RIMS Build

[keelanfish]

I'm keeping up with this thread with anticipation to see how it works out for you. I live in Decatur, work in Kennesaw and brew at my brother's house just over the Paulding County line. I'm in the initial planning phases of going electric for the mash and only using gas for the boil.

Cheers and good luck!

 

[eccsynd]

Thanks for the PID pointers. I'll definitely give that a try. The water is flowing right to left and the amplitude of the temp swings (higher swings on RIMS) makes believe that I had the probes wired correctly. But I'll definitely double check. I had some long (10') extensions on the 'psudo-hlt' probe. Would that matter? It was 14 gauge wire so the impedance should have been negligible.

Wire extensions won't matter with these sensors, even 100'. I agree, larger swings make sense for the RIMS, and its easy to see that trace0 (gray), which I assume is inside the RIMS, is what is associated with the PID control because you can see that the output switches off when you pass the setpoint.

Actually, thinking about it a little more, it makes sense that the RIMS temp is lower than the measuring cup temperature. Its because there is incoming 80deg water cooling it down.

 

[Sizz]

I'd recommend using the Ziegler–Nichols method, set I and D to zero, and increase P until you get oscillation. Which shouldn't be a problem. Make sure to give it enough time to truly oscillate, not slowly converging.
PID controller - Wikipedia

So i tried to tune it today and I failed at step #1. I get oscillation at the lowest allowable P gain of 0.01. I also had to make the set point something insane like 2000 for it to even turn on. Any way you could implement that limiter feature?

I could go to a slightly lower wattage element like 3-4kw but that's limiting my strike water heating ability. I did manage to get a somewhat decent response using P=0.3, I=0.15, D=15. The initial ramp from 80F did boil the water some, so I really need to get a lower P, especially if I don't want to scorch using 240V.

 

[CodeRage]

I am trying to figure out what you have going on here. What are the red and blue trends representing?

 

[slimer]

One is the RIMS Heat Exchanger temp and the other is a measuring cup with water that brought up to sparge temps from 80 degrees.

 

[CodeRage]

okay, you need to measure the output temps in a larger vessel. This will average out your fluctuations on the end. If you are using it for instant on demand water for a sparge type applications, put a settling chamber/vessel before the final output. I would probably start with a half gallon and go from there. Make sure there is a fair bit of turbulence and measure the temp on the output side of the settling chamber.

You definitely have more powered than required

You can see the affect of the averaging in your first test, the amplitude in temp change is proportionally smaller than measured at the HEX.

The output of the BCS, you could set a PID output to rail between 0 and 100%. Then PWM the result out. Not sure if the processor is fast enough to do it with code, but there are I2C D2A PWM drivers that are pretty cheap. Hec, you can get a PIC with a few on board for a couple of bucks a shot.

 

[kladue]

You might want to start with P = 20, I =1, D =2, the setup parameters you seem to be using are mostly resonding to the "D" factor instead of the "P" factor. FWIW with 8 differnent PID loops that control water, wort, boiler fuel flow, and cooling there have been more than a few hours spent working out the tuning and time variables in the pid loops and a fair amount of practical knowledge gained. With the I & D variables set to one you should be able to slowly increase the P value until it hits setpoint within 60 -90 seconds, then start increasing the I value until you can hit setpoint without serious over/under shoot, then increase D to cut down oscilation. The time interval should be the time between peaks in the output.

 

[Sawdustguy]

I am the first one to admit I was wrong. Good job Sizz. I am very curious how the RIMS works with the mash and the high density RIMS element. If it works I will go from my 1500 watt low density element to a higher power high density element to make stepping faster.

 

[Bobby_M]

Just out of curiosity, how close does the hex probe come to the element itself? I'm wondering if it's picking up hot spots just as they leave the surface of the element before it has a chance to integrate with colder water that rode through further away.

Maybe try a longer center nipple to give the water more mix time.

Note: I'm talking out of my ass.

 

[lamarguy]

If it works I will go from my 1500 watt low density element to a higher power high density element to make stepping faster.

I don't believe the caramelization question has been addressed yet, nor has the question for how to maintain both sparge and mash PID configurations. Sounds like he's currently focused on the sparge temperature/flow question, which, I agree is good news.

Have you considered how long it's going to take to get your full volume of strike water up to temperature?

