Is it possible to test a boiler efficiency?

ChrisJ

captainco said:

@ChrisJ
Let's try this. When you burn gas, your combustion efficiency is 99.99% if the CO is less than 100 ppm. 90% of that is sensible heat and 10% is latent heat. In the real combustion equation latent heat at 0% O2 is 18% of the total btus. At 6% O2 latent heat is about 14%. I had an engineer from Bacharach show me and walk me through the formula. I might as well tried readings hieroglyphics inside a pyramid??? Anyway, that would mean the maximum amount of available sensible heat of a non-condensing appliance is 86%. Every percent of O2 in the flue gas lowers that 1% more. Every 30 degrees the gross flue temperature is above ambient or combustion air temperature is another percent. These numbers are programmed in to every combustion analyzer chart there is.

It is not the O2 that steals the heat, it is the Nitrogen.

86% - 6% = 80% available heat
450 degree Flue T - 70 degrees Room T = 380 degrees

380 degrees divided by 30 = 12.67% loss
80% minus 12.67% = 67.33% efficiency.or heat transferred.
Therefore a 100,000 btu input boiler has an actual output of 67,333btus.

That 80,000 btus output rating has never been measured by any manufacturer. It is all assumed based on combustion analysis calculations that have proven to me and most of my students to be inaccurate.

I watched two one hour videos from a major industrial boiler company a few months ago (still learning after 39 years), by an engineer that has been with them for 40 years. I think both were from 2012. One was on combustion efficiency and heat transfer and the other was on NOX and re-circulatiing flue gases to lower it.
The efficiency one started out on the mark for 30 minutes and then it went to pot. The second one was one of the most evasive videos I have ever seen. I know why people are still confused.

There is a reason it takes me 3 days to teach this stuff in class.

Interesting.

So if, in theory, we had a house with a 100K input hot water boiler with cast iron radiation, and that boiler was perfect, as in it ran non stop on the coldest days, but maintained set point, or maybe even a degree under. And our radiation is more than big enough to handle the load at low temperatures, say 130-140F.

If we switch that over to a modcon, would we want to intentionally go smaller? As in, 27,000 btu/h smaller for the same results? Maybe something around 80K input?

captainco

Based on their actual factory settings the 80,000 btu Mod-Con has the same higher btu output than a 100,000 CI boiler assuming they are operating at the same water temperature.

ChrisJ

I meant output not input, but I think you knew that.

captainco

Then output is output but know one really knows what the real output is. We guess at input most the time because we don't the exact btus in the fuel.
If it takes 100,000 btus to satisfy a system the efficiency of the boiler doesn't change that.

ChrisJ

captainco said:

Then output is output but know one really knows what the real output is. We guess at input most the time because we don't the exact btus in the fuel.
If it takes 100,000 btus to satisfy a system the efficiency of the boiler doesn't change that.

I should've been more specific, the DOE output.
Whenever I think "output" I assume DOE not IBR because DOE is the so called gross output, without any deductions for piping losses etc.


Sorry.

j a_2

ChrisJ said:

> @Gordy said:

> If your analysis is accurate and a CI boiler delivers 64% efficiency we should have many three section oil fired boilers (65k net) unable to heat the buildings on the design day (65k x .64= 42 KBTU to the building). The boiler would run at a 100% duty cycle. But, no oil fired boiler EVER runs anywhere near 100%. 60% on the design day would be a miracle. So, obviously, the efficiency is greater than 64%, or we would have no such thing as three section oil fired boilers that can perform on anything larger than a cottage.

