Inside the System

Heating and Cooling Loads in Autodesk Revit MEP 2010: Building Service Type

If you’ve been calculating heating and cooling loads in Revit MEP 2010, you may have wondered how the new Building Service parameter affects the analysis.

Heating and cooling load calculations are affected by variables that are extrapolated from the Building Service type. The most important variable is the Calculation Type, which is set to either Constant Volume, Variable Air Volume, or Radiant.

 

Most of the building service types are Constant Air Volume or Radiant (almost the same). The Variable Air Volume types include the acronym “VAV” in their naming convention. 

There are also smaller characteristics determined by the service type, such as whether Use Reheat or the Fan Configuration (Blow Through or Draw Through) is used. These inputs help determine some of the zone-specific loads.  Currently all of the service types use draw-through as the fan configuration.

 

The following table indicates the Building Service type variables that affect the heating/cooling load calculations.

 

Building Service Type Variables

Building Service Type	Calculation Type				Fan Configuration
	Constant Air Volume	Variable Air Volume	Radiant	Use Reheat	Blow Through	Draw Through
Central Heating: Radiators			x			x
Central Heating: Convectors			x			x
Central Heating:  Radiant Floor			x			x
Central Heating:  Hot Water	x					x
Other Room Heater	x					x
Radiant Heater – Flue			x			x
Radiant Heater – No Flue			x			x
Radiant Heater – Multi-burner			x			x
Forced Convection Heater – Flue	x					x
Forced Convection Heater – No Flue	x					x
VAV – Single Duct		x				x
VAV – Dual Duct		x				x
VAV – Indoor Packaged Cabinet		x				x
VAV – Terminal Reheat		x		x		x
Fan Coil System	x					x
Induction System	x					x
Constant Volume – Fixed OA	x					x
Constant Volume – Variable OA	x					x
Constant Volume – Terminal Reheat	x			x		x
Multi-zone – Hot Deck / Cold Deck	x					x
Constant Volume – Dual Duct	x					x
Radiant Cooled Ceilings			x			x
Active Chilled Beams			x			x
Water Loop Heat Pump	x					x
Variable Refrigerant Flow	x					x
Split System(s) with Natural Ventilation	x					x
Split System(s) with Mechanical Ventilation	x					x
Split System(s) with Mechanical Ventilation with Cooling	x					x

Information in this post provided by Dylan Reid, Martin Schmid and Michael Lavoie

Create ANY Pipe System in Revit MEP

YES.. it is true - it is possible to create ANY pipe system in Revit MEP - that is, you can name a pipe system whatever you want (O2, NO, N, G, Wilma, etc...), and use View FIlters to show/hide as desired.  Refer to the Video below to find out how. Once you start the video, you may want to right click, and selct Zoom > Full Screen.

Create Any Pipe System

Note, for this to work as demonstrated, you must have Revit MEP 2009 with the Web Update 3 Service Pack.

Martin Schmid, P.E.
MEP Customer Success Engineer
Autodesk, Inc.

Revit MEP text_file_lookup and Lookup Tables

The way the parameters work that use the text_file_lookup is that the function ‘looks up’ a value from a table based on values that are specified when creating (or modifying) an instance of the family.  If the ‘look up’ is not able to find a value in the table, a default value (specified in the function’s parameters) is used. 

Click Here for the full document.

Martin Schmid, PE
MEP Customer Success Engineer

Revit MEP 2009 Web Update #1 Released

I wanted to let you all know that we just released the Revit MEP 2009 Web Update #1.  You can download it here.


This Web Update includes numerous fixes to reported issues and performance optimizations, which are documented in the Web Update Enhancement List found on the Download Page.


Go get it!

But What if I Don't Want to Edit XML?

There's a whole lot of variety in the MEP world; from the different system types that can meet the occupancy requirements of a building, to the different standards that can be used to create each of those system types, to the different materials and connection types that can be used to for a given standard for a given system type...you catch my drift.

The Wall of Blinking Lights, Switches, and Knobs

For us as a product team, it means that we need to architect an application that is flexible enough to meet those needs, but is not a "wall of blinking lights, switches, and knobs".  While the "wall of blinking lights, switches, and knobs" certainly does accomplish the task, it's not the most usable or learnable solutions.

