New HVAC System Zones

Something that's been added to Revit is the ability to create an entire air system based on an air handling unit, complete with water loops and the equipment that is associated with it. This allows us to perform overall building loading analysis in a much more concise manner than in previous versions. Also we can tie this into the new Analytical System Zones that Revit has.

Analytical Air Systems

The first thing we need to do is to actually add an analytical air system. This is done in the System browser. Follow these steps:

1. Open the model you wish to add an air system to.

2. Right-click in the drawing area and go to Browsers – System Browser.

3. With the System Browser open, Switch to Analytical Systems

4. Click Add Air System.

5. In the Properties dialog, rename the system to AHU-01.

6. Back in the System browser, click Add Water Loop.

7. In the Properties dialog, rename it to HHW-01

8. Change Loop Type to Hot Water

9. In the system Browser, add another Water Loop

10. Call it CHW-01

11. Change the Loop Type to Chilled Water

12. Change the Chiller Type to Water Cooled

13. Add another water loop

14. Call it COND-01

15. For the Loop Type, add Condensate Water

16. Select the CHW-01 water loop

17. For the Condenser water Loop add COND-01. CHW-01 can now be expanded to show the condensate loop.

18 .In the System Browser, click Zone Equipment.

19. For the name, call it VAV-01.

20. The Equipment Type is Variable Air Volume Box

21. Heating Coil is Hot Water

22. The Heating Water Loop is HHW-01

23. The Air System is AHU-01

24. In the System Browser, select AHU-01

25. In the properties, for the Heat exchanger, select Sensible

26. Preheat Coil is Hot Water set to HHW-01 water loop

27. Cooling Coil is Chilled Water set to CHW-01 water loop

28. Heating coil is set to Hot Water with the water loop set to HHW-01 (you can add a secondary HHW loop here if desired)

Analytical System Zones

With the air system added, we can now physically assign it to rooms in our model. I say “rooms” as opposed to “spaces”, because we don’t need a space to do this. All we need to do is simply draw any shape connecting rooms to a zone. This is quite the departure from the previous workflow.

To add an Analytical Zone, follow these steps:

1. On the Analyze tab, click the System Zone button from the Energy Optimization tab as illustrated below.

2. Go to the rooms you wish to connect, and simply draw a line (or any shape that ties these rooms together)

3. Name it whatever you want.

4. For Zone Equipment, select VAV-01

5. Click the Finish button.

Creating an Energy Model

With the Analytical system in place, we can generate an energy model. This is the step that ties all of our efforts into the new energy analysis tools available. To do so, follow along…

1. On the Analyze tab, within the Energy Optimization panel click the Create Energy Model button.

2. In the next dialog, click Create the energy Analytical Model.

3. In the System Browser, expand VAV-01 : 1

4. Select the space with your room name, and you got it!

So, this is the new process! Once we have added our analytical zones and assign them to an analytical system we can really push the Revit envelope on energy analysis.

That being said, I wish I could keep writing, but there are other authors in this magazine that are much more talented than me. Join me next month as we explore analyzing an HVAC system, creating an annual load report, and creating an Insight model.

Eric Wing lives in Syracuse NY where he is the Director of BIM Services for C&S Companies. Eric is a popular speaker at events around the country speaking on many BIM-related topics.

Eric has authored several books including Autodesk’s official training guide for their BIM solution “Revit” called Revit for Architecture No Experience Required. Eric is also an author for LinkedIn Learning where he has authored around 60 full courses on BIM management, Revit, AutoCAD MEP, Navisworks and Virtual Design and Construction (VDC)

Eric has truly been a leader in the architecture, engineering and construction industry since the conception of BIM and 3D design, and has specialty skills in BIM coordination, training and development of technical staff along with daily application of these tools on multi scale, multi-disciplinary projects.

Eric is also currently a Professor at Syracuse University teaching BIM and Advanced BIM at the School of Architecture, and at the School of Engineering.

Eric has also taught courses at the Rochester Institute of Technology and Clarkson University on the subjects of Analytical tools for Facility Management, BIM, and Integrated Project Delivery.

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