WPStrassburg
Well-Known Member
Can you get a 3/4" or 7/8" od rod/blanked off tube to go inside the 4 tubes inside the MK-I? That would minimize the wort volume inside the tubes and should create a higher velocity.
Can you get a 3/4" or 7/8" od rod/blanked off tube to go inside the 4 tubes inside the MK-I? That would minimize the wort volume inside the tubes and should create a higher velocity.
I've been lurking through this project and have to applaud the fab work!
Honestly I think your boil looks more vigorous with the copper coils because you're causing a more widespread state change from liquid to gas due to the increased surface area of the boiler (as in you can see it ).
The calandria focuses the heat on a much smaller volume of liquid.
It wouldn't surprise me if you're getting the same amount of heat transfer with the two techniques but you can only see it happening with the copper coils.
Based on your current results if you really want to cause the wort in the calandria test to move around you will need to increase the length of calandria to gain more temperature differential between the top and bottom (thus increasing fluid flow) or make the heat exchanger tubes smaller in diameter. (There's probably a trade-off in total amount of these smaller tubes )
My seat of the pants intuition tells me that your ratio of heat exchanger diameter to length is too high.
What's the typical length to width ratio of commercial caladrias and the boil vessel that contains them?
If I know the PSI that the propane is running at, and I know the diameter of the gas orifice. Can I tell just how much gas I am burning? I would like to know just how good or bad I am doing on the gas usage with my setup.
It should not be that hard to come up with a table for pressure vs. flow for a #56 drill orifice gas jet. Once I have the range I can check and see what size flow meter would be usefull to monitor gas flow.
I have taken a look at an orifice chart for high pressure and after a couple calculations I figured out the BTU output and LP flow rates for various pressures. It looks like the flowmeters sent are a bit too small so I will look into aquiring correct size units for testing.
5 PSI LP......53614 BTU's...21.45 CFH...10.12 LPM
10 PSI LP....75822 BTU's...30.33 CFH...14.31 LPM
15 PSI LP....92863 BTU's...37.15 CFH...17.53 LPM
20 PSI LP..107229 BTU's...42.89 CFH...20.24 LPM
25 PSI LP..119886 BTU's...47.95 CFH...22.63 LPM
Flow was based on 2500 BTU/CF LP gas
PSI/BTU's were derived from #56 sized orifice chart
I hope this helps with input heat calculations for boiler
The #56 orifice is the one sold with the 4" burners, with a pressure gauge in the gas line to the burner you can use the chart to see how much heat you are throwing at the boiler. 5 gallons of propane should be roughly 200 cubic feet of low pressure gas / 500K BTU's.
A comparison of 5 gallons propane/electricity/NG
5 Gallons propane = 500,000 BTU's / 146 KWH
5 Gallons propane ~5 Therms NG /478 Cu Ft.
146 KWH @ $.06/KWH = $8.76
146 KWH @ $.08/KWH = $11.68
146 KWH @ $.10/KWH = $14.60
5 Gallons propane @$2.50/gallon = $12.50
5 Therms NG @ $.85 = $4.25
Yes, but typically with electric, the energy transfer is much more efficient than with propane or NG. My electric elements transfer most of those BTUs to the liquid they are heating, which I can't say about my propane.
A comparison of 5 gallons propane/electricity/NG
5 Gallons propane = 500,000 BTU's / 146 KWH
5 Gallons propane ~5 Therms NG /478 Cu Ft.
146 KWH @ $.06/KWH = $8.76
146 KWH @ $.08/KWH = $11.68
146 KWH @ $.10/KWH = $14.60
5 Gallons propane @$2.50/gallon = $12.50
5 Therms NG @ $.85 = $4.25
well, 60% is just a guess. If you are getting perfect heat transfer, the hit exhaust gas from your boiler would be at the steam temp. You get a finite amount of heat available to transfer based on your mass flow rates of your working fluid, your propane, and any air that is also convected through your burner. Really I shouldn't even have said 60% unless were talking about second law efficiencies in which case the Btu's that are available to heat you water are also a variable based on your steam temps.
I think the best way to actually measure how "efficient" your setup is would be to measure the mass of gas used at a constant flow rate. That way you wouldn't need gas orifice sizes. If you are trying to calculate flow rates, most likely you are going to have other differences because of pipe constrictions as well. A flow meter would do the job, but measuring the mass of propane would seem to be much more accurate.
How many watts are you using?
How big of batches do you do?
How fast do you hit a boil?
After looking at the test run results and doing some calculations it appears that the heat transfered with the steam system is nearly 10 times the expected output of the 4 KW electric element. While this heating system approach is not for everyone it appears to be a viable way for a DIY'er to build a system with a single heat source that will give results that are beyond the reach of the current electric systems. With a bit of engineering and design work this could be integrated into a brew system to handle strike water heating, step mashing, sparge water heating, and finally boiling. Scalability of this boiler and calandria design would make it a viable heating system for the 55 gallon drum systems that need more heat than direct fire burners can easily provide. With the ability to heat water to strike at 2.5+ GPM with current design, and deliver 156.9K BTU's/hr to the water for boiling it almost is overkill on 1/2 barrel systems.
This is GreenMonti's wort heating creation, scalability of both boiler and calandria style wort heater to fit larger applications will not be a big factor if he decides to head that direction. It looks like I will be switching from SS coils to copper coils in the automated system to improve on the dismal 25% heat transfer with SS tube boiler after last live testing run data was calculated.
Not sure why you would want to make 30-50 gallons of the same beer at a time, I would rather make 6-10 different beers with same amount of ingredients and less effort. With a brother inlaw that makes SS tanks, scaling up tankage and plumbing is not a challenge, just have not seen a need to build larger, would rather make it more like a Rube Goldberg automated machine.
So, 48oz/min is 2.66 gallons or 3.13lbs. Total heat per pound of water/steam at 5 psi is 1156.3 BTUs. That comes too 3619.21 BTUs/min.
12 gallons needs 113,456.5 BTUs from a cold start of 50* to boil.
At 3lbs/min it would take 31.34 mins to reach a boil in a perfect world.
I reach a light boil in 38mins and a hard boil in 42mins with the copper coils.
I reach a light boil in 35mins and a hard boil in 40mins with the MK-I.
.............
Someone correct me if I'm wrong here, but I think your numbers are off.
Shouldn't it take 16135.2 BTUs from a start of 50 degrees?
(12 gal * 8.3 lb/gal * 162 degrees) = 16135.2 BTU.
Or is my formula wrong?
Your formula is correct for the heating of water to 212 degrees, it is the additional 970 Btu's/Lb to reach a boil that you overlooked. Most times the number used for water is 8.45 Lbs/Gallon for cold water, 8.3 is close enough for this application. Heating the water to 212 usually takes 15% of the total energy needed, the other 85% is needed to make it boil.
I understand about heat losses, efficiency, etc, but help me out with the rest of the BTUs per lb.
Isn't the remaining 970 BTU/lb only if you were boiling all that water off into steam? Or are you saying that going from a 212 degree standing water to a 212 degree rolling boil takes the additional 970 BTU/lb?
Thanks.
Enter your email address to join: