New idea for a HERMS coil

[outdrosman]

Hi everyone, I have been reading the forums for a while now and I have gotten a ton of great information so first of all I would like to thank everyone for all the help with a bunch of projects that have helped me make better beer. I am in the middle of building an automated gas powered HERMS rig but it might take a long time to finish the project so I am not going to post a full build until I finish it. However...

During the planning phase I came across Brewpi's new HERMS coil that runs three short lengths of tubing in parallel for greater throughput in the coil. https://store.brewpi.com/featured/3-way-parallel-high-flow-herms-coil The tests they ran showed that after 25 feet of coil the temperature of the wort in the coil had equalized with the temperature of the HLT. So having a coil longer than 25 feet doesn't help you. It seems that using larger diameter tubing may help but not much. The answer that they came up with was to split the input into three shorter (about 25 feet) coils to increase volume through the coil while keeping a good surface area to volume ratio between the wort and the coil.

This brings me to the two immersion chillers in my garage. I have been planning on converting them to a HERMS coil for a while. My whole system is 1/2". Both chillers are 3/8" copper tubing, that'll really throttle my pump if combine both 25' chillers into one 50' coil as I was planning on doing. My new idea is to make a manifold to run these babies in parallel so I don't have any restriction on my flow. My idea is that this will make a HERMS coil that can change the temperature of the whole mash more quickly than using a larger diameter coil or using a longer coil of the same diameter.

So far I have a 1/2" copper NPT thread soldered to a 1/2" T, I've attached an image of this. To each end of this T I hope to solder a reducer (if anyone actually makes it) to get down to my 3/8 inch copper from the chillers. I plan on having them oriented as a coil within a coil, I also attached an image of this.

To finish the project I need to find out if there is a reducer, otherwise I will have to use compression fittings to attach the coil to the T's. I also need to figure out how to attach the copper 1/2" NPT to the site of my kettle.

Alright everyone, now tell me why this won't work! Seriously I would really appreciate it if everyone would let me know if there are holes in my plans before I spend a bunch of money on this.

Thank you!

 

[Esmitee]

Yea, this sounds like a good idea to me. I'm no fluid engineer, but you will have more surface area to length of tubing. Let us know how it works. I'm pretty sure the 1/2" to 3/8" reducer is pretty common in the big box stores.

 

[outdrosman]

Yea, this sounds like a good idea to me. I'm no fluid engineer, but you will have more surface area to length of tubing. Let us know how it works. I'm pretty sure the 1/2" to 3/8" reducer is pretty common in the big box stores.

So I was having trouble sourcing that reducer locally at big box stores but I went into a plumbing supply store and found something even better. They had a part called a fitting reducer that can slip right into a 1/2" fitting and reduce to 3/8" OD. This is as opposed to using a short piece of 1/2" pipe between my tee and the reducer. Anyway I have made my two copper manifolds and just need to attach my coils and then drill holes in my HLT and attach the coil. I'll post a picture of the manifolds later.

I'm still looking for the best way to attach it to the HLT. I am thinking just a washer, hi-temp o-ring and locknut should do the trick.

Unfortunately I won't have automation for a while but I plan on using the HEX manually for a while until I can afford to automate. I'll let you know how it goes.

 

[Esmitee]

I'm just finishing an 50 amp E build, and decided to do a new hot and I'm thinking about putting your idea to work in my kettle

 

[outdrosman]

I am waiting to be able to afford all the fittings I need to instal the coil. I just ran across a great deal on some Sankeys to turn into keggles so I spent all my money on them. Let me know how it works out for you, you might get to it before I do. This is how I ended up building my manifolds.

HERMS coil manifold

• outdrosman
• Nov 29, 2017

HERMS coil manifold

I plan on just putting a locknut and o-ring on those threads and using them as the bulkhead. If that doesn't work I will have to thread them into couplers.

 

[501irishred]

The male adapter you have soldered on has tapered threads and may give you a run for your money to get it sealed. Have you considered swapping that out for a stub of 1/2" pipe and buying a purpose built bulkhead? Something like https://www.brewhardware.com/product_p/truebulkhead12comp.htm

 

[outdrosman]

The only reason I am using these manifolds instead of a compression bulkhead is that I wanted to split from 1/2" to two 3/8" copper lines. I suppose I could have run a 1/2" piece of copper from the T's to a compression bulkhead but then I would have had to buy some 1/2" copper pipe plus two compression bulkheads. With my manifolds I think all I will need is a locknut and o-ring to get a good seal with my keggle wall. Worst case scenario I have to buy two of these http://www.bargainfittings.com/index.php?route=product/product&path=46_70&product_id=250 for $10 each.

 

[501irishred]

Sounds like a plan! I look forward to seeing the final product.

 

[LarMoeCur]

Like Esmitee stated, I'm not a Fluid Engineer but if I had to bet wort will take the path of least resistance. I'll bet the wort that is forced to take the left turn will stall in the tubing. The flow rate of my chugger running full throttle through 55' of 1/2" tubing with a 4 foot rise is not a whole lot. Now with your setup you have more potential flow rate which will lower the pressure even more.

For just a few more dollars over the cost of those splitters you could have bought the fittings to do a straight 50" run. Once the splitters are soldered to the tubing you will have to try and build a reverse bulkhead fitting and seal it from the outside. Not impossible but you added more fittings and cost to your project which may not work as intended.

 

[outdrosman]

Yeah I had considered that wort might not want to make those 90 degree turns. I didn't want to do it that way but because of the fact the two 25' runs are already coiled in the same direction it was the simplest way I could think of doing it. I'm still hoping that I will get some increased flow rate over a single 25' run.

As far as the decision to use two 25' lengths instead of joining them into a 50', in my first comment I mentioned some experiments the folks at Brewpi have done. They found that the temperature of wort in the coil and HLT temperature had equalized by 25' of 1/2" coil. So using a 50' coil over 25' gives you no gains and might actually hurt you because of the restricted flow rate. The idea they came up with was to run three 25' sections in parallel. That way you have more throughput and can more quickly change the temperature of the whole mash.

Then again I'm not a fluid engineer either and this whole project could totally fail but I'm not out that much if it does, those fittings were like $12 total.

 

[Esmitee]

I'm just finishing an 50 amp E build, and decided to do a new HLT and I'm thinking about putting your idea to work in my kettle