>



It also suggests my boiler can output only 83750 and yet it can fill 94000 worth of radiation with steam not counting piping losses. WM rated it 104000 out from 125000 in but apparently that's a huge lie

HVACNUT

> @captainco said:
> @ChrisJ
> Let's try this. When you burn gas, your combustion efficiency is 99.99% if the CO is less than 100 ppm. 90% of that is sensible heat and 10% is latent heat. In the real combustion equation latent heat at 0% O2 is 18% of the total btus. At 6% O2 latent heat is about 14%. I had an engineer from Bacharach show me and walk me through the formula. I might as well tried readings hieroglyphics inside a pyramid??? Anyway, that would mean the maximum amount of available sensible heat of a non-condensing appliance is 86%. Every percent of O2 in the flue gas lowers that 1% more. Every 30 degrees the gross flue temperature is above ambient or combustion air temperature is another percent. These numbers are programmed in to every combustion analyzer chart there is.
>
>
>> I'll be the first to admit, I don't know much about all these gas equations, but if all "These numbers are programmed in to every combustion analyzer there is", then isn't everything you wrote above take place, aside from flue gas temperature, Pre combustion? The formula is there, but it has no bearing on actual combustion because its already been accounted for.

In a way I can explain my point. If I have a can of caffeine free Coke, and a test was performed to see how much caffeine was in that can, they wouldn't take into account how much caffeine was removed during the decaffeination process, only what is actually in the can. THAT'S the starting point of the test, and nothing before.
It seems like your taking a starting point of 0, using calculations to bring that starting point into the negative, and using that negative as the "new" starting point.
Then again, maybe I just need to smack myself in the head with a 2x4.

captainco

DOE is based on a theory and fictitious combustion efficiency calculation, not an actual btu output measurement. If you read the actual ANSI standard for testing equipment, you would see this.

Relating the de-caffinated senario, what if you were told they don't actually measure the caffeine, they just estimate and assume it? Would you still believe them?

DOE does not measure btus they assume them! Actually they don't measure anything, they just accept what they are given. A combustion analyzer cannot measure btus, it assumes a certain percentage of leftovers. How can you determine how much heat is in the water or air by only measuring flue gas?

Do you think a piece of equipment heats a building because it is firing correctly or because the heat loss calculations might have been a little loose? I have measured much equipment operating at less than 60% of its rating and still was doing the job. It just cost more fuel.

When people talk about combustion they all mention Fuel-Air-Ignition. Rarely do you see the 4th element - Chain Reaction.

When people discuss Heat Transfer it is always Temperature-Mass-Specifice Heat Capacity. Residence Time and Line of Sight are always ignored.

Speaking of Heat transfer. If you close the air shutter on an oil burner what are the reactions as far as combustion and heat transfer are concerned? Which of the things above are affected.

When you adjust the fuel input, which of the above are affected?

ChrisJ

@captainco
The problem is you're saying manufacturers, all of them, are selling equipment as 80%+ efficient when it's really 50-60% and no one has caught that.

Wouldn't this result in a huge lawsuit?

According to most of the steam guys on this forum, wouldn't it also result in systems that are impossible to balance?

I have 94,000 btu/h worth of radiation connected to a steam boiler which you're telling me can only produce 84,000 btu/h worth of output, at best. And that's not including piping losses and yet the house heats evenly, nothing is ever starved of steam. Could the rating on my radiators be off by 10,000 btu/h? I suppose, why not.

The other problem is I know without a doubt a 6 horsepower shop vac cannot produce even close to what they are selling it as. As I said before I've also personally measured home theater receiver power output and that too, was 8 times what they sold it as.

So on one side, I think what you're saying is nuts and on the other side, I've personally seen exactly what you're saying in other areas.

I need a nap.

ChrisJ

Sigh.

captainco

@ChrisJ If what you say were true, how would modulating steam boilers ever accomplish anything or anything thing else that modulates? Unfortunately everyone assumes that what you see is what you get. Those that measure or read, as you did at least on your electronics, reality is another world.

A convector is rated for so many btus per ft. at a certain temperature. Less temperature less btus per foot. Steam would be no different. Less btus, less per radiator I would assume.

The industry as a whole has disavowed and denied most of what I have taught for the last 30 years. However, not one person has disproven it. They just keep hoping I will go away.

HVACNUT

> @captainco said:
>
>However, not one person has disproven it. They just keep hoping I will go away.
>
>
>> Well, now that you brought it up...
>
>
>> I don't think anyone has to disprove it. You have to prove it, and I don't think you've done that. Like @ChrisJ said, where's the backlash? Are the Nat gas and oil guys really buds behind closed doors, and they're all in cahoots with the equipment manufacturers? It's all a diabolical conspiracy?

