Running condensing boilers in condensing mode
- Thread starter chadfieldpropertyservices
- Start date
Sponsored Links
Hmmn, do I sense a little back pedalling?
How competent would you be trying it on this?
There seems to be some confusion about the processes going on in a condensing boiler.
When a hydrocarbon fuel burns, it produces water and carbon dioxide, with some other minor constituents, such as various oxides of sulphur, from impurities in the fuel. The water is formed in its gaseous phase as the temperature in the combustion chamber is above the boiling point. A conventional boiler extracts all of its heat from cooling these gases from, say 1500°C to say 150°C (these figures are illustrative only). A condensing boiler can extract a little more heat from cooling the gases by another 80degC or so, but by far the bulk of the efficiency gain over a conventional boiler comes from recovering the latent heat of vapourisation as the water condenses back from the gaseous to liquid phases. The carbon dioxide, of course, remains a gas.
As the water condenses, some of the oxides of sulphur dissolve in it to form sulphuric acid. This can severely attack a conventional iron boiler, which is why it is important to insure that they do not condense. This is worse in oil boilers because oil contains a lot more sulphur that gas. Hence the reason that condensing boiler heat exchangers are made from copper and stainless steel. They still succumb eventually however, which is why they generally do not last as long as conventional ones.
When a hydrocarbon fuel burns, it produces water and carbon dioxide, with some other minor constituents, such as various oxides of sulphur, from impurities in the fuel. The water is formed in its gaseous phase as the temperature in the combustion chamber is above the boiling point. A conventional boiler extracts all of its heat from cooling these gases from, say 1500°C to say 150°C (these figures are illustrative only). A condensing boiler can extract a little more heat from cooling the gases by another 80degC or so, but by far the bulk of the efficiency gain over a conventional boiler comes from recovering the latent heat of vapourisation as the water condenses back from the gaseous to liquid phases. The carbon dioxide, of course, remains a gas.
As the water condenses, some of the oxides of sulphur dissolve in it to form sulphuric acid. This can severely attack a conventional iron boiler, which is why it is important to insure that they do not condense. This is worse in oil boilers because oil contains a lot more sulphur that gas. Hence the reason that condensing boiler heat exchangers are made from copper and stainless steel. They still succumb eventually however, which is why they generally do not last as long as conventional ones.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
Similar threads
