SURFACE RESISTANCE OF AIR TABLE 3.3

[antony09]

WE HAVE A STEEL ROOF WITHOUT INSULATION, WE NEED TO DECREASE THE HEAT LOAD TO THE ROOM, WE CAN NOT INSTALL INSULATION BELOW ROOF, WE THINK THAT THE HEAT TRANSFER WILL DECREASE WITH THE USE OF ALUMINUM FOIL ABOVE STEEL ROOF. WE VERIFY THE TABLE 3.3 "SURFACE RESISTANCE OF AIR" WE HAVE A STEEL ROOF WITH EMITTANCE OF 0.25 AND R=2.7 (HORIZONTAL SURFACE WITH DOWNFLOW HEAT FLOW). WHEN WE USE ALUMINUM FOIL THE EMITANCE IS 0.05 AND THE RESISTANCE IS 4.55. THE USE OF THIS ALUMINUM FOIL HELP TO DECREASE THE HEAT FLOW 30%. IT IS CORRECT?

 

[antony09]

PLEASE ANYBODY CAN EXPLAIN IT.

 

[pardal]

Hi Antony09 , maybe it is true or not , but a aluminiun foil over a roof will not last so shining as new.
So all the benefits will be lost.

Here we use some white paint specially done for it's purpouse.




Pardal

 

[antony09]

thank a lot pardal. it will be fully apreciated.