I think he is more talking about the heat that the fridge outputs to cool the inside, which is likely warmer than the ambient temperature in the room. Just a guess.
I was; the fridge outputs quite a bit of heat, good for raising seedlings on top of. But I would imagine the expenses involved in this stuff wouldn't make it sensible for a fridge (I don't think they draw that much power anyway).
I just had never heard you could harness this, it's cool.
Edit: Bit late to the party, 1821. Bit of catching up to do.
Okay, then that means you're ventilating the output heat poorly. If there is a significant difference in temperature between the coils and the room, you're spending more power than you need to when you pump heat out of the fridge. Adding fins or fans would save you more power than you could ever recover.
Somewhere on the fridge is a bunch of metal that heats up when it's working. If that gets particularly hot, then you have the potential to save power. You could add more surface area or have low-power fans blow air across it. That would make the actual fridge unit be more efficient. The amount of electricity you would save is much more than the amount you could harvest. Any device that harvests power would also impede the efficiency more and make it work even harder.
But either one would be a pretty small amount.
It's fun as a toy, but not much more.
If you want to save power, buy a more efficient fridge. Maybe also get one where the hot part can go outside.
I just had never heard you could harness this, it's cool.
Edit: Bit late to the party, 1821. Bit of catching up to do.