The sun is lower in the winter and higher in the summer. How does the sun path affect the solar radiation on the city block in our urban design challenge? Is solar heating different in different seasons? Let's find out using Energy3D's solar simulator. Energy3D has a nice feature that allows us to look at the 3D view exactly from the top. This kind of reduces the 3D problem to a 2D one once you complete your 3D construction and want to do some solar analysis. The 2D view is clearer and the drag-and-drop of buildings is easier.
First, we added a rectangular building to the city block and moved it to four different places -- northwest, northeast, southeast, and southwest -- in the city block and set the month to be January and the location to be Boston, MA (which is our hometown). Not surprisingly, the solar radiation on the building is the lowest at the southeast location, almost half of the radiation heating the building receives at the southwest and northeast locations and about 40% of the highest radiation heating at the northwest location. This is because to the southeast of the block, there are three tall buildings that shadow the southeast part of the block.
Now, what about the orientation of the building? Let's rotate the building 90 degrees and redo the solar analysis in January. The results show that the southeast location remains the coldest spot, but the difference between northeast and northwest are much less. This is because the building has a larger south-facing side in this orientation than in the previous one.
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