Positioning HERMS coil in HLT

[Petrolhead]

I have started the remodelling of my Brew Shed and a three vessel electric brewing system.

This brings questions to mind at every step and I am enjoying trawling through Google for answers but could do with a pointer on this one so thanks in advance.

I am converting on of BrewBuilder's 70l vessels into my HLT which will also include a HERMS coil. I am putting an outlet in the base of the vessel to make draining the HLT easier and intend recirculating by pumping to a high level inlet.

My question is should I position the heating element at the bottom of the HLT with the HERMS coil above, position it higher in the HLT with the HERMS coil below it or even fabricate the coil so that it is above and below the element?

Any pointers would be appreciated.

 

[JonBrew]

Element below the HERMS coil for sure.

 

[Petrolhead]

Seems sensible as I thought but if the outlet is in the bottom of the tun if you put the element above the coil you will be drawing the warm water over the coil as you recirculate the water from the bottom to the top of the tun.

 

[JonBrew]

That's an interesting idea but, to my (unscientific) mind, positioning the element above the coil at the top of or higher up the vessel would be an inefficient use of heat. If you're drawing off to recirculate the liquor (with your input being above the coil) I feel like you would still achieve a fairly even temperature throughout the vessel.

 

[Buffers brewery]

My original set up was a combined HLT, HERMS and kettle but gas heated. I positioned the HERMS coil in the bottom half of the pot. The problem I found with this set up was after drawing off the strike water for the mash I had to top up with cold water. I had to wait to get the temperature back up to start HERMS by which time the mash had cooled a bit. I’ve now built a separate (electric) HERMS tank separate from the HLT. I use the coil in the HLT as a chiller after the boil so all is not lost.
To answer your question I’d advise element as low as you can, coil just above element and if you can include some kind of circulating pump to draw off water from the bottom and transfer to the top (or vice versa) that would provide even temperature distribution.

 

[Ghillie]

Element at the bottom of the HLT for the best dissipation of heat through the HLT water.

As your re-circing the HLT water anyway, the temperature throughout your HLT water should be very consistent, if not uniform.

The most critical part you should consider is placement of your thermocouples for the PID controllers (assuming you're including automation of course).

 

[Petrolhead]

Thank you all, a lo clearer in my mind. Buffers, I had been thinking about the delay whilst the HLT comes back up to heat but at present my thoughts are towards preheating enough water as I have capacity in the HLT. Ghillie, I am automating, giving a lot of thought to the panel, but I am going to mount the thermocouple for the HLT in the outlet so I know what temperature water I am pumping into the mash tun. If I am recirculating as I heat the water, wise I think with any reasonable volume of water, this position should give a good reading.