Mk-i

Just a quick note, I am running the test run now. I must say so far I am impressed. It has been running about 7 mins and my temp has gone up 40*. This in a 11.5 gallon test and the temp was measured in the surrounding water tem area. I get more specific in a bit. Stay tuned....

Well, the gods must be angry at me. I am not sure whether to call this a failure or a advancement. I have nice movement, great steam going in but it has hit a wall. I have been struggling to achieve a boil. I am not sure if it is the unit or the wind that has kicked up just after starting the run. Thing just don't look good. What a bummer.

It sounds like it is doing what is expected, the temperature rise is normal for the temperature difference, the boil just takes brute input and time. The plateau is expected, keep the steam going and you should reach the stage where boiling begins in the tubes. Then you should find that the steam needed to keep it boiling is quite a bit less. This is an extreme test, normally you would be starting with 160 degree liquid.

kladue said:

It sounds like it is doing what is expected, the temperature rise is normal for the temperature difference, the boil just takes brute input and time. The plateau is expected, keep the steam going and you should reach the stage where boiling begins in the tubes. Then you should find that the steam needed to keep it boiling is quite a bit less. This is an extreme test, normally you would be starting with 160 degree liquid.

Click to expand...

After I posted I went back out with a mirror to see under the hat section and it was boiling. Just not very violent. Kinda a slow roll. It was pushing up about an 1" above the water surface below the hat section. There wasn't any bubbles or anything just a rolling of the liquid. I tried turning down the fire but I didn't compensate by turning down the water flow. I lost the boil once I got below the 2 turn mark. Point is it was boiling, and boiling for a longer period then I first thought. I think the flow into the tubes needs to be restricted.

What's the tube diameter on the on the big units? Either because they are bigger and the tubes look smaller or they look like 1/2"-3/4" tubes in the big ones. More surface area to volume ratio maybe needed to get the rapid heat transfer?

GreenMonti said:

After I posted I went back out with a mirror to see under the hat section and it was boiling. Just not very violent. Kinda a slow roll. It was pushing up about an 1" above the water surface below the hat section. There wasn't any bubbles or anything just a rolling of the liquid. I tried turning down the fire but I didn't compensate by turning down the water flow. I lost the boil once I got below the 2 turn mark. Point is it was boiling, and boiling for a longer period then I first thought. I think the flow into the tubes needs to be restricted.

Click to expand...

I don't think it needs to be restricted but removing some of the boil volume will help with the air lift affect and velocity from the boil. Have any solid rod that will fit with in the boiler tubes leaving a 1/8" ring or so of free space between it and the boiler tube?
Still sounds pretty promising to me!

WPStrassburg said:

What's the tube diameter on the on the big units? Either because they are bigger and the tubes look smaller or they look like 1/2"-3/4" tubes in the big ones. More surface area to volume ratio maybe needed to get the rapid heat transfer?

Click to expand...

The main body is 3.5" OD. The tubes inside are 1" OD.

CodeRage said:

I don't think it needs to be restricted but removing some of the boil volume will help with the air lift affect and velocity from the boil. Have any solid rod that will fit with in the boiler tubes leaving a 1/8" ring or so of free space between it and the boiler tube?
Still sounds pretty promising to me!

Click to expand...

In a sense, by placing solid rod in the center of the tubes you are reducing the volume, which should be the same as restricting the amount of flow into the tubes, right? By allowing the wort/water inside the tubes to come to temp faster then the flow will allow, you should get a more violent reaction.


Edit: I don't believe all is lost. Not at all. I am just a bit bummed out cause I had higher expectations then what I saw. I believe that is due to a lack of knowledge on the subject. I am gonna try again and hope it is a better result then this time. We shall see......

GreenMonti said:

The main body is 3.5" OD. The tubes inside are 1" OD.



In a sense, by placing solid rod in the center of the tubes you are reducing the volume, which should be the same as restricting the amount of flow into the tubes, right? By allowing the wort/water inside the tubes to come to temp faster then the flow will allow, you should get a more violent reaction.

Click to expand...

restricting the flow with an orifice isn't going to gain much. If the orifice is on the bottom the velocity of the fluid will slow down as soon as it passes. Restriction at the top wouldn't help because you can't overcome the head pressure required to push the fluid up to the top.

You are adding restriction with the solid rod but you are also changing your volume to heat ratio. So if you halve the volume of each tube you are doubling your BTU per volume of liquid ratio. Too thick of a rod will cause too much restriction and may cook the wort but I imagine it would have to be a pretty tight clearance. You can use different diameter rods to try to find a sweet spot.

