Calculating combustion air for kerosene based fuel burner 1

[canmecheng]

Hello,

I have a cooking appliance that burns JP-8 fuel in a confined space. It has a forced ventilation hood and makeup air sized with IMC. Can I use the makeup air for the hood to provide combustion air, or do I need to provide a passive opening sized with NFPA 54?

Best

 

[chicopee]

The amount of combustion air will depend on the rating of the cooking appliance. Any good ME handbook such as Kent"Power" will have a section on combustion air for different fuels including diesel fuel which in essence is what JP-8 is. Combustion air from such books will be theoretical so you will need to increase that value byI would say 15% or more fora complete combustion of the fuel. Your reference to the hood, is that an exhaust hood over the cooking appliance? and if so, that hood exhausts and does not provide combustion air unless may be you are refering to a "push-pull" system over the appliance. JP-8 fuel is for jets and seems extravagant for a cooking appliance unless you expect it to take off on you,HA,HA and have the stomach for it after you have cooked your food on JP-8 fuel because I would expect some malodours permeating the confined space and possibly the food.

 

[chicopee]

Since you got my curiosity peaked, I did some research about the properties of kerosene in my Kent ME and Perry CE handbooks. The kerosene values were for 45 degree API that I used for the attached calculations on an assumed 25,000 btu/hr stove to determine the combustion air requirement. Please see the JPEG attachment.With the stove and JP-8, you may have updated values which you can substitute in the calculations.

 

[canmecheng]

Thanks chicopee!

 

[canmecheng]

After reviewing the Perry handbook I see that the air requirement for kerosene is less that natural gas. I also see that NFPA 54 has a calculation for mechanical combustion air required of 0.35 cfm/1000 BTU. It comes out slightly higher. Since I am using a hood above the appliance I think I need to add a dilution amount too.

 

[chicopee]

Don't forget to compensate CFM for increases in altitude and and changes in ambient temperature. Since JP-8 is a military fuel, you are probably stuck in the "boondocks" where conventional cooking fuel may be unavailable.