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Posted by Ed on November 08, 2003 at 12:15:45:
In Reply to: Re: Combustion Air Supply posted by Ed on November 08, 2003 at 11:07:49:
ASME and local jurisdiction Mechanical Codes specify a set amount of unobstructed air intake openings into a plant based on the BTU/hr input ratings of the boilers. Are the dormers in your boiler room the only source of combustion air? It is preferable to have openings high and low in the room to allow for air circulation....hot air cannot escape from the same opening that combustion air is being pulled into by your blowers. An unimpeded and consistent supply of air is very important to proper combustion. Some plants have problems if a portion of the air supply is provided through windows or doors...in winter time these openings tend to get closed due to cold temps in the boiler room, and this is the time when your boilers require even more air due to higher firing rates for heating buildings, etc. Inadequate combustion air supply can lead to sooting and a resultant loss of efficiency. As to combustion air temp, if you have the ability to preheat the air as it enters the boiler it will burn more efficiently, however, if you are talking about a 20 degree differential between a cool boiler room versus a warm room, I think that the measurable increase of efficiency would be very small. : : The plant I work in is about 100 years old. The current boilers have been there for about 25 years. In the old part of the building, above the boilers are two dormers that are open to the atmosphere allowing fresh air to come in and/or heat to escape. Is there any need to duct in combustion air according to the current ASME standard of X# sq in per Btu in to the boiler? I could understand doing when and if the boilers ever get replaced... but...
: : Also curious about warm to hot combustion air verses cool - which is better? Seems like you might want the boiler room a little warm to increase efficiency if nothing else.