winter came and I felt the urgency to heat my fermentation cell which is, btw, a fridge. I have an electronic controller that acts as a thermostat that turns on the fridge when I the fermenter temperature goes over a certain level. Now that is cold, I wanted to turn something else on when the temp goes down. I thought about terrarium heating pads, but I had two problems:
- decide how many watts are enough for my situation (my basement is about 15°C by now and I want to be able to arrive at 22-23°C in my fermentation chamber);
- buy the heating pad online (the vendor had a problem, things were going longer than expected).
I had a brew coming along and I had to find a solution. What came up is:
- a relay that is triggered by normal AC. I attached the relay trigger to the thermostat exit and the normal AC to the power pin. So the two exits are one identical to the thermostat exit and the other is the opposite (I use this one and I will call it "inverted trigger").
- the "inverted trigger" goes to a 25-50W solder. I was worried to set everything on fire, so I tried to attach an old cpu heatsink to the solder. After some thinking, I decided to make a hole through it: it's more stable and the heat goes away with no problem.
- the "inverted trigger" goes to an electrical transformer used to power up an old phone too. I use this to power up the computer fan attached to the heatsink. I took a look to the transformer to see how to choose the exits for the heatsink. I was lucky, the cpu fan input is 12V but the 9V transformer was enough to make a proper work.
When the solder is turned on, the fan is turned on too so there is no problem. I saw that the heatsink temp goes up to 30°C. The fan helps the temp to spread in the cell too and I found out that 25W are enough for me.
I had everything in my house, no part has been bought and I then was ready for the brewday!
Hope it helps!
Cheers from Italy!