Window U-factor question

asked 2021-04-27 04:02:23 -0600

SH Ko
11 ●1

Hi, I’m SH Ko working in a Korea glass company.

Now, I am studying the effect of glass windows on energy consumption in buildings.

For simulation, I am trying to use Energy plus.

In there, I have a question, I know that basically window is composed glass(Ug) and frame(Uf).

In Energy plus(WindowMaterial:SimpleGlazingSystem category), Does the U-Factor mean Ug(only glass)? Or Uw(glass + frame)?

Please check this out and let me know.

Best regard

SH Ko

answered 2021-04-27 09:36:19 -0600

shorowit

11891 ●201 ●9 https://www.nrel.gov/b...

updated 2021-04-27 09:37:17 -0600

Please refer to the WindowMaterial:SimpleGlazingSystem documentation:

The performance indices are U-factor and Solar Heat Gain Coefficient, and optionally Visible Transmittance. The values for these performance indices can be selected by the user to represent either glazing-only windows (with no frame) or an average window performance that includes the frame. Inside the program the model produces an equivalent window glazing layer with no frame.

If you provide properties that only include the glazing, then you would presumably want to use the WindowProperty:FrameAndDivider object as well. If you provide properties that include both, then the frame does not need to be separately described.