My still

[Twisted Brick]

get 1/2 barbed to 3/4 Mpt Just plain old barbed hose fittings and a hose clamp.

Thats what I use. You will want some kind of valve on the other (upper) end of the condenser to control coolant flow.

[Deplorable]

get 1/2 barbed to 3/4 Mpt Just plain old barbed hose fittings and a hose clamp.

Thats what I use. You will want some kind of valve on the other (upper) end of the condenser to control coolant flow.

I have always controlled flow on the inlet side of my shotgun via my water manifold. Why the output side?

[Twisted Brick]

The way I’ve read it explained here is that by reducing x pressure on the exit end of the condenser maintains input pressure inside the condenser, increasing heat transfer. A secondary reason cited was that said internal pressure could be helpful in bleeding trapped air within the condenser.

I should ask my friend who builds commercial condensers how large an impact internal pressure makes on heat transfer, at our scale. I was in his shop last month and he showed me a 10’ long condenser and mentioned some ungodly huge internal pressure that it ran on.

[Deplorable]

The way I’ve read it explained here is that by reducing x pressure on the exit end of the condenser maintains input pressure inside the condenser, increasing heat transfer. A secondary reason cited was that said internal pressure could be helpful in bleeding trapped air within the condenser.

I should ask my friend who builds commercial condensers how large an impact internal pressure makes on heat transfer, at our scale. I was in his shop last month and he showed me a 10’ long condenser and mentioned some ungodly huge internal pressure that it ran on.

Absolutely you should. And then post the science. Although, I cant imagine this shotgun being anymore effective.

[RC Al]

The other half of the counter flow argument doesn't entirely apply to shotgun Product condensers (unless you can get one to huff n puff - and then i'd be impressed), but certainly dose apply to Reflux condensers (any type) and liebigs.

The thinking goes as follows: With a product condenser, if you let the vapour hit the cold end, it takes a bunch of heat out of the reflux, cooling it more than you need to, so you have wasted some energy AND the cooler reflux creates a bigger disturbance in the temperature gradient of the still, decreasing separation performance. With counter flow the vapour only sees enough cooling to condense and then drop away, keeping more heat in the reflux and it will not fall as far back down the column and get reprocessed further up increasing efficiency.

Counter flow is very well documented as ideal for liebigs to prevent the sudden vapour collapse causing huffing.

Pressurising the condenser will raise the boiling point of the coolant, 3 degrees F for each Psi. The hotter the water the more heat conductivity it has (up to a point, about 300f). The dude is correct in his physics, but as our vapour (almost) never gets to the boiling point of water, I dont think this idea is of considerable use to alcohol condensers - probably of use for some other liquids though. We have enough potentially dangerous things going on as it is...

[jward]

I thought another reason to valve the output was to help keep the condenser full of water/coolant but it seemed to me having the output port at top lets gravity take care of that. One reason to put it on the input was to have lower pressure in the condenser reducing chances of a leak.

[still_stirrin]

The other half of the counter flow argument doesn't entirely apply to shotgun Product condensers (unless you can get one to huff n puff - and then i'd be impressed), but certainly dose apply to Reflux condensers (any type) and liebigs.

The thinking goes as follows: With a product condenser, if you let the vapour hit the cold end, it takes a bunch of heat out of the reflux, cooling it more than you need to, so you have wasted some energy AND the cooler reflux creates a bigger disturbance in the temperature gradient of the still, decreasing separation performance. With counter flow the vapour only sees enough cooling to condense and then drop away, keeping more heat in the reflux and it will not fall as far back down the column and get reprocessed further up increasing efficiency.

Counter flow is very well documented as ideal for liebigs to prevent the sudden vapour collapse causing huffing.

Pressurising the condenser will raise the boiling point of the coolant, 3 degrees F for each Psi. The hotter the water the more heat conductivity it has (up to a point, about 300f). The dude is correct in his physics, but as our vapour (almost) never gets to the boiling point of water, I dont think this idea is of considerable use to alcohol condensers - probably of use for some other liquids though. We have enough potentially dangerous things going on as it is...

Wow guys, talk about “seat of the pants” engineering.

First off, the boiling point of water (a temperature at which it changes state from liquid to vapor) increases as the pressure increases. As an example, breweries that use “steam fired” kettles use a steam generator regulated to 15psi because the boiling point, again the temperature of the saturated steam, is 250*F (121*C). This is hotter than the wort will be even at a strong rolling boil, so heat will transfer from the steam to the wort (heat travels from the higher temperature to the lower temperature always).

An additional physical fact is that the enthalpy (the energy within the steam) is much greater at 15 psi than at atmospheric pressure. At 15 psi, the steam is quite powerful and dangerous if it were to leak, or burst through the piping.

