Need Your Feedback on New Stand Mods

[Yambor44]

This is basically what I should end up with. Small guard on the front (orange) and the tubes to hold the pot (blue). No wind guard.

 

[Yambor44]

Here it is with the guards removed and the pot supports installed. I wanted to go ahead and test it so we didn't install the heat shield on the front yet but after this test I will surely have one put on.




I added the heat shields from Blichmann in the front to keep the test fair in comparison.



I started the flame and it was noticeable right away that the old wind guards were starving it out! Only 2/3 throttle as opposed to wide open last time. If you look close you can see a little glow starting on the front pot support. I need to slide the burner back just about 3/4"-1" so it will be centered. This will help keep more heat off the front of the pot. The thermo and ball valve got a tad warm








Even though the flames looked pretty close to perfect, and the times were much better, I felt it could be better. I'll explain in a second.

15 minutes - 120*
20 minutes - 138*
25 minutes - 150*
30 minutes - 160*
32 minutes - 165*
35 minutes - 172*
40 minutes - 182*
45 minutes - 192*
50 minutes - 202*
55 minutes - 208*
58 minutes - 212* Boil

Boil



I felt I couldn't run it wide ope for fear of the flames coming up around the edge of the pot. Once I was into the test I just left it at 2/3 open. Once I reached boil I turned out the lights and pulled the valve full open. Although it did lick just a tad around the back corner, I think I could get away with it and I would assume the times would be even better.

 

[chrisknight]

Looking nice! Is this with or without the regulator? Also, Your burners *may* be an inch or 2 low. The skirt on a keg makes for a nice heat trap also. I'm amazed at how fast my boil starts. I've never timed it, and time flies when brewing so maybe its just me...

 

[Yambor44]

That was with the regulator on, screwed all the way to close. A good friend of mine explained the numbers on the regulator to me. The 4" to 12" means at the minimum range (closed) the pressure will not drop below 4". At the max, it will not go above 12". Our regulators on the house are at 2" so thats why now change no matter where I put the screw - closed, wide open or anywhere in between.

My thoughts about rasing the burner; won't this make the flames come up and around the pot more?

 

[Yambor44]

Little more progress so far today. You reckon that burner is putting out some heat based on the discoloration of the frame? I need some help to figure out how to make this more efficient.

 

[Ichthy]

The enemy of gas burners is that they are pitching out a lot of BTUs, and your kettle is a small area just sitting there receiving whatever comes its way before the force of the gasses pushes the heat out to your stand and ambient.

The MORE surface area on the pot you can heat and the LONGER you can keep the heat in contact with it, the better.

I want to build a heat jacket for a kettle to run some tests... use it on a turkey fryer burner and have the jacket extend up the sides of the kettle, have it vented at the top so that the hot gasses can flow, but the jacket would concentrate the heat at the kettle walls and increase the contact time with each BTU that is racing past the kettle.

Test it without the jacket, and with the jacket... I bet there would be a marked difference.

I did this with some aluminum roof flashing. THe flashing extends up to the kettle handles. I just mounted some all thread on my turkey fryer legs and let the jacket sit on it. I save a TON of propane now. I maybe use 1-2 lbs per brew (5 gallons). It cost $8 for flashing, a few rivets later and I was in business.

 

[Yambor44]

Playing around with configurations on burner height. This one is about 3 3/4" from tip to pot bottom.

 

[Yambor44]

Ended up more like 4" after I tightened everything down. Whats the word?

 

[viking73]

Ichthy had it right. You're spraying heat all over the place. I have this same problem on my gas stove, takes forever to boil anything.

If you really want to Tim Taylor it, add a compressed air nozzle to the center of your ring and watch the flames go!

 

[willynilly]

WOW, that frame discoloration is crazy! If you could harness that heat and get it in the kettle, youd be :rockin:

 

[Lonnie Mac]

Ah! Now that is a fire my friend! Got your PM...

So, take everything I am about to say with a grain of carafa... Because I don't use NG, and everything on my system is low pressure.

Seems you are a bit too low on your burner height to me... On Brutus, my tips are exactly two inches below the pot. Even with the bottom of the upper frame... Seems yours could stand some moving up a bit, if anything, just to try and see how it works for you... Keeping in mind also, the last thing I am looking for is how fast I can reach a boil, but by moving it up, you will not require as much heat, and more concentrate the heat you do have. Your frame is receiving much more heat than mine does, but then again, I would say that my boil from 65 to 212 takes a good 45 minutes also...

I woud try a few different nipples and see which height is the more efficient use of the heat you have. It very well may be that it works much better closer to the pot, and at half throttle...

