By: Ian Molloy, Senior Product Manager, Building Performance Analysis
Revit 2014 Update Release 2 (UR2) is now available for download from the updates section of Autodesk.com or from within Revit via live update.
Just as we were able to make some valuable improvements in UR1 to the new Energy Analysis using Building elements feature in Revit 2014 I am very pleased to summarize further advances made with UR2 based on user feedback that make real BIM based EAM creation and analysis easier and more powerful than ever.
Revit 2014 Update Release 2 available from within Revit via live update
You can also access it by clicking on the Communication Center (Radar) button and selecting the "Product Update Available" line item. It may not be at the top of your list so scroll through to find it.
In summary UR2 essentially continues with two of main themes addressed in UR1 i.e. the handling of ‘sandwiched’ Revit elements and improved Analytical Surface precision. A couple of other improvements have also been made to some rather specific model element configurations you may encounter. These improvements have been made based on user feedback that highlighted areas where the original algorithms where not performing as expected. The main aspects of UR2 can be summarized as follows:
Material thermal properties of ‘Sandwiched’ Revit elements
When two or more Revit elements like walls, roofs, floors etc. are directly or closely adjacent and parallel to one another we describe that condition as the elements being ‘sandwiched’. This situation is extremely common in Revit models. In UR1 we fixed some issues so the energy model automatically got the correct Analytical Surfaces from these configurations. However, this did not properly include the ability to resolve material thermal properties in the separate sandwiched elements (if present) into an appropriate set of gbXML, DOE2 and EnergyPlus constructions, layers and materials data. This didn’t mean sandwiched elements had no thermal properties but just that you could only use the conceptual or building construction settings for specifying thermal properties and not use the thermal properties contained in the building elements.
Now with UR2 any material thermal properties present in sandwiched Revit elements are correctly translated into construction, layer and material data for use in the simulation (and included in the gbXML, DOE2 or EnergyPlus export). The best way to understand this and the kind of advanced BIM based Energy Analysis it facilitates is with a simple illustration…
Example of material thermal properties of ‘Sandwiched’ Revit elements
Analytical Surface precision
In UR1 we were able to make some pretty significant improvements to Analytical Surface precision based on user feedback. By comparison, those in UR2 are less dramatic but still represent a valuable improvement. Due to the more specific nature of these improvements it’s hard to provide a single example like I did for UR1 but based on our own internal test model set the overall improvement to surface precision is approximately 0.5-1% of Surface area. Although this may not sound like much when you consider we’re generally within around -5% of the ‘true’ values. UR2 actually represents a relative improvement to Analytical Surface precision of around 10-20%. It’s also worth bearing in mind this test model set is fairly challenging.
In very general terms the way in which this improvement has been achieved and the places you are likely to see the improvements is in the precision of horizontal surfaces where they are intersected by small elements such as columns as well as the handling of curved surfaces.
Example of improved Analytical Surface precision (where the roof intersected with columns)
Example of improved Analytical Surface precision (Curved walls)
Overlapping openings of different type
One of the main strengths of this feature is that it can tolerate the typical gaps and overlaps in building elements that occur in normal modeling practices. That said, one situation we discovered this didn’t happen was when two openings of a different type, for example a door and a window overlapped. Of course this situation is a little more obvious and arguably quite wrong from a modeling perspective but when this occurred or even if the two openings were directly adjacent it caused adjacent Analytical Space to be omitted and Shade surfaces to be created. Now with UR2 this will no longer happen and what you will see if you examine the EAM is that where two (or more) openings of different type existed it creates a single opening of type window.
Example of overlapping openings of different type
Recognition and treatment of ceiling void spaces
Ceiling voids are a very common feature of many buildings, especially commercial office type spaces and in practice they can be configured architecturally in a wide variety of ways. In energy terms these spaces are not typically heated or cooled or contain lighting, occupancy or equipment heat gains and power consumption. They do however play a role in the buildings overall heat transfer processes. Based on user feedback we have addressed this issues. Essentially what UR2 does is greatly improve the identification of spaces that appear to be ceiling voids and treat them appropriately in the simulation i.e. free floating spaces with no direct power consumption. Of course, this is all done automatically meaning you don’t have to worry about specifying certain settings for ceiling voids.
Tell us what you think!
If you haven’t got UR2 already go get it and give it a try! As always we’d like to hear your thoughts and questions on these capabilities.