However, for your coolant flow (water always as a liquid), the heat capacity (BTU/lbm or joules per kg) will remain nearly constant, or at least with negligible variation. So, the heat transfer is (almost) a linear function of the temperature differences).

So, the question of “counterflow” for a HEX....counterflow is more efficient at heat transfer than parallel flow. Again, heat will travel (conduct) from a higher temperaure to a lower temperature fluid. This chart shows the parallel and counter flow arrangements:

condenser flow arrangements

8F2D907B-C6BE-4A99-A8B9-D249A6576235.gif (4.73 KiB) Viewed 2187 times

This chart shows the temperature relationship at the inlet and outlet for the respective condenser arrangements:

counterflow and parallel flow efficiency

7E09442B-AAD4-4FC1-BD89-C91B6BA1EE6B.gif (5.96 KiB) Viewed 2187 times

Notice the inlet temperature of the “hot fluid” as the outlet temperature of the “coolant” approach that the temperatures at the product outlet will approach the same temperature as well. Adjusting the coolant flow so that the hot side temperature differences are minimum shows an increase in efficiency for the heat transfer. Conversely, with a parallel flow, increasing coolant flow rate won’t produce the same outlet temperatures.

What happens when the coolant outlet temperature is too cold is that the heat will be lost from the vapor before it enters the condenser. This can cause the collapsed (condensed) vapor to flow backwards, possibly towards the boiler. When it does this, it will suck air into the product outlet, creating the “huffing” sound. Is it dangerous...no, but it is inefficient as you’re wasting coolant flow energy and increasing “waste water”. So, you slow the coolant flow until the coolant outlet temperature is warm, or even hot to the touch. It will ensure that the vapor condensation will occur within the condenser and that it won’t suck air back into the boiler.

One final comment refers to the “valve on the inlet vs outlet” question, and that is of minor consequence.

The advantage for the outlet line is that the water jacket will be pressurized to line pressure (or pump pressure), thereby minimizing the potential for cavitation, or places where the water pressure may duck below the vapor pressure of water at that temperature. This is not likely to happen unless there is extreme turbulence in the water flow channel.

If you valve the inlet and reduce the pressure before the condenser, then there may be a possibility of some air bubbles remaining inside the condenser. Again, this could exacerbate the problem of cavitation inside the water jacket. But the question remains whether or not this would cause damage (hydraulic erosion) of the condenser’s coolant flow channels.

Does this help understand some of the “whys”?

I hope that my mechanical engineering degree is not totally wasted here and that I’ve help bridge some of the misunderstanding.
ss

[Deplorable]

Thanks SS. Not wasted on me.
In my simpleton mind, as I understood you, a valve on the outflow is more helpful on a recirculating coolant system than on a waste water system so long as you can maintain a temperature gradient within the product condenser, and achieve optimum performance.

[still_stirrin]

Deplorable,

Actually, it really doesn’t matter much where you put the “throttle” in your product condenser’s flow circuit, just that it is beneficial to have one. It allows you to adjust the flow rate to get the water temperature closer to the vapor inlet temperature, or at least warm to hot to the touch. This reduces the water throughput and (theoretically) saves water.

When I refer to “waste water”, I’m really talking to those who plumb their condenser to the main faucet, not a recirculating system like you’d have with a water reservoir. If you connect to a faucet, then the discharge often goes down the drain. Or, it gets repurposed to water the lawn, etc.

In the case of the recirculating system, as the reservoir warms up due to the heat recovery in your condensers, the water inlet temperature will rise, thereby reducing the temperature differential inlet to outlet, and it will similarly reduce the heat transfer efficiency.

But, there is a slight (nearly negligible) advantage to putting the coolant flow control on the discharge side of the product condenser as I previously noted, simply to make sure the air bubbles are eliminated from the condenser. That’s about the only reason to favor one placement over the other (on the inlet piping).

OK?
ss

[Durhommer]

Thanks for the valuable input ss

[Durhommer]

So I think I'll get some corrugated hose and practice twisting a reflux condenser.see how many tries it takes me and how many hoses I go thru figure I can fiddle with that and read up on ccvm reflux skill. Hopefully I can make one cos after my condensers I'm putting money in grain for the foreseeable future

[Deplorable]

Deplorable,

Actually, it really doesn’t matter much where you put the “throttle” in your product condenser’s flow circuit, just that it is beneficial to have one. It allows you to adjust the flow rate to get the water temperature closer to the vapor inlet temperature, or at least warm to hot to the touch. This reduces the water throughput and (theoretically) saves water.

When I refer to “waste water”, I’m really talking to those who plumb their condenser to the main faucet, not a recirculating system like you’d have with a water reservoir. If you connect to a faucet, then the discharge often goes down the drain. Or, it gets repurposed to water the lawn, etc.

