[Randy]

Originally Posted by Cd

I'd like to take a medium size refigerator and lay it on its' back to make a chest freezer.

Compressors rely on gravity for lubrication, so they should be oriented base-down. I don't think this would work well compared to a chest freezer.

Originally Posted by Cd

Correct me if I'm wrong, but I got the impression that adding insulation to the OUTSIDE of a refrigerator is not a good idea because of the coils in the walls of the refigerator.
Can you please remind me of what these coils in the walls do ? ( And why adding insulation to the outside is not good )

You can use energy to move heat, but you can't just eliminate it. The outside coils dissipate the heat removed from the inside. Note that they aren't always in the outside walls: they're often in outside radiators or fan-cooled condensers.

Originally Posted by Cd

I have read thar a frig that is packed full of food is more efficient than one that is empty, but I also recall getting the impression that a freezer that needs to be deiced because it is completely packed with ice is less efficient.

In general the thermal loss is the same for the same internal temperature, so if everything was equal these wouldn't matter. The "packed full" idea is that the refrigerator is designed to run longer than just cooling down the air inside it. Water has an enormous thermal capacity compared to air so a full refrigerator has a longer run and off time, minimizing the inefficient start-stop parts of the cycle.

An iced-up freezer is less efficient because the ice insulates the evaporator. The refrigerator works to cool the evaporator, so when iced up it's working to cool far below freezing. The "packed full" effect is much, much smaller than this.