 

[Sizz]

Just out of curiosity, how close does the hex probe come to the element itself? I'm wondering if it's picking up hot spots just as they leave the surface of the element before it has a chance to integrate with colder water that rode through further away.

Maybe try a longer center nipple to give the water more mix time.

Note: I'm talking out of my ass.

That's actually a good idea. The probe is only about 1 inch away from the element because I wanted the fastest response. I was hoping the stainless shielding around the probe would be sufficient to average the hotspots. But that's something I should definitely confirm. The probe has a compression fitting holding it so I will slide it back some and see how that effects the response.

I don't believe the caramelization question has been addressed yet, nor has the question for how to maintain both sparge and mash PID configurations. Sounds like he's currently focused on the sparge temperature/flow question, which, I agree is good news.

Have you considered how long it's going to take to get your full volume of strike water up to temperature?

Ideally, heating 25quarts using my summertime ground water temps would take about 15 minutes.

Currently, I've only confirmed that a 5500w element can produce enough heat for inline heating of sparge water. The good news is that worse case scenario, I can make the system work as is by adding a little more hardware (contactor for 120V mode to prevent scorching). An actual full size MLT will average out the temp swings. I could even add a mini mixing reservoir. The multiple PID issue isn't a problem because I have a spare SSR and will just switch between which SSR i'll use(120V or 240V).

Ideally, the above additions won't even be needed if I can get the software modifications required for this wild system. Fortunately, ECC (maker of the BCS controller), is working with me.

 

[bakins]

I was just thinking related to this thread. I use a 4500W ULD 240V element in my BK and have no caramelization issues. Others report the same with larger elements. Shouldn't the same be true in the mash for RIMS?? I run my RIMS element (which is a 5400W ULD) at 120V, mostly because I don't have "room" for any more 240V stuff.

I'm still interested if the high density element shows any scorching. If it doesn't, that's interesting because those elements are much smaller in size.

 

[Sawdustguy]

I think we are all waiting for the answer to that question. I think there are some encouraging results using the rims heater as a Instant hot water heater but the Scortching issue still remains. Only an experiment will tell.

 

[CodeRage]

Hmm, Im considering putting a Hi/Lo switch in for my Rims element (4500W) so I can heat the initial strike water quickly before adding the grain. Perhaps 2 back to back batches of Ed's Pale one with the RIMS on hi and the other on Lo would be in order..

Maybe should diverge this to a new thread and not derail OP. Sorry

 

[Sizz]

I was just thinking related to this thread. I use a 4500W ULD 240V element in my BK and have no caramelization issues. Others report the same with larger elements. Shouldn't the same be true in the mash for RIMS?? I run my RIMS element (which is a 5400W ULD) at 120V, mostly because I don't have "room" for any more 240V stuff.

I'm still interested if the high density element shows any scorching. If it doesn't, that's interesting because those elements are much smaller in size.

If you can boil with a ULD with no scorching, then it'll certainly function fine as a RIMS heater. The reason I went with a high density element was to reduce costs for the stainless steel RIMS piping. My original intent was to use the 'RIMS heater' in conjunction with a plate heat exchanger, basically a HERMS, which is still a possibility.

If money wasn't an issue, I may have gone with a ULD element in a larger stainless vessel, probably something custom fabricated. The only ultra low density elements i've seen are huge (see the pic in my 2nd post on page 1). I even flattened one out with intentions of using it but it would have required at least 24 inches of 2" or even 2-1/2" pipe.

I definitely plan on doing a scorch experiment, although I'm still unsure how to accurately measure scorching. Maybe run DME through it and check for deposits on the element or discoloration of the wort?

 

[lamarguy]

I definitely plan on doing a scorch experiment, although I'm still unsure how to accurately measure scorching. Maybe run DME through it and check for deposits on the element or discoloration of the wort?

Yes, I would recommend you make a low SRM 1.050 gravity wort and experiment with different temperature differentials (e.g. 10F step, 20F step, 30F step, etc) across the heat exchanger using your PID controller. Then, check for color change and, possibly, taste change in the wort. You should be able to reliably observe and measure scorching that way.

You will also need to control the flow during the experiment, so consider using gravity only.

 

[leboeuf]

I wonder if you could use cheap cane sugar? It dilutes clear and I would think any darkening would be an indication of caramelization. I'm not too sure how close caramelization and scorching are related but it should be roughly the same thing.

