The link provided by another user indicates that the problem with AC units is improper disposal of HFCs contained within.

"HFCs, the primary replacement, spare the ozone layer, but have 1,000 to 9,000 times greater capacity to warm the atmosphere than carbon dioxide."

https://www.drawdown.org/solutions/materials/refrigerant-man...

And that was not the point of the research.

But, it could lead to easier to repair/maintain refrigerators. Right now, if you puncture the cooling tubes and the coolant escapes its usually more cost effective for someone to buy a new fridge. A solid refrigerant can't leak out and would be much easier to replace.