Alright, so I couldn’t handle not knowing…
-1# of ice has roughly 160,500 joules of energy to give up during the melting process
-11 Gal of beer will require roughly 116,500 joules of energy to cool 1 degree.
-So it would roughly take ¾# of ice to cool the fermentor one degree
This is just to be used as a reference, you are likely using this to maintain temps during fermentation, I’m not sure how much heat is generated by the fermentation over how much time. I’m not sure how well insulated the fermentor will be or what the room temperature is in comparison to the fermentation temp.
Assumptions:
-Ice starts at 15* F
-Fermentor has a 12 watt fountain pump being used to circulate ice water
-Fermentor takes 11 minutes of circulating ice water to cool 1 degree F
-Cooling system is 90% efficient in the transfer of heat (not likely that its that high)
Let me know if you’d want me to post more details on the calculations.