AirflowNetwork Duct Autosizing Bug

Issue overview

When the example file was tested, I found that duct sizing is not performed and an additional warning was shown due to small logic error.

   ** Warning ** AirflowNetwork::Solver::get_input: AirflowNetwork:Distribution:DuctSizing object, 
   **   ~~~   ** The number of AirflowNetwork:Distribution:DuctSizing is not avalable. The current requirement for Duct Sizing requires a single object.
   **   ~~~   ** ..Duct sizing is not performed

There are no outputs Duct sizing values in eio

The test file is AirflowNetwork_MULTIZONE_House_DuctSizing.idf

Details

Some additional details for this issue (if relevant):

• Platform (Operating system, version)
• Version of EnergyPlus (if using an intermediate build, include SHA)
• Unmethours link or helpdesk ticket number

Checklist

Add to this list or remove from it as applicable. This is a simple templated set of guidelines.

• Defect file added (list location of defect file here)
• Ticket added to Pivotal for defect (development team task)
• Pull request created (the pull request will have additional tasks related to reviewing changes that fix this defect)

Start with the AirflowNetwork duct-sizing handling and the test file AirflowNetwork_MULTIZONE_House_DuctSizing.idf. Reproduce the example to inspect the warning and missing duct-sizing values in the eio output, then trace why the single DuctSizing object is not recognized. Done means the example performs duct sizing without the warning and produces the expected eio outputs.