Fermentation temp control

[republicofbeer]

So I'm looking into the best way to keep my ferm temperature stable in my 250ltr plastic fermenter.

I already have a maxi 310 chiller and this is connected to a coil which is great for crash chilling. So what I am thinking of doing is building a DIY BrewPi. This will then open a solenoid to send the water in a pumped closed loop through the chiller, otherwise that solenoid will close and open another solenoid and send it through a 300w inline aquarium heater.

Any thoughts on how to simplify or improve this?


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[chris2012]

viewtopic.php?f=6&t=60518 -- Check this thread. Photobucket has really screwed up the images though

I assembled most of my heat pipe, for my chiller, using ss fittings, but never got round to using it at the moment alas, as I can fit my fermenter in a fridge I got.

[Fil]

With 250l in the FV i dont think 300w of aquarium heater will effect significant change in a timely fashion.

and as you will either need heating OR cooling during primary, i would suggest it would be cheaper over the long term perhaps to swallow the cost of changing the temp of the whole water supply including that in the waterbath as well as the pipe work rather than the expense and complication of diverting valves

[republicofbeer]

With 250l in the FV i dont think 300w of aquarium heater will effect significant change in a timely fashion.

and as you will either need heating OR cooling during primary, i would suggest it would be cheaper over the long term perhaps to swallow the cost of changing the temp of the whole water supply including that in the waterbath as well as the pipe work rather than the expense and complication of diverting valves

But it won't need to change rapidly. Just small alterations surely? And the BrewPi learns that to get the temp down to a certain level it only needs to run the cooling circuit to a certain level and then the water in the circuit will stop being chilled and visa versa with the heat. Same way a Pid controlling heating elements cycle on and off when approaching temp do they don't over shoot.


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[republicofbeer]

Also as the maxi will be used to chill other tanks, I can't just turn it off and let the bath water change.


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[guypettigrew]

Let me have a little rant about how people use Maxis, please?

This is my experience of using a Maxi, having come from a position of complete incomprehension about how they worked a year or so ago. Much helpful advice was provided on this forum and I finally bought a second hand one. I developed a way of using it to control the fermentation temperature and to allow for fast chilling at the end of fermentation.

Turning the compressor on and off is not the best idea. Firstly it doesn't do the compressor any good. Secondly, if it's off for any length of time the ice bath will melt and no way will it get back down to temperature fast enough.

The compressor produces an ice bath at about -0.4C. There are cooling coils (three in the case of the Maxi 310) sitting in the ice bath.

The coils in the ice bath need to be the source of cold water for the coils in a ferrmenting vessel, not the python pump outlet on a Maxi.

Here's how I do it. Water is pumped to the input pipe on the Maxi so it goes through the chiller coil. The output pipe from the Maxi is connected to one side of the coil in the FV. The cold water flows through the coil in the FV, back into the pump and back into the chiller coil again. It's easy enough to set up as a closed circuit once the air is purged.

I use a 12v submersible pump to run the system, controlled by the temperature controller from Ss Brewtech. This turns the pump on and off depending on the temperature in the FV. The hysteresis setting on the system is variable. Mine is set to give +/- 0.5C. Good enough for me.

Doing it this way means the Maxi is left on all the time and the pump just comes on when the temperature in the FV gets too high. There's always an ice bath, there's always water at just below 0C available to go through the chiller coil in the FV.

This doesn't allow alternating hot or cold water to be pumped through the coil in the FV, but the Ss Brewtech chronical system provides for a separate heater pad at the bottom of the FV, also controlled by the temperature controller.

As an aside, the heating function on the US 7 gallon chronical is provided by a 60 watt heat pad round the conical base. This can, possibly, be scaled up for larger volumes.

Hope someone finds this useful!

Guy

[republicofbeer]

Let me have a little rant about how people use Maxis, please?

This is my experience of using a Maxi, having come from a position of complete incomprehension about how they worked a year or so ago. Much helpful advice was provided on this forum and I finally bought a second hand one. I developed a way of using it to control the fermentation temperature and to allow for fast chilling at the end of fermentation.

Turning the compressor on and off is not the best idea. Firstly it doesn't do the compressor any good. Secondly, if it's off for any length of time the ice bath will melt and no way will it get back down to temperature fast enough.

The compressor produces an ice bath at about -0.4C. There are cooling coils (three in the case of the Maxi 310) sitting in the ice bath.

The coils in the ice bath need to be the source of cold water for the coils in a ferrmenting vessel, not the python pump outlet on a Maxi.

Here's how I do it. Water is pumped to the input pipe on the Maxi so it goes through the chiller coil. The output pipe from the Maxi is connected to one side of the coil in the FV. The cold water flows through the coil in the FV, back into the pump and back into the chiller coil again. It's easy enough to set up as a closed circuit once the air is purged.

I use a 12v submersible pump to run the system, controlled by the temperature controller from Ss Brewtech. This turns the pump on and off depending on the temperature in the FV. The hysteresis setting on the system is variable. Mine is set to give +/- 0.5C. Good enough for me.

Doing it this way means the Maxi is left on all the time and the pump just comes on when the temperature in the FV gets too high. There's always an ice bath, there's always water at just below 0C available to go through the chiller coil in the FV.

This doesn't allow alternating hot or cold water to be pumped through the coil in the FV, but the Ss Brewtech chronical system provides for a separate heater pad at the bottom of the FV, also controlled by the temperature controller.

