Hydra JV3 Code Compliance Script

Hi @chris , this is great! Thanks so much for everyone involved putting this together!

One thing that I have noticed overviewing the file and maybe could be included (and unfortunately I don’t know how to do it) is that depending on the climate zone we need to reduce the R-value of the south facing walls by 0.5 in the reference model.

@mtonellis ,
Thank you for the feedback and for taking a look at the script. I will add something in now that allows you to reduce the R-value by 0.5. I don’t know if I am understanding the table correctly. Am I right in understanding that only these cities need to have - 0.5 R-value:


… and these cities do not have this:

Port Headland
Richmond RAAF
Wagga Wagga

@mtonellis ,
I pushed a change to the example file assuming that the climates above follow the condition of having Wall R-values with - 0.5:

Let me know if you get the chance to check it out and confirm that it is working as you expect.

Hi @chris, you are kind of right. But there are more weather files and areas than the 10 defined cities.
Maybe it would be better to break down in Climate Zones 1-8 (instead of cities) to define the properties of the reference model and Weather File to select manually the one closer to the project site you are analyzing.

Another thing is that walls shaded by a projection angle more than 30 degrees (orange marker in the image below) reduces the r-value of the wall for the reference model aswell …
In my opinion there a lot of conditions to be analyzed to define the r-value of walls. Maybe if we add another part in the end to overwrite some r-values of particular orientations or external walls for finer analysis.

I believe having a preview of both files side by side (reference and proposed) with information about the r-values and glazing would be a good way to QA this issues we have been discussing before running the simulations.

Thanks again ! Its an amazing work.

@mtonellis ,

Ok. So is the climate zone just the ASHRAE climate zone or does Australia have its own climate zoning system?

For some reason, I thought those cities were selected because they were representative of some Australia climate zones. Maybe I just didn’t realize that ASHRAE is used in a lot of other places outside of the US.

If it’s just the ASHRAE climate zones, we can import the .stat file that sits next to the .epw to automatically set the south wall R-value based on the climate zone.

For the 30 degree angle projection, maybe we just pick the more conservative R-value for the baseline since this seems like we are letting the edge cases drive the core functionality of the tool. We can do a QA visualization in the Rhino scene, though, as that is easy to set up.

Ok. I just set it to read the ASHRAE climate zone since these seem to be the same as the US’s ASHRAE climate zones:

I also fixed a few minor errors that @Edmund made me aware of including:

  1. Changed OA per person to 0.0075 m^3/s

  2. Defined Solar absorptance for reference roof to 0.7 (default 0.7)

  3. Defined Solar absorptance for reference wall to 0.6 (default 0.7)

Actually, now that I check it, it seems that the ASHRAE climate zone of Melbourne is 3 but the Australian Climate zone is 6. If anyone knows if it’s possible to get the Australian climate from the EPW or STAT data, please post here. Otherwise, we can add a manual input for Australian climate zone.

Hi @chris , sorry for the late response. Yes, Australian Climate Zones:


I’m not sure if you can get this information from the weather file.

Kind regards,

The problem is, climate zones don’t correlate between Australian BCA and ASHRAE.
I did a quick comparison, but even by looking at two maps, they split the country in different ways.

Ashrae BCA
Canberra (CTA) 4a 7
Sydney (NSW) 3 5
Penrith/Richmond (NSW) 3c 6
Bathurst (NSW) 3c 7
Griffith/Dubbo (NSW) 3c 4
Melbourne (VIC) 3c 6
Brisbane/GC (QLD) 2 2
Cairns (QLD) 2a 1
Adelaide (SA) 4 5
Albany (WA) 3c 6
Perth (WA) 3 5
Alice Spring (NT) 2 3
Darwin (NT) 1 1
Hobart (TAS) 4a 7


Hi All,

I was playing with this today and note there is an issue in the glazing calculator cluster.
There is anomalies in the code the calculate an SHGC >1 for a small number of scenarios.

I have added an equation to the cluster.

Let me know if this is unclear.


Thank you for all of your comments and feedback. I have just pushed an updated version of the script to the hydra download link. The new Grasshopper def now has the following fixes:

  • I no longer use the ASHRAE Climate zone and I added a list of climate zones that correspond with the city selection in the slider in the upper left.

  • I added @Sam 's fix to the cluster.

If anyone else finds anything that needs to be changes, just post here and I will make sure that it gets into the file.

Hi all, there is an issue with the REFERENCE MODEL that it is not creating the core zones that I can’t find a solution. I believe it has to do with the last update when applying a different wall performance to the south zone.

@mtonellis ,

Good catch. There was a small bug in the script and I have just fixed it in the online example:

Thanks for reporting and I apologize for the late response.

hey, the updated file shows different issues when the schedules are turned on, also it shows different errors at the end part for different classification of the building. when the schedules are turned one is unable to analyze the result.

Hi guys,
Testing different building classes I ran into a problem

export to OS:

  1. Solution exception:‘AirTerminalSingleDuctParallelPIUReheat’ object has no attribute ‘setZoneMinimumAirFlowMethod’

It’s been raised here before, but there was no response.

Is it still an issue, or there’s a way to resolve it?

Also, it’s necessary to add “Temperature” in the shedTypeLimits for HeatSetPt and CoolSetPT to run the calc.


@ishanshah4343 ,
I see that there was an issue where the original file did not specify that thermostat setpoints were supposed to use temperature values and not fractional ones. I just fixed this in the file at the github issue.

@ale_bog ,
Thanks for bringing that to my attention and I should have responded to Leland a year ago. I just responded now and pushed a fix for the specific error that you found:

…so everything should work fine now without errors.

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i have changed the python script of the given component ‘export to open studio’, how ever it shows error and also you need to add one more variable in the component named
’ HVACSystem_’

Thank you, Chris, for such a prompt response on the issue.
I updated HB and ran the script, everything works now.

@ishanshah4343 ,

Just re-download the file from the hydra example. Some of the inputs changed on some of the components so updating the file yourself requires some manual replacement of components. It’s likely faster to just start from the hydra example.