How many watts to heat 50 litre FV?

[dean_wales]

Hi guys,

I am just working out how to heat my 50 L stainless fermenter this winter.

I want to do it from the outside the FV but not by using a chamber or fridge.

I have two things to hand... A 12m long soil warming cable that puts out 150w and a small A4/A3 heat mat that must be pretty low wattage.

If I insulate the FV well (over the heat source) how much power do I need.

Worst case scenario would be just under 50L of barely fermenting saison that needs to be kept at up to 30c in a shed that could be anything down to 0c or below in winter!

I am guessing the cable? I don't want too much over kill though.

I will have some form of thermostatic control.

Thanks,

Dean.

[bluezephyr]

An upscaled version of a trug and aquarium heater?

[dean_wales]

Yeah I want something family neat and contained. I have the vessel and a few bits I just cannot even hazard a guess at home much power is needed.

Jim's calculator suggests that it would take 2hrs for 150w to raise 50L by 5c. That's without losses and accounting for the heat being indirect. Maybe that's about right?

Dean.

[Blackaddler]

Check this thread.

I use the tray in my shed, with an STC-1000.

It'll warm up 60L without problem, even in the depth of winter.

[dean_wales]

Nice.

So the question begs... Is 150w too much?

Dean.

[asd]

Use the cable, lots of insulation, and a thermostat or PID. 150W is not too much.

[b2b]

I have a 45W trace cable attached to an STC1000, two passes round the 60l FV, then everytinhg wrapped in B&Q silver coated bubble wrap.
Even in depths of winter in garage, it keeps it nicely at 20.0C. (I also have a 30W one, which struggles below about 5C).

If you've got 150W, response time will be better than mine (can take a day if I forget to turn it on!), but you must put temp control in place to stop it getting too hot. STC1000, tape the sensor inside the bubble wrap to the FV wall. Allow 1 or 2 degrees difference between the outside and the middle (so set it to 18C for ferment temp of 20C).

[dean_wales]

Hmmmm...

I am starting to wonder whether I should tackle heating and cooling simultaneously.

If I do decide to wrap microbore copper around the FV to cool it maybe I should fit an inline heater to do both at the same time rather than separately?

Dean.

[asd]

Yes, you could wrap a soil heating cable as well as microbore.

OR you could decide to pump warm or cold water around the microbore.

Both solutions work, obviously. It's up to you.

[dean_wales]

Hi guys,

I think I have decided to heat and cool seperately. That way I can avoid bouncing between heater and cooler etc.

What do you reckon to one of these stuck to the base of the fermenter? It's stainless so should spread the heat OK. It would be very efficient as no wasted heat. Sorry photos are huge - eBay wont give me a smaller version.



http://www.ebay.co.uk/itm/271358250188



http://www.ebay.co.uk/itm/271413531944

I would probably go with a 200w one to be on the safe side capacity wise. I worry about any heat stress though to the yeast localised to the pad area unless I could vary the power/cycle the pad? Maybe a smaller 100w one would be a better idea?

Dean.