Here comes the sun

Written by Greg Corke

Published Fri 11 Dec 2009

If you have read the previous articles on sustainable design and building analysis, the case has been strongly made that the earlier architects use analytical tools, such as in the conceptual design phase, the better the design. At the moment all these tools are add-on extras that require some expertise and training in different interfaces and analysis methodology. Autodesk is clearly not going to let that remain the status quo.  

Using a portion of the Ecotect engine, the Solar Radiation Technology Preview gives Revit and Revit MEP customers accurate visual feedback as to a design’s solar ‘hot spots’.

By visiting the Autodesk Labs website (labs.autodesk.com) Revit and Revit MEP customers can download a free version of the Solar Radiation Technology Preview. This powerful application embeds a solar surface analyser into Revit, enabling the study of solar heat gain on all the surfaces of a model. 

For now this application only works in the conceptual massing part of Revit but it’s here that fundamental design decisions can be made that impact the final building shape and orientation. Based on Ecotect technology, the feedback is exceptionally visual, colouring the surface with an indication of the intensity of solar radiation, ranging from red (hot) to blue (cool). This is very useful for noting glazed areas that will need shading or pinpointing the best place to put photo voltaic cells or solar heating.    

In use  

The first step is to create some geometry in the new conceptual mass environment of Revit 2010. This can be anything from a simple single mass or a whole cityscape. The next step is to create a new project environment and load the mass into the project. From within the project environment settings, use the Manage Place and Location dialogue to allocate the location and North orientation. This can be done by selecting a city name or specifying longitude and latitude. The model origin needs to be unpinned to allow rotation of the geometry to align to the chosen North position.  

The Solar Radiation Technology Preview icon is available from within the add-ins tab. By activating it, the analysis software will bring in only the geometry that is visible in the window. Once in the analysis window, by right clicking on the geometry you can select and deselect faces on the model to be analysed, ignored or assigned to just to cast shadows.   

Before entering full analysis the weather data for the target area needs to be loaded, all of which is provided from the Ecotect library but additional libraries can be added from other systems. A span of days can be chosen as well as the season, showing the dates and the daily time range - for instance sunrise to sunset or just the hours the building is occupied. The user has the ability to set the number of divisions or tiles that a surface gets sectioned into for the analysis, with the associated computation time implications. Then the legend can be set to provide the information in the format required. These include cumulative, average or peak readings and the energy settings in Btu/ft2, Watt hours or Watt hours/m2. The resolution of the output image can also be set. Then hit the calculate button.   

On small models, the results come back in the blink of an eye. By altering the various settings it’s possible to perform many iterative analysis cycles and gain a lot of knowledge about the solar radiation characteristics of the building over a complete year, defining the maximum and minimum radiation levels.    

The output can be saved as images in the same Revit project that contains the massing elements. After these images are added to the project, they can be placed on sheets and printed. It’s also possible to  export the images from Revit for use in presentations. However, the images can be quite large and multiple images can cause project files to bloat.    

Conclusion  

Combining Ecotect’s powerful visual analysis with the new mass modeller makes a lot of sense and this is a brilliant tool to have in your Revit armoury. It’s is easy to use and gives meaningful results in seconds. Suddenly even conceptual designs can go beyond the aesthetic.   

Autodesk is intent on ‘democratising’ sustainable analysis and design. I think  we can expect to see some great ‘green’ functionality added to future releases of the Revit Suite.  

The technology preview expires on January 13, 2010 so get downloading now. 

www.labs.autodesk.com/utilities/ecotect

System requirements

The Solar Radiation Technology Preview is compatible with the following operating systems:
Autodesk Revit Architecture 2010 Update 1 (32-bit and 64-bit)
Autodesk Revit MEP 2010 Update 1 (32-bit and 64-bit)
Runs on Microsoft Windows XP or Microsoft Windows Vista