My move to refrigeration was by accident. We had insurance on the Hotpoint fridge/freezer and the light started to flash on/off when we opened fridge door, the Hotpoint man took one look at back of fridge and condemned the lot saying the ice forming at back was a sign the thermal insulation had failed. I moved into garage as a handy insulated box allowing me to move brewing into garage. At first I only brewed in winter, but found keeping the brew in the box required the ambient temperature in garage to be 16ðC to ensure the brew did not exceed 20ðC in first few days, once first 10 days had elapsed then there was no problem, but it is those first 10 days which are all important.
So this year run out of stock so started summer brewing, I used an energy meter on the freezer to see how much cooling it needed. My thoughts were if the freezer failed I would know if there was a chance of using bottles of ice to keep it cool. It was not promising, on the 22nd June this year started a new brew, by the 27th June it had used 0.52 kWh to keep it cool, I was holding it at 18.5ðC but 1872000 Joules or 447.418738 k Calories where a calorie is the energy required to raise one gram of water 1ðC so water out of the fridge at 4ðC to keep at 20ðC it would require 14 two litre bottles of water cooled to 4ðC over 5 days, so it would need changing twice a day. OK freezing the water may help, but can you afford to be freezing two x two milk bottles full of water in freezer without risking over heating the food.
I considered no, specially when I found my cool box bottles had been removed from freezer as my wife follows her buy food, dump food strategy, I still have not worked out why we need two freezers crammed full, leaving no room for my ice cream, but that's the way she works. So for me at lease swapping bottles of frozen water is a non starter.
As to the old tried and tested idea of a towel draped over the fermentor with the ends in water with a fan blowing on it, yes in Algeria hanging the water bottles off the wing mirror worked, but in the Sahara it is rather dry, at the moment outside my house is 83% humidity at 19.6ðC it is just not dry enough here for it to work.
I have looked at my electric cool box with uses the Peltier effect very inefficient, but the lid of the cool box in theroy at least could be put on top of any insulated container. However having tried to use one in my car on a 4 hour drive I am sure a simple cool block would have worked better.
So I have really just two options, only brew in the winter, or use refrigeration. The main problem with putting bottles of cold stuff in the brewing beer is it can get too cold you really have no control, plus you can introduce bugs. If I put bottles of cold water in the door of the fridge it may save the day with an unexpected hot spell in September or May, but not really a method that can be used in June, July and August.
