Air Temp rise across heater in machine
Air Temp rise across heater in machine
(OP)
I hope somebody can explain how to calculate the following problem to me. Here we go
I have an air duct approx. 2ft by 5ft. the duct has an airflow of 2500CFM. I have a constant 27 degree C air coming into the duct and a 1kW heater element in the middle of the duct. What will be the temperature of the air leaving the duct. If the air entering the duct increases to 32 degrees C, what will be the temp of the air leaving the duct. Thanks for the help
I have an air duct approx. 2ft by 5ft. the duct has an airflow of 2500CFM. I have a constant 27 degree C air coming into the duct and a 1kW heater element in the middle of the duct. What will be the temperature of the air leaving the duct. If the air entering the duct increases to 32 degrees C, what will be the temp of the air leaving the duct. Thanks for the help





RE: Air Temp rise across heater in machine
B.E.
RE: Air Temp rise across heater in machine
Q [BTU/hr] = 1.08 x CFM x (delta Temp)
Delta Temp = Q / (1.08 x CFM)
Change the electric heater capacity to BTU (1KW = 3412 BTU)
Delta Temp = 3412 / (1.08 x 2500) = 1.26 deg
Entering air temp = 27C / 32C
Leaving air temp = 28.6C / 33.6C
----
A green thought..."We don't inherit the earth from our ancestors, we borrow it from our children." (unknown)
RE: Air Temp rise across heater in machine
works in F, not C.
RE: Air Temp rise across heater in machine
For some reason I thought delta T applies to any temperature scale.
----
A green thought..."We don't inherit the earth from our ancestors, we borrow it from our children." (unknown)
RE: Air Temp rise across heater in machine
RE: Air Temp rise across heater in machine
If 1.08 is considered then the temperature rise is 1.26F.
TADiep,
Get your hands on Uconeer from www.katmarsoftware.com and you will have even temperature difference conversion in it.
TD of F varies by 9/5times TD of C.
RE: Air Temp rise across heater in machine
As posed in the OP, if the 1-kW source is small compared to the dimensions of the duct opening, the local air temperature might be considerably higher.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Air Temp rise across heater in machine
RE: Air Temp rise across heater in machine
TTFN
FAQ731-376: Eng-Tips.com Forum Policies