Helene, did you get an answer? Looks like there's an A/C vent in the floor. There would have to be some kind of exhaust vent into the house if there was a cooling unit installed.

Hi Helene, our sincere apologies for missing your question! If you're still wondering--this is a custom cellar with internal cooling and vent. Thanks!

Specifically - where is the vent for the cooling unit?

After double checking floor plans, I believe cooling is just A/C with floor vent seen in the bottom left corner of the picture. Unfortunately, we don't have any other details recorded. On many of our other projects, however, we've installed Sub-Zero wine storage, a great option for more controlled cooling.