Same fridge - fermenting and serving. brew at fermenting temps and beer at serving temps. No need to compromise, you just burn a little extra energy when you are actually fermenting a beer. But if you think about it - not as much extra energy as you would burn to run a seperate fridge.
Proof
As you can see, although i only have one tap, there is room for two kegs, assorted beer and a fermenter in there. The second keg is cold conditioning, but i could put in another tap if i wanted. Plus the freezer still works as a freezer, so thats where all my hops etc are stored. Note - freezer was defrosted shortly after photo taken, so no smartarse comments OK.
As Spills said, been doing it for years. Also posted numerous times about exactly how. You can do a search for my posts and you should find them. Essentially its
*Fridge normal, no temp control
*Fermenter with aquarium heater submerged in it. Insulated as in the picture. Less insulation is no good (use too much energy) more is no good (beer gets too hot)
*For ales at 18+ thats all you need as the AQ heater has its own temp control
*For temps below 18 (never found an aquarium heater that goes lower) you need an to plug the heater into an external temp controller. For this application, IMHO a fridgemate is not good enough, its temperature hysteresis is too high. I use a PID, but strongly suspect one of the Tempmate style controllers with the sub 0.5 accuracy and low hysteresis would be OK too.
Now i have to note that i keep my fridge at about 6 not the normal <4, so if you run your beer fridge super cold... Then it will run a fair bit while you have a beer fermenting. But mine probably only runs 20-25% more when i am fermenting an ale and less than that for a lager.
It works very well indeed and solves the OP's problem without ever having to let his beer warm up at all.
TB
