Calculate complicated construction, energy losses and U-values.

[aroraror]

How should one calculate an A-frame structure with a 58-degree slope, light beams, and various insulation materials combined?

From the inside:
12.5mm gypsum 0.25
vapor barrier 0,?
47mm air gap 0,?

Between the light beams:
50mm PIR 0.020
303mm wood fiber loose fill 0.038

On top:
18mm roofing plywood 0.14
roofing felt

How does the slope of the structure affect energy loss? I imagine that heat moves vertically, which means it must pass through ~770mm of structure instead of the actual ~420mm?

Open to the ridge and an open floor plan makes me suspect that a lot of the heat will collect and exit at the top of the structure. Am I right to insulate this part thicker than the rest in that case?

 

[surris]

How should one calculate an A-frame construction with a 58-degree slope, light beams, and different insulation materials in combination?

from the inside:
12.5mm gypsum 0.25
vapor barrier 0,?
47mm air gap 0,?

between the light beams is:
50mm PIR 0.020
303mm wood fiber loose-fill 0.038

on top:
18mm roof plywood 0.14
roofing felt

How does the slope of the construction affect energy loss? I imagine that the heat moves completely vertically, which means that it must pass through ~770mm of construction instead of the actual ~420mm?

Open to the ridge and an open floor plan makes me suspect that much of the heat will collect and pass out at the top of the construction, am I right to insulate this part thicker than the rest in that case?

Don't complicate things. You will have the same transmission losses in the construction if it looks the same regardless of whether it is at an angle.

If the heat only moved vertically, then there would be no transmission losses in any other building part than the roof.

 

[aroraror]

Don't complicate it. You will have the same transmission losses in the construction if it looks the same whether it's at an angle.

If the heat only moved vertically, then there would be no transmission losses in any other part of the building than the roof.

Alright, Completely vertical might have been an exaggeration but.. I prefer to complicate it a bit as I need a fairly accurate calculation.

 

[surris]

Alright, completely vertical might have been an exaggeration, but... I like to complicate things a bit since I need a fairly exact calculation.

About 0.1

 

[aroraror]

Approximately 0.1

Thank you, but I didn't get any wiser.

 

[surris]

Thank you, but I didn't get any clearer.

You need to calculate the resistance for each layer, which you do through thickness/lambda. Then you sum the resistances and take 1 through the resistance, 1/total resistance. In the layers with light beams, you have to calculate the ratio between light beams and pir/loose fill.