Anyone got experience with glycol temp control at home?

[Chad Keven]

Ive got brewer's brain again, but this time its getting serious; I'm entertaining the idea of building a conical fermenter, mostly to up scale, so i can brew with mates who are keen. this leaves me with a few new hurdles; the main one being temp control, atm my fridge/freezer only just fits my fermenter, which dosnt matter cause it still works well. if i build this new monstrosity it will stand higher than the fridge.

i could get a bigger fridge, but this would restrict me in a couple of ways; a) space b) only one temp at a time.

ive been trolling the interweb and found a few hardcore dudes in the states who have aircon units with the radiator part submerged in glycol in a chillybin, fitted with controllers like this ,to circulate the coolant which is a bit techo/expensive for me.

so looking for elcheapo alternatives; could a resevoir of glycol in a deep freeze do the same? keep the glycol at aprox -10C and fit the temp controller to the cooling side to activate a pump that circulates the glycol around the copper coil on the fermenter?!

this has the advantage of fitting more than one pump/controller for more than one fermenter.

does anyone out there have experience with this sort of thing in a Homebrew situation?I

how big would the tank of glycol need to be to keep 100L of beer at 0C?

has anyone in the Auckland/Waikato region got somthing like this opperating that i could have a look at?

am I barking up the wrong hop bine thinking about this shit?

I suppose some experimentation might be in order

the second hand guy down the road said he would do me a swap on a deep freeze, (which will acommodate my current fermenter aswell)

all of this relates back to wether i should build the conical at all

any help is greatly appreciated, regards, Chad

[Ralph]

Sounds like a plan. I have no experience of home scale cooling systems, but I had previously been thinking about putting a glycol jacket on a conical. If you are getting the conical made to order it should be easy enough to get them to put a jacket around the sides of the conical to pump the coolant through with fittings to attach a hose for in and out. A jacket should be more efficient than coils, and probably wont cost any more if you get it done at manufacture.

You would definitely want insulation around the outside of the cooling jacket or coils so that heat is taken out of the beer and not out of the atmosphere around the beer. Without a jacket I would think you would have trouble cooling it right down.

Just operating cooling would be easy enough using a glycol reservoir in a deep freeze, but you would have to make sure that the cooling in the deep freeze was able to extract the heat out of the glycol pretty efficiently. If it is just a tub of glycol sitting on the bottom of a deep freeze you may have trouble getting it to cool down enough if it is having to work hard.

The amount of glycol needed to keep 100L cool will depend on a few things including 

How well insulated the conical is

How well insulated the pipes to the conical are

How efficiently the freezer motor can cool the glycol

How fast you are pumping the glycol, and whether it is turbulent or laminar flow and what the surface area is of the cooling area.

I dismissed doing this and bought a big fridge for my conical as I need to be able to heat and cool and I could not think of a simple way to circulate a fluid that could be heated/cooled to the temperature needed. If you are just after cooling it is easier...

[Chad Keven]

thanks ralpho was thinking, mount a heat pad on the cone and chiller on the cylindrical part controlled by my stc1000 so the glycol would only ever be cooling

[Horace]

Glycol shouldn't be too cold (-1 or -2) or you will probably end up freezing beer/ wort to the inside of the conical, reducing the effectiveness of your cooling. When keeping beer at 0 deg there is essentially no heat being produced by the beer, so not a lot of glycol should be required. At a guess 20- 30 L of diluted glycol should be heaps (I think heat transfer is better if it is mixed with water but the freezing point is higher).

The hardest points of work for the system would be during fermentation and crash cooling to 0, actual heat loss required can be calculated easily enough. 

Make sure you get food grade glycol. Let the alcohol wreck your kidneys slowly rather than antifreeze doing it overnight.

Heat transfer across a metal walled fermenter will be much better than from air, but like Ralph said insulation is a good idea or you will have frost forming on the outside of your tank.

[Chad Keven]

thanks all good would love to see somthing up and running, the jacket idea is sound

[martin w]

from what i understand,unless your going to keep the glycol at low minus temperatures then your better of using water at just above freezing,the reason is that glycol affects the heat transfer ability of water.

if you had glycol at say -2 and water at +2 the water would be more efficient at cooling the fermenter.

when i eventually gather all the bits together i'm planning on using a dehumidifier/ac unit to cool a chilly bin of water to 2 degrees,i'll probably use a brewtroller/fermtroller to do this as its easy to add extra zones later on

[Ralph]

These guys happen to have food grade mono propylene glycol http://www.formulafoods.co.nz/ and should be able to sell you a 20L cube of it if you ask nicely... It is what people use when designing food grade systems or potable water systems (solar hot water etc).

[Chad Keven]

thanks all valid stuff to consider, according to wikipedia:

Due to its low freezing point ethylene glycol resists freezing. A mixture of 60% ethylene glycol and 40% water does not freeze until temperatures below −45 °C (−49 °F).

pretty techo might be time to do some experiments with different proportions of glycol/water in the freezer, see how they behave

[Ralph]

You want to avoid ethylene glycol due to it being poisonous if consumed... and it would not be hard to have contamination in the beer from the coolant system... however monopropylene glycol has reasonably similar characteristics and will not harm you if consumed in small amounts.

[Chad Keven]

thanks very valuble info, kinda not the sort of sh$t you want around the house either

[Liam Callaghan]

This is one of my projects too, we are looking at a few options of either running it in the wall of the fermentors or with a jacket.  Had to wait until we had the fermentors to try it though and I just took home the very first prototype!

I'll let you know how we get on.

[Chad Keven]

cool, exiting!

[Fairlane]

I'm doing this currently on a 50L scale.  I prefer it to the fridge concept as it's more responsive and accessible.

Here are some pics

 

Fermentor

Control Box

Complete unit before insulation

Pump

 

So the actual chiller is an Ice Bank Chiller which I got off trademe.  I have modified it so that it runs off a temp controller and filled the tank with a 50-50 mix of glycol and water (and a bit of algae killer).  Generally I set this at 0 deg C but it can go down to -10 quite happily.

 

I have another temp probe which goes down the middle of the fermentor to about 80mm from the bottom and this controls either the pump or if I have it on heating mode, the wine tank heater that is also wrapped around the fermentor.  Obviously it is preferable to have a controller that does both heating AND cooling but since I got mine for free I just had to wire it up so I could switch it manually from one to the other.

 

Costs (approx due to failing memory...)

Chiller             $80

Glycol Pump    $10

Temp probes    $20 ea

Wine Tank Heater  $60...?

Temp Controllers    $0

Switches etc          $20

Frame                   $5   (Made from offcuts from mitre 10)

Wheels                 $10 

Insulation              $5    (Old camping matress, car sunshade and pool noodle)