Hide quoted text -
condensing furnaces and water heaters dont use a chimey they exhaust thru PVC pipe thru the wall at a very low but slightly warm temperature.
condensing is more efficent than tankless, if you doubt this just hold your hand in a standard tankless exhaust:) get the burn cream ready you will need it
- Hide quoted text -
I didnt state anything different on condensing systems. There are tankless condensing, how do you think a 94 EF rating is acheived, 94EF the highest rating of any water heating system. One of the highest rated tanks I know of is my AO Smith Cyclone a condensing commercial unit. It is in no way more efficient than my cheapy bosch non condensing tankless, Read the EF number on AO, if you can find it, because they hide the sad truth.
one of the AO Smith condensing water heaters get the fed energy credit.
thats a wonderful tax break
- Hide quoted text -
Dumb, completely dumb you are.
You're a puzzler alright, Harry. You've got this right, but you're so wrong about your world history.
This apparent violation of the laws of thermodynamics actually happens to be true. The trick to being over 100% efficient comes from condensing the flue gases to BELOW the input temperature of the fuel and air it's burning. As Harry stated, it depends on (ironically) having cold incoming water that's able to cool the exhaust gases (and water vapor) to below room temperature, extracting the energy of the room temperature air and fuel. So no, Carnot is not turning over in his grave over this perfect engine that he could only dream of, but he would be mightily impressed by such efficiencies even if they involve a little slight of hand like extracting latent heat energy (which it can only do because of the differential between inlet water temperature and room temperature.
Now we'll deal with your rabid Americaphobia, a disease so far progressed that you've lost your ability to deal with the subject rationally.
-- Bobby G.
ed-
You both are wrong, standardised testing in the US for boilers and furnaces measure Btu per hour input and Btu per hour output , and nobody has even got to 99% yet. Net Btu input is still more than Net Btu output, thats a fact. You of course save energy condensing the moisture out of the combusted gas, about 13-15%, Net output still is below input. The most efficient heat is unvented , they are 100%, there is no exhaust but a downside is they can kill you easily.
...and have done *nothing* since. Well, there is that RR engine on the A-380. That's a nice piece of work. Oops!
temperature,
You might want to read up on this, because I was surprised when I did because I also thought you can't get more energy out than you put in and
101% ratings were impossible.The trick is that you're exhausting cooler air than the incoming air because of the heat exchanger's ability to cool down the exhaust way below room temperature and extract the heat energy that was required to bring the fuel and air to room temp. When the exhaust is below room temperature it means that energy has been removed from it and reclaimed *somewhere*.
True, it's not really the heat energy produced by the combustion process, but it is heat energy, and adding it into the mix is what propels the numbers to seemingly impossible "greater than 100%" efficiency. As Harry noted this trick only works well if the inlet temp of the water is very low, allowing it to cool the exhaust below the temperature of the incoming fuel and air and thus condense the water vapor back to water, recovering the energy it took to change water from a liquid to a vapor in the first place. The "trick" is the cooler than room temperature exhaust whose heat has been transferred to the incoming cold water, requiring less energy to heat it to usable temperatures. It's quite the engineering marvel, I think.
-- Bobby G.
They were leaders in jet aircraft. Remember the DeHavilland Comet?
On 10 January 1954, 20 minutes after taking off from Ciampino, Comet G-ALYP ("Yoke Peter"), BOAC Flight 781, broke up in flight and crashed into the Mediterranean off the Italian island of Elba, with the loss of all 35 on board.'
And who could forget the White Star Line's most famous ship, the Titanic?
-- Bobby G.
Not true, the rating-testing your heating system has been subjected to is done by measuring Btu input, and Btu OUTPUT. They measure it , the condensing effect is figured is in the rating. As i said it equals about10-15% gain, and doesnt bring it over 100%, or 99%
I thought the Titanic was built in Ireland? Oops, Northern Ireland, does that count? :-)
TDD
:
c-9bed-
ide quoted text -
Since you want to use Wikipedia and I dont know how to paste look up Condensing boilers, you will find what I said is true that 98% is the highest claimed for Condensing boilers, but also that figure is optimistic, a bit high, and a reduction of 4-5% is more realistic or real world performance. That makes condensing boilers about 93% efficient Maximum.
By SEDBUK this gives Condensing boilers a typical seanonal efficiency of 82-89% HHV.
I quote Wikipedia
""When installed in real houses, the performance of condensing boilers is typicaly 4-5% lower than in laboratory tests by groups such as SEDBUK . This gives the typical seasonal efficiencies of 82-89% in the UK [ HHV ]. ""
This is your testing done by your SEDBUK, we in the US have the same ceritified Gav standardised testing and sind same results, end use results are less optimistic than advertised by manufacturers and probably put units condensing units around 90%, you just dont get more Btus out than you put in.