 

[Yambor44]

Makes sense. I was wondering and asked Tom the same thing about throttling back being more efficient. I did move one up 1.25" to 4". I may raise another up even closer and try the throttle back idea. Thanks for chiming in.

 

[willynilly]

Throttling back most gas burners makes them more eff. but that doesnt necessarily mean a faster boil.

What this means is that you will get more eff. transfer of heat, but you are also throttling back, so you are creating less heat as well.

100K BTU at 30% transfer is 33,000 BTUs
70K BTU at 40% transfer is 28,000 BTUs

Greater eff, but less heat transfer.

 

[Yambor44]

One on the left is 2.25" from tip to bottom of kettle, the one on the right is the 4" one above. I'll try the 2.25" one out today.

 

[tomroeder]

That thing is looking really good...I am glad you got your combustion problem handled. Once again, makes my stand look like something from a bad science fiction movie!

 

[Yambor44]

76 minutes to 200F in 8 gallons?

140F rise in 8 gallons equals 9380 BTUs

Meaning that 9380 BTUs are being transferred in 76 minutes

That is only 7400 BTU/HR

Something is amiss... this is not right

So if it took 50 minutes to hit 202* this time, whats the BTU's on that?

 

[Yambor44]

That thing is looking really good...I am glad you got your combustion problem handled. Once again, makes my stand look like something from a bad science fiction movie!

Thanks Tom. Won't be lookin too good if the whole thing turns brown from the heat though! Did you ever say what the height was on your burners?

 

[tomroeder]

The top of my tips are 2 3/4" from the bottom of my pots

 

[Yambor44]

So far at 2.25" and 2/3 throttle. Hard to tell in the daylight but I think the flames are licking up around the corners of the pot. Thats what the hair on the back of my hand told me anyway!

10 minutes 115*
15 minutes 132*
20 minutes 150*
25 minutes 165*

 

[Yambor44]

And the final tally -
10 minutes 115*
15 minutes 132*
20 minutes 150*
25 minutes 165*
30 minutes 182*
35 minutes 196*
40 minutes 206*
43 minutes 212* Boil

As long as my frame and boil kettle didn't suffer any harm, I think we found our height!

 

[willynilly]

And the final tally -
10 minutes 115*
15 minutes 132*
20 minutes 150*
25 minutes 165*
30 minutes 182*
35 minutes 196*
40 minutes 206*
43 minutes 212* Boil

As long as my frame and boil kettle didn't suffer any harm, I think we found our height!

In 8 gallons I presume?

80F rise in 28 minutes (132-212)
67 pounds of water

67 pounds x 80F rise is 5,360 BTUs needed
5,360 BTUs / 28 minutes is 191.4 BTU/MIN
This equals 11,485 BTU/HR

 

[Yambor44]

Wow. That sure doesn't seem right does it? I have a 70,000 BTU burner, is this normal?
Yes 8 gallons.

 

[willynilly]

Wow. That sure doesn't seem right does it? I have a 70,000 BTU burner, is this normal?
Yes 8 gallons.

That is not entirely normal, most burners run between 20-30% eff. at transferring heat.

The calculations are correct though.

To boil off 1.5 gallons/hr requires 12,100 BTUs
(970BTU/lb water vapor x 1.5 gallons x 8.34 pounds per gallon)

So at 2/3 open on that burner you can expect to boil off slightly less than 1.5 gallons/hr

 

[Yambor44]

So my burners should run 14-21,0000 to be considered in the normal range, correct?

 

[Yambor44]

That is not entirely normal, most burners run between 20-30% eff. at transferring heat.

The calculations are correct though.

To boil off 1.5 gallons/hr requires 12,100 BTUs
(970BTU/lb water vapor x 1.5 gallons x 8.34 pounds per gallon)

So at 2/3 open on that burner you can expect to boil off slightly less than 1.5 gallons/hr

That's wild! I ran my boil for 70 minutes just to check my boil off rate and I had just a smidge over 6.5 gallons left. Science!

 

[P-J]

Wow. That sure doesn't seem right does it? I have a 70,000 BTU burner, is this normal?
Yes 8 gallons.

Ha.!

Another reason I'm so much a believer in electric.

Ok.. Ok, Yambor44 - you can bash the hell out of me now. You have license.

What you said is really true. With a gas fired system, most of the heat is dispersed to atmosphere. It is extremely difficult to direct it to its intended target - the wort, water, 'stuff' you are trying to heat. You have the same result (more or less) with an external electric element. In that case you are counting on heat conductivity through the kettle. With an element immersed inside (water heater style) you are only dealing with heat loss through the kettle wall. (Not conductivity into - > the liquid - plus the losses into the air.)

