Double Batch with 30 Amps - HEX in BK for strike water?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

kpr121

Well-Known Member
Joined
Jul 30, 2009
Messages
3,117
Reaction score
138
Location
Pittsburgh
Been a while and never really got around to a solid plan for double brew days (12 gallon batches last a while in our house since my wife is now pregnant!) but here's an idea I just thought of during last brew day:

Leave a heat exchanger hooked up in the BK during the boil, and use a temp controller on my HLT pump to recirculate the HLT water as well as maintain a boil. I have rolling boil with the PID set to 55-60% of 5500 watt power, if I ramp that up I should be able to transfer heat over to the HLT without losing a boil. I can pinch down the flow rate with a ball valve in order to maintain a boil. Just a matter of how slow is too slow?

The last couple of brews I have been maintaining a full HLT at 170 during sparge, this leaves me with some hot water at the end of the session to use for cleaning. I guess I could probably use that leftover water as strike for the first mash, and let the BK boil and heat sparge water for the hour long boil (and mash).

Anyone done something like this?
 
I have been thinking the same thing. How to do a double batch only using 30 amps. I was thinking a putting an extra switch that can only turn on an extra ssr when boiling. if you use a normally open ssr for the bk, have the switch control a normally closed ssr for the hlt. So if your boil is set to 60%, your hlt will be running at 40%. I figured that would be enough to heat it to strike temp during an hour long boil. I don't see why this wouldn't work, both elements would never be on at the same time, they would just be flipping power back and forth. You wouldnt have precise control, but if you have a thermometer in your hlt you can just flip the switch off when it gets up to temp. Maybe someone can chime in if this is possible. I'm no electrical engineer.
 
Hmm that is an interesting idea too.

While I wouldnt really mind doing the whole thing manually, I think digital controlling could be possible as well:

Im sure in your method one could hook up a temp controller on the output side of the 40% SSR leg. Once the HLT hit the desired strike temp, it shuts off the power and your back to only using 60% for the boil.

Similarly, in my pump and HEX method, a temp controller is set to turn on the pump when the temperature is too low. Once the set temp is reached it shuts off the pump. You would need to manually throttle a ball valve to get a flowrate slow enough that it does not interrupt the boil.

We are both in it for the same reasons (why have all that power if you cant use it for something?), but I'm thinking more mechanical and your thinking more electrical.

FWIW I am a civil engineer so that doesnt help us much either lol.
 
Easy theoretical calculation... we know that 60% of 5500 (3300 watts) can keep a 10 gallon batch boiling. How long does it take the other 40% (2200 watts) to heat up 10 gallons (approx volume of sparge water needed for average 10 gallons brew) from say 70 to 170 degrees? Without doing the math, I found this thread that has some information that says it takes anywhere between 50 and 90 minutes. I think that is reasonable. Plus like I said before I usually have some more hot water left over in the HLT so that starting temp would be higher, say around 100?
 
Hmm I'm in the middle of testing my mechanical HEX theory, and it seems I forgot one important part of thermodynamics - ENERGY REQUIRED FOR PHASE CHANGE!

Got 14 gallons up to a boil in the BK with HEX immersed. Have 10 gallons sitting in the HLT connected to the HEX. The instant that I turn the pump on, the boil stops because it is cooling down the BK water. I thought it may be because I was starting so low in temp, so I let it run for a while to equalize temps, but it still wasnt working at HLT @ 100F.

My idea isnt looking very good.... Im currently attempting it at a higher HLT temp to see whether I can even boil while maintaining 170 (sparge temps). I will update when Im done.
 
Hmm I'm in the middle of testing my mechanical HEX theory, and it seems I forgot one important part of thermodynamics - ENERGY REQUIRED FOR PHASE CHANGE!

Got 14 gallons up to a boil in the BK with HEX immersed. Have 10 gallons sitting in the HLT connected to the HEX. The instant that I turn the pump on, the boil stops because it is cooling down the BK water. I thought it may be because I was starting so low in temp, so I let it run for a while to equalize temps, but it still wasnt working at HLT @ 100F.

My idea isnt looking very good.... Im currently attempting it at a higher HLT temp to see whether I can even boil while maintaining 170 (sparge temps). I will update when Im done.

I think you would have to recirculate through the hex at a trickle for this to have a chance and in that case it really wouldnt heat up the HLT water.
 
