G'day All,
OK, all this talk of Fridgemates [post="411990"]here[/post], and a string of scorchers all round the country have prompted me to pull the finger out & post a few pics of my modified fermentation fridge setup.
So, after setting up the old fridge and doing a few months worth of brews, I decided that:
Someone's probably done something similar before, but thought this might be worthwhile to post anyway....
The setup consists of a plastic recycling bin full of water being circulated through a cooling loop in the (otherwise unused) freezer. Here are a couple pics:
General setup
Modified freezer with heat exchanger
Door mod to accomodate cooling lines
Indoor fountain pump (12V, 500lph)
Please forgive me for the mexican... I promise its not mine...I'm keeping it cool & fresh for a friend...
Anyway I'm nearly ready to go to the dark side....thanks for spending my K. Rudd bonus on pots & burners, Butters! :beer:
Ok, so since the fridge and freezer are run off the same compressor & circuit, the Fridgemate control of the lagers results in pretty damn good "indirect" control of the ale temp.... The hotter the ambient, the more the fridge runs & hence the more the freezer is cooling the bath. I have found that I am able to easily maintain temps in the "ale bath" as low as 15deg & up to 20deg, depending on some tweaks. At the same time I'm keeping two in-fridge fermenters at the Fridgemate set temp (12deg).
Over the past few weeks the temps in the garage have hit 35-40deg, so the ability to keep two lagers & an ale all happy is sweet. At the moment I've got a Belgian Wit fermenting happily; here's a log of the temps over the past few days:
Not bad in terms of temp control. Improvement possible!
So far I've only done tests on a few control variables (apart from the fridge set temp). These ones seem to be most important:
Cheers,
Niggles.
OK, all this talk of Fridgemates [post="411990"]here[/post], and a string of scorchers all round the country have prompted me to pull the finger out & post a few pics of my modified fermentation fridge setup.
So, after setting up the old fridge and doing a few months worth of brews, I decided that:
- lagers take too damned long
- lagers can prevent tasty ales being fermented at controlled temps in summer
- the freezer compartment is too cold to cold-coldition.
Someone's probably done something similar before, but thought this might be worthwhile to post anyway....
The setup consists of a plastic recycling bin full of water being circulated through a cooling loop in the (otherwise unused) freezer. Here are a couple pics:
General setup
Modified freezer with heat exchanger
Door mod to accomodate cooling lines
Indoor fountain pump (12V, 500lph)
Please forgive me for the mexican... I promise its not mine...I'm keeping it cool & fresh for a friend...
Anyway I'm nearly ready to go to the dark side....thanks for spending my K. Rudd bonus on pots & burners, Butters! :beer:
Ok, so since the fridge and freezer are run off the same compressor & circuit, the Fridgemate control of the lagers results in pretty damn good "indirect" control of the ale temp.... The hotter the ambient, the more the fridge runs & hence the more the freezer is cooling the bath. I have found that I am able to easily maintain temps in the "ale bath" as low as 15deg & up to 20deg, depending on some tweaks. At the same time I'm keeping two in-fridge fermenters at the Fridgemate set temp (12deg).
Over the past few weeks the temps in the garage have hit 35-40deg, so the ability to keep two lagers & an ale all happy is sweet. At the moment I've got a Belgian Wit fermenting happily; here's a log of the temps over the past few days:
Not bad in terms of temp control. Improvement possible!
So far I've only done tests on a few control variables (apart from the fridge set temp). These ones seem to be most important:
- Total volume of water in the bath; the more the warmer (though less water obviously gives higher temp fluctuations)
- Setup of the copper coil in the freezer, e.g. immersing it in a stockpot full of water increases conduction/cooling efficiency as long as the stockpot surface area is large. Salty water in the stockpot may help.
- Insulation around the bath is important. A doona and an old exercise mat that the dog half ate help.
- Fridge & freezer control knobs I'm assuming the controls divert cooling capacity via some sort of proportioning valve in the coolant circuit (can anyone confirm this?). This allows the extra freezer cooling to reduce the ale temp independently of the fridgemate setting.
- Pump flow rate will change the system slightly, but according to my guestimation shouldn't be critical.
- It is possible to cool down to say 15-16 & then use an aquarium heater or similar to adjust up to 17-18deg as needed. This dual control will result in excellent temp stability, but being an engineer (can you tell? ), I don't like the poor efficiency of this solution! It's like burning coal to make steam to make electricity to power a de-sal plant to make water to water the garden & flush the toilet with! Or like the oil-wells/power-stations/indoor-ski-range in the middle of a desert (Dubai). Well...not quite.
- Additional baths could be set up in series, i.e. the cooling water pumped between two or more containers. Additional insulation and freezer power would be required. My guess is the fridge might consume an extra 25% power or so, depending on insulation. I will have to test this out....hmmmm, more beer!
- Obviously, anti-microbial measures as per other bath setups are a good idea, especially if your fermenter has a tap. Note that overly acidic/oxidising/corrosive solutions like Star-san, bleach/vinegar etc will cause the copper to corrode. Salty water may be a better option, inhibiting growth of nasties as well as improving thermal capacity & cooling efficiency. I'm pretty careful with my taps & seal them with a small rubber bung as well as spraying with Star San.
- Additional electronic control could be used (e.g. another fridgemate controlling the pump). If the pump is stopped for long periods, the water in the loop may freeze again salty water may solve this. Given my results so far I'm happy with one fridgemate.
- A small difference between the bath temp & beer temp is to be expected (see linky above). I expect the additional specific heat and conduction between the water & the fermenter would make this effect much less than for a fermenter sitting in a fridge (i.e. much<1deg). Note this also makes the beer temp a lot closer to the bath temp, so beer temp fluctuations are higher.
- In my setup, the heat input from the cooling loop raises the temp in the freezer to around +3deg... perfect for additional cold-storage/conditioning. Before the loop was installed, the freezer easily froze water.
- I need to think my way around some issues like need for D-rests or lagering periods screwing with the ale bath temp. Any thoughts? Maybe good scheduling will do.
Cheers,
Niggles.
