Showing posts with label Revit HVAC. Show all posts
Showing posts with label Revit HVAC. Show all posts

Monday, January 9, 2017

Thank you again – another Top Speaker award at AU 2016!!!

Man…I can’t tell you how happy and honored I was to find out one of my labs at Autodesk University 2016 (au.autodesk.com) finished in a two way tie for top speaker. The lab, Perfecting the System for Revit, included my first ever perfect score in one category, with an overall rating of 4.79 out of 5, based on a minimum number of responses. The class tied with another lab taught by one of my good friends, Mike Massey from Applied Solutions. This was Mike’s first win, and well deserved. He’s taught at AU for many years, and now that I’m out of the Autodesk reseller channel, has been the guy in the Southeast US that I’ve been referring people to for years. He provides the same service I used to – training, consulting and program optimization, and came up through the Building Design solutions ranks the same time I did. He was one of the first MEP Implementation Certified Experts, a title we both received at the same time when Revit MEP was first getting its feet wet.

It’s a tough job to win one of these awards, but the real effort goes into the prep and planning for the class. The lab this year was the first time I taught three sets of discipline tools – duct, pipe and electrical circuiting – concurrently in a lab. We went through each of the keys areas, focusing on the similarities and differences. The course would up with five – yes, five – handouts, including an overall document that explained the features; three separate lab exercise documents for each track; and an overall tips and tricks document that featured key takeaways.


But I think what made the difference was fixing one of the things about labs that drove me nuts – and almost got me to where I didn’t want to teach them anymore. For years, we had problems with datasets in the labs – the wrong files, users not be able to locate the files, as well not understanding the software well enough to know the difference between the applications (yes, I had users a few years ago open AutoCAD MEP in a Revit MEP lab before). We also had users that could not keep up due to the lack of familiarity with the software.


To make it easier, it started with Autodesk using a web-based version of Revit for the labs this year. This made the files open quickly, and kept local users from editing items like the interface and location of palettes, etc. Another key step was having the lab datasets stored by lab location and day of the lab, which helped us locate the files easily. But I think what made the biggest difference came from my lab assistants – Matt Dillon, Matt Stachoni, and Ron Onderko – who went around and opened Revit 2017, opened the dataset project files (2) and made sure they were all already open to the view we needed to start in. When the student came into the lab, everything was ready to go, allowing us to focus on the lesson, rather than waiting for everyone to get where they needed to be. Even a few of the early arrivals pitched in and helped the lab rats get everything open and ready – for that, I can’t thank you guys enough.


The course included learning how to use Revit software systems help us to define the MEP (mechanical, electrical, and plumbing) design in several ways, but the main purpose is to understand the relationships between system equipment, such as air terminals to air handling units, or from light fixture to panel. We taught the users comprehensive steps needed for controlling project system settings, and then demonstrated how to capitalize on (or disable) sizing and analysis tools related to the system. We also covered creating the target-source relationship between parts, and then how to use the systems to improve the quality of documentation. Included were project files based on a project template that already defines everything in the class, so the user could take advantage of these topics right away. The class covered HVAC (heating, ventilating, and air conditioning), piping, and electrical items.

AU is already over, but if you want the handouts or datasets for the lab, let me know and I’ll send you a link.


And for all the folks that came in, spent 90 minutes and walked away with a fresh perspective, or learned something new, and showed your appreciation – I can’t thank you enough. We’ll see you again next year!

Thursday, January 10, 2013

Getting in the Flow with Revit HVAC


Been spending some time trying to get more into the sizing part of duct for Revit… we’ve been working on a project for a client that required well formed systems.  When I turned the duct systems checking tools on, I kept getting some really nasty little errors that I couldn’t figure out…and a couple of items that should work, that didn’t…at least from my understanding of how duct systems should be defined. So here’s the notes from what I learned.

         Regardless of whether the program can define a system when adding  a duct or not, I found that systems normally aren’t “well connected” when you follow this method. I’ve gotten repeated errors, that I believe came down to how I was adding the duct.  The safest method for defining a system and getting the duct sizing results needed, is to create the system first by selecting the targets, such as air terminals. Selecting the source equipment (such as a VAV) once you’ve defined the duct system usually creates the most stable system, and results in the fewest errors with the data tables.

         This includes upstream systems, such as the primary air supply to the VAV boxes. One big issue we’re having with vendor provided air handling units is the lack of good, clearly named connections. No matter who the vendor is, open the family up and put in a connection name, such as primary supply or return air intake. This way, when you are defining the upstream systems, you can select the correct connection even if there are multiple connections.

         The biggest problem I ran into happened in regards to the flow direction settings at the connectors. In order for a system to be sized correctly, the source (such as the VAV box) should have the flow direction set to OUT, and the Flow Configuration set to Calculated:
  
         A loss method should also be specified – so if you set this to specific loss, make sure you put a value in here – leave it at 0 and you’ll get an error.

         The reciprocal is on the target, or air terminal. Check the flow connection, and make sure it’s set to In for supply air, and leave the flow configuration set to either preset or system. The default air terminals are set to Preset, but you can change this. If it’s set to Preset, flow factor is disabled, and you can set the loss method to coefficient or specific loss. As with the VAV, if no value is set for specific loss for pressure drop, you’ll get an error.
          
When using the Calculated/Preset combination, the airflow for the equipment is set to match the total airflow assigned to all components downstream. If you have 10 diffusers at 50 CFM, that means you’ll have 500CFM assigned to the VAV box as the calculated value in this configuration.

System flow configuration is a little different – instead of using an aggregate airflow total from all diffusers, the system will calculate the equipment airflow based on a percentage allocated to each air terminal.  If you set the flow configuration to System, and have the loss method set to specific loss, you can specify a flow factor (using a factor between 0 and 1 – with the total of all air terminals equal to 1):

If the loss method for a system flow configuration is set to Coefficient, then you can also set the loss coefficient value for the connector itself(and pressure drop will be disabled):

As with the specific loss method, if you leave these values set to 0, you’ll get an error.

Be aware that Revit already has a loss coefficient tables defined for fittings, based on ASHRAE  Duct Fitting Database, which assigns a loss to specific fittings and accessories. By assigning a coefficient directly to the air terminal, the Equal Friction/Static Regain methods for duct sizing will return better results.

If you are using specific loss, I’d recommend using a shared parameter for that value, so it can be changed without having to directly edit the connector in the family. Use the Associate Parameter tool to add the parameter. By using a shared parameter, you can also include this as part of a schedule or tag.

Here's the help file's description of what each of these settings is for:


This should help you a few of those nagging duct sizing issues - have a great day!

David B.