You could also use excess energy to pull a vacuum in an external tank, then use that stored vacuum to quickly return the fridge to a near vacuum after opening.

You could also use excess energy to pull a vacuum in an external tank, then use that stored vacuum to quickly return the fridge to a near vacuum after opening. Or maybe just build up the vacuum externally throughout the day until a certain time, then use it to pull the air out of the fridge for the night when it won't be opened and won't have power.