fermentation fridge heater

[paulg]

I have a fridge about the same size as a tall domestic fridge.It is similar to a coke fridge with a glass do but a bit smaller.It is set up with a atc800 controller and 60 watt tubeler heater.
I am currently fermenting a 40 litre batch (my first one of this size in winter) and the temp is struggling to get up to 20 c.
my question is what size heater do people with large fridges use,I see many using 60 watts like mine but i wonder with the bigger size fridge maybe a larger heater is required.
I have never had problems when fermenting 25 litre batches before in the winter,I have allowed 2 days now for the temp to rise after I had it at 18c for 4 days with no problems

[BenB]

Can you not insulate the outside of the fridge somehow? I've got a 60w tubular heater in a homebrewed chamber which will take two massive FVs at the same time. It's sat in my unheated shed and I can confirm that at present (using my wifi IP camera pointed at the external thermometer mounted on top of the chamber) that it's 5 degrees in the shed and 20.4 in the chamber. Fermentation is an exothermic reaction so it shouldn't be an issue IE if my chamber full of 40L of conditioning beer is able to keep the temp a fermentation chamber in use should be fine... unless the fridge is leaking heat like crazy.....

[jimpy0]

I think coke/can chillers are just that chillers, Not fridges and arnt insulated as good as a fridge i doth think a glass door will help any either, as they don't vacuum seal.

[BenB]

I would imagine an outer celotex sarcophagus of celotex which goes inverted over the top of the fridge would do the trick nicely. Trapping in warm air as well as insulating it. Wouldn't cost the much either. Given the price of electricity I would imagine it would quite quickly be cost effective.... The only issue would be ensuring the back of the fridge isn't covered when the fridge is in use to cool the brew.

[paulg]

that may be the case,I know that the internals are filled with foam as when I drill a hole for the cable there was foam inside but it maynot be as well insulated as a fridge.The door is double glassed with a magnetic seal the same as a fridge.The cooling radiator is mounted under the fridge so if I insulate the chamber only then not a problem
I will look at ways to improve the insulation maybe using sheets of styrofoam type

[Hogarth]

I've had problems with a tube heater struggling during a cold snap. Thread about it here.

[paulg]

it may have been that because my atc800 has a differential +/- 1c that the fridge was in a warming cycle after dropping to 19c from the 20c setting.Last night I increased the temp setting to 21c this morning when I checked the temp was 20.8c,so the heater can get to 20c.

[Fil]

fwiw i use a smaller glass door fridge and have a square of camping mat gaffertaped oc=ver the glass to aid insulation

A fan is important to move the heat about too, if no fan is running while heating consider adding a 2ndary fan to help move the heat about too. basic 12v 8cm sq black pc fans work well, mine last about 2 years or more (had one go a couple of years ago) so dont jbweld em in place

[paulg]

thats a good idea fil ref insulation on the door and no I dont have a fan .I did post something similar about my cellar fridge over on the home brew site.I will investigate fitting one .do you have any sort of boxing in around the fan/heater

[Fil]

just point the fan in the general direction of both the heater and if possible the cold radiator, my fridge has a blower which blows over the cold radiator when the compressor is on so mine just blows over the heat tube.. an old phone charger works well as a psu if under 5v use red and black wires to power red+ve black -ve, if between 5 and 12v use the black -ve and yellow +ve wires for a basic pc fan, they are not designed for a humid environment so dont last forever but do give a good length service in my limited experience and are fairly cheap to replace when needed.

[paulg]

thanks fil ,my fridge also has a fan that runs when in the cooling mode.I will visti the computer shop on my next trip to town and buy a fan.
The weather yesterday das foul raining all day and thunder storms/freezing,i had increased the temp setting to 23c with the hope to get a steady 22c-23c .the temp never got above 21.6 c so definitely struggling.
fan/insulation required.

[ciderhead]

I have a BrewPi and 60w tube heater in a large larder fridge, before I installed fan it heated for 10-15mins now it's 5-7 mins, the probe is in a thermowell in beer

[BenB]

In my brewfridge I've got a mains 120mm 240v AC fan directly behind the heater blowing air over the tubular heater. Works very nicely. I got the fan off Ebay, it's an old RS components fan. I new it was old when it came in the post when it said "Made in W.Germany" on it! Works very nicely though- proper bearings, all metal etc etc.

I made my brewfridge out of a mini-freezer attached to the side of a larger compartment (MDF lined with celotex). The tubular heating sits in the lower half of the freezer (under the ice shelf) and then I've got a smaller fan in the upper compartment. The smaller fan I leave on all the time to keep the air circulating and the bigger fan comes on during heating cycles.. Obviously the mini freezer bit takes up some space in the shed but it does mean the entire temp controlled chamber bit is available for FVs, bottles conditioning etc.

[jimpy0]

off on a slight tangent, having a shufty round seems the 1 footers come in 3 sizes 40,45 and 60 watt, have just double checked the one ive ordered and its a 45w.
am guessing that as with fishtanks underpowered heaters cost more trying to heat the volume, is it the same in a brewfridge ?

[BenB]

It doesn't matter from an efficiency point of view whether it's 30W, 45W or 60W. If you put 60W into your system unless some of it is turning into noise and leaving the fermentation chamber it will all be turning into heat (conservation of energy rules).

Not sure why anyone would say an underpowered heater would cost more.... Doesn't make sense empirically.

My worry would be <60W might struggle to maintain a temperature but it depends on ambient temps etc...