Dedicated Herms Guide, Problems And Solution Thread

[dmac80]

Just regarding the eherms discussion, I had intended on using contactors with my PID outputs. The fact that they are probably only rated for 1000 coil operations had crossed my mind but I have a pretty steady supply to replace them. Where can I find a price for the SSR's? I had assumed they are quite expensive and written off the option but if they are a reasonable price I'd rather use them.

Also looking at using the ramp/soak PID's so I can program the alarm outputs to operate my pump. I've got a schematic at home that I can post if anyone is interested or willing to offer advice.

Auber instruments have ssr's from $15 (US $ i'd guess), i haven't checked other suppliers but i'd imagine they might have similar prices.

http://www.auberins.com/index.php?main_pag...a2935d3f96a7c79

Cheers

 

[NDH]

Sorry, two unrelated points I probably should have been more clear.

Point 1, just looked at your link, I had no idea they were that cheap for such a high current rating. Will definitely be using SSR's. The constant latching sound of a coil would piss me off with a contactor anyway.

Point 2, I have been doing some schematicstrot the control panel that I'm hoping to find some help/confirmation with.

Cheers for your help.

 

[kymba]

i picked up my SSR for $15 delivered from clints components

and i won a RKC REX C100 PID for 99c US (+ $25.99 USD delivery)

stoked both arrived today so i'm gunna be blowing shit up this weekend!

 

[kymba]

I have wired everything up like the attached finger painting...anything wrong with what i have done?

i wired it similar to this, but they have sent neutral to the SSR - what's the diff?

View attachment BUZZ_BOX.pdf View attachment PID___c100_another_Manual.pdf

 

[dent]

I have wired everything up like the attached finger painting...anything wrong with what i have done?

i wired it similar to this, but they have sent neutral to the SSR - what's the diff?

View attachment 47454 View attachment 47455

The diagram you have made is for a PID unit that puts out a DC voltage that controls a SSR directly. The model you have written on the diagram is the relay type unit, so your diagram will not work if that is indeed the unit you have.

If you have a DC controlled SSR you will need another DC supply to get this to work. Or you could use an AC controlled SSR which will allow you to use 240V through the relay output.

 

[kymba]

damn, thanks for pointing that out - goes to show where buying blindly from ebay gets you

one question - will the residual current from a phone charger (or any wall wart converter) have any effect on the SSR? you know like when the LED indicator stays on for a few seconds after you unplug a phone, and especially a laptop

The diagram you have made is for a PID unit that puts out a DC voltage that controls a SSR directly. The model you have written on the diagram is the relay type unit, so your diagram will not work if that is indeed the unit you have.

If you have a DC controlled SSR you will need another DC supply to get this to work. Or you could use an AC controlled SSR which will allow you to use 240V through the relay output.

 

[dent]

damn, thanks for pointing that out - goes to show where buying blindly from ebay gets you

one question - will the residual current from a phone charger (or any wall wart converter) have any effect on the SSR? you know like when the LED indicator stays on for a few seconds after you unplug a phone, and especially a laptop

It would, but you don't hook it up so you are switching the mains to the plugpack. Just have your plug pack on constant power, and put the DC output of the plug pack through the relay contacts of your PID controller.

Looks like just about any DC plugpack would do the job, the input range is pretty broad.

 

[kymba]

cheers dent

as luck would have it i already have a transformer in there to run an old cpu heatsink + fan attached to the SSR

 

[Tim F]

Is there an ideal rate to pass your whole mash volume through the HEX? The research I've seen usually uses a certain flow rate but I'm not clear if this is dependant on system size. Like if you recirc at 5 litres per minute in a 20 litre system should you go for 2.5L/m in a 10 litre? Or is the ideal flow rate just the fastest speed you can pump without it sticking?

 

[raven19]

Comes back to your grain bed depth to a fair degree, along with batch size. As if you pump too fast it may compact the grain bed and result in a stuck sparge.

Its a bit of trail and error based on your system imo.

I find a slower rate on my (RIMS) system is required when the grain bed is deeper in bigger batches.

 

[mxd]

Is there an ideal rate to pass your whole mash volume through the HEX? The research I've seen usually uses a certain flow rate but I'm not clear if this is dependant on system size. Like if you recirc at 5 litres per minute in a 20 litre system should you go for 2.5L/m in a 10 litre? Or is the ideal flow rate just the fastest speed you can pump without it sticking?

I go as quick as possible, I haven't had a stuck sparge so it seems fine.

