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Dew point on condensing boilers
Discuss Dew point on condensing boilers in the USA Plumbers Advice area at PlumbersForums.net
How accurately do you need the answer? From memory, for natural gas with 10% excess air (for maximum efficiency) the dew point is about 58°C, for oil it's about 49°C.
Don't forget that if you need a boiler to condense a useful fraction of the water vapour in the flue gas you need the return temperature to be significantly (say 5°C or more) lower than the theoretical dew-point.
Don't forget that if you need a boiler to condense a useful fraction of the water vapour in the flue gas you need the return temperature to be significantly (say 5°C or more) lower than the theoretical dew-point.
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Condensing Boilers Can Ensure a 90% Efficiency Rate
but Generally, conventional boilers can only reach 70-80% efficiency. These high-efficiency boilers owe a great deal of their heat conversion to their combustion chamber.
but Generally, conventional boilers can only reach 70-80% efficiency. These high-efficiency boilers owe a great deal of their heat conversion to their combustion chamber.
The big easily got gain with a HE boiler vs a SE boiler is the extra sensible heat extracted from the flue gases due to another Hx installed (called a economiser on steam boilers) which reduces the flue gases by ~ 150C leading to a 7% to 10% gain in efficiency, any condensing effect is a added bonus, fairly easily attained with outside temperature compensation.
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