Making a SOF chiller - thermostat?

Since my new heat pump/ac unit won't be in until at least Tues., I've decide to make a fermentation chiller so I can brew this weekend (can't miss a weekend of brewin'). It seems pretty straight forward, but does anyone have an suggestions for a thermostat to use?

Buy a simple manual thermostat. Do not go digital.

EdWort said:

Buy a simple manual thermostat. Do not go digital.

Click to expand...

why? care to elaborate?

They require 24v AC to operate. The simple $15 thermostats run on 12v DC just like the fan you will use.

EdWort said:

They require 24v AC to operate.

Click to expand...

That may be true for some, but I bought a digital thermostat at home depot that is designed for the standard 24VAC system but also allows you to power it with a AA battery. So far the battery has lasted several months, so battery life doesn't appear to be a big issue either. I then just have a 12v wallwart that it switches to run the fan.

Do you use a heat/cool thermostat or a heat only?

It needs to be heat/cool or cool only. (Unless you use a relay to reverse the output of the thermostat). Heat only would turn OFF your fan when it drops below the setpoint.

-D

The one I'm using is heat/cool. Cost me 5 bucks at home depot - I got lucky and they were on clearance. So, I have no concept for how expensive these things are normally

use this

linky

works great, runs on AA, digital. Cheap ($20)

Here is the one I use...runs off of a AA battery and has been fine for 9 months so far.


RiteTemp Off White, Manual Thermostat, Heat/Cool With Fan Control, Low Battery Indicator, Fully Digital




Model GPMG8099

$16.97/Each

Hope this helps,

Shoopdog

I looked at that one Chris K but I'm not so good at soldering. I was planning on getting the one Shoopdog has. Thanks everyone for your help.

Professor Frink said:

I looked at that one Chris K but I'm not so good at soldering. I was planning on getting the one Shoopdog has. Thanks everyone for your help.

Click to expand...

you don't HAVE to solder to use the one Chris K used, that's only if you want the temperature probe to be remote - you would have to do the same thing to the one Shoopdog mentioned if you wanted a remote probe, so there's no advantage there one way or the other. And, it's nicer than that other one because it actually has a display so you can set it to a specific temperature instead of having to mess with the hot/cold knob and use a separate thermometer until it happens to reach the right temp... And if the temperature isn't AT the setpoint it'll still tell you where it is. The one I am using is essentially the same as Chris K's (Ritetemp 8025), and I didn't modify it at all.

For those of you that have built a chiller like that one, how often do you have to change the ice to maintain a decent temp. And, what type of exterior ambient temps are you keeping your chiller in.

I'm thinking about building one under my bar in my basement. The ambient temp in the basement is usually between 65 and 70 F degrees. I don't really want to build one if I have to change the ice once a day, but if I have to change it once every 3 or 4 days, then I'll probably do it.

srm775 said:

For those of you that have built a chiller like that one, how often do you have to change the ice to maintain a decent temp. And, what type of exterior ambient temps are you keeping your chiller in.

I'm thinking about building one under my bar in my basement. The ambient temp in the basement is usually between 65 and 70 F degrees. I don't really want to build one if I have to change the ice once a day, but if I have to change it once every 3 or 4 days, then I'll probably do it.

Click to expand...

it depends heavily on what temperature the wort is at the start, how hot it is outside, and how active fermentation is.

When I've put a fermenter in that's in the mid 70's, when I wanted to ferment in the high 60's, it really burns through ice for a day or so getting cooled down, usually I change it twice a day. And when fermentation is really active, it eats ice pretty quick, usually on the order of one ice change a day. Once fermentation slows, it barely uses any ice - quite often, after it's been in there 3-4 days, the fan completely stops kicking on because just the cold seeping through the separator between the two compartments in my fermentation cabinet is enough to keep it at like 67 degrees or so, and I only change the ice every couple days at that point. This would be different in the case where your two chambers are actually insulated, rather than just separated with plywood like mine are.

At 65-70 degrees ambient you would probably not have to change the ice very often at all, especially after fermentation died down a bit. In fact, you may even have to be careful not to put too much ice in and over-cool it without the fan ever kicking on like I just mentioned.

evandude said:

At 65-70 degrees ambient you would probably not have to change the ice very often at all, especially after fermentation died down a bit. In fact, you may even have to be careful not to put too much ice in and over-cool it without the fan ever kicking on like I just mentioned.

Click to expand...

Actually, I was thinking of building it big enough to house either a couple of fermenters, or one carboy and a couple of Corney. I was planning on using it either for lagering or housing my finished beer for dispensing and keeping the temp at around 36-38F.

I was planning on using 2" polystyrene and the natural insulation of my bar (since it would be build underneath it on five of the sides to help insulate it. And, like I said the ambient temp never really gets above 70-72 degrees and usually hovers around 68.

srm775 said:

I was planning on using it either for lagering or housing my finished beer for dispensing and keeping the temp at around 36-38F.

Click to expand...

I don't have much experience with temps that low, but 36-38F seems like a pretty tall order for an ice-cooled fermentation cabinet... I guess anything's possible with enough insulation though... But at those temps it seems like you should be looking into simply refrigerating the thing.