A thermal stainless steel wine chiller will work in one of two ways: with a thermoelectric current, or by surrounding the bottle with a frozen substance. A "wine chiller" is different than a "wine cooler" --- a chiller brings down the bottle temperature before serving, whereas a wine cooler is like a refrigerator.
Thermoelectric Current Wine Chillers
Many thermal stainless steel wine chillers circulate a thermoelectric current around the bottle. Inside the wine chiller are fused metal wires, which contract at different rates in response to temperature change. When an electrical current is passed through them, one metal will get hot while the other grows cold. The cold metal is closest to the wine bottle, and cools the air around it, chilling the wine.
Ice Water Wine Chillers
Other thermal wine chillers use ice water to chill the bottle. The ice water is either circulated or shot through jets to surround the bottle with a flow of cold water. Some wine chillers will also rotate the bottle within the chiller. Ice water chillers work faster than thermoelectric chillers, because cold water is denser than cold air.
Removable Cooling Element Wine Chillers
Some stainless steel wine chillers use gel packs or re-freezable liquids to chill the wine. The gel packs or freezable units can be removed and placed in the freezer in preparation for use. The frozen substance is then placed back into the unit before the wine bottle is inserted.