Copernicus PROVED that the earth revolves around the sun using astrological measuring points.

Columbus (supposedly, I think it was the Knights Templar, lol) PROVED the earth is a sphere by showing the gradual disolve of a ships sail on the horizon to Queen Izzy.

Again, I don't fully understand all you've speculated here, but a lot of guys and gals do, as well as people in the fields of chemical reaction and all that. I feel that your field contemporaries have crunched the numbers and don't come anywhere near your conclusions, and that's why they want you to go away.

I'm in no way trying to be disrespectful (too late?). You're obviously a very bright guy. And no need to be specific, you can generalize.

What kind of establishment do you teach in? Is it an accredited institution? Is your curriculum approved by a Dean or superiors? Do other faculty members in your field concur with your findings?
Do you eat by yourself in the cafeteria? (Just kidding)

All HVAC equipment manufacturers, as well as others, i.e., automobiles, pad their efficiency results. Nothing beats a lab bench test under controlled conditions. But the industry as a whole has progressed leaps and bounds, and you or your data can't disprove that.

The great George Carlin was quoted here saying "Question everything! "

He also said, (paraphrasing) "There are no alternative facts. There's only fact facts. You can't have two sets of facts. When you were in school, and the sign in the cafeteria said 'Today, Meatball Heroes'. You knew you were getting f@$#ing meatball heroes for lunch. It was a FACT!"

captainco

I prove to my students and they prove to themselves everyday that this is correct information.
National Comfort Institute is one of the most recognized, independent training organizations in the country. We have a website. If you haven't heard of us it means you have never read a Trade Magazine.
People with all their faculties agree with what we teach. I have had multiple Deans in my class that also agree. We definitely have credit!!

Not saying I know your age but I might have been combustion testing while you were still potty training or in diapers. Of course it might not be too long before I am back in diapers but it Depends on two things- #1 and #2.

Have you read the ANSI Standard for testing equipment? Have you read the CGA Standards for testing and certifying equipment? I have. Have you ever read the first page of the National Fuel Gas Code that states nothing in this document has been tested or verified for accuracy, correctness or sound judgement. Scary!

Fuel and Air are the two major parts of combustion. Which one of those does our industry say is not important to control or almost ignores totally? The exception might be oil but then does anyone know how that works?

Maybe, just maybe this winter, not that you shouldn't be testing things now, everyone will pay more attention to combustion numbers in the field.
The only single arguable point in this whole discussion is that the efficiency of combustion analyzers is bogus and that is how equipment it rated. Everything else is factual.
Let me know what part of the country you are in and the next time I am in the area teaching I will come and prove it to you. Proof is in the field, not on paper.

I know that smarter people than both you and me also once doubted but that will always be one of my favorite challenges.

D107

@captain co. A very illuminating discussion. I was speaking with an NCI rep on the phone, and if I understood him correctly, he said that many specified flex chimney liners a) are undersized; and b) are not preferable to the original terra cotta liners. When I asked if the boiler companies do not test properly to ascertain the correct liner size, he said things similar to what you have been saying about the lack of accurate testing results. I had always assumed that a good 316L flex smooth wall liner was the 'state of the art.'

ChrisJ

captainco said:

I prove to my students and they prove to themselves everyday that this is correct information.
National Comfort Institute is one of the most recognized, independent training organizations in the country. We have a website. If you haven't heard of us it means you have never read a Trade Magazine.
People with all their faculties agree with what we teach. I have had multiple Deans in my class that also agree. We definitely have credit!!

Not saying I know your age but I might have been combustion testing while you were still potty training or in diapers. Of course it might not be too long before I am back in diapers but it Depends on two things- #1 and #2.

Have you read the ANSI Standard for testing equipment? Have you read the CGA Standards for testing and certifying equipment? I have. Have you ever read the first page of the National Fuel Gas Code that states nothing in this document has been tested or verified for accuracy, correctness or sound judgement. Scary!

