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Energy use does not change upon change in window to wall ratio

asked 2019-10-30 15:24:18 -0500

Rezvan's avatar

updated 2019-10-30 23:52:46 -0500

I encountered an issue regarding energy simulation of buildings using a combination of SketchUp, OpenStudio, and EnergyPlus. I wanted to try how the energy use of a building changes as I change the value of window to wall ratio. So, I created a very simple 3D model in SketchUp and assigned various values for WWR. Interestingly, the energy use did not change at all even in decimal points. Does anyone know why this happened? I read many papers on the significance of WWR on the energy use of buildings. Am I missing something? I should say that I assign the value of WWR to 3D model that I created in SketchUp using OpenStudio extension.

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answered 2019-10-30 22:45:47 -0500

The first thought is that you either don't have thermostats assigned to the thermal zones in the model, or you have thermostats, but there is no system, or ideal loads trying to met those setpoints.

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Thank you so much for your answer. That is true I did not define and assign any thermostats. I am a PhD student and really new to these software platforms. I wanted to see how a very simple model in which only geometry, materials, construction, internal gains (people, lighting, and electric equipment) are assigned would react to change in window to wall ratio. SO what I understood from your answer is that I will not see any change unless I assign thermostats, am I right?

Rezvan's avatar Rezvan  ( 2019-10-31 08:31:35 -0500 )edit

Correct, you will not see changes in energy use without a thermostat and some system (or ideal air load) to serve it. You can however report out zone temperatures for your model and should see changes.

David Goldwasser's avatar David Goldwasser  ( 2019-10-31 09:36:24 -0500 )edit

Thanks a lot. I checked the average zone temperature and as the WWR changes the temperature changes too.

Rezvan's avatar Rezvan  ( 2019-10-31 10:40:24 -0500 )edit

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Asked: 2019-10-30 15:24:18 -0500

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Last updated: Oct 30 '19