Edit: Hmmm maybe I'll try this out some time with glowing hot metal and a small vessel of sugar water to see if this whole scorching thing is valid...

 

[lamarguy]

I'm not too sure how close caramelization and scorching are related but it should be roughly the same thing.

All kettles (gas-fired, electric, and steam-jacketed) caramelize the wort to some degree (some less than others), which is a desirable flavor in most beers. Scorching results in burnt flavors and colors. Once the burnt flavor is there, the entire batch is ruined.

 

[Lil' Sparky]

Just thinking out loud here...

What if you had a single RIMS unit that had two different kinds of heating elements - one screwed into each end. The HD element (and possibly the LD element together) would be used to heat strike/sparge water additions, and the LD/ULD? element would be used to maintain mash temps. I guess you need two PIDs/SSRs, but the layout/footprint could be greatly reduced. Of course, if it turns out that you can maintain mash temps w/out scorching the wort with the HD elements, I guess it's a moot point.

 

[CodeRage]

might as well just use one LD element and switch it between 240 and 110 for high low like kladue suggested.

Or... You could get 4 LD elements (say 5kw) and run them at 120v. This would be like one 4x UUULD 5kw heating element. I dont think density is going to affect the rate at which the water heats, total wattage is really the factor.

Or maybe I am missing something.

 

[bakins]

I even flattened one out with intentions of using it but it would have required at least 24 inches of 2" or even 2-1/2" pipe.

My 5400W element (I think it's just very low density, not ultra or whatever) fits easily in a 1.5" pipe about 14 inches long (the element). This element is not "wavy" like alot I've seen.

 

[TheProph3t]

How would you switch between 240v and 120v on the 5500 element?

 

[CodeRage]

How would you switch between 240v and 120v on the 5500 element?

to run 240v you have both of the "hot" legs hooked to the terminals of the element. to run 120 you just remove one of the hot legs and put neutral on it instead. You could use a few high current contactors to do it.

There is a drawing I put up on Brew Pastors page that shows how to do it with a PID controller.

https://www.homebrewtalk.com/f51/57-gallon-electric-hlt-build-129898/index4.html#post1470392

 

[bakins]

FWIW, my elements look like this:

5500 Low watt density.

 

[Sizz]

Small Update 8-12-09

Good news:

I got a sneak peak version of the next BCS build and was able to test some new features. I was able to limit the maximum pulse width which effectively limited the wattage of the element and I was able to heat 80F ground water and maintain steady temps targeted at 140F at a 1.2qt/min flow rate. This also means I don't have to switch the element to 120V for mash recirc mode. Thanks ECC!

Bad news:

I boiled water when I tried to go to 170F. The surface area of the high watt density (HWD) element is just too small to apply the heat required for that temp differential. I did get to 170F but I could hear bubbling in the RIMS. Conviently as Bakins just posted, there is a solution. Not sure how I missed it but I returned to Home Depot and finally found the 5500w LWD (low watt density) element. It has twice the surface area (75w/sq in) vs (150 w/sq in) while maintaining the same 1" profile. It's 4 inches longer so I had to order another pipe nipple & coupler to expand the RIMS piping a little.

 

[slimer]

Nice. I love my BCS and hope to finish my project within the next few months.

 

[leboeuf]

Nice!
I had a feeling all it would take would be a little PWM

That's a bummer about the boiling.... Technically if the water was at 170F at your MLT then you would be ok for sparging. I'm not too sure what negative effects this would have on your brewing hardware...

 

[Bobby_M]

I'm wondering what the worry of some boiling is. I suppose steam pockets could screw around with the probe reading but as long as the tube is oriented vertically, is it really a problem if your output water is at your target?

 

[Sawdustguy]

I'm wondering what the worry of some boiling is. I suppose steam pockets could screw around with the probe reading but as long as the tube is oriented vertically, is it really a problem if your output water is at your target?

Maybe it's me but I would be concearned about steam pressure building up in the RIMS tube. I did have concearns about the high density element from my post earlier in the thread but I was hoping it would have worked out. If the high density element was enough to boil the water, my guess is that it would have scortched the mash also. I hope the low density element works as it would be a neat little two vessel RIMS brewery.

 

[Bobby_M]

It sounded like it was only a problem when going for a large in/out delta such as heating for strike or sparge. In that case, it's only water and the output tube is never blocked off so pressure wouldn't build.