I am new to the community but have been lurking for a while, trying to get as good of an understanding as possible…with limited success (not due to the information available, due to my inability to comprehend the vast amount of information presented).
Understanding that they are inefficient and that it is a questionable decision, I really want to use Peltiers to heat/cool my fermentation chamber. The only thing keeping me from purchasing the Spark is my own ignorance and not knowing how to code/setup everything.
Could the a valve control board to power the Peltiers, reversing polarity to heat/cool as needed to stay within predefined parameters? Or is there an alternative option that is more direct/effective (like this board which has been referenced a few times: http://www.amazon.com/SMAKN®-Double-Bts7960b-High-power-Arduino/dp/B011HF48MM?ie=UTF8&psc=1&redirect=true&ref_=ox_sc_act_title_7&smid=A2OCOGC9B25845)?
Either way, if it is possible, would I be looking at a fair amount of change to the code or would it be “simple” to get this to work?
I tried searching and came across a few threads where the Peltier idea was proposed but didn’t see any information (that was available at the time of each thread) that explained how/if this would work.
Thank you in advance for any ideas/input/guidance.
The valve controller board cannot switch enough current for a peltier. The board you link is better. If you connect a heating and cooling output to it, it will already work. The heating and cooling will be either 00 (off), 10 or 01.
However, peltiers are terribly inefficient. If it is is 20% efficient (which is optimistic), it transforms 80% of its energy to heat on the hot side. So you will have to cool the hot side very well, because the cold side will be offset from the hot side. So the peltier is self heating a lot. Take that into account.
I have played with petliers a bit, but decided that they were not the right tool for the job. Maybe to keep a beer around 20 degrees, but forget cold crashing.
I am not saying it will not work, but it will not be efficient or performant.
My peltier cooled morebeer conical works just fine, see current lager fermentation thats almost done. Will be transfering to keg for final fining (gelatin) and lagering in chest freezer.
Cool! What’s the offset you can get from ambient?
Got any more details about your setup? mostly how you cool the peltiers?
How many of them do you have?
The MoreBeer conicals are what continued my interest (paired with some “experiments” revolving around computer cooling) in TEC/Peltier units. MoreBeer advertises about 30-40*F offset from ambient, but I’m also curious about the “real world” results.
I was initially going to design a “case” to sit an individual keg/carboy in and have one peltier/heatsink underneath (with a copper disc between brew and peltier unit)…I still may try and do that, but have since decided to build a cabinet - constructed of Oak wood, 2-3" of insulation, and aluminum panels lining the inside that will serve as my serving unit (taps on top) and “temporary” fermenting chamber.
I have quite a few heatsink/fan setups around and even more 6A Peltiers so I’m going to try and use 2-4 units to get down to ale temperatures…if it doesn’t work I also have a few mini fridges that will likely be torn apart in hopes to use in the cabinet. The cabinet will be indoors so ambient should stay “reasonable” (we usually have the thermostat set between 66-74*F).
Here’s the one I have
Mine is located in the basement ambient temps in the middle of a Midwest summer hit 65-68 F and I’m still able to get down to lager fermentation temps (low 50’s). I’d say 15 F lower than ambient is a safe assessment of real world results. There’s only one peltier with a large aluminum block that’s milled to the radius of the conical. Heat from the peltier is dissipated by a heat sink and small computer fan.
So I’ve tried to research and get a better idea…but everything I read is going over my head in terms of function or trying to adapt to this use.
On the board linked to earlier (http://www.amazon.com/SMAKN®-Double-Bts7960b-High-power-Arduino/dp/B011HF48MM?ie=UTF8&psc=1&redirect=true&ref_=ox_sc_sfl_title_1&smid=A2OCOGC9B25845)…I can’t seem to understand what the function of each pin is and how that would translate to the BrewPi/temperature control…
Specifically, the R_IS, L_IS, R_EN, L_EN pins (but really my understanding of RPWM and LPWM is extremely basic, too).
Is there any resource/guide that may shed light on these?
It’s pretty straight forward once you see the data sheet for that h bridge. Feed the board steady voltage to vcc and both enable pins ( R_EN and L_EN) given you want to enable both polarities. I think i took 5v to vcc and jumpered to enable pins. Of course connect ground. The pwm pins connect to brewpi device output. Can’t find data sheet but this diagram should help https://www.google.com/search?q=h+bridge+arduino+43+a&client=tablet-android-google&biw=600&bih=960&source=lnms&sa=X&ved=0ahUKEwjMjavGubrMAhWIPiYKHdl5CNUQ_AUIrAEoAA#q=h+bridge+bts7960+datasheet&imgrc=3VRHwCcHTTvxqM%3A
I’m running an old wine fridge down to 50F, hits 20 degrees F lower than ambient using two 6 amp TECs