The guy who's been working at that wall for 10 years?  Well he's got that wall down, ask him to do something and he know which knob to turn to get the desired result.  If that guy gets hit by a bus, or decides he wants to work somewhere else, then the next guy just kind of stares at the wall in awe while there is a near meltdown because the Safety Inspector in Sector 7G is working from home due to an obesity disability claim (Simpsons referenece).

The contrary solution involves good UI design, user testing, and a lot more resources.  Therefore, as a product team we must pick and choose where we apply our finite resources to provide the more usable and learnable product, while still making sure it is still a capable one.  Just a little insight into our decision-making process.

The Old Way - In an XML File

With that in mind, we've made a nice step (admittedly biased opinion) forward with Revit MEP 2009 regarding a piece of functionality that was previously such a "wall of blinking lights, switches, and knobs".  As a way of delivering the aforementioned application flexibility, we previously kept record of the sizing information available for both Pipes and Wire for a given Revit project in XML files.

We willed these XML files with the information we felt was needed for a good chunk of our users' projects.  But, due to the aforementioned variety in the MEP industry, there was need to add more information to these XML files.  Simple enough, if you were comfortable editing XML files.  That is a big "IF", and certainly not the most learnable or usable solution.

Add to that fact that for projects with customized XML files, those XML files had to be accessible to every user working on that project, or else some users would not be able to use these custom sizes/materials.  This created an additional coordination hurdle for CAD/BIM Managers.

In short, we had a bit of a "wall of blinking lights, switches, and knobs" on our hands.

The New Way - In the Project

So in Revit MEP 2009 we have moved this previously XML-based information into the Revit Project file itself, creating a much more usable/learnable solution.  At the same time, we have made users aware that such capability existed in the first place...all good things.

Size List Migration

Note: Be sure to Right-Click->Zoom->Full Screen inside of the embedded video player to see it in all its 1024x768 beauty.  You you can download the full video by clicking on the linked title.

As you can see, this is a nice enhancement to the previously available functionality, and with the Transfer Project Standards functionality, it's a straightforward process to move your customized settings from one project to another.

Now, for those of you who managed to navigate the previous "wall of blinking lights, knobs, and switches", we did not forget about you.  Watch the following video for the process to migrate this previously customized data from Revit MEP 2008 into Revit MEP 2009.

Migrating Custom Settings from 2008 to 2009

Note: Be sure to Right-Click->Zoom->Full Screen inside of the embedded video player to see it in all its 1024x768 beauty.  You you can download the full video by clicking on the linked title.

I hope that helps to cover this new functionality.  As always posts comments/questions you have and I'll try to answer.

Making the Selection

A recent post on our discussion forums asked a pretty basic question about how to select multiple elements at the same time.  To me this is Revit 101, but the more I thought about it, the more I realized that I've had the luxury of learning this stuff from the gurus that roam the halls of the Revit Factory.  Not all of you have this opportunity, so hey, let's spread the wealth.

When you select something in a Revit view, it highlights in Red to let you know it's selected.  When I have multiple Elements selected, we call that a Selection Set.  If I have similar items selected, like Pipes and Pipe Fittings, I can make changes to all the Elements in the Selection Set, which is quite handy.

Being the huge dork that I am, I've put together a video explaining the various options in Revit to select Elements in a Revit view.

Selection Options in Revit

I know was probably a bit basic for some of you out there, but I've got to lay the foundation from time to time.  I hope you all learned something today, at the very least that my dork quotient continues to remain high.

Heating & Cooling Load Analysis in Revit MEP 2009

One of the most powerful value propositions of the Revit Platform is a model-based environment.  I knew that when I first read about the product and saw it years back, before I started working at Autodesk.  To me, the writing was on the wall...an intelligent model can be leveraged for so many design tasks.  Pretty pictures of your designs, composed with lines, arcs, and circles?  Well, let's just say that there's a little less long-term value embedded in such a deliverable.

One of the immediate values to MEP Engineers, even before they have made any major decisions about their building service designs, is to leverage the architect's model to determine the peak energy requirements of their design.  That peak energy requirement needs to be met by the building services, which are up to the MEP Engineer to design.  Their designed systems must remove from the building the peak cooling load in the summer, and add to the building the peak heating load in the winter.  How they go about achieving this task plays out later in the design process, but you must start with the energy requirements.

