Questions on Building a Fermentation Chiller

So I don't yet know how feasible it is for me to try and build one of these. But I'm wondering what I might need to take into account if I change the overall dimension to make the chiller bigger. I want to try to make a chamber that can hold 3 cases and 2 cornies and hold 65-70deg when the ambient temp is 90+. Anyone have any thoughts?

I made mine large enough to hold 3 carboys and I made 4 changes to the original design. I added internal bulkheads between the sections so I could isolate any section I wasn't using (use less ice that way). Instead of having the lid open up, I have 2 panels on the side that come off. I added a structural support at about the halfway point on the inside just to support the top (so I can keep stuff on it). I also added a second circulation fan. One fan blows out of the ice chamber, the other sucks air into it. With a single jug of ice that lasts 2 days I can keep my chiller at 65F when the room temp is 75F.

If you want to go that big, it might be more economical to try and find an old used chest freezer and rig up an external temperature controller. I am considering a similar setup, and the cost of materials for a big chiller or two chillers is about the same as an old freezer from the buy'n'sell and a cheap temperature controller.

Of course the added benefit to a freezer & temp. controller is that you set it and forget it. No messing with ice blocks every few days.

That would have been my preference, but I live in an apartment and am not allowed any extra appliances. My chiller runs on 12VDC so I can sneak it by despite its size.

I'd have to agree w/ FlyGuy. Between the time for building and the cost of material a used freezer chest or upright would be a better option for something that holds as much as you describe.

I'm leaning towards an upright for myself because I don't see me rasining and lowering a 5 gal. carboy into a chest type. But a chest type is more energy effecient all things being equal.

Yeah, I'm slowly leaning in the direction of just buying some big coolers. Extra appliances are not feasible for me which is why I was thinking of the chiller, but that is a long shot too. I figure if an igloo icecube is good enough for fermenting, I may as well use a cooler for bottle and keg storage too; simplest solution in my mind.