Solar Radiation Feature Overview

Designing for sustainability requires many analyses, including an understanding of the incident solar radiation on a building façade. The Solar Radiation feature enables you to study incident solar radiation on a building form within the conceptual massing environment.

This feature visualizes the distribution of solar radiation on various areas of a mass by taking into account the shading effects from adjacent objects, such as vegetation and surrounding buildings in an urban setting. This feature can help you identify the best areas to maximize solar gain by considering the effect of shading and seasonal variations in solar radiation. The analytical results of this functionality are not meant to size photovoltaic panels.

There are many examples of how the information can be used, but some typical ones are:

• Studying how incident solar radiation on the façade of a specific form differs by orientation. This could be as simple as analyzing a basic rectangular form. It is easy but important to look at incident solar radiation on pitched roofs to understand the impact of various roof pitches and nearby shading elements early in the design process if solar panels are being considered.
• To understand the relative importance of glazing for daylighting and solar heat gain of the building, it is useful to quantify the difference between the incident solar radiation that occurs on the lower floors vs. the higher floors of a tall building. This is especially significant in an urban context. Studying incident solar energy is one step towards understanding what types of glass might be appropriate different façades or floors. If the solar radiation on the north façade or lower floors is much lower than the flux on the southern or high floors, varying glass type and performance by face may be appropriate.
• Much of the analysis associated with low carbon building design and sustainability is very numerical and not visually compelling. The Solar Radiation feature is a great way to provide visual feedback within the context of a design whether as a means to communicate a design choice, or as part of a presentation.

For sustainability, solar radiation analysis should be done very early in the design process, and repeated as needed when the form and design evolves.

Before you begin using the Solar Radiation feature, make sure that your model contains conceptual massing elements. Select a weather station in the Location and Weather Site dialog. Then choose a date and time range for the analysis. Finally, you select the surfaces to be analyzed.

You can set the number of divisions or tiles that a surface gets sectioned into for the analysis, with the associated computation time implications. The results can be displayed as cumulative, peak or average values in user chosen units. The computation time varies depending on the calculation resolution. For example, a simple analysis for the simplest forms could take about 10 seconds to complete, while more complicated forms and analysis could take about 20 seconds.

When you are satisfied with your analyses, you can publish the results in the form of images, or you can output results to a printer, or export the results to XML or CVS formats for use in spread sheet applications.