There are mainly 3 different types of Wine Cooling Units presently on the market, they are:
Self-contained cooling system.
Duct cooling system.
Ductless split cooling system.
In these system, all the elements are compacted into one single unit, the condenser and the evaporator are combined inside the appliance, which makes it easy to install, simply ensure you can cut a large enough pass through in the wall to install, have the proper electrical hook up for it, and plan on a large enough space outside the cellar to dissipate the heat it gives off (roughly twice the size of the area being cooled). If budget is limited or the space is small, these handy units are great options.
Duct cooling system
Both the evaporator and condenser are located outside the wine cellar, the evaporator connects to the condenser via line set, and the condensers pushes and retrieves air from the cellar using traditional ducting. When budget is less of a factor and a client wants the least invasive footprint in the wine cellar, these powerful systems are a great call.
Putting the evaporator in the cellar (thus, splitting it from the condenser) provides flexibility in larger cellar projects when budget is a consideration and the project is too large for a self-contained unit. In this scenario, the evaporator is mounted in the cellar (usually in the wall, high up) and connected to the condenser via line set.
When it’s the best choice: When balancing between budget, power, and aesthetics is of high importance, these versatile systems work great.