thermostat offset, because even if it's a couple degrees warmer you still get moving air. Compared to rolling down the window you don't get the loud buffeting sound, it acts as a really good aero-brake, and it pulls in huge amounts of air. There's the downside that it will preferentially pull in air around intersections, where traffic pollution tends to peak due to braking and accelerating (EVs help but there's still brake and tire dust). Love this honestly. It has definite "shitty project" potential...
    - inigyou 2mo ago
      Planes generally avoid braking. Many are equipped with explicit "speed brakes" and all can use their control surfaces to create inefficient aerodynamic configurations, but fuel is expensive so they avoid it unless there's a situation like getting cleared for a shorter approach than expected. Ordinarily, they plan a descent path which can be accomplished naturally with a lower than normal thrust. The standard is three degrees below horizontal. Of course they also activate all braking possibilities upon touching down, but you can't keep the fridge cold by cooling it only upon landing. When cruising (most of the flight), smooth aerodynamics are extremely important, and you wouldn't mess them up just to keep the galley fridge cold. Example: whenever a plane has the landing gear out it burns 2-3 times as much fuel, because that's just how much it costs to not be smooth. That's why they retract the landing gear almost the moment the plane leaves the ground, and why a plane with its landing gear stuck has to return home (despite not being a serious emergency).
      - schiffern 2mo ago
        For cars not planes, but apparently you're an LLM so....
        inigyou 2mo ago
        Am I? Uhhh, I mean, you're absolutely right! Honestly, that's load-bearing. It's not a bird, it's Superman. Punchy sentences. Stupid metaphors. No substance. 100% pure LLM slop delivered straight to your retina.
gosub100 2mo ago
Maybe the refrigeration is shared with the galley (food storage), and/or is only needed when the plane is on the ground?
tecleandor 2mo ago
Seems like the galley air cooling system is designed for cooling the equipment and food in the galley, not the general air supply for the passengers. https://aviateai.com/efficient-galley-cooling-system-optimizing-comfort-aboard/ https://aviateai.com/efficient-galley-cooling-system-optimiz...
r2sk5t 2mo ago
At altitude you can reject heat straight to the aircraft skin. Some designs run an internal heat sink on the ground and during climb, watch altitude, and only switch on the skin-exchanger coolant pump once outside is cold enough to cool the loop for free. The reason it stays a refrigeration unit and not just vents is the ground case. Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work. One published point-of-use chiller design specs roughly double the load on the ground vs in cruise (order of 700 W vs 300 to 400 W per unit). So the vapor cycle is sized for the ground, and most of a 20 hour flight is spent in the regime where you barely need it. And these aren't fridge boxes at each cart. It's a central vapor-cycle chiller cooling a glycol/water loop piped to air chillers at the galleys; the carts get chilled air. The heat comes off the condenser and goes to ram air, a skin exchanger, the cargo hold, or back into the ECS, depending on the aircraft. Which one the new ULR units use, Airbus hasn't said. For a 22 hour flight the interesting number isn't peak capacity, it's efficiency and weight in cruise, which is probably what "lighter and more efficient for very long flights" is pointing at.
- AYoung010 2mo ago
  Presenting raw LLM output as your own writing in a human-to-human context is rude and antisocial, not to mention incredibly transparent.
  - lostlogin 2mo ago
    I was oblivious - how did you tell? There are a lot of commas.
    - inigyou 2mo ago
      I didn't notice but this sentence feels like AI: > Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work.
- inigyou 2mo ago
  Was once on a flight sitting at a gate with a faulty ground air connection or something, and they weren't allowed to run the APU at the gate due to pollution. It must've been 40 degrees (Celsius) inside, at Singapore Changi, and they were delayed at the gate too. Everyone breathed a sigh of relief when we started moving and got air conditioning from the engines.
t0mas88 2mo ago
[dead]
inigyou 2mo ago
I think once bleed air is compressed to a suitable pressure it's hotter than room temperature, and has to be cooled down.

lazide 2mo ago

Or just… computer controlled air vents?

