Eli5: How did people make and keep ice in medieval times, and how do we manufacture ice cubes now ?

Question

Eli5: How did people make and keep ice in medieval times, and how do we manufacture ice cubes now ?

In: Technology

Answer 1

Old time: Let a lake or river freeze. Then cut ice blocks, store in insulated ice houses, cover with sawdust for extra insulation and use it during the warmer months and hope to not run out of it.

Now: use some freezers to freeze the water in molds. Alternatively, use metal mold in vertical position (holes on the side) with refrigeration tubes inside it, this freeze the mold. Flow water on the mold, the water freeze. When there is enough ice you reverse the refrigeration cycle, warming up the mold and releasing the ice. Once released put back the cycle in “freeze mode” and repeat.