In the case of the recirculating system, as the reservoir warms up due to the heat recovery in your condensers, the water inlet temperature will rise, thereby reducing the temperature differential inlet to outlet, and it will similarly reduce the heat transfer efficiency.

But, there is a slight (nearly negligible) advantage to putting the coolant flow control on the discharge side of the product condenser as I previously noted, simply to make sure the air bubbles are eliminated from the condenser. That’s about the only reason to favor one placement over the other (on the inlet piping).

OK?
ss

Gotcha. We're both using the term "waste water" the same way. My cooling water drains to waste. I dont have a vessel large enough for recycling cooling water other than my fermenter, and city water, when using it properly hasn't been a big deal.
I built a two knob water manifold for my cooling needs and it puts both "throttles" in the same convenient location.

[Durhommer]

Well not ready to make a reflux condenser yet it's a little bit hard to find the right length of hose

[Deplorable]

You can order it on line uncoated, but I couldn't find it local in any hardware store.

[Durhommer]

Got my brass water connection for the condenser

[Durhommer]

Great...my condenser is shipped and will be here Thursday. I'll be up and running by the weekend I'm happy about that! I cant wait to see it on my setup for electric

[Durhommer]

New condenser is here lost my fittings so back to home depot then off to the races

[Durhommer]

Ok so this shotgun is a beast! My 30 gal cooling water tank handles a whole gallon strip with no ice

[Zeotropic]

Ok so this shotgun is a beast! My 30 gal cooling water tank handles a whole gallon strip with no ice

How hot can you get the output water while still maintaining cool distillate?

[Durhommer]

Ok so this shotgun is a beast! My 30 gal cooling water tank handles a whole gallon strip with no ice

How hot can you get the output water while still maintaining cool distillate?

Didn't measure it but it was way better than the hot output I got from the original mile hi cm still. Technically it was my first run with it

[Deplorable]

Hahaha. Wait until you run it in CCVM. You won't be able to get warm water out the hot side. I'm barely running any water to mine and its 61°f on the output, 64 on the input right now running a reflux run.

[Durhommer]

Hahaha. Wait until you run it in CCVM. You won't be able to get warm water out the hot side. I'm barely running any water to mine and its 61°f on the output, 64 on the input right now running a reflux run.

Keep me informed on your refluxing

[Odinson88]

20210114_180427.jpg
New condenser is here lost my fittings so back to home depot then off to the races

Looks good.
Why did you opt for such a tall stack on a pot still?
Also, I like the use of the 90* and triclamps. This allows you to adjust the drain angle by loosening the upper clamp, and pivoting the 90*. You can go from horizontal to vertical and every degree between. Great feature.

[ShineonCrazyDiamond]

Looks good.
Why did you opt for such a tall stack on a pot still?
Also, I like the use of the 90* and triclamps. This allows you to adjust the drain angle by loosening the upper clamp, and pivoting the 90*. You can go from horizontal to vertical and every degree between. Great feature.

Funny. I have just the thread for that, lol.

https://homedistiller.org/forum/viewtop ... 801&hilit=

Also, tall riser keeps you from collecting on the floor. Ain't got to be old to be kind to your back.

[Durhommer]

20210114_180427.jpg
New condenser is here lost my fittings so back to home depot then off to the races

Looks good.
Why did you opt for such a tall stack on a pot still?
Also, I like the use of the 90* and triclamps. This allows you to adjust the drain angle by loosening the upper clamp, and pivoting the 90*. You can go from horizontal to vertical and every degree between. Great feature.

Yes it's a simple pot still with the option to go ccvm

[Deplorable]

Looks good.
Why did you opt for such a tall stack on a pot still?
Also, I like the use of the 90* and triclamps. This allows you to adjust the drain angle by loosening the upper clamp, and pivoting the 90*. You can go from horizontal to vertical and every degree between. Great feature.

Funny. I have just the thread for that, lol.

https://homedistiller.org/forum/viewtop ... 801&hilit=

Also, tall riser keeps you from collecting on the floor. Ain't got to be old to be kind to your back.

Yep. Anyone still building pot stills without a T is missing out on some serious opportunity. Just a few bucks more in parts, and bam! Instant reflux column

[The Baker]

20210114_180427.jpg
New condenser is here lost my fittings so back to home depot then off to the races

Sounds like you and I run on the same system.

Geoff

[Durhommer]

20210114_180427.jpg
New condenser is here lost my fittings so back to home depot then off to the races

Sounds like you and I run on the same system.

Geoff

That's cool knowing someone else has the same still I do. I put copper pipes in my vapor path and the boiler and I've been using the same cooling water for 6 months now