Ok, finally got my lazy butt in gear and took some pictures.
I got this idea in my head after seeing a few wine fridges on Craigs list for free or almost free($20). Insulated, nice glass door to watch the process and cheap but mostly not working.
As I found out most of the thermoelectric fridges are made in China. The thermoelectric units(TECs) that cool the fridges are not the best quality and are the first to break down. I found some replacements for this fridge on ebay for $2.
TECs are a flat square ceramic unit with two wires, a positive and a negative. Heatsinks and fans are attached to both sides of the TECs to remove the hot or cool air. When you run 12v DC through the TEC, one side will become hot and the other cool. If you reverse the + and - the opposite sides will be hot and cool. This, in theory, will keep the fridge at a constant temp.
OK, so this is what I started with… a Haier fridge.[attachment=2]HVTB18DABB-Haier.jpg[/attachment][attachment=1]HVTB18DABB.jpg[/attachment]
I placed it on it’s side, removed the shelves and divider. Moved the LED light from the middle shelf to the ceiling. Moved the light switch from the side to the top of the fridge. Removed the LCD temperature control - I didn’t disconnect it in case it stopped working so I just left it on top.[attachment=0]DSCF3247.JPG[/attachment]
now to control the temp I bought this[attachment=2]DSCF3250.JPG[/attachment][attachment=1]DSCF3258.JPG[/attachment]
because I have two TECs I had to use a switch to turn both on and off and reverse both currents. I was able to find this switch made to order, again on ebay[attachment=0]DSCF3257.JPG[/attachment]
To monitor the temp of the koji (not the air inside) and the humidity, I found this at Wall Mart and just extended the sensors with a length of telephone wire and solder gun into the fridge.
[attachment=1]DSCF3249.JPG[/attachment]
the nice thing about this thermostat is it will remember the highest temp. So it’s easy to check and see how the koji did if you step away for a while.
What else, after I ran a batch I realized that I needed more oxygen in the chamber so I added a fish tank aerator. There, top right.
[attachment=0]DSCF3254.JPG[/attachment]
For humidity I just placed the air stones in a water dish in front of the fans.
here are some pics of the inside[attachment=2]DSCF3252.JPG[/attachment][attachment=1]DSCF3253.JPG[/attachment]
There is the humidity probe on the ceiling, the two air hoses, the temp probe for the controller is just hanging out of the hole and the temp probe for the koji is on the floor wrapped in plastic wrap.
I used shallow sheet pans for the koji, this way it can’t get too hot too fast and the fridge can keep it under control.[attachment=0]DSCF3251.JPG[/attachment]
There are some other things, like temperature carry over which you will have to work with. The heatsinks will still have some residual heat or cold in them when the correct temp is reached inside so there is a little under or over by a few degrees. The controller I use has a delay so I use that to stop it from constantly cycling hot and cold and hot.
I can’t think of anything else - I know I didn’t get into too much detail here. Just ask me about anything and I will explain in more detail.
Dang Trex!! – And I thought I was inclined to being somewhat too ‘over-the-top’ with my builds! (( :shock:
Very nice! ~ very nice indeed! Congratulations!
Don’t have the time at the moment… but I’ll get back soon and share my fermenter ‘box’. Not that original I confess… just a large upright freezer picked up on craigslist. Cost me $30 cuz the previous owner couldn’t figure out how to get the gasket to re-seal properly following a house move. Took an hour for the haul-home, door tweak, complete sanitizing clean up, & final set up in the living room (yes… that’s right the LR! [don’t ask! :roll: ] ) –
— But WAIT!! ~ What’s my $22 Temp Controller doin’ at your place?? :?
Love them jewels! – so impressed with the first two…that I just couldn’t help myself. Wound up ordering another two more ~ and coincidentally… the last one arrived here just today. ((no honestly!..it did)) :mrgreen:
Gotta’ go now… got an important event to attend to.
