Antique Stove Efficiency

DePippo79 wrote:Just got home. Will be back once I get settled, but need to comment. Loaded my Oak 40 0400 this morning. Stove still cruising at 400 deg. House 72 deg. Stove heating basement, two floors, and breezeway. Probably another one that thinks just because something is old it's not good anymore. I'll take my 100+ year old stove and 130+ old house over anything new anyday. I do just fine with my MPD also. It's all about knowing your set up. They didn't have Barometric Dampers 100 years ago. My wife can even run the stove. Matt

Matt, just curious what your set-up is? Is the stove in the basement? And if so, how are you circulating the heat in the house?

TIA,
Rick

Larry, power plants have to achieve that combustion efficiency while dealing with a whole host of other concerns such as emissions, equipment and material life, slagging and on and on ....

Are most coal appliances beating 80% operational combustion efficiency ? probably very few real world. With excellent design, tuning, coal, and care can some break 80 or even 90 combustion efficiency? Sure.

You need to make a better argument than "100 year old technology can't do this (or that)" simply because it's old technology.

Berlin, where is the independent testing that verifies the 90% efficiency of the 100 year old technology? In the NG, propane, and oil heating world it takes condensing technology to break above about 85% to 87% efficiency (which in and of itself takes some pretty good technology, and was only recently achieved). Why should coal be different?

lsayre wrote:Berlin, where is the independent testing that versifies the 90% efficiency of the 100 year old technology?

I put up the results of a study that the Detroit Stove Company did on three types of base burners. Did you not see that? The best design was found to AVERAGE at 85%.
There was information from another article that I put up that stated that the AVERAGE coal stove was around 75% this was from 1912.

wsherrick wrote:

lsayre wrote:Berlin, where is the independent testing that versifies the 90% efficiency of the 100 year old technology?

I put up the results of a study that the Detroit Stove Company did on three types of base burners. Did you not see that? The best design was found to AVERAGE at 85%.
There was information from another article that I put up that stated that the AVERAGE coal stove was around 75% this was from 1912.

I'd certainly like to see some independent and modern verification. Of course, I'd like to see the old information also.

The circa 1949 research done on the AA-130 boiler concluded that when it was firing it eventually reached a maximum of about 81.5% efficiency, and that was with fan assist. Irregular draft from chimneys seems hard pressed to do as good, let alone better.

As late as the 1970's a NG, propane, or oil fired appliance was doing pretty good if it had an output BTU efficiency of 70%. Perhaps I'm looking at this entire argument form the perspective of output efficiency, and not from the perspective of combustion efficiency? Doesn't a lot of heat go up the stack unless you condense the flue gas?

When I say 60% to 65%, I mean output efficiency.

lsayre wrote:do you still think a turn of the century residential hand fired coal stove burning odd sized rocks of anthracite can sustain 90% efficiency in real world use?

Absolutely. We are using a far easier fuel to burn efficiently and not pushing things to a maximum trying to super heat steam. Push your stoker to maximum output and it will suffer if it can even reach that figure. It's a lot easier to heat a stove to 5 or 6 hundred degrees than to design something to melt iron and do it with the same efficiency. At those temperatures and firing rates whole new classes of materials and design are needed to stand up to the stress.

As an example a far better fire pot for coal could be made out of insulating fire brick but it would not stand up to the abrasion of coal so we have to use a lesser material in terms of combustion efficiency. What could be worse than cast iron, but we use it because it resists the heat.

By using a great deal of excess air very high combustion efficiency can be easily obtained in terms of complete burning, but the trick is then to make use of that excessive stack temperature with massive heat exchange. A rocket stove is a good example. Almost always the limitation is space and cost and the best designs make best use of both as they did in some of the stoves of the last century.

Is coal easier to burn than natural gas, propane, or heating oil?

Are we talking about both radiant efficiency and combustion efficiency or just combustion efficiency? An open fire place has almost complete combustion efficiency, but; you don't get much heat to warm the room.
These base burners are designed to maximize both efficiencies which are often at odds with each other as has been discussed many times.

lsayre wrote:As late as the 1970's a NG, propane, or oil fired appliance was doing pretty good if it had an output BTU efficiency of 70%. Perhaps I'm looking at this entire argument form the perspective of output efficiency, and everyone else is looking at some other efficiency?

As early as the 1940s there were oil burners that could burn with 14 percent CO2 which few modern burners if any can match. 15 percent is considered perfect. Most burners of that time were smudge pots with CO2 around 8. How the heat from the fire is handled is something else and two different burners in the same furnace or boiler can have dramatically different overall efficiency.

lsayre wrote:Is coal easier to burn than natural gas, propane, or heating oil?

They all need an appliance designed for each particular fuel.

franco b wrote:

lsayre wrote:As late as the 1970's a NG, propane, or oil fired appliance was doing pretty good if it had an output BTU efficiency of 70%. Perhaps I'm looking at this entire argument form the perspective of output efficiency, and everyone else is looking at some other efficiency?

As early as the 1940s there were oil burners that could burn with 14 percent CO2 which few modern burners if any can match. 15 percent is considered perfect. Most burners of that time were smudge pots with CO2 around 8. How the heat from the fire is handled is something else and two different burners in the same furnace or boiler can have dramatically different overall efficiency.

What is the BTU transfer efficiency of these stoves into the home? And where are these in the real world? The reality is that residential oil heating appliances from this era have output efficiencies as low as 50% in the real world, to perhaps 60-65% at best, with much of their potential heat going out the stack. Perhaps you are talking from a lab environment perspective. Enter the real world where people heat their homes with what is available and show us examples of the common people heating their homes in the late 40's with oil burning appliances so efficient that they can't be improved upon today.

Even today if it doesn't condense the flue gases to scavenge the heat that will be lost to the chimney, I can't see how it is going to be better than about 85% to perhaps 87% maximum real world efficient at heat transfer, regardless of the fuel source.

Larry, How do you like your antique AHS boiler...1946 design concept?

McGiever wrote:Larry, How do you like your antique AHS boiler...1946 design concept?

I like it just fine, including the roughly 63% overall BTU transfer efficiency that it is giving me (vs. our resistance boiler), and the roughly 81.5% maximum efficiency that it provides when firing. I'm glad that Penn State University and Axeman Anderson joined forces to come up with the design.

lsayre wrote:

McGiever wrote:Larry, How do you like your antique AHS boiler...1946 design concept?

I like it just fine, including the roughly 63% overall BTU transfer efficiency that it is giving me (vs. our resistance boiler), and the roughly 81.5% maximum efficiency that it provides when firing. I'm glad that Penn State University and Axeman Anderson joined forces to come up with the design.

Here is a 1940's boiler design that achieved 90 percent in practice. (Pennsylvania T-1 and Q-2 Locomotives.) This is a fire tube design of course. These locomotives had the most efficient boilers ever designed for railroad use. What hasn't been brought up here is efficiency at different rates of combustion, locomotives, power plants and other such commercial applications have to achieve efficiencies at high rates of combustion. A residential appliance doesn't have to meet those extreme demands, so I expect that a boiler rate versus just a fire radiating heat are two different animals all together.

(edit) Sorry Richard, I didn't realize the picture was copy written.