Vern Smith's profile - activity

Under the Tools Menu, select Optimisation/Parametric Analysis Settings. From there, under Design Variables enter the variables that you want to explore. The Parametric settings can also be accessed under the Simulation tab. DesignBuilder creates a copy of the base model, changes the specified parameters, and runs the simulations. Be sure to read the help files before starting this. Start simple, one variable at a time, to learn how the process works.

Another way to do it is to copy the base model (save as a different name), make changes, and run it. Do this for each scenario you want to review. So, changing the roof U-value from 25 to 40 in increments of 5 requires 4 separate simulations.

Thanks, Matt. I had reviewed the Q&A's here as well as researched the EnergyPlus documentation that you referenced before posting. For this particular zone, which does not have a cooling system, I set the cooling setpoint to 99 F (even tried 150 F, same result). My thinking was that it should report hours above 99 F, but instead it's reporting all hours above 76 F. The Tolerance for Time Cooling Setpoint Not Met is 1.11 C (2 F) in DesignBuilder, and to the best of my understanding this variable affects all reported zones, not just my vestibule. I think there may be another issue.

I am using Design Builder ver 5.0 to model a small retail store with an entry vestibule that has a small electric cabinet heater, but no cooling unit. The vestibule floor area is 5-ft by 4-ft and has an exterior glass door, an interior glass door, large windows on two sides, and is exposed to ambient on three sides. In the summer it's basically a walk-through oven. Not a good design solution, but one that we've all experienced. For purposes of ASHRAE 90.1, I think it is classified as a conditioned heated space. The simulation location is in Climate Zone 6B. The zone heating setpoint is 50 F and cooling setpoint is 99 F. The maximum simulated dry bulb temperature is 105 F, but zone cooling set point not met time exceeds the number of hours when the temperature is above 99 F. From the attached chart, it appears that the simulation controls think the cooling set point is around 74 F, which is the cooling setpoint for other zones in the store. I have turned off mechanical cooling and the Design Builder inputs require a number between -58 F and 176 F. I need to reduce or eliminate the unmet hours. So, my question is, how does EnergyPlus (or Design Builder) determine the setpoint for calculating unmet hours for a zone? What have I overlooked? EntryVestibuleCoolingSetPointNotMet.png

I don't think it undergoes a public review, but there is definitely a review by an internal panel selected by ASHRAE.

Interesting. Within minutes of sending my original question, I found another workflow that worked perfectly. I used: Extensions > Open Studio User Scripts > Alter or Add Model Elements > Merge Spaces from External File.

On to dealing with the atrium spaces!

I am modeling a three story (basement + 2 floors) 35,000 sf institutional cafeteria with complex floor plans. There are three atrium spaces in the above ground portion. So far I have created spaces for each floor using imported DWG files. The atriums are divided horizontally by floor at this point. I used a workflow based on this link: (https://unmethours.com/question/3951/...). It seemed to work very well to stack the three floors in the proper position. The geometry showed up as white spaces. I saved and closed the osm file, restarted Sketchup and opened the osm, there was no geometry at all. It occurred to me that perhaps some of the space names were identical, so I repeated the process after assigning unique space names and had the same results.

I am using Sketchup Pro 2016 and OpenStudio on a Windows 64-bit machine.

Any ideas on the best workflow? Thanks!

@rpg777, Thanks, that was the issue! I watched one of your videos before running it, so I should have realized that it needed to run in the measure workflow.

Hi, I am using EP version 8.5.0, OS 1.11.0 on Windows 7 64-bit. When I run the simulation with the Radiance Measure (Apply Measure Now) it terminates with the following error message.

A copy of the weather file is located here: C:\Users\Vern\AppData\Local\Temp\OpenStudio.nP3000\resources\files, so I'm not sure why the script can't find it. I did not see any other Unmet Hour questions/answers that dealt with this.

Any ideas?

Thanks, Vern