Start with maybe a 3/8" rod and work up from there maybe? this will bump your btu/gal ratio by 2.

Edit- I went with 1" od I dont know what the thickness is but with that said
Four 1" dia tubes 11" long has an approx volume of 0.15 gallons, a little more than a pint.
with the 3/8" filler you're looking at 0.06 gallons. roughly a cup. I'd SWAG it and say a cup at a time would be pretty impressive.

In a commercial calandria or external wort boiler, they also have the steam input under pressure. At 2-3 bar the steam is between 270F and 292F which would drive a harder boil in the wort.

Before trying to create more pressure, I would certainly try the recommendations of CodeRage above. It makes a lot of sense and would be a much easier start than creating a pressure system.

Still an amazing build....

GreenMonti, it occurred to me this morning that you will get an added benefit by doing it this way. It's the same reason CFCs work so well, a very high surface area to volume ratio. So the transfer of heat into the fluid would be greater than using smaller tubing that held the same volume. Basically it works out to be a more efficient heat transfer.

The rods may be the trick, not only increasing the btu/gal ratio, but decreasing turbulance by just taking up some space. The boundary layer of wort that is in contact with the inside surface of the tubes is obviously boiling, but may be mixing with cooler wort in the center of the tube and killing the overall rapid boil. Either more heat or less fluid should solve the problem.

Can you measure the steam temp and pressure just before it enters the calandria as well as the condensate temp and volume leaving it?

Rock on, this has to be right up there with the first home brewer to use a laughter tun in terms of accomplishments on the small scale!!

Based on the volume and temperature rise information it looks like you were adding about 33K btu's/hr (10.6 KW) to the water during the heating phase. The main thing that is going on is it takes 15% of the total energy to heat the water to boiling, the other 85% is needed to make it boil. A likely operating scenario would have higher flow rate and lower steam temp during heating, and lower flow higher superheat during boil. The superheat will keep the temperature differential and heat transfer rate up at boiling temperatures. It appears that the surface area of the 1" tube inside 3.5" calandria is about 120% (1.59 sq ft) , a 1/2" X 20 tube inside 4" should be about 200% (2.63 sq ft)of keg bottom area (1.31 sq ft). The thing that controls heat output is the temperature differential and the ability to superheat the steam to a higher temperature will be the key to making this work well. What was not calculated was the effect on heat transfer due to the movement of liquid in the tubes, this has a greater effect than just temperature differential across material. The wall thickness effect on the heat transfer is being researched for the difference between .025" vs. .049" tube walls to see if it has a major impact. You might drop a piece of the 4" around the existing 3.5" to make another tube-tube passage for thermosiphon flow on the next test to see how much that helps the exterior tube flow and heat transfer.

Here is how things were setup. I am gonna run it again today. All I have handy is some 1/2" tubing that I can put inside the exchanger tubes. Or tack on some washers. I could try Kladue's idea with a piece of 4" around the whole thing too. I am not sure what or how much I will get done today.



That's 11.5 gallons of water

Were off to the races again. It has been running about 10 mins now. I have the tube around the MK-I and I put 1/2" tubing inside the 1" tubes to gain BTU/gallon. As always things happen fast at first. In the 10min its been running I have raised 11.75 gallons of water from 50* to 130*. That's raising almost 12 gallons of water 8*/min. I hope this keeps up......

The modifications seem to have increased the heating effort 50%, it calcs out to almost 48K btu/hr - 15KW now.

kladue said:

The modifications seem to have increased the heating effort 50%, it calcs out to almost 48K btu/hr - 15KW now.

Click to expand...

The total time to reach 160* from 50* was 20min.

The time from 160* to start to boil was 35min. After the 40min mark the boil didn't get any bigger/harder. So total time from 50* to the hardest boil was 1 hour. I had 11.75 gallons this time and I didn't cover the top during heating.

Here is the boil at the 35min mark.
http://s385.photobucket.com/albums/oo300/pentair/?action=view&current=P1010056-2.flv

Here is the mods that were done. Notice that nothing permanent was done to the MK-I.

A piece of 4" tube was placed around the calandria and held off the bottom 1/8". I just tacked on 2 pieces of 1/16" weld wire for a spacer.


Here it is around the calandria with some 1/4" filler for a spacer.