We understood this requirement at Autodesk, and saw the potential for Revit MEP to meet this need for MEP Engineers.  With the release of Revit MEP 2008 last year, we delivered the first version of this capabilty to our user base.  This year, we're delivering the second release of this capability, which takes advantage of the capabilities I have outlined extensively in previous posts.  Let's see how it all works.

Heating and Cooling Load Analsis in Revit MEP 2009

I'm sure you can see the value here, and the capabilities that we've provided to MEP Engineers even before they model a single duct, pipe, or circuit.  With the major capability of the application covered, we can move on the other enhancements that are delivered with Revit MEP 2009.

Note: For those of you checking the site for updates on a daily basis, why not just add my RSS Feed to your RSS reader?  That's how I keep up to date on my favorite blogs.

Building Performance Analysis - Spaces & Zones

The geometry defined by the Bounding Elements in the Revit Physical Model, in conjunction with the Volumes they define, make up a critical piece to accurate BPA.  Without the proper metadata to define the conditions in those Volumes, one must make a lot of assumptions to produce BPA results.  Like I spoke about in my last post, this metadata is the "fuel" that gets fed into our BPA capabilities.

In Revit MEP 2009, we define that information in 3 places:

• Project Information
• HVAC Zone Elements
• Space Elements

We covered the Project Information in my past post, today we're going to cover the fuel that exists on the HVAC Zone and Space Elements.

It's important to note that while this information exists on these elements, that information can be authored:

• In the Heating & Cooling Loads dialog: In this dialog you can multi-select Spaces or Zones, and author the information for all selected elements.
     
   
• On the Elements themselves: In a view you can select individual elements or multi-select elements and then author this data from the Element Properties dialog.
     
   
• In a Schedule: Much of the information can be scheduled in a Zone or Space schedule, and then be authored there.

Just like many other things in Revit, you have access to that same data in many interfaces, and a change in one location updates the core definition of that data.  That means that all locations update immediately.

2009 Improvements
With the release of Revit MEP 2009, we've completed two different categories of improvements to the metadata that exists on HVAC Zone and Space Elements.

• Additional "Overrides" of Space Assumptions - We make a lot of determinations for the environmental conditions based upon the Building Type/Space Type that's defined in the Revit Project.  We have allowed for explicit control over additional environmental conditions in Revit MEP 2009.  This will allow you to override the Building Type/Space Type assumptions if desired.
  
  For example, the Outside Air (AKA fresh air) quantities can now be explicitly defined by the user on the HVAC Zone, rather than be defined by the Builging Type/Space Type assumptions.
• Location of Metadata - The introduction of the HVAC Zone element creates a more logical location for some of our metadata than the Space Element, so we've moved some metadata to these more logical places.

Now let's cover this information in detail in a video.

Building Performance Analysis Data - HVAC Zones & Spaces

Next we're going to put this all to work and discuss using the Heating & Cooling Loads dialog to calculate the peak loads for our Revit projects.

Building Performance Analysis - Project Info

For those of your following along thus far with my overview of the upcoming release, we've covered the major changes to Volumes in Revit MEP, and discussed the new recommended workflows.  I hope all that is clear.

These volumes, in combination with the metadata associated with the volumes and project, constitute the input data required for our Heating and Cooling Load calculations.  Today we're going to take the next logical step, and discuss the metadata that's used as "fuel" for our Building Performance Analysis (BPA) capabilities.

Although I have been focused on "new things" for the past couple of weeks, this discussion is focused on all of the "fuel" that's used for our calcs.  In my cutting of the video, it seemed that this didn't hurt the process.  I hope this all makes sense to you all.

Building Performance Analysis Data - Project Info

Now you all can say "I know the data that's captured at a project-level for BPA calculations."  Tomorrow, I hope you can all say "I know the data that's captured on HVAC Zones and Spaces for BPA calculations."

Zoning it Up

Now that you've all had a day to calm down from the excitement induced by my last post, I thought I'd continue the momentum into the next logical step...creation of Zones.

Those of you familiar with Groups, MEP Systems, or MEP Circuits will feel right at home with the user interaction that's been implemented around Zones.  Spaces are the building blocks and you can either use existing Spaces or add them from within the Zone Editor.  There's my 2 sentence explanation of the workflow.  For a more detailed explanation, go ahead and watch my video below.

Zone Creation

As always, comments/questions/showering of praise is always welcomed.