LayMeister
Well-Known Member
Hi,
I've been thinking about building an insulated box, cooled by a Peltier device, to use for lagering or even just controlling primary fermentation temperature. I have been looking for a device to use and almost bought a 5 gallon Coleman cooler today for $100 so that I could rip it out.
Then I started thinking about how many watts of cooling I really needed. The Coleman was about 50 W, but it said it could cool the inside (empty) to 40 degrees F below ambient in 3 hours. The assumption here is that whatever you put in should already be cold for it to work.
Then I saw a bunch of devices on E-bay with ratings up to 545W! And only $20, but it would require a 40A 12V power supply.
So I decided to do some basic calculations. I have a attached an image of my excel spreadsheet for you all to have a look at. If my calculations are correct then steady state load for a full 23l glass carboy in a 4" thick Styrofoam box is only about 10 W. (Looks like the Coleman cooler should work). However, even with 80W it takes about 10 hours to cool from 30C to 0C.
Given these results, I think I'll go for 168W device for $6.95 on Ebay
Comments?
Paul
PS If you are interested in a copy of the excel file, let me know.
I've been thinking about building an insulated box, cooled by a Peltier device, to use for lagering or even just controlling primary fermentation temperature. I have been looking for a device to use and almost bought a 5 gallon Coleman cooler today for $100 so that I could rip it out.
Then I started thinking about how many watts of cooling I really needed. The Coleman was about 50 W, but it said it could cool the inside (empty) to 40 degrees F below ambient in 3 hours. The assumption here is that whatever you put in should already be cold for it to work.
Then I saw a bunch of devices on E-bay with ratings up to 545W! And only $20, but it would require a 40A 12V power supply.
So I decided to do some basic calculations. I have a attached an image of my excel spreadsheet for you all to have a look at. If my calculations are correct then steady state load for a full 23l glass carboy in a 4" thick Styrofoam box is only about 10 W. (Looks like the Coleman cooler should work). However, even with 80W it takes about 10 hours to cool from 30C to 0C.
Given these results, I think I'll go for 168W device for $6.95 on Ebay
Comments?
Paul
PS If you are interested in a copy of the excel file, let me know.