Temperature Control System

[Smok1]

I ferment both my reds and white down in my wine cellar now, 68f, i use to ferment upstairs (74f) sometimes id even use a heatbelt and get it to 80f, but i find i like the taste of a slower cooler ferment.

 

[sour_grapes]

I like solid-state relays!

 

[Stressbaby]

OK my 2nd version of this project is done and in initial testing seems to be working well. Holding steady within 0.1C.

The first version used just one peltier cooler and was underpowered. We upgraded the power supply and switched to a 3 block unit with good results.

We went with 3 24v13 motor drivers and an Arduino programmed PID controller. It will heat or cool either way. The pump runs continuously, it just varies the direction and voltage over the peltier coolers to achieve and maintain the set temp. I need to let it run longer to be sure it continues to cycle properly and doesn't need any "loop tuning." Details and pics to follow.

 

[Stressbaby]

It looks like a mess as I still need to add the LCD, power (apart from the computer) and a container. But after some tuning the system is stable. The system heats AND cools. Today in testing with set point at 58F, I added an ice pack and the temp never went below 57.76F before returning to normal. I added 1 pint of boiling water and the temp rose to 61.7F before setting back down over 10-15 minutes.

Complete parts list on my blog at https://relatitude.blogspot.com/2017/12/wine-temp-control-system.html
If interested in the code or wiring detail, DM me.

 

[Stressbaby]

Update:
First batch, guava wine using QA23. I put the temp probe directly in the wine. The lower temp limit for QA23 is 59F so that is the setting I used. It still seems to be ripping through in about a week, so next time I do this I will try to slow it down even further by going to perhaps 55F.

The temperature graph shows the temp starting at 59 but quickly jumping to around 70F due to the addition of more (warm) water to the system. It then drops over the first few hours, then sticking right around 59F. There is some oscillation due to the constants in my PID controller. It is pretty clear where I tweaked settings: 10000, 22000, and 30000. This last adjustment helped a lot - you can see the temp oscillations even out at the 30000 mark on the chart. Starting at 30000, those swings are from 58.89-59.22F so about 1/3 of a degree F - which from a winemaking perspective is way past "good enough."

Equipment list
Blog update

 

[Stressbaby]

Here is the temp curve for a second wine. This is elderberry. I initially set at 70F, then after a few hours dropped it to 68F. At around 1.020 I bumped it to 72F (just past 30000) until it finished up.

 

[sour_grapes]

Looks like you got it dialed in!