New article: NHC Fermentation Controller - Build

[admin]

JD's been busy....
http://www.nationalhomebrewclub.com/the-nhc-fermentation-controller-hardware-build/

[Ciderhead]

nice work jd

[imark]

broken link? 

[imark]

Ah fixed now...good work JD

[alealex]

Thats the sophisticated answer to my need of fermenting lagers and ales in the same fridge, ah well.
Great tidy job JD.

[Will_D]

Agreed great work JD.

However I do see a problem with contention:

The Low temp is controlled by one sensor and sets the compartment to that set point.

So for a Lager it may be set at 10C. If the ambient drops below 10C then sensor mounted on the lager switches on the Lager brew belt or whatever and the fridge is Off.

This is how a single product lagering fridge works.


You have now also got two more containers fitted with brew belts.
So the lager wants to be at 10C

But Ale number 1 wants to be at 16C so its belt is on putting heat into the beer but also the surroundings.

Same for Belgian Ale number 2 that wants to be at 24C. So its heater is on!

The only way to stop heaters 2 and 3 from heating the overall container space (which will trigger the cooling system) is to heavily insulate the Ales. Maybe also use baffles.

HTH

[JD]

Thanks guys. Overall intention is to build something and go through it step by step so that others can build it themselves if desired. I suppose I should really include a parts list in the next blog posting as well.

@Will_D
The heating of the freezer interior by the brew belts is countered by the freezer chilling the same space. Insulating each vessel's brew-belt so than all the belt's heat goes into the vessel would be a good idea but, ultimately, the benefit would only be one of efficiency. In the end, it doesn't matter if the interior of the freezer is heated by the outside ambient temperature of by one or more brew belts doing their thing inside. Using uninsulated brew-belts should all still work just not as efficiently as isolating the effect of the brew-belt to the one vessel it is heating.
Using baffles would not be a good idea, I think, as it would introduce impediments to air flow and that would cause hot and cold spots. I anticipate I will need to include a fan in the chamber to ensure the chilling effect is even distributed.

Overall, the control system will be complicated but doable. I believe the whole system is controllable and stable but I don't have an analysis that  proves this. The fact that the BrewPi system can do it adds credence to the argument.

The upcoming articles in the series will concentrate on the software side of things. I will start with the UI and web interfacing. The next article will move into managing a single vessel using bang-bang control. This is the approach used by systems based on the likes of the STC-1000. I will follow this with an article on updating the system to do single vessel PID temperature control. The next article will address adding a time varying temperature profile. The final software article will be about upgrading the system to multi-vessel. Source code will be published via github for those interested.

If anyone wants to suggest ideas for the software, I'm all ears. The plan is to use an adaptive approach so that the UI will work equally well with mobile devices and PCs. Twitter's Bootstrap library, I expect, will suffice for this. After that, anything is possible at this stage.

Anyway, after all that is completed, I think I will move on to something a bit easier like world peace.

/JD

[Simon]

That's very nice. I did one myself a year or so ago but is no where near as advanced as yours. might have to upgrade now after reading about it.

Simon

[cpb]

Really good work JD.
I've spent the last couple of days investigating the possibility of doing this.
I recently got a Galileo board as was trying to think of a good use for it.

Have you considered trying to port the brewpi software to the Galileo? Its all open source and linux based. I recon it could be done.

Also are you going to use thermowells for the sensors? I've read that the senors are a common cause of contamination if you don't use them. 
Can't wait to see the next installment.
C

[JD]

I will be looking at the brewpi sources for sure for inspiration if nothing else. I'm going to try and keep things Arduino for this project if I can. Ultimately, this project is to show the average club member how they would go about building one of these if they so desired. I'm thinking that more people would be comfortable with the Arduino approach than the Linux option.

Regarding thermowells, the sensors I've chosen are encased in stainless steel and PVC. I think they will suffice once sanitised. If it turns out that they are not easy to keep sanitary, I'll acquire some thermowells then. So now, we'll just remain optimistic

Next instalment will be a few weeks away. I've to debug the hardware first.

/J