In theory, as long as you extract heat from the BK at a rate less than you put heat into the BK from the element, you should be able to achieve your goal. It takes 4.13 (ish) joules to heat 1 gram of water 1 degree celcius. We can look at the specific heat of water and do some math. Assuming 10 gallons of water weighs 37.8kg, and assuming you're going from 100*F to 170*F (38.89*C change) then it comes out to requiring 6159KJ of energy. That works out to about 1.71 kWh, or 1710 Watts in an Hour. So, let's say you want to get your water up to temperature during the hour long boil, you'd pull 1710 watts of the element's 3300 available watts out through the HEX. That leaves you 1590 watts to maintain boil.

Of course, this is all theoretical. I have no idea how much energy it would take to maintain boil, how much energy is lost to the environment, what the efficency of the heat element actually is, etc. But, in theory, a heater putting out 3300 watts of energy could boil the water and heat through the HEX.

Or, I have no idea what I'm talking about.
-Kevin
 
I had to quit my testing today, but its not looking good. I had the temp in the HLT up to 165 and every time I turned the pump on the boil stopped. So if the plan was to decrease total time during a double batch day I dont think this is the best idea.

FWIW I am using a 5500 watt element, not 3300. I really think this isnt going to work the way I planned due to the temperature differential. Electrically like JRems idea might work however.
 
I am not sure your setup. Assuming you are boiling in a keg conversion.

I would guess if you made a heat ex changer that was wrapped on the outside of the boil kettle (not in the liquid) your theory would work out. You would get enough heat transfer from this to get what you want in the HLT without slamming the boil liquid. You would still have to play with flow rates, but the metal of the kettle will act as a capacitor and you will not kill the boil I would guess.

Again... just a guess
 
I'm glad you tried it out. I don't think your hex method will work out, even when running boiling wort through my counterflow chiller to sanitize instantly kills the boil. With my method I was just trying to get the strike water heated, not keep precise mash temps, so as soon as the boil is over I can dough in and start the mash. When I get a chance I'll try to work it out I'm sure it can be done. I searched but haven't seen anyone try a setup like I described.
 
You guys got me thinking and I think I know how I am going to do this in the rare case I need to.

Im planning on using runs4beer's method of switchcraft plugs on my element housings. https://www.homebrewtalk.com/f170/s...ow-did-you-do-212079/index10.html#post4472090

With that in mind I can swap out the 220 cord for a cord that goes to a 20a 120v gfci outlet and use that to heat strike water. I wont have any control other than plugging it in but running a 5500w element on 120 gives you 1375w. Would probably take awhile to heat strike that way but it will get it started and take minimal cost.
 
3500w * 2 elements = 7000w / 240v = 29amps. you could run both these elements at the same time on the dedicated 30a circuit no problem.

OMJ's comment about flipping them from 240v to 120v also works but will take longer to heat the water since you have less watts
 
You guys got me thinking and I think I know how I am going to do this in the rare case I need to.

Im planning on using runs4beer's method of switchcraft plugs on my element housings. https://www.homebrewtalk.com/f170/s...ow-did-you-do-212079/index10.html#post4472090

With that in mind I can swap out the 220 cord for a cord that goes to a 20a 120v gfci outlet and use that to heat strike water. I wont have any control other than plugging it in but running a 5500w element on 120 gives you 1375w. Would probably take awhile to heat strike that way but it will get it started and take minimal cost.

Hmmm I like this thought. Better solution than some of my other ideas (heat stick, adding additional 2000W 110V element to HLT, going back to propane for second batch, etc).
 
3500w * 2 elements = 7000w / 240v = 29amps. you could run both these elements at the same time on the dedicated 30a circuit no problem.

OMJ's comment about flipping them from 240v to 120v also works but will take longer to heat the water since you have less watts

Running two elements would be a valid solution if I was starting all over again, AND planned on doing double batches all the time. I dont plan on reworking my control panel any time soon, and really would probably only double brew a few times a year.

Of course the question with your idea is how much longer does it take to get the initial volume up to temps with 3500 as opposed to 5500 and does that save you time overall?

I'm afraid the answer to our questions (speeding up a double brew day) is, like always, MORE POWER!
 
uh, aren't you already running two elements? one in the BK and one in the HLT? you just can't run them simultaneously right now.

