Damn you're good, Joe <grin>.

Circulating the wine during fermentation will improve heat transfer to
the heat pipe. But that circulation will also cause the yeast to
undergo frequent temperature excursions (which makes them not so happy),
and the circulation will affect extraction of tannins and phenols and
other stuff from skins in fermenting reds (oh the variables one must
consider).

By the way, cooling liquids with submerged heat exchange tubing induces
temperature gradients in the must. The bulk liquid will be a few (to
several) degrees warmer than the liquid in contact with the cooling
tubing, depending on the surface temperature of the tubing.

Gene

Joe Sallustio wrote:

> We used to use peltier devices as a passive cooling system for the
> military back in the 60's. We built the first ones where I used to
> work; they were heat pipes in effect. They are not very efficient from
> an electricity usage standpoint, are affected by ambient conditions;
> they are rated by temperature across the faces at a given current.
>
> You did hit the nail on the head when you questioned the heat transfer
> required if placed into a carboy. Your surface to mass ratio with any
> material is too low if you intend to insert it into a carboy. You
> can't use copper or copper bearing alloys in winemaking as you know
> from others so the thermal conductivity will be lower to make matters
> worse.
>
> If you wrap the tubing around the carboy that might be another matter
> but all of this would turn out to be an expensive proposition.
>
> If you live in an area where the relative humidity is low the
> evaporative cooling idea sounds good, you could wrap a towel around the
> carboy and drip water onto it and blow a fan across it to improve the
> efficiency.
>
> If you are willing to pump fluid you may be able to place a tank in a
> refrigerator or freezer and pump fluid out through copper tubing
> wrapped around a carboy foamed over with an insulation package.
>
> I apologize for not giving you values but I just can't see it working;
> you can gather thermal conductivity data from the CRC handbooks, any
> version would do. That won't be the issue. The available surface area
> of the tubing inserted and in contact with the wine will be the issue
> no matter how cold you can get the liquid in the tubing or how fast it
> flows.
>
> Joe
>
>
>>So long as the reduced thermal conductivity doesn't present a problem,
>>stainless would be fine in place of copper.
>>
>>When Scott pointed out that, without a pump, the amount of pipe within
>>the fermenter may not be adequate for the amount of heat to be moved, he
>> may well have hit the nail on the head, but I'd like to see if I can
>>locate some precise figures or a formula or something like that. That
>>was one of the main questions that I'm researching
>
>