I don't want to get into any conflict on my first post, but using the solid walls/top of a fridge sounds incredibly inefficient. The fridge shown in the link looks like what we would call an under-counter fridge in the UK, and these have a radiator at the back like most other fridges. I do agree that the design may stress the compressor though, but I guess it depends where it's sited. If it's not having to do a lot of cooling, then it's probably OK.