rough calculations from sunday's brew day (5500w element, 1 at a time)
need 17 gallons total, but can't heat all of that at once.
start with maybe 12 in the HLT at 50F (ground water).
50F -> 165F = 39 minutes
then i mash in, add more water to the HLT and heat it enough to get the HERMS to the right temp plus sparge. it's done at about the time i'm done mashing in and stirring. (10 min)
mash out at 168 (about 10 min to ramp via herms)
add to boil kettle. sparge.
13.5 into the kettle around 165F
13.5 gal 165F => 212F = 18 minutes

total water heating time: 39 + 18 = about an hour

***************************
proposed method
2 x 3500W elements. can be run simultaneously
i need 17 gallons so i split it into 2 vessels (HLT + BK) and get all my water at once!
50F -> 165F 8 gallons = 43 minutes [4 minutes over my last brew day]
BK water goes into the mash, and i'm instantly able to control temps with herms, no lag. [now 10 minutes up on my last brew day]
at the end of the mash, ramp the 8 gallons in the HLT to mash out temp. [net result same as before. the herms will still take the same amount of time to ramp the mash]
13.5 gal into kettle. 165F to 212 @ 3500W = 28 minutes [10 min longer than last brew day, net result is 0 minutes longer total]

with this method, however, i can be heating water in my HLT for my next batch just as soon as it's empty. with the above method i would have had to use propane or some other method to heat the second batch water.

so the net result is basically a wash... and can be shortened by simply starting the BK as soon as there's enough liquid to cover the element. i didn't put this into the calculations because i couldn't account for the math as easily.

the answer to this particular question is technically MORE POWER, but not the way you think. by expanding your total heatable volume into 2 vessels at 7000w total you can heat water quicker than with 1 5500w element, and also free yourself up to double batch days. :)
 
Nice concise writeup, I’m picking up what your throwing down! I think that if I were to redo my control panel this is exactly what I would be doing (maybe even upping everything to 40 or 50 amps so I could run dual 4500 or 5500 elements).

But… I was not planning on redoing my control panel at this point in time. Which led me to the theory that I could do this mechanically. That theory has been proven incorrect. Which leaves me with getting heat (power) from somewhere else.

So for my situation, I guess it’s a choice of the following:
A. Quit whining, dedicate an entire day to brewing double batches and be done in 8-10+ hours
B. Whip out the ol’ propane and turkey fryer and get the second batches volume going with that (issue: don’t want to put my electric HLT on flame due to plastic housing and potting)
C. Conjure up some adapter to allow me to plug my existing HLT 5500w element into a 110 outlet, getting 1375w to heat up batch 2’s sparge water during batch 1’s boil.
D. Add additional 2000w 110 element to HLT. This will both increase first batches heating time and also give me more power than C for batch 2’s heating time.
E. Build a heatstick that I can move from either HLT or BK (I don’t like this idea-most likely to kill me)
F. Man up and rebuild my CP (this aint happening, my man card will be completely removed in a short time with my wife expecting in January).

I honestly think I like option D the best. Only downsides are that there will be another hole in my keggle (join the club), and some extra cost up front for mounting it. I bet I can get 13-14 gallons of water up to 170 in 30 minutes with 7500 watts. Saving time on both single AND double brew days!
 
F. Man up and rebuild my CP (this aint happening, my man card will be completely removed in a short time with my wife expecting in January).

LOL you have a kid coming and you're thinking about double batches? Just start building the new CP now. You're going to need it just to optimize a single brew day.;)
 
LOL you have a kid coming and you're thinking about double batches? Just start building the new CP now. You're going to need it just to optimize a single brew day.;)

+1

We just had a kid and I'm lucky to get half a batch kegged. I've been working on a keezer build for almost three months now!
 
+1

We just had a kid and I'm lucky to get half a batch kegged. I've been working on a keezer build for almost three months now!

I didnt brew for a year after my first was born. Certainly makes it tougher
 
LOL you have a kid coming and you're thinking about double batches? Just start building the new CP now. You're going to need it just to optimize a single brew day.;)

+1

We just had a kid and I'm lucky to get half a batch kegged. I've been working on a keezer build for almost three months now!

I didnt brew for a year after my first was born. Certainly makes it tougher

Thanks for all the encouragement :p:eek:. Maybe I should at least get the SSRs, thermocouples, and PID ordered now before 99.999% of my discretionary income goes to diapers!

And yes one of the primary reasons I have been thinking double batch brew days is to optimize seldom alone time!
 
I just found another thread on this and someone mentioned that the total wattage capacity of a 30 amp system is approx. 7000 Watts (7000/240=29.16). He mentioned that he was able to run this without the breaker tripping due to temps too. So the idea behind it was basically that you run one 3500W element in each vessel so you can run both at the same time. Thus you have 7000W running and heating as opposed to having a maximum of 5500W heating and running, thereby increasing the efficiency of your system.

Not my idea but makes perfect sense to me. I think I'll be dropping by HD tonight to grab two 3500W Camco elements. It may increase the time it takes to reach a boil but I figure if I turn the element on as soon as its covered that will be minimized. Also that time will probably be made up for by being able to heat strike and sparge water at the same time.

