Question

a friend of yours explains that they are desinging a cold plate. according to her it works just like a hot plate the surface that object are put on is now very cold instead of very hot. will it be just as effective for cooling water is a hot plate is for heating water? explain the process that occurs

Answer 1

The cold plate is not going to work.

How hot plate works:

The hot plate has heating elements that heat up the bottom of the objects kept on the plate, and the water molecules at the bottom (water is always there in food, and this is why steaming is highly recommended for ironing clothes) take the heat from the bottom and transfer it to the other water molecules. This heats up the whole thing contained by the object.

Why cooling isn't the same as heating:

Cooling is nothing but taking heat out of something. Just like the absence of light is darkness, similarly, absence of heat is cold.

Heating can be done by contact and in open, while cooling requires closed volumes because cooling requires compression of air, which wouldn't be possible if air were allowed to flow. This is why airconditioning requires closed doors, and refrigerators are air-proof.

So, if we attach a compressor with a conducting plate and keep extracting heat from the plate to make it work in a manner like a hot plate does, this wouldn't work because it'll lead to an endless heat extraction process because whatever amount of heat shall be extracted by the plate, the air around the objects will always drain its heat into the object kept on the plate.