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Reflux condenser sizing, cooling water consumption?
Posted: Tue Sep 28, 2010 4:53 am
by Dr. Forrester
Pardon, but I have two questions:
#1. What's an appropriate size condenser for a 1.5" x 36" Boka mini running at 1500w? Using the el cheapo refrigeration grade 1/4" tubing from the hardware store, unsure of the length needed.
After poking around the on the parent site's condenser calculator etc. it doesn't seem to give much guidance on sizing reflux condensers, or if it does I'm ignorant and missed it.
#2. This is dependent on #1's answer, and may be too subjective but how much cooling water will be required during a 20 liter run with this rig once equipped with a properly sized coil?
I'm trying to determine if a pump and reservoir would be necessary to keep that condenser working economically. I saw someone say their reflux rig consumes about 6 gallons of cooling water in two hours while running at 1900w, which seems like a drop in the bucket (sorry), but there was no mention of coil size or column diameter.
Thanks. I apologize if the answers to these are too obvious. I promise I google'd first.
Re: Reflux condenser sizing, cooling water consumption?
Posted: Tue Sep 28, 2010 5:02 am
by Kentucky shinner
For a 1.5" bok, you need 6 feet of 1/4", The reason I say you only need 6' is my experience was it will be a single coil with a 1/2 cold finger. If your making a coil for a 2" then you will need 10' and wind a double coil for best results. Your condenser only needs to be about 6-8 inches long when finished.
as far as the water consumption, I have no Idea I have never checked that. It wont be very high but I don,t have the numbers on that.
Kentucky Shinner
Re: Reflux condenser sizing, cooling water consumption?
Posted: Tue Sep 28, 2010 1:24 pm
by Dr. Forrester
Thanks, Kentucky shinner. You're a lifesaver.
What size mandrel did you form your coil around, 3/4", 5/8"?
Was the condenser a tight fit in the column?
Do you have any pictures of your cold finger?
Would you say you're happy with your 1.5" Bok overall?
Sorry for all the questions, I'm a little excited
Re: Reflux condenser sizing, cooling water consumption?
Posted: Tue Sep 28, 2010 7:33 pm
by rad14701
Your mandrel should be 3x the tubing diameter, minimum, so wind the coil using a 3/4" mandrel and then use a 1/2" coldfinger down the center so you have some air space... The resulting coild will be ~1.25" in diameter so it will fit nicely in a 1.5" column... A 6" - 8" single coil over coldfinger should give plenty of reflux cooling capacity...
You should only need ~1 liter/quart per minute of coolant flow, at most, to adequately knock down 100% of the distillate vapor... You can use a reservoir and a recirculating pump if you want to conserve water... I am not aware of any accurate measurement of required volume when recirculating but double to triple the boiler charge would probably suffice as the water doesn't have to stay extremely cold in order to knock down the vapor...
My 1.25" LM column uses .5 - 1 liter per minute of un-recirculated 65F tap water that exits the condenser between 80F - 110F...
Re: Reflux condenser sizing, cooling water consumption?
Posted: Tue Sep 28, 2010 8:13 pm
by Dr. Forrester
Thanks for the info, rad. Those are just the answers I was looking for.
Now to go re-read those soldering and coil winding tutorials!
Re: Reflux condenser sizing, cooling water consumption?
Posted: Fri Oct 01, 2010 8:58 pm
by Kentucky shinner
Dr. Forrester wrote:Thanks, Kentucky shinner. You're a lifesaver.
What size mandrel did you form your coil around, 3/4", 5/8"?
I used 3/4" then used 1/2" for the coldfinger
Was the condenser a tight fit in the column?
not really.
Do you have any pictures of your cold finger?
http://homedistiller.org/forum/viewtopi ... 5#p6825008
Would you say you're happy with your 1.5" Bok overall?
yes very I just wanted to go bigger later. you will be happy
Sorry for all the questions, I'm a little excited
Sorry I took so long to answer
Re: Reflux condenser sizing, cooling water consumption?
Posted: Fri Oct 01, 2010 10:57 pm
by Dr. Forrester
No sweat, Kentucky shinner.
Thank you!
Re: Reflux condenser sizing, cooling water consumption?
Posted: Sat Oct 02, 2010 9:32 pm
by nevadadrifter
Ahhh dammit! I was gonna go with Tom Servo as my username, but I wasn't sure if anyone here would get the reference! Nice to see another MSTie here!
Re: Reflux condenser sizing, cooling water consumption?
Posted: Sun Oct 03, 2010 10:02 pm
by Dr. Forrester
Haha, nice avatar drifter! Long nights spent watching MST3k (and
UHF) made me the man I am today.
You watch the Rifftrax they're making these days? I feel like they're hit or miss. I miss the interaction with the screen, not to mention the really BAD movies they riffed way back when.
I'm allowed to derail my own thread, right?
Re: Reflux condenser sizing, cooling water consumption?
Posted: Sun Oct 03, 2010 10:58 pm
by nevadadrifter
PM sent. Thread is officially back on topic!
Re: Reflux condenser sizing, cooling water consumption?
Posted: Wed Nov 12, 2014 12:52 am
by Fidget
rad14701 wrote:
You should only need ~1 liter/quart per minute of coolant flow, at most, to adequately knock down 100% of the distillate vapor... You can use a reservoir and a recirculating pump if you want to conserve water... I am not aware of any accurate measurement of required volume when recirculating but double to triple the boiler charge would probably suffice as the water doesn't have to stay extremely cold in order to knock down the vapor...
Interesting. So if recirculating around 40 - 60 litres would a '300 Litre Per Hour' pump be more than adequate? 5L a minute at full speed certainly sounds like plenty...
Re: Reflux condenser sizing, cooling water consumption?
Posted: Wed Nov 12, 2014 1:54 am
by Hound Dog
Fidget wrote:
Interesting. So if recirculating around 40 - 60 litres would a '300 Litre Per Hour' pump be more than adequate? 5L a minute at full speed certainly sounds like plenty...
Until the 40 - 60 liters of water gets hot. Just remember that your cooling coil has to remove the BTUs of heat that you are putting into your boiler. You are just transferring energy.