Cooling Load vs Orientation

I have a Honeybee model for a building in a cooling-dominated climate (Houston). When the longer side of the building faces south, the cooling loads are lower than when rotated 90 degrees.

This doesn’t make intuitive sense to me - with more glazing and opaque area facing south, I would expect the cooling loads to be higher. Does anyone have an idea why this might be?

The glazing in the model is fixed at 20% for all sides and everything else is equal between the 2 simulations.

Here’s an example file (with a few modified parameters) that gives the same effect.

Does this seem like a bug or is there a physical explanation? (74.3 KB)

Hm, makes some sense to me. With EW orientaion, your northern facade gets very little solar exposure. NS orientation your eastern and western each have exposure during the day and because EW sun has a lower altitude you potentially see higher gains. You should check your solar gain results. They will likely look something like the attached image where gains drop in the middle of the day because of the sun’s altitude.


Thanks @jgbrear, I think that’s it exactly! Here’s the solar load with the 2 orientations.

For the unit with long axis running EW:
During the summer, the big south facing window is more shaded because the sun is higher in the sky.

For the unit with long axis running NS:
The low morning/afternoon sun through the windows on the EW sides of the building really add to the solar load, even in the summer.

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