I'll probably try to get the elements potted this weekend and maybe do a double batch next weekend. This of course is subject to the approval of SWMBO and child. I'll try to remember to time everything and update here with results.
 
Thanks for the response. To be PC id like to point out that most code and general electrical practice says not to run more than 80% of your breakers rating.

With that out of the way... you COULD heat half your initial strike water in each vessel to minimize time lost in the first batch.
 
that code is for new installations, not dedicated runs for "appliances". you can absolutely run 30 amps of service on a 30 amp breaker and appropriately sized wire all day long.
 
slakwhere said:
that code is for new installations, not dedicated runs for "appliances". you can absolutely run 30 amps of service on a 30 amp breaker and appropriately sized wire all day long.

Good to know, I will definitely try this now.
 
Yeah I wasn’t at all saying it couldn’t be done in this application, I just felt it was a good thing to point out. If you are safe and sound with your electrical and follow common sense it shouldn’t be a problem.
 


if you have some kung foo with micro controllers, this seems like exactly what you want. you could even build it in parallel with your existing PIDs and switch from auto to manual mode for both vessels.
 
Last edited by a moderator:
If the strike water for batch 2 was heated in a cooler with an element installed in it which was powered by a 15amp (better yet 20amp) 120v wall outlet, I would think that you could reach strike temperature in less then a one hour boil. Sparge water could be preheated from water exiting the chiller (chilling batch 1) and then heated in the real HLT before the MLT drops in temp much, maybe? If the batch 2 strike water was collect earlier (day before) and could come up 20° to room temp that might help.
 
If the strike water for batch 2 was heated in a cooler with an element installed in it which was powered by a 15amp (better yet 20amp) 120v wall outlet, I would think that you could reach strike temperature in less then a one hour boil. Sparge water could be preheated from water exiting the chiller (chilling batch 1) and then heated in the real HLT before the MLT drops in temp much, maybe? If the batch 2 strike water was collect earlier (day before) and could come up 20° to room temp that might help.

I like your thinking with using the chilling water output for sparge! That’s a pretty nifty time saver there even if it’s not up at the 170 degree mark straight out of the chiller.

I was thinking about volumes, and for ten gallon batches I am usually forced doing double sparges of approximately 4 to 5 gallons each. My thinking here is that I may be able to end up with enough hot water left over to use for the second batches strike and thereby start mashing as soon as the first batch final runnings are drained to the BK (and the mash tun emptied and refilled with new grain).

Here’s my (latest) rough process plan:

1. Start off with an absolute full HLT (~15 gallons) set at ~170 strike temp. I don’t consider this really a time-loss here since I usually have the water measured out the night before anyhow. All this would take is going down to the brewery as soon as I wake up (who doesn’t do this everyday anyhow?) and flipping a switch. Go back upstairs and get my coffee started like I normally would. A timer could make this even easier.

2. Strike volume is typically around 7 gallons. Get the mash going and fill the HLT back up to full. For 60 degree tap water temp the new average temp of the full HLT would be ~120F. Should be back up to 170 very quickly (prior to first runnings).

3. First batch sparge ~5 gallons. Fill HLT back up to full (new average temp of full HLT = ~135). 15 minute rest of the first sparge while the HLT is on full blast should get the temps up but honestly I don’t think it needs to get to 170 since the second sparge is really just rinsing the grains further (conversion should stop during the first sparge).

4. Second batch sparge ~5 gallons. Allow the rest of the HLT volume (~10 gallons) to continue rising to new strike temperature (carefully entering new higher MLT start temperature in Beersmith). Once strike temp is hit, switch power to BK element.

(OPTIONAL STEP – AUGMENT HEATING WITH SEPARATE HEATING ELEMENT, PROPANE BURNER, ETC.)

5. Drain second sparge into BK.

6. Clear mash tun and add second batch’s grains. Add strike water (approx 8 gallons).

7. When first batch is done boiling, shut off BK element, chill with plate chiller where output water is sent to HLT. I think this water can sometime be up in the 150’s depending on flowrate. As soon as the HLT element is covered switch power back over to HLT.

8. Clean BK and finish rest of batch 2.
 
I think Im going to go with a separate 2000w 120V element in the HLT.

I just remembered I even have an element wired up that I pillaged from when I was doing 5 gallon batches in a 20 qt pot. I think I just need a new locknut and make sure it’s still potted well. Should only cost me 5 bucks or so total if all goes as planned.

I need to cut a hole in my HLT to install a sight glass this weekend anyhow, whats another gonna hurt?! Heck I might even install a thermometer that’s been sitting in my brewing odds-and-ends drawer.
 
Back
Top