The thermal efficiency of gas stoves and the issue of flue gas exit temperature
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I would like to ask everyone: I found that the thermal efficiency of burners that use natural gas can be 80% to 90%. So how is this thermal efficiency defined? Does it refer to the thermal efficiency of pure combustion, or does it already include the heat loss due to radiation from the furnace chamber? Based on an excess air coefficient of 1.05 and a thermal efficiency of 80% for the combustion furnace, I calculated that the flue gas exit temperature would be 1500°C. However, the furnace manufacturer insists that the flue gas exit temperature calculated using an excess air coefficient of 1.05 is not that high, being around 800 degrees only. So, what factor have I overlooked? Urgently waiting!
I don’t know how you did the calculation; since you reached 1500℃, I was wondering what the radiation area of the furnace chamber is? If the furnace chamber doesn’t absorb heat, then what’s the use of it? Just go straight for a waste heat boiler! The thermal efficiency of conventional fuel and gas boilers is over 90%, while that of condensing boilers is even above 96% (excluding heat recovery from condensation). A boiler is a device for generating and distributing heat; both radiation and convection heating surfaces are essential. How is it possible to consider only the heat absorbed by the furnace while ignoring other components?~
Hey, has this issue been resolved? I want to learn *it too?
He might have calculated it based on adiabatic combustion, without considering radiation heat transfer.