There are a lot of ways to cool down white wine fermentation. In mid-September we planned to make a muscat blanc/canelli with some residual sugar, and a local grower in Amador County (CA) sold us 1/2 ton at 22.5. Our challenge was to find a cheap way of cooling the juice. I had done about 50 liters years ago using large carboys and an old refrigerator, but we needed to do a larger quantity.
A winery nearby was using a high cost SS plate through which prop. glycol was circulated, and this plate chilled about 150 gallons in a square plastic bin covered with plastic. the plate alone was more than $2500.
What we decided to do is buy a small chest freezer (new they are ~$150+ and there were many used on local Craigs Lists--free to $100), and pump the chilled water around the SS 55 gallon drum where most of the juice was placed. After some messing around before the crush we came up with a solution that is working. Aquarium supplies have very cheap small submersible pumps that are quiet and don't use much electricity. We bought two ($15 each) with 3/8" hose and they move the water back and forth. Because it's hard to sync the pump rate exactly and leave the whole thing unattended, we added two siphon hoses that would kick in if one pump got ahead of the other and the level changed drastically. So far that has not happened. It's stable.
I had scrounged or bought years ago the fermentation drum and the open SS tank (about 100 Gal. or 400 L.) at a scrap yard. I suppose it would work just fine with a large food grade plastic drum and a surrounding tank. The chest freezer is 5 cubic feet and has a drain at the bottom. I don't think you will need a larger one. The lowest setting (highest temp) will not freeze water, and depending on the ambient temperature of your room, you may not need to run the freezer too much. We put a timer on ours and run it a few hours a day. The must drops about one point a day. It's working great. It's running about 12C or 54F.
We are using a white wine yeast that is not very tolerant of alcohol. However we might try a strong dessert wine in another year. We just tasted Sobon Estates orange muscat: 16% alcohol and 11% residual sugar. Figure out what the grape must have been at the start!
An alternative way is having a cooling coil (old refrigerator) that sits in a water bath and a pump is used to pump over/around a fermentation tank/container. A white grape bin can hold six or so carboys or kegs with smaller amounts of juice.
You can see an early picture of our set up (without all the siphon hoses,etc) on
Steve Cisler