BTUs / % Year End Savings

Gene_7

Can anyone calculate for me what would be the % of fuel savings at the end of a year, if we are using same boiler (X), in the same house and the differences below, knowing that the extra BTUs would satisy the boiler quicker, at the same fuel rate? 

Burner A - 88100 BTUs per hour using an X boiler in a 1600 sq ft home with a .75 gals per hour fuel rate

Burner B - 116000 BTUs per hour using an X boiler in a 1600 sq ft home with a .75 gals per hour fuel rate

Thanks for any help!

Mike Kusiak_2

???

Don't quite understand your question. If both burners are burning .75 gal/min, then why would you expect a different BTU input? With #2 oil, .75 gal/min will give a heat input of 105,000 BTU/hr regardless of the burner.



In general, with the same boiler a slightly lower firing rate within reason will give you better efficiency.

Gene_7

Burner B

Burner B is a new prototype burner that has been tested at an approved testing facility and the flame is 440 degrees hotter than Burner A, due to a more complete combustion of the #2 oil. We are looking for the mathematical formula to figure the % difference.

bob eck

BTUs / % Year End Savings

OK what brand is the new burner that will burn 400*F hotter?

Steamhead

I'd like to know too

we're always looking for something better. 

Gordy

Then all you need

 Is what temp burner A is operating at, And burner B operating temps.



If both burners are getting the same fuel.Tthen those two temps would be able to give you what percent burner B is more efficient.



An arbitrary example would be if A is 1000*, and B is 1440* then you would be getting 44% more btus from burner B at the same fuel delivery rate.....Neat trick. Then that should mean you could reduce the delivery rate by 44% to .33 gph to get the same btus as .75 gph with burner A... No. Then that would mean year end savings of 44% in fuel consumption.

Mike Kusiak_2

Efficiency?

If your prototype burner is burning the fuel more completely, this will

translate into a higher combustion efficiency test reading. Perfect

stoichiometric combustion at .75 gal/hr will result in a release of 105,000 BTU/hr of

heat energy. It cannot be any higher than this figure because that is

the total amount of energy contained in the fuel. A real burner will

always have an output less than the ideal due to incomplete combustion. Any excess air will reduce the recoverable energy to less than what the fuel contains.



How does the combustion efficiency of the prototype compare to a standard burner in the same boiler? Combustion measurements don't lie. If the new burner is indeed more efficient at burning the fuel, the combustion efficiency will be higher, but never more than stoichiometric efficiency. You cannot extract more energy from the fuel than it contains.

Jean-David Beyer

How much can the boiler stand?

If a boiler, to use your numbers, is designed to run with 1000 degree fire and you put in a more efficient burner that burns at 1440, can the boiler be assured of taking the increased temperature? At some point, does not the boiler at the fire|water interface get too hot and melt or burn? Or is the margin of safety much higher than that? If you put in more heat than the boiler can sink into the water, would not a lot of the excess just go up the chimney?

Gordy

JDB

 I picked those numbers out of thin air. But you are right in your thoughts. Simply designing a burner that burns hotter with the same amount of fuel input would create problems with the boiler HX a more robust hx design needed to take the hotter temps. Simply backing off on the fuel supply rate would still not lower the temps in the HX.

Brad White

BTUs and Temperature

It is still a first law equation.   Sort of like ten pounds of water held at 100 degrees above ambient and twenty pounds of water held at 50 degrees above ambient. Both have the same BTU content but have entirely different temperatures.



I fully agree with Mike Kusiak on this.



The only way I can think of to increase the temperature of combustion in a given fuel is to use pure oxygen, sparing the generation of nitrogen compounds (78 percent of nothing!) But to generate the oxygen separate from air or water, takes more energy than you would save. Unless you are NASA, then you get us all to chip in and the numbers do not seem so bad



A given amount of any fuel with X amount of air will burn at a given temperature. Add fuel and less air, it will get hotter until such time as the combustion is affected (when air -oxygen of course- drops below critical levels). Add more air and the flame temperature cools.



The other end of the process, transferring the heat to a medium, will cool  the combustion gasses to their dew point and your materials have to handle that.



Getting back to the question- efficiency, how that is affected. I could argue that a hotter process is not necessarily more efficient (more nitrogen compounds are produced as byproducts) and that a chronological combustion test would be needed to track overall efficiency. Rather, the coolest process which fully uses the fuel supplied with the most fewest byproducts (CO2 and H20) would get the efficiency nod.



If I am all wet, someone let me know?

Gordy

Brad

 Your all wet......With knowledge that is. Me I'm all wet with the thirst for it. I thoroughly enjoy your postings.



Gordy

Gene_7

Thank you

First off, I want to thank everyone for your input so far.

Burner A is your typical burner which burns at about 1800 degrees. It runs about 11.5% to 12% CO2 and is rated around 78% to 82% Efficiency.

Burner B burns burns at a temperature of around 2200 degrees. It runs between 13.5% to 14.5% CO2 and is rated around  84% to 86% Efficiency.

We have talked to the boiler manufacturer and the boiler can withstand temps over 3000 degrees, as long as the flame is not hitting the back wall (which in our case it is not). 

We turn the fuel down in the Burner B to match the Burner A to produce the same amount of heat  in the burner and to handle the same heat load as Burner A . Although the flame is hotter, it also shorter. If Burner A flame is 3" off the back wall and is X degrees and Burner B

is 5" off the back wall and is X degrees, also, then you can still

achieve the same heat in the combustion chamber and use less fuel.

We have set up some prototypes, in this fashion, in several homes and all are experiencing fuel saving of 20 to 40%. We are looking for a mathematical equation to explain these results.

We are hoping to go into production with this burner, later this year, and we will post on the board when we do.

Brad White

Hotter and Shorter

No, not Snooki!



The flame.

I think what you are describing illustrates the point I was trying to make.



The concentration of a flame or "smaller combustion" can be hotter.  However,  given the lower throughput of fuel and air (the mass of it all), the gasses will cool to a greater degree given higher retention time within the heat exchanger. This is due to a greater drop in flue gas temperature due to higher transfer to the heating medium (water).



(In English: The small flame enters on Sunday and makes it out by Wednesday afternoon, cold and tired.)



As for the formula, heck I will have to dig out the old books, but it is in Thermodynamics II.



Not tonight dear. I have a headache.

Robert O'Brien

Damn physical laws!

Always getting in the way of great ideas!

Steamhead

Those of us who've been around for a while

remember when flame-retention burners came out- in the 1970s. The Sunray Golden Cup, Wayne FlameLock, Carlin Flame Funnel and others could produce clean, smoke-free combustion with less excess air than older burners could- when set up properly, which was problematical back then and still is. But they quickly became the standard because of their efficiency.



One of the things we ran into with flame-retention was higher flame temperatures, which let us drop the actual firing rate while producing the same amount of heat. This was part of their efficiency gain.



Is this new burner the next "killer app" like flame-retention was? Maybe, maybe not. But I think it deserves a look.