With coderage's suggestion, all I have on hand is 1/2"OD tubing. I think it will work better with solid rods but....I welded on small pieces of weld wire and bent them down to act as springs to keep the tubes centered.


Here is the bottom with the tubes in place.


A view of the tubes from the top with the calandria in the kettle.

GreenMonti,
So it sounds like things have improved? I can't tell if you're happy with the results or not.

It's hard to tell from the video but is that the surface of the water in the kettle or is it the spray from the scatter shield? It's definitely boiling though.

Solid rods would definitely improve performance to some degree. There is cooler fluid in there and probably mixes at the top because of the thermo siphon effect. The tube wall is also cooler but as is, it seems to have helped. I said 3/8 to be modest, with the results it may be worth changing them out to 5/8 to see how much performance is impacted.

The outer shield also seems to be insulating the steam vessel from the rest of the liquid in addition to attributing to the thermo siphon affect. Sounds like the energy is being utilized better between the two changes.

Lookin good Monty!

CodeRage said:

GreenMonti,
So it sounds like things have improved? I can't tell if you're happy with the results or not.

It's hard to tell from the video but is that the surface of the water in the kettle or is it the spray from the scatter shield? It's definitely boiling though.

Solid rods would definitely improve performance to some degree. There is cooler fluid in there and probably mixes at the top because of the thermo siphon effect. The tube wall is also cooler but as is, it seems to have helped. I said 3/8 to be modest, with the results it may be worth changing them out to 5/8 to see how much performance is impacted.

The outer shield also seems to be insulating the steam vessel from the rest of the liquid in addition to attributing to the thermo siphon affect. Sounds like the energy is being utilized better between the two changes.

Lookin good Monty!

Click to expand...

Your right, I just don't have solid stock on hand. I started to weld the ends shut to have solid rods but I didn't want to take the time right then. I also thought of using 5/8" solid stock for the plugs. There is most certainly some brain storming going on now. I am not sure how yet but, Kladue mentioned about running steam down the 1/2" tubes to really heat things up. I am not sure how I am going to pull it off but I really like that idea. Maybe a new build is in order. Of course the original idea was to use 20-24 1/2" tubes for the heat exchange. I changed it last minuet so I could just see something. I am the type that learns more from experiences. That's why I melt metal for a living.

I am not sure if I am happy or not myself. I mean it does work. I was/am after more though. I don't have enough experience in this area to know whether or not what I am getting is really good or bad? What you see in the video is surface rippling, not the spreader. It was really hard to get any kind of a shot of what I was seeing. Given the fact that I think it doesn't boil very well, I lost what I believe to be a lot to evap. I only let it boil for a short period of time and I lost about a gallon. I would estimate a loss close to 2 gallons over an hour of run time. I don't know if it is flashing off due to heat or what.

Here is another video. This is at the 40min mark. So only 5 mins had gone by from the last video.
http://s385.photobucket.com/albums/oo300/pentair/?action=view&current=P1010057-2.flv

You're saying you lost 2 gallons of the preboil volume over the whole 1 hour time period? If that is the case then it sounds pretty good to me with 12 gallons of water, considering part of that time it was getting up to temp.

Looking at that 1/2" pipe in the 1" pipe I just realized my late night drunk math was a little off. I calculated the area using a 3/8 radius not diameter... whoops. The 1 cup is using a 3/4" OD pipe. Very sorry about that. With the half inch spacer you had .112 gallons.

heh, oddly enough, 24 1/2" tubes is almost exactly twice the volume of what you are running now with the slugs.

with 24 1/2" tubes you would have a 1848 square inches per gallon, the current set up has 1232 square inches per gallon. The question is, currently how much of the energy in the steam is being used and what is being wasted? If there is significant waste than doubling the volume with 24 1/2" tubes may give you good results, but if you are using most of the energy of the steam then you're going to need to find more steam some where .

With a 3/4" rod your square inches per gallon ratio goes up to 2123 in^2/gal.
If you can run steam down the 4 3/4" rods that number jumps to 3722 in^2/gal.
EDIT If you ran steam down the 1/2" tubes in the current config you will have 1848 in^2/gal. Interesting, EXACTLY the same as 24 1/2" tubes.

In addition the exterior jacket you put on the unit is also heating .068 gallons with a 1779 in^2/gal ratio.

I need to go back and study all the steam talk you guys were doing earlier. My eyes just glazed over and I skipped it the first time . I'll have something to read at work tomorrow.

I would say once you can figure out how many BTUs, surface area, and volume is required to get either a rapid boil and/or high velocities from the tubes then you can scale up the volume in the boiler tubes themselves with some predictability.

The only thing that kind of has me worried is the exit towards the wort spreader. The volume really does open up there and I am afraid that unless the wort is REALLY moving it isn't going to hit the spreader with any real momentum if it hits it at all. The direction you're heading now with the smaller tube volumes it may be necessary to restrict the exit closer to the spreader stem creating more back pressure.

Wait, isn't this the same kind of principle you needed to get the original boiler to work? This just may be the next logical step now that the wort is able to overcome the static head pressure. Err, was the wort exiting the top opening in the new configuration? If not I doubt this will help until it does.

What do you think Monti / Kladue?

We may not be able to get the type of flow in the larger calndria's because of the size constraints of using a 1/2 barrel keg. the longer the vertical tubes the greater the exit velocity, 10 inch tubes may not be able to create the same flow speed as tubes 6' or longer can. It will be interesting to see if a 1/2" tube version can generate more steam bubbles and faster flow than the 1" tube version did, it might be that we do not need the spreader after all. The evaporation rate is a good measure of the heat applied to boiling, just need to do the math to get the total heat applied during the test run. I think that it worked better than expected, although not as impressive as the large scale versions.

Since you were able to get a good boil with the immersion coil we can assume your boiler is capable of putting out enough btu's, which again is evident by your temp rises. Would you say you are running more, less, or the same amount of water into the boiler at this point and what does the condensate look like (all steam, water, mix)? If you're running the same amount of water into the boiler and getting solid condensate at 212 or less, then the calandria is transferring more btu's than the boiler can put out. If you're running the same amount of water into the boiler and getting steam out of the calandria, then there isn't enough surface area in the calandria to transfer the energy and you've got to start looking for more surface area or a way to increase thetransfer rate(smaller diameter tube, smaller gap with bigger rods)

WPStrassburg said:

Since you were able to get a good boil with the immersion coil we can assume your boiler is capable of putting out enough btu's, which again is evident by your temp rises. Would you say you are running more, less, or the same amount of water into the boiler at this point and what does the condensate look like (all steam, water, mix)? If you're running the same amount of water into the boiler and getting solid condensate at 212 or less, then the calandria is transferring more btu's than the boiler can put out. If you're running the same amount of water into the boiler and getting steam out of the calandria, then there isn't enough surface area in the calandria to transfer the energy and you've got to start looking for more surface area or a way to increase thetransfer rate(smaller diameter tube, smaller gap with bigger rods)

Click to expand...

I was running the same amount of water through the boiler as before when I boiled with the copper coil. That rate was 1qt/min.

Today I came home and ran the boiler again with the copper coil (I have rebuilt it so it looks a little different) and ran 1 1/2qt/min through the boiler. I increased the rate cause I was thinking about this today at work. Tomorrow I think I am going to run it again, and run it at the 1qt/min with the copper coils to do sorta a control test. My idea is that if I get the same results with the copper coils as the modded calandria, then the issue is delivery from the boiler. As for the condensate output, here is how it is at 1 1/2qt/min.
http://s385.photobucket.com/albums/oo300/pentair/?action=view&current=P1010060-2.flv

Here is the copper coil in the kettle. Sorry, a little steamy.


Here is how it boils about 12 gallons of water. I started off cold (50*) and hit a boil in 40-45mins today. It took 15mins to hit 160*.
http://s385.photobucket.com/albums/oo300/pentair/?action=view&current=P1010061-2.flv

CodeRage said:

with 24 1/2" tubes you would have a 1848 square inches per gallon, the current set up has 1232 square inches per gallon. The question is, currently how much of the energy in the steam is being used and what is being wasted? If there is significant waste than doubling the volume with 24 1/2" tubes may give you good results, but if you are using most of the energy of the steam then you're going to need to find more steam some where .

Click to expand...

Can you help me out with your math. If the circumference is pi x diameter. Then the circumference of a 1/2" tube is 1.57". If were looking for sq,inches then the width x the length is what we need. Split that tube down the seam and lay it flat you would get the 1.57" x ?. So a piece 12" long would be 1.57" x 12"= 18.84" sq. Then multiply that by the quantity. 18.84" x 24= 452.16" sq. Am I going wrong somewhere? I understand this is area but it is square inches. If you divide that by the number of gallons you only get 37.68 square inches/gallon.

