Heating Element sizing

Found this calculator

Here is my kettle size and related element size based on this calculator:
BK - 40 gallon - 2/5500 Elements (starting temp 170F)

RIMS tube - 1/1500W Element

Can anyone confirm this or provide me with a better selection?

2 @ 5500w seems good for the boil...1500w for the rims seems light for such volume pending insulating the vessel...but you can discount this as I am a shoot from the hip type FWIW. I am envious BTW

Wat until the system is done. Full automation sans level control...

1500 should be good for a rims tube. i have a 2000w element in a herms pot and it cycles at 40% (800w) to keep temperature of a 10 gal batch. a rims tube would cycle less, maybe 20-30% (400-600w). so for 40 gallon batches, 1500 full blast should be fine. 2kw would give you more headroom, but at the risk of overpowering. depends on the insulation though.

for RIMS you might want to look at a phase angle controller rather than a simple on/off pwm. ive been playing with the idea- should eliminate most scorching troubles.

The actual batch size is 20 gallons. 30 gallon hot liquor tank/ boil kettle and 40 gallon mash tun. It's a 2 vessel system so the full volume needs to be able to fit in the mash tun. No insulation on the mash tun. I'm spec'ing a tankless water heater so strike temperature 'should' be reached fairly quick.
The system will be controlled by a BCS-462. For the boil kettle, which method do you suggest for controlling boil? PWM or phase angle controller (PAC)? Is there an adjustable manual potentiometer for manual control? i.e. how is boil over prevented?

One more question: PWM / PAC for oxygen solenoid so O2 can remain on for duration of transfer to fermenter or regulated pressure?

with that PAC i linked, theres a potentiometer for varying the 'intensity' between 0 and 100%. im liking the PAC instead of the standard PWM just because its much more fine-grained control. with PWM its only on or off, which when you slam 20 or 50 amps on and off rapidly it can effect other things in the house (lights pulsing, havoc on digital voltage regulation circuits on your TV or computer, etc). a phase angle controller is more gentle; instead of just varying the rate and time of the on/off switching to equal the overall desired duty cycle, a PAC actually modifies the waveform to equal the % power you set.

One more question: PWM / PAC for oxygen solenoid so O2 can remain on for duration of transfer to fermenter or regulated pressure?

Click to expand...

you dont want to pwm a solenoid. if you want to adjust the flow rate ofa gas you can use a needle valve, especially for the flow rates you will probably be using with oxygen (low flow). once you set the needle valve to the rate you want, you can control the gas line with an on/off solenoid if you want it to interface with the BCS. a solenoid doesnt control the flow rate though.

and remember to use oxygen-rated equipment! pure oxygen can be very dangerous and can cause regular valves to spontaneously catch fire (thats right- steel or brass valves can spontaneously catch fire).

thanks!
after I posted the O2 question I thought... duh! Regulator- of course!

So how did the 1500w element work out for the RIMS or have you tried it yet? I'm thinking about going RIMS for my 1 bbl system and I'm getting frustrated trying to find information on how to size/utilize a RIMS tube/heating element based on batch size. There's a ton of information out there but not what I'm looking for. I've found information on what to expect from a heating element in terms of volume and time it takes to change temp, but I'm not sure how to apply that to a RIMS set up vs having the element in the kettle. I'm thinking about trading for a nice RIMS tube but I need to make up my mind rather quickly and I'm pretty ignorant when it comes to electric brewing.

The batch size is not the determining factor. The diameter of the RIMS tube and the volume of wort being pumped through are. If you are using a 1.5" tube and a March 8 series pump, 1500 watts is correct. If you are not getting enough heat you can also throttle the out port.

OneHoppyGuy said:

The batch size is not the determining factor. The diameter of the RIMS tube and the volume of wort being pumped through are. If you are using a 1.5" tube and a March 8 series pump, 1500 watts is correct. If you are not getting enough heat you can also throttle the out port.

Click to expand...

Throttle the out port? Meaning reduce the flow rate?

I guess that wasn't very clear. A valve after the heating element and before re-entering the kettle. Control the flow with this valve. I've never needed one but that is how it would be done.

That's what I thought. So, have you run your set up yet? The tube I'm thinking about getting is a 2" tube. See pic below. Would I want to jump to a larger element for this? Also, I don't really understand why reducing the flow rate at the out port of the RIMS tube would increase heat to the mash tun. I've been giving it some thought and it seems to me that heating a larger volume of wort to a lower temp or heating a smaller volume to a higher temp would accomplish the same thing heat wise. BTU's going into the system would remain the same right? Just trying to wrap my mind around this.

ahh, Stout RIMS tube.
The longer the wort stays in the tube, the hotter it will get if the element is on, thus the use of a valve.
Photo is one of our units using an electric RIMS tube.

The element only comes on as needed which isn't that often. Be sure to have an inline flow switch to make sure the element is not on when wort isn't flowing.
The elements are cheap, so start with a 1500W, if it's not enough, go bigger.

So, you're saying that you adjust the flow rate with a valve in order to keep from overheating the wort in the tube?

actually the valve is for just the opposite: reduce flow to increase heat if not getting hot enough. We place a temperature probe on the outlet side of the tube and a second probe in the mash tun about mid grist level. The 2 temperatures can be averaged if you have BCS or PLC system.

OneHoppyGuy said:

I guess that wasn't very clear. A valve after the heating element and before re-entering the kettle. Control the flow with this valve. I've never needed one but that is how it would be done.

Click to expand...

I agree with the idea of controlling the wort flow through the RIMS tube by slowing it down to make it hotter, but I don't like the placement of the valve after the RIMS tube.

My preferred method is to place the valve between the pump and the RIMS tube with no restriction between the RIMS tube and the return to the mash tun. I like this just as a safety feature in case the RIMS tube overheats and starts to boil the wort. I would like to eliminate the possibility of steam pressure bursting pipes or splitting a silicone hose. Flow sensors help in shutting down the heat if no flow, but even safety devices fail, so redundancy helps.

ChuckO, that makes total sense. We've never found need to restrict the flow, have you implemented this method? What type of flow sensor are you using?

OneHoppyguy, at present I haven't implemented flow sensing, but it's an idea that I want to investigate. I did have a problem with low flow through the RIMS tube allowing boiling during some water testing. Steam returned to the mash tun for a few seconds. It happened because the temperature sensor had a wire disconnect due to a bad solder joint at a connector. In this case flow sensing wouldn't have helped, low flow rate coupled with no temperature input kept the PID on with a 5500watt element.

Sometimes you have to devise safety requirements for accidents that you don't foresee, difficult at best.

The flow switch I posted a photo of is a simple plunger with magnetic pickup. The challenge with that design is the spring tension is a little high for the 8 Series March pumps but works great with the AC5 series.

Note the lackluster performance. This is with a March series 8 pump

I have a 1500W rims tube that has no trouble hitting my target temperature on 35L of water with 16 pounds of grains, outside in -5C weather and no insulation on the mash tun.

I think I loose a degree or two as the liquid goes through the grains due to lack of insulation, but the rims tube maintains my target temp on the top of the grainbed without too much effort.