Fuel and Air are the two major parts of combustion. Which one of those does our industry say is not important to control or almost ignores totally? The exception might be oil but then does anyone know how that works?

Maybe, just maybe this winter, not that you shouldn't be testing things now, everyone will pay more attention to combustion numbers in the field.
The only single arguable point in this whole discussion is that the efficiency of combustion analyzers is bogus and that is how equipment it rated. Everything else is factual.
Let me know what part of the country you are in and the next time I am in the area teaching I will come and prove it to you. Proof is in the field, not on paper.

I know that smarter people than both you and me also once doubted but that will always be one of my favorite challenges.

Years ago when we were talking a lot via email, and on the phone a few times I tried to find out exactly how boilers were tested.

I seem to recall giving up trying to find the information as it either was buried in other documents, or I couldn't find it. Either way, I came up empty handed and decided the best way was to try and measure the condensate coming back from my radiators over a fixed amount of time. And after that, I became lazy and did nothing.

captainco

A little different subject that drives me nuts.
I think I understand flow dynamics. When we teach duct design we are taught the larger and smoother the pipe the better the flow. I sure that works in hydronics also.
How all of a sudden did someone come up with the concept that smaller diameter flex pipe promotes better flow? Also when did flues become heat exchanger instead of chases or containers?

Whether you use a liner or not it is so simple to determine if a liner or flue is too small or restrictive using a simple draft test.

If one reads the original GAMA venting table design parameters they state that they are designed for areas without wind, buildings that are not tight or loose, only one exhausting appliance in the building and buildings without any other conditions. Someone's really covering their butt on that one!

captainco

@ChrisJ For $900 you can buy the ANSI standard and $90 for each revision. Then plan on being bored and confused for hours.

ChrisJ

captainco said:

A little different subject that drives me nuts.
I think I understand flow dynamics. When we teach duct design we are taught the larger and smoother the pipe the better the flow. I sure that works in hydronics also.
How all of a sudden did someone come up with the concept that smaller diameter flex pipe promotes better flow? Also when did flues become heat exchanger instead of chases or containers?

Whether you use a liner or not it is so simple to determine if a liner or flue is too small or restrictive using a simple draft test.

If one reads the original GAMA venting table design parameters they state that they are designed for areas without wind, buildings that are not tight or loose, only one exhausting appliance in the building and buildings without any other conditions. Someone's really covering their butt on that one!

My understanding is smoother is obviously superior.
However, the smaller the flue, the easier it is to get hot. Also, installing a liner makes it easier to heat the flue, and a hot flue works better than a cold flue.

A properly sized insulated smooth rigid liner should be the best of them all.


Interestingly in duct work, a smooth large duct flows the best. But apparently, it also transmits sound the best. So it appears anything that flows good attenuates poorly and anything that attenuates good will not flow good. Everything is a compromise, even with unlimited space. I'm not positive this is correct, but it sure seems to be.

ChrisJ

captainco said:

@ChrisJ For $900 you can buy the ANSI standard and $90 for each revision. Then plan on being bored and confused for hours.

I don't think you'll find it near my John any time soon at that price.

Jamie Hall

Just for laughs... I've been lurking here for quite some time, and I have to admit that it's interesting... but a good bit of it reminds of the "debates" (polite word) we used to have, years ago, regarding automobile engines -- you know, my Flashfire Eight has more horsepower than your ThunderJet. The best way to answer the question was to line up side by side, and see who could make it to the other end of a quarter mile first... a lot cheaper than finding a chassis dynamometer! And much more informative than the literature from the various companies (Same thing is true today of the EPA mileage ratings).

Point is, in the heating game there are just too darn many variables, and the best we can hope for is to tune the burners for the cleanest reliable burn, and tune the rest of the system to make the best use of the heat from the flame.

