I think you have way too much time on your hands... a single wet towel and
a fan will work much better for a 5 gallon carboy

That's not nearly enough cooling for where I live. I've certainly thought
about doing the same thing for the same reasons, but not for a 10F drop tops
that you can achieve with the wet towel and fan method. I need to drop 25F
and hold it from ambient during our very long summers here in San Diego.

Plus, brewers are gadget geeks. Does anyone need a better reason to make a
new toy for brewing?

Scott Lindner wrote:
Plus, brewers are gadget geeks. Does anyone need a better reason to make a
new toy for brewing?

That only holds true for some brewers. See the "sparge arm"
thread in rcb-- some of us still enjoy doing things using very
simple procedures and equipment.
--
Joel Plutchak "People who drink wine with barbecue deserve to be
plutchak@[...] jeered at and socially ostracized." - Mike Stewart

Scott Lindner wrote:
I think you have way too much time on your hands... a single wet towel and
a fan will work much better for a 5 gallon carboy

That's not nearly enough cooling for where I live. I've certainly thought
about doing the same thing for the same reasons, but not for a 10F drop tops
that you can achieve with the wet towel and fan method. I need to drop 25F
and hold it from ambient during our very long summers here in San Diego.

Plus, brewers are gadget geeks. Does anyone need a better reason to make a
new toy for brewing?


Why not use an old fridge?? it will give you the temperature control you
need (you may need to tweak the thermostat to get it to go a bit higher)
but it will be stable and quite cheap to run as it is already insulated.
Ben.

That only holds true for some brewers. See the "sparge arm"
thread in rcb-- some of us still enjoy doing things using very
simple procedures and equipment.

I did intend that to be a comment for some of us, and not all of us. We all
brew for different reasons.

Why not use an old fridge?? it will give you the temperature control you
need (you may need to tweak the thermostat to get it to go a bit higher)
but it will be stable and quite cheap to run as it is already insulated.

That's been my feeling for the past couple of months. I'm about to move to
a new house. I see a fermentation shed in the back already. :-)

That's what I do, it works great.

Joe

For completeness of the discussion, I spoke about the 'other'
circulation possibility (i.e. circulating the must). Yes, I was aware
you were speaking about recirculating the coolant in the chiller lines.

Thanks for noticing.
Gene

Scott Lindner wrote:
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).


I believe we are talking about circulating the coolant in the chiller lines,
and not circulating the beverage. At least that's what I was referring to
when I mentioned recirculation.

I originally cross-posted this to r.c.m and r.c.w., in addition to the
beer brewing groups, because I know that we all use carboys and other
fermenters, and believed that we are all concerned with heat. Judging
from the replies, it looks like there have been many responses from
r.c.w., but since it is fairly clear that my idea is less likely to
work with wine (and possibly not mead), all future posts by me on this
subject will be limited to the beer groups, i.e., this will be my last
post on this to r.c.m and r.c.w. However, I do want to take this
opportunity to thank everyone, and to let you all know that I will be
responding further to some posts by Joe Sallustio, gene, Mark R, Hershel
Roberson, Scott Linder, Droopy, QD Steve, and Ben -- but only through
the beer forums; I don't know which of you are subscribed to them, and
if any of you belong only to r.c.m. or r.c.w. but are particularly
interested in discussing this further, I'll be happy to include you in
direct emails if you don't want to visit the beer groups.

Meanwhile, let me just end here with a few general statements that some
of you might find interesting or useful.

First, based on further research, I still think this device might work,
and actually work well enough to even permit _lagers_ to be made in an
unrefrigerated carboy -- dropping the temp down close to freezing. I
will explain why in a longer post on r.c.b., a.b.h-b., and a.h.

Second, "Heat pipes have an effective thermal conductivity _many_
_thousands_ of times that of copper", and they are used in a wide range
of applications, from refrigerators and air-conditioners to even lap
tops computers.

Third, even water can be used as a refrigerant inside of a heat pipe,
although alcohol has a more useful range for my idea.