As an aside, the heating function on the US 7 gallon chronical is provided by a 60 watt heat pad round the conical base. This can, possibly, be scaled up for larger volumes.

Hope someone finds this useful!

Guy

Thanks Guy. With regards to the maxi my intention is to leave it left on. What I didn't explain was I am using a pumped system not the python pump. The reason mine has to be left on is because the python line is being used as intended, to run to my tap.

Do you think the online heater solution is feasible? It seems the most straight forward solution to me rather than having another thing added to the tank.


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[jaroporter]

guy, can you explain why it is preferable to use the a second set of coolant in the maxi coils rather than the coolant resevoir in the maxi please?

[guypettigrew]

guy, can you explain why it is preferable to use the a second set of coolant in the maxi coils rather than the coolant resevoir in the maxi please?

Hi Jaroporter

Part of it was simple practicality. I already had the Ss system which includes a temperature controller, 60 watt heat pad and 12v submersible pump for the cooling water. I'd been using a cool box with frozen water bottles in a water bath previous to buying the Maxi. Very primitive and not very effective!

I didn't want the Maxi to turn on every time cooling water was needed and off again when the set temperature was reached. I liked the idea of having the ice bath permanently on so sub zero water was available whenever needed. If the Maxi turned off for a few hours because its cooling function wasn't needed then the ice bath would have melted. When the temperature in the FV went up and cooling was needed it would take ages to get the ice bath back.

It might have been possible to isolate the pump, leave the ice bath permanently on and just switch the python pump on and off as necessary. But this might have resulted in an ice bath full of ice and no water. I didn't know enough to make a decision about this. It would certainly have meant me getting into the Maxi and doing some re-wiring. Not an appealing prospect after I'd taken the lid off!

I also had no way of turning the Maxi on and off in response to temperature changes in the FV. I could have got hold of a suitable controller, temperature probe etc, but it felt like a more elegant solution to use the permanent ice bath and internal chiller coil. Using the coil in the Maxi just meant using a couple of extra metres of silicone tubing to connect it all up to the pump I already had.

As it is, there is always very cold water in the coil in the Maxi and it drops the temperature in the FV really quickly.

Using the python pump seems to work for a lot of people. Perhaps everyone on here. I've not seen any posts where people are using the Maxi in the way I do. It's just that doing it that way felt a bit lacking in control. And if I had more than one FV and a Maxi with more cooling coils, this would be the only way to do it.

Hope this gives some additional perspective on why I use the Maxi in the way I do.

Guy

[republicofbeer]

Also the maxi uses more power in the initial period. Mine will be connected to several fermenters so cycling the whole unit on and off seems a bit silly. I also use the python recirculation through my plate chiller.


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[jaroporter]

cheers guy. my query was because i have recently set up a cadet (same thing really, still cornelius brand) to use the inbuilt pump (like the python recirc) to circulate the coolant. the icebath will continue to be controlled independently. in theory i can't see a difference between that and using a separate coolant loop like you suggested (in fact it seems more efficient to me, hence why i have done it) but i have no practical experience of it yet so i was thinking i may have overlooked something in the practical operation.
i agree that plugging the whole unit into an stc and only turning the whole unit on when cooling is required is not a good idea, but i'm not sure if that's what most are doing?

[guypettigrew]

My main worry with controlling the inbuilt pump separately was the possibility of the whole ice bath freezing solid when the pump wasn't recirculating. I didn't know if one of the functions of the inbuilt recirculating pump was to stop this happening.

Guy

[guypettigrew]

Also the maxi uses more power in the initial period. Mine will be connected to several fermenters so cycling the whole unit on and off seems a bit silly. I also use the python recirculation through my plate chiller.


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Absolutely. Controlling the temperature in more than one FV can only be done with individual pumps connected to temperature sensors in each FV. And the pumps circulating the cold water through cooling coils in each FV independently. The thermostat in the Maxi can then keep the ice bath at just below zero.

Guy

[jaroporter]

My main worry with controlling the inbuilt pump separately was the possibility of the whole ice bath freezing solid when the pump wasn't recirculating. I didn't know if one of the functions of the inbuilt recirculating pump was to stop this happening.

Guy

the cadet has an agitator in ice bath (basically just a propellor) that is on all the time, dunno bout the maxi? but i figure that is just to make sure the temperature is even all over. i got the impression the thermostat is calibrated to keep the bath liquid in the middle and only freeze around the cold coil but i dunno really. where did you get the -0,4c figure from? i have replaced the thermostat with an stc1000 (in case i need glycol for anything later) so am thinking it'll be trial and error to find the optimum temperature

[guypettigrew]

My main worry with controlling the inbuilt pump separately was the possibility of the whole ice bath freezing solid when the pump wasn't recirculating. I didn't know if one of the functions of the inbuilt recirculating pump was to stop this happening.

Guy

the cadet has an agitator in ice bath (basically just a propellor) that is on all the time, dunno bout the maxi? but i figure that is just to make sure the temperature is even all over. i got the impression the thermostat is calibrated to keep the bath liquid in the middle and only freeze around the cold coil but i dunno really. where did you get the -0,4c figure from? i have replaced the thermostat with an stc1000 (in case i need glycol for anything later) so am thinking it'll be trial and error to find the optimum temperature

I dropped a temperature probe with a long lead through the hole used for filling the bath with water. It dropped to -0.6C at one point, but stabilised out at -0.4C.

Guy