Firing Rate vs Boiler Load
Firing Rate vs Boiler Load
(OP)
Hi there,
Is there a graph on how firing rate relates to boiler load?
I'm wondering on how does combustion efficiency relates to boiler efficiency.
On my perspective, a boiler with a burner turndown of 4:1 (25% lowest firing rate) for example, will have 4 different efficiencies (100% to 25%) but it does not take into account the boiler load.
Is there a graph on how firing rate relates to boiler load?
I'm wondering on how does combustion efficiency relates to boiler efficiency.
On my perspective, a boiler with a burner turndown of 4:1 (25% lowest firing rate) for example, will have 4 different efficiencies (100% to 25%) but it does not take into account the boiler load.





RE: Firing Rate vs Boiler Load
RE: Firing Rate vs Boiler Load
I'm not sure if you are familiar with the brand.
RE: Firing Rate vs Boiler Load
RE: Firing Rate vs Boiler Load
RE: Firing Rate vs Boiler Load
A chart or graph, you are looking for, is not general in nature but specifically developed for a particular boiler, therefore your vendor is the right source to get one for your boiler
Combustion efficiency is the ratio of fuel energy liberated and the useful heat absorbed by the system. It may be understood from the following relationship
Heat Input = Fuel Fired Kg/h x Lower Heating Value (LHV) KJ/Kg
Losses are Stack Losses (typically 7-10% depending on final stack temperature and Oxygen level) and Radiation Losses (0.5 - 1.0%)
Typical LHV based combustion efficiency comes out to be 89-92%). The easiest method of calculating the combustion efficiency is
1-losses where reliable stack loss charts are available in the literature and vendor's documents may be referred for radiation loss.
Boiler efficiency is slightly different and lower than combustion efficiency since it takes another loss into account, which is blowdown loss, not very significant, but accounts to 0.25-0.5% depending on the prevailing water chemistry.
RE: Firing Rate vs Boiler Load
Boiler Efficiency = (1 - Stack Losses - Other Losses) x 100 where stack losses include dry and wet losses and other losses include radiation and blowdown losses
RE: Firing Rate vs Boiler Load
I don't know anything about Mechmar, however, any respectful boiler manufacturer should have the info. that you seek.