Thirsty Boy wrote:Are PIDS and SSRs the right control solution in this situation?? My understanding is that they don't throttle the power density in a way that will gve you control over your boil vigor. After all.. it all going to be at 100°C (give or take a tiny bit) boiling hard or boiling soft... all still at 100°C. So whats the PID going to control?
The PID is primarily to control the on/off cycling of the element in the HLT (HERMS) via the SSR to hit/maintain a particular temperature in the MT (via thermocouple).
Thirsty Boy wrote:I know that you can set-up certain types of SSR with a manual dial type control.. (I am sort of guessing / remembering someone elses set up here) I think its basically a rheostat that alters the voltage across the SSR which in turn alters how much electricity it lets through - thus controlling your element.
So a PID / SSR is great for controlling an element in a way that maintains a set temperature - say 78°C in your HLT... basically switching the element on and off quickly and in a cleaver way that avoids over/undershoot - BUT in the kettle situation... what temperature are you going to set it at? At 100C it'll be all 5.5KW till you hit the 100 . . then it'll just sit on 100 and basically not boil.... so you set it to 101 or 102 and its going to try with all its 5.5kw to get there and it never will because boiling water is at 100C no matter how vigorously its boiling. So what you need is a "throttle" for your element that isn't Dependant on temperature to regulate the output. Like the rheostat (thingy) I talked about before.
As for the boil, I'll control the juice to the element in the BK via a rheostat - or through a manual setting for power output % for the secondary setpoint on the PID (haven't made up my mind yet). I just left the rheostat out of my last reply because I needed to type/submit quickly to grab my crying 4-month-old... Once she's old enough, I'm hoping that telling her "Daddy's doing beer stuff..." will hold off her fussing a little longer...
But thanks for the reply as this will hopefully help avoid confusion for those who get to this thread via a search for electric brewing systems...Thirsty Boy wrote:Like I said, sorry if you already know all that stuff - you probably do - but if you didn't, I hope its helpful.
TB
