E+ Envelope U-Factor
I have a problem with envelope U-Factor. I modeled a Single layer polyethylene Surface and according to literature its U-Value should be around the 8 (Fig Below) but E+ calculate (U-Value =3.7).
I've changed the thickness and conduction coefficient, but they do not have remarkable effects.
I've changed the inside and outside convection coefficient at SurfaceProperty:ConvectionCoefficients according to what was discussed here (I checked Surface Face Convection Heat Transfer Coefficient at Output: Variable and it had been changed according to number I had assigned to SurfaceProperty:ConvectionCoefficients).
But the u-factor of my surface hasn't changed!!! What should I do?
I have read these topics:
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"I've changed the thickness and conduction coefficient, but they do not have remarkable effects"
When you say they do not have remarkable effects, what are you looking at? Are you looking at energy consumption for the building, surface temperatures, reported conductivity value in EnergyPlus HTML? Also have you confirmed that the material used is applied to the proper construction in the model?
"I've changed the thickness and conduction coefficient, but they do not have remarkable effects"
I mean: After changes had been made, I've checked the U-Factor (Glass U-Factor) in Envelope Summary, Exterior Fenestration section at EnergyPlus HTML file
The model is a greenhouse with polyethylene envelope. so my model has wide windows and set the windows' material =
WindowMaterial:Glazingas polyethylene specification.Here is the simplified model: link text