heat doesnt like state changes. That’s how insulation foam works. presumably the solids and liquids you’re refrigerating would be more reluctant to provide heat transfer to the warm air youre letting in, allowing the refrigerator to work less hard and just cool the new air. you may be able to pack insulation foam in there strategically , as far from the cooling mechanism as possible with little harm if your refrigerator is too empty. I did not vote on your comment.