Hi Chris @chris and others,
I’m working on a Dragonfly + URBANopt workflow to simulate a 300m × 300m residential block using district heating. I noticed that the URBANopt simulation runs successfully when no HVAC system is assigned (i.e., exporting a geometry-only model without HVAC).
However, when I assign certain HVAC templates, the simulation fails during the OpenStudio model conversion step, even though the same model runs normally when other HVAC templates are selected.
For example, the model runs successfully with:
- DOAS with fan coil chiller with gas unit heaters
However, when I switch to other HVAC types (such as PSZ-AC with baseboard district hot water), DF Run URBANopt returns an error indicating that uo cannot execute or the workflow stops during OSM-to-IDF conversion. The same building geometry, schedule, and scenario settings are used—only the HVAC template is different.
Environment
| Item | Version |
|---|---|
| OS | Windows 10 |
| Rhino / Grasshopper | Rhino 8 |
| Ladybug Tools | 1.9.0 |
| URBANopt CLI | 1.0.1 |
| OpenStudio CLI | 3.9.0 |
According to the Solution exception, I checked the run.log files. Hier ist one of the log files contents:
Error Log
[20:09:22.932201 ERROR] [ruby] Error activating gem :/ruby/gems/3.2.0/specifications/matrix-0.4.2.gemspec
[20:09:22.933227 ERROR] [ruby] Error activating gem :/ruby/3.2.0/specifications/rake-13.2.1.gemspec
[20:09:22.934782 ERROR] [ruby] Error activating gem :/ruby/3.2.0/specifications/ast-2.4.2.gemspec
[20:09:22.939392 ERROR] [ruby] Error activating gem :/ruby/3.2.0/specifications/openstudio-extension-0.8.2.gemspec
[20:09:34.503881 ERROR] [openstudio.measure.OSRunner] SWIG director method error. NoMethodError: undefined method `empty?' for nil:NilClass
Traceback (most recent call last):
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/openstudio-standards-0.7.1/lib/openstudio-standards/prototypes/common/objects/Prototype.hvac_systems.rb:6896:in `model_add_hvac_system'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/hvac/Model.hvac.rb:414:in `add_cbecs_hvac_system'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/hvac/template.rb:92:in `to_openstudio'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/model.rb:604:in `block in create_hvacs'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/model.rb:577:in `each_value'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/model.rb:577:in `create_hvacs'
C:/Users/zmy49/simulation/TestModel/.bundle/install/ruby/3.2.0/gems/honeybee-openstudio-2.38.19/lib/to_openstudio/model.rb:209:in `create_openstudio_objects'
C:/Program Files/ladybug_tools/resources/measures/honeybee_openstudio_gem/lib/measures/from_honeybee_model/measure.rb:116:in `run'