Yes, good point! A fan would help. There are a couple of good articles online about using computer fans to blow air over condenser coils like the fan on a car's radiator.

Another way to help in regards to airflow would be to make sure there's good spacing between the condenser coils and the wall or anything else that could trap or hold heat. Some people have moved the condenser coils and compressors away from the actual box so that they could further insulate around the entire refrigerator/freezer

I must admit here that I'm not a refrigeration expert. This information comes from various places on efficiency, off grid living etc.