@NY_Rob -- I didn't realise you were a chopper pilot. Always wanted to try that, but settled for fixed wing instead...

captainco

@ChrisJ Do you have to heat ductwork to get better airflow? Do you have to heat copper and cast iron pipes to get hot water to flow?
Does the insulation on an electric wire have to get hot to flow electricity better?
Flues are much warmer in the summer than in the winter but you will never find higher draft in the summer.
There is a boiler and a water heater vented into the same flue. The boiler has an 8" flue and the water heater has a 4" flue. The main flue is 9". In the summer, when the boiler is idle, does the water heater heat the flue by itself or does it not heat it at all. Why is the flue not too big for the water heater when the boiler is idle but as soon as the boiler is replaced the flue gets too big. Venting is cold air displacing hot air. The hotter we keep the flue gases the better they vent. If they give off their heat to the flue they are less likely to vent. The less contact the flue gases make with the flue the less heat they give off and the easier they escape.

Another question I ask my students is" what vent material cools flue gases the most and can cause condensation - B-vent!
#2 is liners. Measuring the flue temperature exiting the equipment and then measuring it at the cap has verified this.

ChrisJ

captainco said:

@ChrisJ Do you have to heat ductwork to get better airflow? Do you have to heat copper and cast iron pipes to get hot water to flow?
Does the insulation on an electric wire have to get hot to flow electricity better?
Flues are much warmer in the summer than in the winter but you will never find higher draft in the summer.
There is a boiler and a water heater vented into the same flue. The boiler has an 8" flue and the water heater has a 4" flue. The main flue is 9". In the summer, when the boiler is idle, does the water heater heat the flue by itself or does it not heat it at all. Why is the flue not too big for the water heater when the boiler is idle but as soon as the boiler is replaced the flue gets too big. Venting is cold air displacing hot air. The hotter we keep the flue gases the better they vent. If they give off their heat to the flue they are less likely to vent. The less contact the flue gases make with the flue the less heat they give off and the easier they escape.

Another question I ask my students is" what vent material cools flue gases the most and can cause condensation - B-vent!
#2 is liners. Measuring the flue temperature exiting the equipment and then measuring it at the cap has verified this.

Comparing current flow through a wire to a flue makes no sense. I would avoid using that.

Your ductwork example also likely assumes an inducer (blower) is used, so that too doesn't apply. Though perhaps a gravity hot air furnace may benefit from warm ducts........


However.
A smaller flue is likely to heat up faster and therefore will cool combustion gasses less.

An insulated liner, even more so.

A B vent has a thin aluminum liner with an air gap between it and the exterior which also absorbs less heat than say a masonry chimney. I'd bet a whole lot less heat.


I cannot say why a water heater can vent into a 9" flue all summer long, as long as there's a boiler attached to it that is only used in the winter. That obviously doesn't make sense, but often, codes don't make sense. No one is expected to think anymore and codes must cover every scenario possible.

That said, I'm betting that water heater will vent into a properly sized flue much better in the summer than it will into the 9".

captainco

@ChrisJ Okay forget the wire.
Which flue has the highest draft assuming the same appliance is connected.
A 50' tall flue or a 15' tall flue? Which flue would be the hardest to heat if ever? What about a 100' tall flue. Yes I been been on jobs, mostly hospitals, with 100' tall flues.

Also, aluminum absorbs and transfers heat much faster than clay.
One of my students called me a few years ago with this problem.
60,000 btu induced draft furnace(brand new). Flue temp exiting at the furnace was 290 degrees. It was vented in 4"-B-vent, inside, up through the center of the house. 5' from the furnace the temperature in the B-vent was 190 degrees. At the flue cap, 15' vertical, the temp was 130 degrees. Definitely condensing. This was after the furnace had run for more than 5 minutes. Explain?

ChrisJ

captainco said:

@ChrisJ Okay forget the wire.
Which flue has the highest draft assuming the same appliance is connected.
A 50' tall flue or a 15' tall flue? Which flue would be the hardest to heat if ever? What about a 100' tall flue. Yes I been been on jobs, mostly hospitals, with 100' tall flues.

Also, aluminum absorbs and transfers heat much faster than clay.
One of my students called me a few years ago with this problem.
60,000 btu induced draft furnace(brand new). Flue temp exiting at the furnace was 290 degrees. It was vented in 4"-B-vent, inside, up through the center of the house. 5' from the furnace the temperature in the B-vent was 190 degrees. At the flue cap, 15' vertical, the temp was 130 degrees. Definitely condensing. This was after the furnace had run for more than 5 minutes. Explain?