GreenMonti, your math is correct. The math that CodeRage has done is square inches per gallon of wort inside the calandria tubes. I assume his math was to illustrate that you could theoretically put more energy into the wort in the tubes with the 24 1/2" tubes because there is more area to transfer heat (assuming there is heat left to transfer and the energy in the steam was not entirely consumed).

Hey GM, I used 11/inches as length which is wrong, but the nice thing is when you are using a ratio it all works out to be the same.

Surface are of a cylinder = length*pi*2r, the volume = length *pi&r^2

for the 1/2" tube (I didn't take wall thickness into account so it is slightly off, So I was using 1/2" ID)
Sa=11"*pi*2*(.25") = 17.28 sq inches
Vol=11"*pi*(.25")^2 = 2.16 cubic inches
1 gal = 231"^3 cubic inches
2.16"^3/231"^3 = 0.0094 gal per tube
17.28"^2 / 0.0094gal = 1838 in^2/gal
I must have lost 10 square inches in my rounding somewhere

With the rods, volume of the tube - the volume of the slug = total liquid volume in pipe.
then surface are of the pipe / total liquid volume in pipe = surface area to volume ratio.


This doesn't take into account the entire volume of the kettle. just the fluid in the tubes and how much steam heat surface area they are exposed to because this is where the system is dumping the majority of the heat into the liquid. Everything else is absorbing heat from the liquid coming out of the heater.

calculating it this way is the only real way to compare different tube sizes heat transfer efficiency and keep it apples to apples. So a tube with a higher ration than another tube of a different diameter will transfer heat better.

With that said, you will also need to figure out how much water you are trying to heat at any instant. Let's continue with the following system
24x 1/2" x 11" tube
48k btu/hr of heat transfer (kladue's calc from the last run)
0.0094gal and 17.28"^2 per tube

24 * 0.0094gal = 0.2256gal ,
17.28"^2 * 24 = 415"^2 , 0.2256*1838 = 415 as well.

(48k btu/hr) / 415"^2 = 116 btu/hr per in^2
, sounds a little low to me compared to an electric heating element, that is my only point of reference tbh.
(BTW 415"^2/0.2256gal yields the same in^2/gal ratio as a single tube.)

So to get velocities up you need to put a lot of heat into a small volume as quickly as possible. So high ratio and low volume should result in higher fluid acceleration. Now that I think about it though, that will require a lot of heat to move.

Kladue, do you know what the exit velocity of the wort in one of those things? If you do we could calculate the rate of acceleration in a 12" tube is needed and some how translate that to a btu to volume. I'm thinking it is going to be a ridiculous number though.


Man my head is spinning now... I'm calling it a night

Here is what I came up with for the areas of the tubing and outer tube

.5" Tube 4" Tube
Tube OD 0.500 4
Wall Thickness 0.049 0.402
Square inches 1.263 12.564 Combined Areas
Length 11 13.890 138.204 Sq Inches
# of tubes 20 277.790 1 138.204 416.0 Sq Inches
Square Feet 1.929 0.95975 2.9 Sq Feet

Here is what I came up with for heat transfer, does not seem to look right though
Calculated for 11" length .5" Tube 4" Tube Combined

Liquid Temperatures BTU's BTU's BTU's
120 2174.3 1081.7 3256.0
140 1839.8 915.3 2755.1
160 1505.3 748.9 2254.2
180 1170.8 582.5 1753.2
200 836.3 416.1 1252.3
212 635.6 316.2 951.8

Areas were PI*D*H
Heat Transfer coefficient Btu/h ft 0F 8.67
Steam Temperature 250
Hope you can read this, the formatting is lost when posted

OK, since I am waiting for the new end plates to be lasered out I figured I would run the boiler again for fun and to try something new. Something I have been thinking about since I was able to boil the very first time. I am running it with the copper coils again but with a shroud in place. Kinda like a calandria. I will put up pics and a video or two in just a little while. As far as heating times go I was able to decrease the times a little more. I had the starting of a boil in 40 mins. That's no different right? Wrong, I had 14 gallons in there this time. I also got a recirc system going and boy what a difference.

Once the water tank got up to temp 200 degrees, I was able to increase the flow through the boiler and turn down the fire. I am boiling about 13.5 gallons right now with the burner at only half fire. SWEET!! I have been running it a while now playing with different fires and flows but, after an hour I lost a little over 2 gallons to evap.

With the boiler running at half firing rate and at .5 gallons of flow though the boiler I added the 2 gallons (of cold water) back into the kettle. I almost lost the boil after that, but once I turned off the hose and looked back in there is was starting to roll again. Just a minuet or two and I was back to boiling.