 

[mobrien]

Great thread/ideas/discussion - this has helped me a lot.

So, in the redesign of my post flood brewery, I'm planning to make it a herms capable system, either running that way from the start or as an upgrade down the track - depends on how the $ all pan out.

The main thing I'm trying to work out is:
a) Probe placement points (mainly, do I get thermowells welded into the mash tun or HLT)
B) HEX size (mainly, do I use the HLT as the HEX or have a separate vessel).

I asked these questions over here: http://www.aussiehomebrewer.com/forum/inde...mp;#entry805625 but have moved the discussion here as it makes a lot more sense.

Having read through this thread at length (all 27 pages) as well as reading a few of my brewing books, I'm still undecided about the design. I want a double batch capable system, so will go with 70 (electric)/70/100 (gas) as I know my previous 50/50/80 always pushed the limit of a 42L into the conical batch. So the vessels I'm happy with, and I can reuse the stand and march pump from the previous brewery (the march pump was stored above the flood level!).

Being a bit (or a lot) of a geek, I've done some quick calculations to look at the ramp time on various configurations for the HEX. All these calculations are based on a 9kg grain bill, 2L deadspace in boiler and mash tun, and a 3L/kg water:grain ratio, with a 10deg C step increase, 4400 watt element (actually 2 x 2200) running at 75% heating efficiency (to account for true inefficiency, heat loss in the lines/vessels and having to also heat the containers). And yes, I have a dedicated 15A circuit for the HLT (which also was above flood level!).

Scenario 1
35L mash volume
10L HEX unit (a separate vessel)

Element size 4400 watts (J/sec)
Element efficiency 75 %
HEX volume 10 L
Mash Tun volume 35 L
Step temp rise 10 oC

Time to heat HEX only 2.11 min
Time to heat HEX and Mash tun 9.51 min

Scenario 2
35L mash volume
30L HEX unit (a HLT with enough volume to do the sparge)

Element size 4400 watts (J/sec)
Element efficiency 75 %
HEX volume 30 L
Mash Tun volume 35 L
Step temp rise 10 oC

Time to heat HEX only 6.34 min
Time to heat HEX and Mash tun 13.74 min


Between the two scenarios there is only 4m:15sec of heat time difference overall (9.5 v's 13.75; these are decimal times), but the separate HEX vessel does do it in the recommended 10 minutes for a step increase.

If we make the mash a bit thinner, 4.0 L/kg, there is less sparge water required, so a third scenario:

Scenario 3
35L mash volume
20L HEX unit (a HLT with enough volume to do the sparge)

Element size 4400 watts (J/sec)
Element efficiency 75 %
HEX volume 20 L
Mash Tun volume 35 L
Step temp rise 10 oC

Time to heat HEX only 4.23 min
Time to heat HEX and Mash tun 11.62 min


Now this is pretty close to the right time.


So after geeking out for that little while, I guess the question now is:

Is the smaller HEX really worth the extra cost/connections/space if you can design a HLT and mash profile that will still run around the specs needed? And, how thin is too thin for the mash? or rephrased, how much of a reduction in sparge will start to create lower efficiencies (due to not washing the grain bed) that start to matter.

I am now thinking probe placement is much easier (having read all this thread) - thermowell in the HLT for sure, if seperate HEX one here also and another in the mash return line from the HERMS coil. But I'm open to more opinion/suggestions!


Thanks for all opinions and debate!

Matt

P.S. Just for clarity, the way I did the time calculations:

deltaH=m x C x deltaT
m=mass of mash + mass of HEX water in g (assume 1mL = 1g, its not for wort, but it'll do)
C=4.184J/g.oC (assuming pure water, its not for wort, but it'll do)
deltaT = step rise, in this case 10oC

Once delta H is calculated, divide by the adjusted element size (efficiency x size=adjusted size in watts or J/sec) to get the time in seconds; divide by 60 to get time in minutes

 

[razz]

Hey Mobrien. Using a seperate HX to the HLT will most likely give you a more flexible system, but it's just another piece of equipment you have to build/buy. If I had my druthers I would have done that instead of my HLT having a copper coil mounted in it. It should give you faster ramp times and oyu don't have to worry about how hot the water is in the HLT. As far as probe placement goes I only mounted one at the outlet of the HX, all my other temp indicators are dial thermometers. The probe goes back to a PID and thurns the element on/off in my HLT.

