Compact Temp Control

New to the Forum. Nice to meet everyone. I have been brewing beer in my house near Kamakura, Japan for a few years now. I started out with kits and extract and I recently started doing five gallon all grain batches. I use a ten gallon pot on my gas stovetop, a 10 gallon Rubbermaid with a false bottom to mash and lauter and a six gallon Better Bottle carboy. In the cooler months of the year I have been using a brew belt and a Ranco 2 stage with the probe in a thermowell to keep my temps where I want them. I have been reluctant to buy a fridge or build a box for cooling in the warmer months because I live in a small house and I need to be careful about filling it up with big objects like refrigerators. No basement, attic or spare rooms. Consequently my brewing has been limited to an October to April season where the max temp in the room where the fermenter sits is about 65F. I like that all of my brewing equipment packs up compactly and out of sight until I want to use it. Mashtun fits inside the brewpot and the fermenter fits inside the mashtun. It all fits in the back of a closet and gets pulled out when I have a rare Saturday or Sunday to do a brew. This summer I felt like doing some brewing and began to think about figuring out how to keep my fermenter cool without the box or fridge. I looked around on the web, did some thinking, and came up with the pictured Peltier-based (Ice Probe) solution. From a space-saving perspective it is great because I modified an existing vessel (my mashtun) to also act as my fermentation chamber. From a performance perspective it is working out pretty well too. I get about a 12F max difference between ambient and wort temp as measured by the Ranco. This lets me brew except for July and August when its too damn hot for me anyway. I think the 12F limit is more a limitation of the 45 watt chip in the Ice Probe than the overall design of the chamber. A higher wattage chip would probably provide more cooling. The responsiveness of the system seems to be pretty good too. Whenever I check it, it is within a degree of the target temp regardless of ambient. My guess is that the efficiency comes from the good insulation of the cooler and the relatively small (but not too small) amount of water needed for the water bath - maybe one or two gallons max. The tip of the Ice Probe is almost touching the better bottle and there is about an inch space between the cooler wall and the fermenter. The two holes in the cooler, one for the Ice Probe and one for the neck of the fermentor are fitted with PVC plumbing – drain pipe? - fittings that have screw in caps that are used when I am in mash mode. They are sealed into the cooler with food grade silicone. The fittings are probably not food grade but they are very hard plastic and only the one mounted in the side actually touches the wort and only when I am brewing a big beer. The fittings were a couple bucks each and the Ice Probe was $100. Any comments or ideas for improvement would be appreciated.

Looks Pretty Cool! (pun intended)

How high do you fill the tun with water during fermentation?

I would wager a guess that excess headspace would decrease cooling efficiency. Just as excess headspace during mash usually causes faster heat loss.

Do you leave the false bottom in during fermentation?

if the better bottle is sitting directly on the bottom of the tun, water can't get under it. Maybe more surface area in contact with chilled water(with false bottom in place) would help get temps lower.

Using an aquarium pump to circulate water could raise cooling efficiency too.

I generally fill the water up pretty high. Usually an inch or two above the level of wort and 3 or 4 inches below the rim of the cooler. I need to add more water now as you can see. I take out the false bottom to ferment. The carboy floats with enough water so there is good circulation underneath and this also helps seal the neck of the carboy into the top of the cooler. I thought about a pump to circulate water but I want to keep it simple, avoid noise, reduce cost and save electricity. These DIY projects can get out of hand.

Nice setup! I have been holding off getting a freezer but the summers are downright impossible to brew in without something actively cooling. I have never heard of an ice probe until just now, going to do some Googling and find out more! - - - This might take a while now that I am on Youtube, but there are a lot of possibilities I think! Now I am seeing people cooling 10 gallon aquariums with these devices and no insulation!
Cool stuff!

Oh sweet, if you reverse polarity on a peltier device the cooling side becomes the heating side and vice versa! You could use these things to warm and cool! All of a sudden I am browsing through lot prices for the plates on Aliexpress and trying to figure out how to make my own version of an iceprobe with a smaller budget. I'd love to have an all-in-one heat/cooling unit.