The higher the flue, the greater the pressure difference.
It's beneficial to go higher, not to go wider.

captainco

The pressure outside and the pressure inside do not change with the height of the flue. What changes is the volume of cold air displacing the hot air. Wider has same effect. I have tested equipment on flue 3" diameter and 60" diameter. On commercial installations there may be 2,4,6, or more pieces of equipment using the same flue. They run by themselves just as easy as they all run together.
A few years ago I got a call from a manufacturers rep in Edmonton Canada needing help. A contractor he had sold 4 boilers to couldn't get them to vent and they were melting their wiring and controls. He said he made calls to places all over Canada and the US and told me that he was told I was the only one on the continent that knew how to vent things properly, After several minutes of laughing and calming down, my response was "Ain't that a sad state of affairs" True story.

I told him how to fix the installation, which was probably against some Code and definitely the manufacturers recommendation. But what do you do when those things don't work?

captainco

Just for the fun of it Google - Jim Davis combustion

At first,I didn't know who they were talking about.
Might give you some idea I have a little experience. Heck, some of these posts might end up there?

ChrisJ

captainco said:

Just for the fun of it Google - Jim Davis combustion

At first,I didn't know who they were talking about.
Might give you some idea I have a little experience. Heck, some of these posts might end up there?

Oh no...
I know what happened the last time someone said "Just for fun Google "".

And it wasn't good.


Right now I'm reading about stack effect and actually went on a tangent regarding how drafty my house is........

Harvey Ramer

How is the BTU content of fuel measured? Or the total available energy?

Gordy

Here's my question. What do you say to the homeowner who isn't sold on condensing equipment because the efficiency difference does not justify the cost difference, and maintenance from a ci to a mod/con?

Seems the industry manufacturers are doing themselves a financial disservice by listing false efficiency ratings seemingly more so on their basic boilers, and furnaces........seems there should be more money to be made on the condensing equipment. I mean the comparison goes from 80 ish/95% to 65ish /95% under the right conditions of course.

How do you argue with the consumer with a bright yellow efficiency tag, and all the literature to back it up?

Gordy

I'm also wondering as @harvey on how the btu content is calculated, and measured? By whom is the btu content checked, and proven, and how often?

For NG we get a btu content on our bill. Who checks it? How often? Does it vary wildly? If you commission, and walk away what happens as the btu content varies?

Gordy

If I go to the bank, and ask for 100.00 am I only getting 65.00?

NY_Rob

Jamie Hall said:

@NY_Rob -- I didn't realize you were a chopper pilot. Always wanted to try that, but settled for fixed wing instead...

They're both fun... I actually started in fixed wing, then switched to helicopters.

When I was working as a flight instructor- we had a well off student who had a large water front property in Glen Cove.. we used to land in his back yard (approach was over the LI Sound) to pick him up for his lessons.

We also had one student who's husband bought her a JetRanger ($200,000+ back in 1988) just for lessons!

I was forced to land at Brookhaven National Lab at rifle point by MP's.

We also flew VIP's from the battery park heliport in Manhattan to Trump's casino in AC....

Fun stuff for a 26yo kid

Tim McElwain

As to the BTU Content of gas most utilities are required to test the gas they send out on a daily basis. You sort of have to trust them. I know the utility I worked for was pretty good about it. Our typical average send out back in those days was around 1025 BTU's per cubic foot. I still check my bill from time to time and it stays pretty much around that number.

