circulating fan

[tourer]

Greetings all, could someone help with this question please. Using a STC1000 a heater and a fan to move the warm/cold air round the fermenting fridge does your fan run continuous or does it only operate when the temperature calls for heat/cold?
Many thanks

[bquiggerz]

Although I don't have a fermentation fridge yet I'd have it running all the time. Computer fans are so cheap it doesn't matter if they need replacing, the ones in my PC are OLD. like over ten years old and are still going. That PC didn't get turned off because its also the file server. So they should last as long as the fridge. But like I fair even if they don't its cheap, just make it easy to get them out.

[BertB]

I have mine plugged in so they only come on when the heater is on, and they blow over the heater.

I use a couple of

http://www.ebay.co.uk/itm/ULTRA-QUIET-C ... 4ad3310877

and a charger from my old beard trimmer

[DethApostle]

Do you really need a fan in a fridge? I can't imagine the temperature varies that much in such a small space?

DA

[tourer]

Do you really need a fan in a fridge? I can't imagine the temperature varies that much in such a small space?

DA

I'm no expert obviously Tall Larder fridges are quite big so it seems to make sense to ensure that their are no hot/cold spots so a fan would eliminate this. I used to think the same about oven fans but my better half says that ovens do work better so the temperature is even (no hot spots). Like many of us i gather most of my Techy info from the knowledgable people on Jims.
Thanks

[tourer]

I was thinking of using computer fans, and for it to operate only on heating as this may be the most critical.
thanks everyone for the input.

[Aleman]

I've been playing with my new BrewPi, and the temperature is much more stable with the fan on all the time, and temperature changes are 'faster' as well. You can see the current log here. Unfortunately I didn't keep the logs of it when it was on cooling only / heating only / only while cooling / heating . . . I suppose I can always set it up again when I'm not fermenting and see what happens.

[vacant]

It is an interesting topic. Regarding keezers, for a chest freezer with a collar I had a fan as the cold air was generated at the bottom so wouldn't circulate to the top - that would apply to the kegs as well - heat transfer would be only by conduction.

With my fridge supplying cold air from above/back (bent down lower portion of freezer compartment) I have no fan.

If a fermentation fridge has heat at the base and cooling from the top, air would circulate when either was on, I don't think a fan would add much. When the heating/cooling is off, difference between the fridge and ambient temperature would be equalised by conduction through the fridge and air against the internal fridge surfaces would conduct that temperature and circulate slightly by convection.

Off-topic bit:

I found the rate of temperature drop increases if the compressor is on for longer. The increased efficiency is only to be expected as the radiator at the back gets hot it can lose heat better - same as an immersion chiller cools faster when in hot wort than cool wort. I don't know how much electricity is saved by running the compressor for longer bursts, these things don't cost much to run anyway.

To keep a large thermal mass of beer in a keg at 12±0.5C I keep my probe up against the keg and insulated from the fridge air to get the compressor on for longer but less frequent bursts.