HELP - Trying to get near boiling temps out of a RIMS

[Douglefish]

I'm trying to recirculate wort to simulate a Zymatic style boil in my conical. Reason is mainly to get to a single vessel + RIMS. I'm using a BCS-460 controller and a 5500W element for the RIMS. The issue I'm running into is that as I get closer to boiling, (200ish in Denver 203 Boil Temp) I start to boil in the rims tube.

1st question is should I care? Is there any harm that can come from boiling wort in a rims tube?
2nd question is can this be fixed by tuning the pid?
Final option could be reducing the element size, but I would rather not.

The BCS allows me to tune the standard pid settings plus Min/Max pulse % and period settings.

Thanks in advance

 

[FunkedOut]

I don’t see any other way this can play out.
Your only heat source is in the RIMS tube.
The wort will experience heat loss from the tube to the conical.
You can’t get boiling temps in the conical without first getting them in the RIMS.
I’m not sure you’ll be able to get boiling temps in the conical.
You’d have to inject enough steam from the RIMS tube into the conical to raise the wort temperature.

What about adding a boil element to the conical itself?

 

[Douglefish]

Thanks FunkedOut, you are right. I'm actually not super worried about actually boiling the wort in the conical, I just want to get it as close as possible. The circulation from the pump will drive off the DMS and the temp will be for hop utilization. Just want to get it as high as I can consistently and the current temp fluctuations are pretty big.

 

[augiedoggy]

Thanks FunkedOut, you are right. I'm actually not super worried about actually boiling the wort in the conical, I just want to get it as close as possible. The circulation from the pump will drive off the DMS and the temp will be for hop utilization. Just want to get it as high as I can consistently and the current temp fluctuations are pretty big.

Playing with the flow speed will help. Also insulating the rims tube wont hurt. I have found that in many rims setups the liquid that comes in actual contact with the LWD rims element surface will boil but the other liquid will remain cooler thu resulting in much lower than you would expect temps exiting the rims when they mix as they exit. one way around all this (for me) was to use long ulwd cartridge heaters and built a longer rims tube with some bends for agitation and mixing to allow longer contact time for more consistent heating of the wort on each pass. (its also gentler less likely to denature enzyme heating which is what I want for my use) I built a C shaped rims with sits horizonantally and is mounted on my wall for my 3bbl system and it utilizes 2 28inch long 2200w elements.

 

[Douglefish]

Thanks augiedoggy, what exactly will insulating the rims tube do? I'll run the system and monitor the temps coming out of the tube itself to help debug. Good thoughts!

 

[BrunDog]

@augiedoggy is right. You actually would want not a smaller RIMs element - you want bigger. Or better said, you want as low a heat density as possible combined with as much flow rate as possible. You will never be able to get too close to boiling temp since heat transfer in the tube will cause local boiling - lower heat density improves this.

 

[augiedoggy]

^^ brundog does sell a sweet Quadzilla element which will fit in most off the shelf rims tube kits and would work better than a standard lwd element.

 

[FunkedOut]

Thanks augiedoggy, what exactly will insulating the rims tube do? I'll run the system and monitor the temps coming out of the tube itself to help debug. Good thoughts!

Insulating the RIMS tube will minimize the heat loss from the tube itself to the air.
This, in turn, will minimize the heat gradient from the wort touching the nesting element(s) to the wort touching the tube itself.
With the heat gradient minimized, you will achieve maximum heat transfer out of the tube and into your mash vessel.
For similar reasons, you could insulate the tubing between vessel and RIMS tube.