Analyze the building's orientation

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Analyze the building's orientation to determine the energy, daylight, and thermal comfort impacts associated with how the building sits on the site and its relation to solar exposures.

Getting started

During the conceptual design phase, a simple box model is generally the appropriate level of detail to use as a starting point for this analysis.

Choosing appropriate options to compare

At this stage, the architectural designer has likely developed a conceptual design of how the building will sit on the site. Therefore, there may be some limitations on what orientation options may be realistically considered. For example, rotating the building 90 degrees may have a significant impact on the building's aesthetics and this may be unacceptable to the design team. However, if you have reason to believe that the building could perform significantly better with a 90 degree change in orientation, then this analysis may still be warranted and you may be able to bring good data to the designer.

There are also likely to be other design constraints to consider. Be sure you understand any site-imposed limitations before performing the analysis.

In many cases, the orientation analysis is a fine tuning exercise where you begin with the "baseline" as defined in the architectural concept designs, and then perform a sensitivity analysis of modifying the orientation +/- 10 degrees in small increments (e.g. 1 degree increments).

Creating the design alternatives

There are a few ways to go about creating design alternatives with differing orientation. As discussed in the tutorial on setting the building's orientation, an energy model is often drawn aligned to the 3D drawing interface's axes and then the exact orientation is defined by setting the building's azimuth angle with respect to the drawing axes. Creating the design alternatives is a simple matter of changing the azimuth angle in small increments to represent the desired alternatives.

You could create a series of model files, each with its own orientation (i.e., different input for azimuth angle) and then simulate them individually. However, a more expedient approach would be to treat the azimuth angle as a parametric input, and then define each desired azimuth angle as alternative values for the parameter. This of course assumes that the software program you are using includes the capabilities for parametric analysis. If it does, then use the software's capability to run the parametric alternatives (it will simulate all of the options for you and typically save the results files using a naming convention to distinguish between the simulation runs).

Comparing the results

A good way to compare the results of the analysis is by using a bar chart that shows the magnitude of energy consumption for each of the design alternatives. Sorting the results from smallest to largest will help to visualize which alternative is the most efficient, and the magnitude of savings compared to other alternatives.

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