Recirculating cooling water for my Boka

Anything cooling/condenser related.

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Shaggy 1
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Recirculating cooling water for my Boka

Post by Shaggy 1 »

I ran a 5 gal batch last summer on an average 75F evening. For coolant, I filled a 55 gal barrel with water from my hose,and hooked the condenser into a 1/4hp utility pump, allowing the output to rum back into the barrel. I thought 55 gal's would suffice for the run. About 4 hours into it, the pump suddenly shut down, and I saw hooch vapor blowing out the top of my Boka! Apparently, over time the water had gone from about 50F to over 150F! (And I learned that my pump had a thermal shutdown feature I never knew it had...)

So I quick turned down the flame, grabbed a 5 gal bucket and filled it with new cold water, and used that to buy time while I created a small "cooling tower" made from an 8' step ladder, 2 BBQ grills and some aluminum foil. Rigged the condenser output hose over the top of the ladder, and aimed the hot water to land atop the two grills poised above the 55 gal barrel in an inverted "V" shape (imagine geese flying straight UP). The ambient air temp had dropped by then to around 70F, and the hot water stream breaking up and dripping down each grill section gave the water time to exchange heat with the air, and voila! I was able to finish the run using only about 60 total gal's of water!

That got me thinking...

So this year when the grocery store I work in needed to replace the evaporators in our dairy cooler, I grabbed one of the discarded evaporators out of the trash, and took it home to experiment with. I tested it and the fans still work and the unit is water tight. So I wanted to see how it might do at cooling hot water. (Not it's intended purpose, but I figure a heat exchanger is a heat exchanger, y'know?) http://homedistiller.org/forum/posting. ... =post&f=87#

So, to test it I hosed it's supply side up to a 5 gallon bucket of 125F water from my water heater, and the discharge side into another empty bucket on a recent 80F day. Using my pump to push the hot water through, the output water was 90F, for a difference of 35F in a single rather short 5 gal. run. (I also tried to see how it would work as a "swamp cooler", using ice water, but was disappointed in the result.)

So anyway, here's my question: From your experience, do you think my "evaporator-turned-cooling tower" will work well enough to allow me to run for 8 or 10 hours on the same 55 gal drum of water without the coolant over-heating? I usually do this in the late afternoon into the evening, so a 70F average ambient air temp is probably about right. (Of course it will be more efficient in the winter.)

My thanks to all who took the time to read all this! I look forward to your replies. PM me it you'd like.
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thatguy1313
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Re: Recirculating cooling water for my Boka

Post by thatguy1313 »

I'm really surprised you had this problem with 55 gallons of water. My reservoir is only 22 gallons and I only start having issues after 4 hours. Then I just swap out the water with cooler water and add some soda bottles that were filled with water and frozen to bring the temp back down. Of course this is with a pot still so, not sure how the thermodynamics are different in a bok.
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bearriver
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Re: Recirculating cooling water for my Boka

Post by bearriver »

It doesn't surprise me. I'd dump 50 gallons 3-4 times easy in a 12 hour day with high ambient temps. That's using a radiator and fan. :wtf: Then again I never had to dump it in the winter.

Last run I switched to getting it from the ground and dumping it right back. I could not possibly be happier with that decision... I was worried about pressure changes as the well's pressure tank is doing its thing, but it was not an issue at all with my LM reflux setup.
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still_stirrin
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Re: Recirculating cooling water for my Boka

Post by still_stirrin »

The evaporator coil should be good for your heat exchange if the flow rates are proper, that is, you want the fluid's contact time in the coils to be long enough to conduct the heat to the fins. Obviously ambient temperature and humidity affect the air's ability to take the heat away, but with the fans running you should not have any problems.

If your cooling water system is truely a 'closed system' adding ethelyne glycol (antifreeze) would help the heat transfer capacity of the coolant. But it would be a biohazard if spilled and it certainly would add cost.

Without doing heat calcs on your exchanger, I still think the A-coils should be adequate if the water flowrate is correct.

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TDS
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Re: Recirculating cooling water for my Boka

Post by TDS »

I run a 35 gallon trash barrel with a recirculation pump. When it gets warm, I drop the out hose into a 5 gallon bucket and use another one to add cool water. Repeat as needed.
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BentJar
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Re: Recirculating cooling water for my Boka

Post by BentJar »

Keep on working with that radiator/fan set up. Its the very best solution to cooling the water from the still.
Mine has been working for 2 years running only 5 qts of water thru it.
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335Guy
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Re: Recirculating cooling water for my Boka

Post by 335Guy »

A 35 degree temp difference is pretty good, in my opinion... How big is the coil? I managed to get a smallish condenser coil (18" X 14" and about 2" thick - three passes) that I was going to try to employ for some cooling. I'd be happy w/ a 35 degree temp drop.
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Re: Recirculating cooling water for my Boka

Post by BentJar »

One thing that I found out when working out the bugs of the radiator cooling system is that a wide, thin radiator that was designed to remove heat from water worked.

my experiments with AC condensers DID NOT!

The water flowing into my system from the still condensers is hot @140 and 90 degree after the cycle.
If I need to strip run, all I have to do is turn up the fan speed one click. I never have to use Hi speed.

It is an open system with no reservoir, just the hose running into the top radiator connection, pumped out the lower one.
I add 1 pint of water every couple of runs due to evaporation.

The pump needs to move a lot of water so I use a dishwasher drain pump. You can get them off ebay used for very little money and they fit the lower radiator connection. Its the GE style shown below.

I worked with this system for weeks and I can swear to all it will work like a charm.
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JIMB
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Re: Recirculating cooling water for my Boka

Post by JIMB »

Hi,
I like your radiator/fan set up. I recently made some Grappa and my only issue was keeping the water cool.
Specifically was size radiator would you recommend? Height, Length, and width. What ge water pump part number are you using?

Thanks,

Jimb
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