The goal for wine storage is stable cool temperature with no vibration & no strong odors.
I have an uninsulated 5' crawlspace with poured floor. Ditto with the ducts. It never gets above 65 & never freezes. I bought cheap utilitarian racks for about $70. They bolt to the wall, but would be very easy to move. I mounted them on a north wall that never gets sun - in theory the coldest spot in the basement. I position hard insulation around them in the summer months to keep it around ground temperature & remove it in the winter to stay above freezing. Therefore I slow down any temperature change & keep the mean temp roughly stable +/- <5 degrees.
I have had wines that I have stored for 10 years & they were great.
Ian
A picture without the hard insulation in front.