I would like to automate my wort chilling process so that I can set a temp and pump the wort from the kettle to carboys with it arriving at the set temperature. My thought was to have a variable speed pump pushing the hot wort through a plate chiller using a thermocouple on the output as feedback. Since my ground water temp is around 55f - 60f this should work fine as long as the pump can modulate. I was thinking of using the Steelhead 2.0 since it is DC and should modulate based on input voltage. However, I’ve only ever used PWM to control a brushed DC motor. My questions are: Has anyone here done something similar? Are there potential problems with using PWM on a brushless DC motor? Would the flow vs rpm be sufficiently linear to be able to use a PID without a tuning nightmare?
Also, I know this is overkill but I like these type of projects.
Thanks
Lets start simple first. Put a valve at the output side. It won’t harm yer pump like altering voltage while under load can. I still use an IC and just about to switch to a CFC and believe you can slow down the output of wort and git satisfactory result… Heck, even if you git to 60 and yer fermenting chamber is set at 55 for a lager, you’ll be just fine. Sneezles61
Lowering the voltage of an AC motor will cause damage since it is synchronous (or near synchronous). It still has the same amount of work to do, but less voltage, therefore the current increases. However, with a DC motor, lowering the voltage should reduce the speed and current. But I’m not sure that brushless dc works with PWM since there is some sort of electronic commutation happening inside the motor. But yes, using a valve would be the straightforward way. Just not the way I want.
I love projects like this too. I agree that a valve wouldn’t work well because you need some level of continuous flow of your wort for your thermocouple to give you continuous feedback unless there is some kind of flow regulator that can be installed. I know nothing of how a variable speed pump works, so I’ll leave that part to you. I have a PID in my electric brewing system. The thing you’re going to need is fast feed back for fast changes in flow rates. I’m not sure how fast a PID can respond to those fast changes. You’ll have to research that. At any rate, at some point, you will find that there is a certain flow rate that gets your wort to the temperature you want, and then you could just adjust it to that flow rate. If you’re looking to cool different worts to different temperatures, then you’re idea sounds great. If you use a good size plate chiller, you might find that you can push the wort through it at a fairly fast rate and still get to your target temperature. I am currently working on putting together a mechanical system involving a plate chiller. I am going to use a DC pump to push hot wort through a plate chiller and then back to the BK via a whirlpool arm I’m going to build until the wort has reached the desired temperature at which point I will divert the wort to the fermenter. Not nearly as cool as what you’re planning.
Sounds like a cool idea. Me not a big electricain but lowering the ac it might burn the pump. Or you will not get the result you want. But not 100% sure
I like that idea too. My thought was that by getting it out of the kettle while it is still hot, the viscosity would be low enough to use a kettle screen or hop blocker. When the wort cools, it can clog much easier. But it seems like you have a solution with the whirlpool.