(laying low in a crouched position & expecting to be kicked unmercifully)

Paul

 

[willynilly]

That's wild! I ran my boil for 70 minutes just to check my boil off rate and I had just a smidge over 6.5 gallons left. Science!

Yes... you cannot argue BTUs baby

Well, "normal" is considering LP burners that are typically somewhat shrouded... but yeah, they are 20% on the LOW end and up to about 35% on the HIGH end eff.

Like P-J said... a 3500W element is equal to what your burner is producing. 3.5 kW is 12,100 BTUs. This is the main draw for the electric builds, speed of heating.

 

[Yambor44]

Coming along! I will run the wires in some conduit after a brew or two. Anyone know how to convert the water lines on the Thermometer over to NPT fittings?

 

[hopfool]

Yam, I thought Henny Youngman said that (about the evils of reading).

Any who, new here but this caught my eye. Not a geek but just my gut on the thermodynamics involved. First, AJ et al seem right on about the air flow since there is an obvious and audible difference when the kettle is put in place. Is this the pot that you will likely be using there all of the time? You might want to consider that before you go cutting and drilling just in case the size or material changes.

If you look at commercial gas cooking stoves they all use some sort of very dense cast iron or thick steel burner grate to support the vessel over the burner and to allow adequate flame spread. The flame doesn't have to contend with the wind so what they use just makes it easier to slide big stock pots around while storing some of the flame's heat energy and imparting it through direct conduction.

Your tubular frame being in close proximity of blow back from the burner flame plus being in contact with the pot and the wind guard may actually be acting as a heat sink. In other words, if the pot was only in direct contact with a big chunk of solid iron that was also being heated by the flame then all or most of the heat absorbed by the grate would likely be conducted directly into the pot and consequently its contents. The effect of retarding the flame spread by choking the air flow would likely be that the flame is spreading laterally but not necessarily finding enough room to try and wrap around the base of your pot evenly. Meanwhile your tubing is wicking heat away from where you're trying to concentrate it.

You're basically trying to capture the exhaust heat of a jet engine with your pot. Without gettin' too tech'ed out maybe try observing your flame pattern after dark when you can see the full spectrum better. Then try different height spacers when you're able to observe just how they are affecting the flame spread before you go making any permanent adjustments.

It seems that there are limited possibilities, either inadequate oxygen for combustion, dissipation rather than concentration of the heat, or a combination of both.

I'm not certain exactly how it could be done but radiant heat can also be reflected very effectively using shiny metal, such as you see used under the resistance coils on an electric stove top. Maybe some way to incorporate that with the idea of the heat concentrating jacket that was mentioned, after you get the air flow straightened out.

I'm a newbie and usually just gopher when my friends brew, but we usually set up on a sunken patio in my back yard where we are screened from any wind by a 5' stone wall right behind us. Sometimes a wind break can actually worsen heat loss from wind by being positioned incorrectly relative to a lateral air flow. Was there any significant breeze blowing the day that you were doing this. If you were set up just inside the garage door and the prevailing breeze was blowing across the door opening it would create a low pressure just out side of the opening, thereby pulling your heat and oxygen out away from where you needed it. Maybe try some sort of floor standing screen that sits a foot or so to the windward side and use a shorter ring close to the burner? Just a thought. Interesting conundrum. Good luck.

I was also curious though about the reflectivity of the s/s and aluminum pots. The gas flame is just like the heat energy from the sun, so dark colors absorb it more readily and light colors reflect. Just wondering why a pot on a gas burner wouldn't heat more quickly if the bottom of the pot was coated with carbon. Another off the wall shot...if rapid heating is the ultimate, why not do the reverse of what your doing to cool for pitching yeast. Maybe a s/s immersion cooler placed in the pot while heating somehow and circulate H/W off of your water heater to help from the inside. Maybe an acoustical Sterling engine for a heat source coupled with Peltier effect heat exchangers. Just kiddin', I was just reading about them for a different project.

Isn't this one of those times when you're just supposed to relax and have a home brew?

 

[willynilly]

Bottom line, he is right in the ballpark with the eff. of the burner. 2/3 open and about 12K BTUs from a 70K BTU burner is about 20%, which is not uncommon.

When you see the flame, and see the rating of the burner, it seems as if it should heat much faster. This is just the nature of the beast... throwing heat across a space, hitting an object and measuring the % transfer. The bottom of that kettle can only transfer so much heat in a given time frame, the rest just blows right by it from the force of the flame/gas.

He is in the ball park, just the nature of the beast.