Sorry for the ramblings and no real thorough thought process here. I am pretty pumped.

Nice, very nice!

I didn't want this thread too get derailed from the calandria. So I started a new thread on just boiling using the copper coils.

https://www.homebrewtalk.com/f51/boiling-fb-166785/

GreenMonti said:

I don't have a metal lathe.

Click to expand...

But that's a pic of an RC collet. Yah it needs to be slit, and looks like you made it to custom fit something, but still, only one kind of machine in the world takes them and it's a machine tool lathe.

And you talk like a machinist, and you cut iron like one.

I am perfused.

Cliff897 said:

But that's a pic of an RC collet. Yah it needs to be slit, and looks like you made it to custom fit something, but still, only one kind of machine in the world takes them and it's a machine tool lathe.

And you talk like a machinist, and you cut iron like one.

I am perfused.

Click to expand...

What pic are you in reference too?

Cliff897 said:

But that's a pic of an RC collet. Yah it needs to be slit, and looks like you made it to custom fit something, but still, only one kind of machine in the world takes them and it's a machine tool lathe.

And you talk like a machinist, and you cut iron like one.

I am perfused.

Click to expand...

You forgot to mention a milling machine, Bridgeports different with R8 collets vs RC collets granted.
A slitting cutter in vertical mill or Bridgeport can make slit collets or any other required slitting needs..

GreenMonti said:

What pic are you in reference too?

Click to expand...

Dis one:
http://i385.photobucket.com/albums/oo300/pentair/P1010060-1.jpg

Dats why I think you is a machinist and you got a lathe.
Or access to one.

Not to mention the nice turning you produced.

The thread looks almost ground.

Cliff897 said:

Dis one:
http://i385.photobucket.com/albums/oo300/pentair/P1010060-1.jpg

Dats why I think you is a machinist and you got a lathe.
Or access to one.

Not to mention the nice turning you produced.

The thread looks almost ground.

Click to expand...

That's a half coupling welded to a 3.5" pipe nipple. I welded all the way up to rid the threads. Then using a 90* die grinder I blended it all in. The final polish did come from a lathe but.....all I have is a wood lathe. So it only sees the parts for a polish job. I hold sand paper to it while it turns.

GreenMonti said:

That's a half coupling welded to a 3.5" pipe nipple. I welded all the way up to rid the threads. Then using a 90* die grinder I blended it all in. The final polish did come from a lathe but.....all I have is a wood lathe. So it only sees the parts for a polish job. I hold sand paper to it while it turns.

Click to expand...

Sei ruhig!

BrewBeemer said:

Sei ruhig!

Click to expand...

Is calm, clammy. I don't get it?

It means "keep quiet" in German. hold some of your secrets was what I wanted to say. Yes you need a lathe and Bridgeport to fully have fun and play.

Alright folks. Those of you following along, help me out a little bit. Since I am waiting on those other plates, and even if I wasn't. I still want to try things but only if worth while. After doing the test runs with the copper coils, both in a cylinder and out of a cylinder. The test runs were very close to one another. Now if you look at the calandria run after the quick mods, I was at a boil in a little less time. The difference was the vigor of the boil. I am now wondering if the wort spreader has anything to do with that? That and all the steam bubbles being generated at a lower depth with the coils.

The copper coils out of a cylinder got to a boil in 40-45 mins. This was 12 gallons.
The calandria got to a boil in 35-40 mins. This was 12 gallons.
The copper coils in a cylinder got to a boil in 42 mins. This was 14 gallons. This also recirculated hot waste water.

After a little math. My Brinkman burner is rated at 170,000 BTUs. Though the Bayo Classic SP-10 is rated at 185,000 BTUs, same burner. Point is that at 170,000 BTUs of near perfect heat transfer, the water isn't going to come to a boil any faster then the 35-40 min mark. Not with a cold water feed. I am beginning to think that the MK-I isn't all that bad. In fact I almost think with the mods done right it will perform quite well. Though I don't think the wort spreader is ever gonna work. We just aren't running enough temp difference. I really think this deserves the time and effort to make the mods right and solid, and give it another run. Possibly without the spreader in place. I know from a science stand point I should run the spreader but....I will weld up the ends of the 1/2" tubes so they aren't moving any liquid. I will do the outer shroud proper.

What say's the group?
Am I far off in my thinking?

Cheers.