For a single small fermenter (say 250l) I was able to get away with a underbar chiller with a recirc loop.
I took one underbar chiller that no longer worked and ripped out one of the stainless steel coils. I cleaned and sanitised the coil and dangled it in the fermenter, pushing cold water from the recirc of a functioning underbar chiller thru it. I wired a thermostat into the chiller to switch the recirc pump on and off depending on the temp of the fermenter. Was able to get the beer to 4C, no problem...in mild weather.
Underbars are pretty easy to come by here, cheap or free, just get to know some bartenders/publicans...
Jeff Rosenmeier (Rosie)
Chairman of the Beer
Lovibonds Brewery Ltd