Super efficient food heating system idea.

So, everyone knows the fridge cools the food, but then releases the heat into the room.
We could use an inverse fridge (which I will call "!fridge") to heat the food, by reusing the energy coming from the fridge!

Why isn't this used everywhere?

@ranfdev it's not efficient enough or rapid enough.

There is actually very little heat transfer occuring in a refrigerator once it reaches steady state. We are talking on the order of tens, or at worst low hundreds of watts.

To rapidly heat food, you need to deliver around a thousand watts continuously in a short period of time.

@ranfdev think of it this way. You have a liter of water that you need to take from near freezing (1-2 °C) to near boiling (98-99°C). How much energy do you need to deliver? Ignoring heat loss, about 410kJ, or 410kilowatt-seconds. Need to heat it in 5 minutes? You are talking a 1400 watt oven.