Here's a link for some of the above:
http://www.cheresources.com/htpipes.shtml

And now I just have a quick reply for Mike, below.

Mike McGeough wrote:

Bill ,

snip

My one thought on your heat pipe setup is that you might well want to
limit the contact between copper and an acid medium like wine.

snip

Understood. Because I don't think stainless steel is a viable option,
the only other solution I can think of regarding wine is to possibly
coat the heat-pipe with something like very thin plastic -- maybe a
food-grade plastic paint -- but I don't know how much of an effect that
would have on the efficiency of the heat pipe. Also, it might well be
that there is never a need to drop wine fermentation temp down that far,
so please excuse me if I was out of line to post in your forums.

Sounds like fun though. Let us know how it turns out.

If I decide to proceed further and manage to get one built and working
well, I'll post a final report in your wine and mead forums just to let
everyone know.

Cheers, Bill Velek
Join "HomeBrewers" international grid-computing team and help mankind by
donating spare computer power for medical research such as cancer; we're
in the top 7%, and we beat the MillerTime team: http://tinyurl.com/b7ofs
The life that your computer can help save ... might be someone you love.

Bill Velek wrote: (months ago)
Rob wrote:

True, but stainless would work, and there are folks who sell steel
Hypodermic Needle tubing with very thin walls.

Personally, not a big problem for me, but I live where it usually isn't
too hot outside during fermentation season, and my batches aren't big
enough to need such cooling.
Very cool idea, though.

Rob


Thanks, Rob, for the encouraging words. Also a thank you to Mike and
Droppy for pointing out the problem with copper, and to the other
posters for their comments, too. I'll just cover everything in this one
post.

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 -- how efficient is a
heat pipe, and how can I build or acquire one if one should work? The
question has never, in my mind, been about the peltier.

What no one mentioned about a heat pipe is how they work. When a heat
pipe is working as intended, heat at the bottom boils the working fluid,
which rises as a vapor to the top where it condenses and heats the
condenser while cooling the working fluid. The transition from liquid to
gas and back is called the heat of vaporization, and it's large compared
to convection which is all you get if you don't boil the fluid.

I heat my house with heat pipes, the working fluid boils at the bottom
of the pipe, rises and condenses. It's called steam heat and was
installed when my house was new, about 1895. All it takes is heat and
gravity, so it's dead reliable.

As a cooler there are many problems, however. You absolutely need the
state change to make any appreciable heat flow, so you need a heat pipe
with a working fluid which boils at or below the target temperature, say
32F to 55F depending on what yeast and process you want to use. Needless
to say there aren't many heat pipes which function at that range, so you
need to find such a thing before going to step two.

There was a lot of calculation of watts and BTU which was very confused.
A BTU is a unit of heat, a watt is a rate of heat. They don't directly
without bringing time into or out of the calculation, in watt-hr or
BTU/hr. In any case it's irrelevant, the cooling you need depends on
insulation, wrap the carboy in copper pipe, pack it in foam, and a very
small cooler will do it. The idea of an old fridge is good, adding a
bunch of insulation will drop the cost of operation by a bunch. It
doesn't need to be pretty, yeast don't give style points.

On peltier junctions: there's a curve of temperature flow (BTU/hr)
between the ends based on power applied. It's largely immune to
temperature, so a ten degree head of 40-50F will take about the same
power as 55-65F. It's hard to get a big temperature delta with peltier,
lots of info on the topic.

Standard cooling methods are very efficient. When you see an air
conditioner labeled as EGR of 10, it means it pumps 10 BTU/hr for every
1 BTU/hr of electricity used (293mw = 1 BTU/hr). Peltier is quiet,
reliable, but not particularly efficient. The old refrigerator approach
is a good one, even if it's not as fun as heat pipes and peltier.

--
bill davidsen
Beer blog: http://blogs.tmr.com/beer
Unsigned numbers may not be negative. However, unsigned numbers may be
less than zero for suffietly large values of zero.