I'd say both you and Bobby G have valid points. I can see how a condensing heating system could theorectically achieve greater than
100% efficency. The essential point here is that the extra heat would come from heat energy contained in the air and fuel that go into the heater. If you cool the exhaust gas down to say 33 degrees, you could extract out heat that normally would be wasted. I can see this in a theoretcial or lab experiment application, but doubt it's possible in a residential boiler.What Hary claimed in the context of this discussion was that this greater than 100% efficiency was available in gas boilers today. I'd like to see Harry provide a data sheet for one that we could buy for a typical house.
Hide quoted text -
Since you want to use Wikipedia and I dont know how to paste look up Condensing boilers, you will find what I said is true that 98% is the highest claimed for Condensing boilers, but also that figure is optimistic, a bit high, and a reduction of 4-5% is more realistic or real world performance. That makes condensing boilers about 93% efficient Maximum.
By SEDBUK this gives Condensing boilers a typical seanonal efficiency of 82-89% HHV.
I quote Wikipedia
""When installed in real houses, the performance of condensing boilers is typicaly 4-5% lower than in laboratory tests by groups such as SEDBUK . This gives the typical seasonal efficiencies of 82-89% in the UK [ HHV ]. ""
< This is your testing done by your SEDBUK, we in the US have the same ceritified Gav standardised testing and sind same results, end use results are less optimistic than advertised by manufacturers and probably put units condensing units around 90%, you just dont get more Btus out than you put in.>You do if you siphon off that energy from a source other than the direct combustion of fuel. Fuel and air are burned at room temperature. That is usually around 70F. Inlet cooling water is around 40F. The cooling of the exhaust below room temperature allows the boiler to extract the energy of water vapor that's a byproduct of combustion by causing more of it to condense than it would at room temperature. The cooler- than-room-temperature exhaust of a process that's burning gas is a big clue that it's not a typical combustion process and something extraordinary is going on. How many engines or combustion processes do you know that have not just a cool, but a cold tailpipe?
The phase change energy of condensation plays a key role. If your exhaust energy is reclaimed and exits below room temperature, you've captured and reclaimed the thermal energy stored not only from fuel combustion, but also the heat both fuel and air bring into the process just having mass. A cool exhaust from a combustion process *has* to mean that both the waste heat that would normal go up the flue and the energy it took to warm the fuel/air to room temperature is recaptured and extracted. How else could there be a colder than room temperature exhaust product by combustion? The laws of thermodynamics are scrupulously obeyed and no energy is created, it's merely scavanged from a source other than direct combustion. The BTU's used to heat the air and fuel to room temperature are recovered and not sent up the flue. That sort of energy scavenging is not accounted for in typical efficiency calculations.
The key is that the energy is extracted from the fuel in different ways: from its thermal mass, from the heat from its combustion and by the energy that comes from water changing phase from a vapor to a liquid. Lower the exhaust below room temperature and you've extracted close to "free" energy (it's not really free since someone paid to heat the air and fuel in the first place). It's a pretty remarkable process. Is saying 101% efficient a gimmick meant to grab people's attention? U-Betcha (wink, wink!) There are so many way to slice and dice data, I'd want an asterisk next to that number, but in terms of squeezing every last BTU out of fuel, including recovering the energy that it took to raise it to room temperature, it's pretty slick.
-- Bobby G.
"How many more must die!"
harry's favorite.
Silly boy. The English owners wouldn't want to pay British steelworker or real estate rates. They exploited the Irish in the finest tradition of an Empire:
-- Bobby G.
"Cool down" implies that it was "warmed up" to begin with. How did that happen?
I'd want to see the method used to measure the efficiency, too. No marketeering allowed.
:
..
:There are none over 98% efficient, even Englands rating agency Sedbuk states so. Theory is all well and good , actual products are what matter. To me its also illgoical that you can get more than 100% out of burning a fuel, it takes energy to condense that vapor, its not free, and exhaust temps prove energy is wasted on condensing units. its really pointless arguing, his own counrtys rating agency disputes his claim and he refuses to see that fact.
rote:
com...
rote:
n 100%)
Im tired of your hearing your lies and stupidity, educate yourself, post one just one manufacturer that sells a SEDBUK Certified over 100% efficient heat plant fired by fossil fuel, or one 99% 98% 97% 96% 95%
94% 93%. You cant. Post just one tested by SEDBUK England, your own governments efficiencys standards system.UK SEDBUK - Standards Efficiency Database for Boilers in the UK.
Your own, UK, certified testing standard, you are a nuts to keep this crap up because none are certified over 100%, none are even 91%. Your rating is more conservative than our US rating, read it and please stop the missinformation.
Hang it up Harry your to old for this. SEDBUK shows no Warmflow over
90.4% Thats your UKs agencys ratings. But just to show you you can`t even read a simple spec sheet . The Warmflow GS 25a is a Sedbuk A class. It has an input rating of KW 25 output KW 24.6. Now you simply take out your pencil, sharpen it, get some clean paper and subtract the two numbers and you will see your spec sheet shows it to be 97.6% efficient. Just what I said that 98% is the high and nothing is at or over 100%. Its real simple to grasp Harry, output is less than input. Hey Harry, I own the Brooklyn Bridge, I will sell it to you real cheapTry snipped-for-privacy@warmflow.co.UK
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.