Scoundreller 2mo ago
may not be worth the aero hit. Kinda like running a/c in a car at high speeds instead of opening the windows. Not sure where the crossover point is. In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one.
- schiffern 2mo ago
  >In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one. Or use those triangular vent windows / wing windows, as seen on old trucks and classic cars. https://www.fastlanecars.com/blog/wing-windows-history-and-classic-car-design https://www.fastlanecars.com/blog/wing-windows-history-and-c... https://www.ccjdigital.com/trucks/article/15749837/the-story-of-truck-wing-windows-the-end-of-the-traditional-truck https://www.ccjdigital.com/trucks/article/15749837/the-story... You could quickly flip it open with a servo when braking, controlled by a differential thermostat so it only pulls in air when the outside isn't too much hotter than inside. I think you actually want a negative thermostat offset, because even if it's a couple degrees warmer you still get moving air. Compared to rolling down the window you don't get the loud buffeting sound, it acts as a really good aero-brake, and it pulls in huge amounts of air. There's the downside that it will preferentially pull in air around intersections, where traffic pollution tends to peak due to braking and accelerating (EVs help but there's still brake and tire dust). Love this honestly. It has definite "shitty project" potential...
  - inigyou 2mo ago
    Planes generally avoid braking. Many are equipped with explicit "speed brakes" and all can use their control surfaces to create inefficient aerodynamic configurations, but fuel is expensive so they avoid it unless there's a situation like getting cleared for a shorter approach than expected. Ordinarily, they plan a descent path which can be accomplished naturally with a lower than normal thrust. The standard is three degrees below horizontal. Of course they also activate all braking possibilities upon touching down, but you can't keep the fridge cold by cooling it only upon landing. When cruising (most of the flight), smooth aerodynamics are extremely important, and you wouldn't mess them up just to keep the galley fridge cold. Example: whenever a plane has the landing gear out it burns 2-3 times as much fuel, because that's just how much it costs to not be smooth. That's why they retract the landing gear almost the moment the plane leaves the ground, and why a plane with its landing gear stuck has to return home (despite not being a serious emergency).
    - schiffern 2mo ago
      For cars not planes, but apparently you're an LLM so....
      - inigyou 2mo ago
        Am I? Uhhh, I mean, you're absolutely right! Honestly, that's load-bearing. It's not a bird, it's Superman. Punchy sentences. Stupid metaphors. No substance. 100% pure LLM slop delivered straight to your retina.

gosub100 2mo ago

Maybe the refrigeration is shared with the galley (food storage), and/or is only needed when the plane is on the ground?

tecleandor 2mo ago

Seems like the galley air cooling system is designed for cooling the equipment and food in the galley, not the general air supply for the passengers. https://aviateai.com/efficient-galley-cooling-system-optimizing-comfort-aboard/ https://aviateai.com/efficient-galley-cooling-system-optimiz...

r2sk5t 2mo ago

At altitude you can reject heat straight to the aircraft skin. Some designs run an internal heat sink on the ground and during climb, watch altitude, and only switch on the skin-exchanger coolant pump once outside is cold enough to cool the loop for free. The reason it stays a refrigeration unit and not just vents is the ground case. Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work. One published point-of-use chiller design specs roughly double the load on the ground vs in cruise (order of 700 W vs 300 to 400 W per unit). So the vapor cycle is sized for the ground, and most of a 20 hour flight is spent in the regime where you barely need it. And these aren't fridge boxes at each cart. It's a central vapor-cycle chiller cooling a glycol/water loop piped to air chillers at the galleys; the carts get chilled air. The heat comes off the condenser and goes to ram air, a skin exchanger, the cargo hold, or back into the ECS, depending on the aircraft. Which one the new ULR units use, Airbus hasn't said. For a 22 hour flight the interesting number isn't peak capacity, it's efficiency and weight in cruise, which is probably what "lighter and more efficient for very long flights" is pointing at.

AYoung010 2mo ago
Presenting raw LLM output as your own writing in a human-to-human context is rude and antisocial, not to mention incredibly transparent.
- lostlogin 2mo ago
  I was oblivious - how did you tell? There are a lot of commas.
  - inigyou 2mo ago
    I didn't notice but this sentence feels like AI: > Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work.
inigyou 2mo ago
Was once on a flight sitting at a gate with a faulty ground air connection or something, and they weren't allowed to run the APU at the gate due to pollution. It must've been 40 degrees (Celsius) inside, at Singapore Changi, and they were delayed at the gate too. Everyone breathed a sigh of relief when we started moving and got air conditioning from the engines.

t0mas88 2mo ago

[dead]

inigyou 2mo ago

I think once bleed air is compressed to a suitable pressure it's hotter than room temperature, and has to be cooled down.