 

[mxd]

The main thing I'm trying to work out is:
a) Probe placement points (mainly, do I get thermowells welded into the mash tun or HLT)
B) HEX size (mainly, do I use the HLT as the HEX or have a separate vessel).

for me, the probe is on the return back to the mlt and a seperate hx.

here's mine, this was my original setup the issue here was Ihad to screw the probe onto the MLT so I went to cam locsk as below.


and some close ups of the temp probe and how it attaches to the MLT.

the return goes in right angles to the probe




you can see the probeso all the return flow goes past the probe




I use the cam lock so I can remove the controller faway from the MLT and frame

 

[cdbrown]

I have a probe in the HLT (it's not fixed, just hangs through the opening in the top) to control the water temp, another at the outlet of the HERMs to control the recirc temp. Have a dial gauge on the HLT and mash tun. Don't really need any more than that as you're not interested in the herms water temp or the kettle as it's purpose is for boiling.

I do doubles in a 50/50/50 - I have to add 10L of water after the boil to bring the vol up to 42L.

2 elements in a HERMS would be overkill IMO as the limitation is really the recirc rate you can get without a stuck mash as the pump will just suck the grains down onto the false bottom. Increasing the L/kg ratio will help a bit but then there's a greater volume of liquid that needs to be heated. A coarser crush might help avoid this but will most likely need to increase the mash duration.

 

[mobrien]

Thanks for the comments and ideas.

So when it comes down to it, it seems there are two main ways to control/run a herms system.

1. Hex a fair bit higher than target step temp, 10 deg or so controlled by a thermostat, and the flow rate of the pump controlled via probe in the hex outlet to control the temp of the mash tun.
2. Hex the same or 1 deg or so higher than the target step temp, the temp controlled by a probe in the hex, and the temp controlled by a thermostat, the flow rate is constant and the temp of the mash tun is controlled by equalization (with a system fudge factor) between the hex and the mash tun.

If you have a herms system, which method do you use and why?

Regards

Matthew

 

[Tim F]

I could be wrong but I imagine it working as HEX temp = whatever it needs to be so the wort temp at HEX outlet = desired step temp. PID reads temp at HEX outlet and cycles the HEX element appropriately to maintain desired outlet temperature. This is how I'm building mine anyway!

 

[mxd]

I could be wrong but I imagine it working as HEX temp = whatever it needs to be so the wort temp at HEX outlet = desired step temp. PID reads temp at HEX outlet and cycles the HEX element appropriately to maintain desired outlet temperature. This is how I'm building mine anyway!

yep, except I measure my wort temp at the MLT return, I set my PID to be my Mash Temp, I have no idea what temp the water in the HX is, I know what my MLT temp is but that's just because it had a thermometer in it before I went HERMS

 

[cdbrown]

Thanks for the comments and ideas.

So when it comes down to it, it seems there are two main ways to control/run a herms system.

1. Hex a fair bit higher than target step temp, 10 deg or so controlled by a thermostat, and the flow rate of the pump controlled via probe in the hex outlet to control the temp of the mash tun.
2. Hex the same or 1 deg or so higher than the target step temp, the temp controlled by a probe in the hex, and the temp controlled by a thermostat, the flow rate is constant and the temp of the mash tun is controlled by equalization (with a system fudge factor) between the hex and the mash tun.

If you have a herms system, which method do you use and why?

Regards

Matthew

I've not come across any system as you've described. The simplest way is to have the probe at the outlet of the HERMs to measure the wort recirc temp. The probe connected to a temp controller which in turn is connected to the HERMS element. The controller will switch the element on/off to reach the target wort temp. The pump generally recircs the wort at a constant rate, however a compacting grain bed will slow the flow and you will naturally see a higher recirc wort temp due to increased resident time in the HERMS (the controller would have switched off the element). Stirring the grain bed will increase the flow and the temp will drop slightly while the controller tries to catch up to the change in conditions.

Don't worry about the HERMS water temp, just the wort temp coming out of the HERMS.

 

[mobrien]

Hi everyone,

OK - I've got it now, and realised my stupidity - of course you can't raise the mash temp if you don't have a differntial between the HEX and the mash temp... well duh

I've drawn up a not to scale diagram to get my head around all the connections and the way it would work - think I'm somewhere close now.

Any major issues anyone can see? Will do either a 10L HEX unit, with either a 2200W element, or a 20L HEX (with 15L water, i.e. 5L headspace) with a 3600W element. The rest of it is self explanitory I think.

I'm getting excited now - time to stop planning and start rebuilding!

Thanks,

Matt

View attachment Brewery_V3.pdf