I don’t thunk your model is correct.
Opening the fridge causes the accumulated cold air to fall out over a period of a few (maybe 4-7?) seconds, after which it doesn’t really matter how long you leave it open, as the air is all room temp.
The stuff will slowly take heat from the room temp air, at a rate of about 1 degree/minute.
Once the door is closed, it takes a few minutes (again, IDK how long) to get the air back to 40F, and then however long to extract the heat from the stuff.
If you are chosing between “stand there with it open” and “take something out, use it, amd put it back within a few minutes” there is no appreciable difference in the air temp inside the fridge for those two options—in both cases things will return to temp some minutes after the last closing.
You can empirically test how long it takes to re-cool the air simply by getting a fridge thermometer and seeing how the temperature varies with different wait times. Or just see how long before the escaping air “feels cold” again.
I mentally visualize the cold air as a liquid when I open the door, or maybe picturing it looking similar to the fog from dry ice.
Since it’s cold, it falls downward, “pouring” out onto the floor, and probably does not take more than a few seconds, though I would love to see someone capture it on video with a thermal camera.
After that, I figure it doesn’t really matter how long the door is open, until you start talking about leaving it open for 10+ minutes where you can then start to worry about the food’s temperature rising, and the fridge wasting energy trying to cool the open space.
On the timescale of just a few moments while you grab stuff, the damage is already done once you open it the first time, and leaving it open or opening/closing it again doesn’t really affect anything.
This is also why grocery stores and restaurant kitchens tend to have reach-in fridges, open from the top like a chest freezer, instead of vertical doors (though, that’s also for convenience).
I don’t thunk your model is correct. Opening the fridge causes the accumulated cold air to fall out over a period of a few (maybe 4-7?) seconds, after which it doesn’t really matter how long you leave it open, as the air is all room temp. The stuff will slowly take heat from the room temp air, at a rate of about 1 degree/minute. Once the door is closed, it takes a few minutes (again, IDK how long) to get the air back to 40F, and then however long to extract the heat from the stuff. If you are chosing between “stand there with it open” and “take something out, use it, amd put it back within a few minutes” there is no appreciable difference in the air temp inside the fridge for those two options—in both cases things will return to temp some minutes after the last closing. You can empirically test how long it takes to re-cool the air simply by getting a fridge thermometer and seeing how the temperature varies with different wait times. Or just see how long before the escaping air “feels cold” again.
Something that may help build a better model/intuition is this video from Technology Connections: https://www.youtube.com/watch?v=CGAhWgkKlHI
I mentally visualize the cold air as a liquid when I open the door, or maybe picturing it looking similar to the fog from dry ice.
Since it’s cold, it falls downward, “pouring” out onto the floor, and probably does not take more than a few seconds, though I would love to see someone capture it on video with a thermal camera.
After that, I figure it doesn’t really matter how long the door is open, until you start talking about leaving it open for 10+ minutes where you can then start to worry about the food’s temperature rising, and the fridge wasting energy trying to cool the open space.
On the timescale of just a few moments while you grab stuff, the damage is already done once you open it the first time, and leaving it open or opening/closing it again doesn’t really affect anything.
This is also why grocery stores and restaurant kitchens tend to have reach-in fridges, open from the top like a chest freezer, instead of vertical doors (though, that’s also for convenience).