Can you operate a deep freezer in an unheated garage during winter months with temperatures reaching -20c and all year round? Thank you

Hello Kirwin

No problem. There are no parts open to weather/temperature conditions outside the freezer.
There could be a slight problem with the door seals. Put a very thin layer of vaseline on them to protect the seals.

Success !

:)

The only real problem that I can forsee is the generation of water from the exterior coils. Dew point table

The temperature in the cells is the temperature of the surface, below which ice or water will form.

You might invest in a compressor heating blanket. This might take a little work. Not sure if they are available for small compressors. It would extend the life.