LACH_RADandDL

Last fall a custom data visualization developed by our research team was featured on the information is beautiful website as part of their information is beautiful awards. In this post we discuss why we developed the graphic and how it is used.

Incident Solar Radiation is one of the most common types of analysis performed by architects at the conceptual design stage. Results indicate where solar heat gain might be an issue. These are areas where glazing should be minimized and exterior sunshades should be considered. Unfortunately, Ecotect does not have a way of communicating all of the results of this analysis in a single concise graphic format. As part of the research effort, we have developed a grasshopper definition that generates a graphic representation of both heat intensity and panel orientation in a single frame.

Typically, results from solar radiation analysis in Autodesk Ecotect are displayed in 3d. Surfaces are color coded to represent varying levels of solar heat gain. Users can rotate a model in real-time while the program is running or export screen captures to share results. In order to effectively share information for all sides of a building, multiple images are required.

cj-eco3d-white

The images above demonstrate a typical set of screen captures used to communicate the results of Solar Radiation Analysis. Reconciling multiple 3d images can be confusing and very difficult to put into context. While Ecotect does have the ability to produce tabular representations of this data (shown below), it does not have a way to plot both solar heat gain and orientation in a single graphic.

radiation_with-shade-graph

Ecotect does provide raw analysis data which can be exported as an excel file and referenced into grasshopper. Our visualization requires two sets of data: cumulative incident solar radiation and the “normal” direction of each face (panel) analyzed. Once a link to the data is established, the grasshopper definition draws a type of bar graph. Each bar is oriented to face in the direction of the panel it represents.

FBG_dark-p2

The following analysis was performed for the CJ R&D Center. Using the rotating bar graph, the analysis shows the effectiveness of the exterior scrim.

FBG_dark--p1

RBG_Dark-CJ-1

The chart above illustrates the glazed panels facing south/ southwest (orange circles) are being exposed to the greatest amount of solar radiation. Notice that some panels that share this orientation are being shaded. On a typical 4 sided building without any projections, we would not expect to see this. The mass of the CJ R&D Center has many layers, some which cast shadows onto others and account for the the layered rings visible in the graph.

RBG_Dark-CJ-2

The second chart above shows the results of a continuous pleated shading device without variation. There is a 54% reduction in cumulative solar radiation overall, but this is evident from the numeric data. The graphic representation shows that the shading device is most effective on the southern orientation where high angle light is easily blocked by horizontal shading. Peak values on the south east are also tempered, while low angle morning and late afternoon light is the least affected.

RBG_Dark-CJ-3

The third chart displays analysis results for a pleated shading element that has been pinched in selected areas to increase natural day lighting and to celebrate views. This design represents the result of tuning the system based on the preliminary analysis. The amount of solar radiation for the optimized system is not drastically different. There is a further 2% reduction where peak zones on the south east are the most visibly improved.   This isn’t the whole story of course. The optimization strategy here is to position the openings in locations where day lighting can be of greatest benefit while avoiding zones with high amounts of solar radiation.  However, neither day lighting nor user comfort are represented in the graphic above. Both are also in direct conflict with minimizing solar exposure. The more the shade is opened to increase natural light or improve views, the more the building is exposed to the sun’s heat. To more comprehensively quantify energy benefits, day lighting analysis must be used in tandem with the solar radiation analysis performed in this study.

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