this response is in no way an endorsement
I'd bet you encountered this or a knockoff of it. These tanks are used to heat wort(pre-hopped extract and water) to a sterilizing temp, cool it down so you can pitch yeast, ferment,condition and serve all out of one tank.
There was one back in the Boston area where I used to live in a bowling alley. The sad thing was for the money they spent on this set up the could have installed an actual brewing system (mash tun,kettle,fermenters,serving tanks) but they opted with the " And Most Important-NO BREWMASTER..Just real profits for your brewpub". The beers were very much of a Mr. Beer Kit quality. The great thing is the brewed 3 beers but offered 5-6 on their menu by blending a pilsner and stout and calling it a amber or brown ale ect.
They could have saved themselves a lot of money and would have been better off just installing a nice draft system and had 12-20 craft beers on tap. It would be a better money maker in the long run.
Franklins Restaurant,Brewery & General Store