- #1
forrestkk
- 3
- 0
Hello All! I am new to the forum and need help. I have looked at multiple sites an looked at 328 threads titles and about 20 actual threads today to find the info I was looking for...no luck.
Here is my question:
I have a 12.5KW natural gas generator and want to know much heat and I can get from the exhaust, which of course leads to tube-in-shell heat exchanger sizing requirements. At 1800 RPM it uses 64 CFM of combustion air (cooling air is obviously a lot more). At 1800 RPM and full load it uses 230 CFM of natural gas p/hour. Each cubic foot of natural gas has 950-1150 BTUs and a net heating value of 850-1050 BTUs. I have no idea if this is right, but trying to be conservative I am assuming about 1000 BTUs per cubic foot of natural gas is being used for combustion. Simple math tells me that 23,000 BTUs of natural gas are being burned in the engine p/hour. How do I figure out how many BTUs are going out the exhaust? How much exhaust air flow should I have (I am assuming at least 64 CFM but does it expand when the natural gas and air burn)?
Numbers:
At 1800 RPM and full load
64 CFM of combustion air charge
1000 BTUs p/cubic foot of natural gas
230 CF p/hour at full load
Thank you in advance.
Kevin
Here is my question:
I have a 12.5KW natural gas generator and want to know much heat and I can get from the exhaust, which of course leads to tube-in-shell heat exchanger sizing requirements. At 1800 RPM it uses 64 CFM of combustion air (cooling air is obviously a lot more). At 1800 RPM and full load it uses 230 CFM of natural gas p/hour. Each cubic foot of natural gas has 950-1150 BTUs and a net heating value of 850-1050 BTUs. I have no idea if this is right, but trying to be conservative I am assuming about 1000 BTUs per cubic foot of natural gas is being used for combustion. Simple math tells me that 23,000 BTUs of natural gas are being burned in the engine p/hour. How do I figure out how many BTUs are going out the exhaust? How much exhaust air flow should I have (I am assuming at least 64 CFM but does it expand when the natural gas and air burn)?
Numbers:
At 1800 RPM and full load
64 CFM of combustion air charge
1000 BTUs p/cubic foot of natural gas
230 CF p/hour at full load
Thank you in advance.
Kevin