How can I calculate the U-value for a wall with a cavity filled with styrofoam?

[Emmett McD]

Hey there, I'm pretty new to physics and need to learn how to calculate the U-value for a wall.

I do have an assignment to do with this but won't post that here as I'd rather learn to do it myself but could someone please post some sort of example of finding U-value using a brick wall with a cavity filled with syrofoam please.

I just need to be able to calculate it myself and any links you think could be useful, would you please post aswell.

Much thanks :)

Emmett

P.s. misspelled the title >.< finding it was to be :P

 

[Valerie Park]

Calculating the U-value of a wall is quite complex, but here's an example of how to calculate the U-value for a brick wall with a cavity filled with styrofoam. First, you need to determine the thermal conductivity of the materials used in the wall and the size of the wall. For this example, let's assume the thermal conductivity of the brick is 0.7 W/mK and the thermal conductivity of the styrofoam is 0.03 W/mK. The wall is 2m high, 0.2m thick and 3m long.Next, you need to calculate the overall thermal resistance, or R-value, of the wall. This will involve calculating the resistance of each material, based on its thickness and thermal conductivity: Brick: R = (2m x 0.2m) / (0.7 W/mK) = 0.57 m2K/WStyrofoam: R = (2m x 0.2m) / (0.03 W/mK) = 6.67 m2K/WThe overall thermal resistance of the wall can then be calculated by adding up the resistances of each material: R = 0.57 m2K/W + 6.67 m2K/W = 7.24 m2K/WFinally, the U-value of the wall can be calculated by inverting the R-value: U = 1 / 7.24 m2K/W = 0.138 W/m2KSo the final U-value of the wall is 0.138 W/m2K. If you want to learn more about calculating U-values, here is a helpful guide from the UK government: https://www.gov.uk/guidance/u-values-calculating-the-overall-heat-loss-of-a-building-element