By the way this is a very interesting posting and I tend to agree with Jim Davis on pretty much everything he brings forth. With Jim you should sit back and let it all sink in and then run the numbers. Better yet attend his classes.

captainco

Thanks Timmie. One of those smart guys I was talking about. I know in Ohio the btus in gas in one week was measured as low as 930 btu per cu.ft. to a high of 1020 btus per cu.ft.
Back in the early 90's we started importing liquid natural gas from other countries because it was cheaper than ours. Instead of using propane to keep the pressure up in the lines this gas was mixed in. But the btu content of this gas is not consistent which is why there is a swing in the btu content. At higher altitudes the btus in natural gas is much lower than 1000 btus per cu.ft.. 700 to 800 btus is fairly common. This is why setting things up with gas pressure is not very accurate.
Somehow ASHRAE decided to do a study at higher altitudes and found out de-rating equipment up to 7000 ft. wasn't necessary. But if you check, all installation manuals tell you to still do it.

This is why combustion analysis is the only way to set up equipment and maximize its efficiency and safety. But you have to know what the numbers mean and I have explained some of them.

Manufacturers do not set the standards for efficiency ratings, but just try to conform to them and make their equipment look as efficient as possible based on these standards. That is their job. Our job is to make things work in the field. I teach there are two ways to do things in the field. You can be politically correct or you can be mechanically correct. If you are one of these you can be the other.

captainco

That was the early 2000's not 90's. There was an article in GAMA magazine addressing this in 2005. Of course the guy that wrote the artilcle stated that the btus in the gas has no effect on efficiency. He is their chief technical advisor. This was when I first heard the term "Wobbe". which is what you need to mathematically calculate the btus in natural gas.

hot_rod

Energy meters, BTU meters are currently available if you want accurate data. Most of the meters are built to the Euro EN1434 standard, very accurate and reliable. The US standard that has been in the works ASTM E44.25 is allegedly in the home stretch. This will allow manufacturers of energy meters to certify their performance and accuracy.

Flow meter, temperature sensors, and a control to capture and record data are the main pieces, it will not be an crazy expensive tool, probably less than a good combustion analyzer.

The meter could be jumped out and control moved to other applications as a test device.

Energy metering, even residential units are very common in Europe Caleffi has modules that record hot, cold, and heating energy used in many flats for billing purposes.

Steamhead

captainco said:

Flues are much warmer in the summer than in the winter but you will never find higher draft in the summer.........

Less ΔT between the flue gases and the outside air, reduces the available draft.

captainco

@Steamhead Therefore it makes no difference if the flue is warm or not. It is the temperature of the outside air and the temperature of the flue gases that determine the draft of a flue. Obviously inside and outside pressure is another factor assuming the inside pressure is greater than the outside pressure. But how often does that occur?
Neither Code or manufacturers instruction address room pressure whatsoever.

ChrisJ

captainco said:

@Steamhead Therefore it makes no difference if the flue is warm or not. It is the temperature of the outside air and the temperature of the flue gases that determine the draft of a flue. Obviously inside and outside pressure is another factor assuming the inside pressure is greater than the outside pressure. But how often does that occur?
Neither Code or manufacturers instruction address room pressure whatsoever.

The temperature of the flue effects the temperatures of the flue gasses.

You yourself said that.

A cool or cold flue most certainly cools the gasses. I believe you've also talked about boilers having trouble drafting when they first fire due to a cold flue.

Steamhead

captainco said:

@Steamhead Therefore it makes no difference if the flue is warm or not. It is the temperature of the outside air and the temperature of the flue gases that determine the draft of a flue. Obviously inside and outside pressure is another factor assuming the inside pressure is greater than the outside pressure. But how often does that occur?
Neither Code or manufacturers instruction address room pressure whatsoever.

This is something to watch out for when setting up an oil or power gas burner using a barometric draft regulator. If we do the start-up on a mild day, the chimney won't develop as much draft as on a very cold day. So if after setting the draft, your barometric is opening up most of the way on that mild day when you're tuning the burner, it probably won't be able to handle the excessive draft when the weather gets cold. This will affect the fuel-air mixture and reduce efficiency.

We solve that problem by installing a barometric one size larger than the chimney connector, and enlarging the opening in the chimney connector to match.

I've read that a LOT of scorched-air systems cause room pressures to change when they're running, causing excessive infiltration and exfiltration. There were some articles online that discussed this, I'll have to see if I can find the links. Not sure if anyone's ever set up a differential manometer to show ΔP between inside and outside.