Reference Condenser Fluid Flow Rate in the AirCooledChiller.idf data set file

Locate the AirCooledChiller.idf data set file and compare each chiller's Reference Condenser Fluid Flow Rate with its Reference Capacity. Read the Input Output Reference guidance for the autosizing calculation, then determine whether the dataset should use calculated explicit values or autosize fields. Done means the chiller objects no longer share the incorrect 0.0011 m3/s value and the dataset is consistent with the documented method.

Issue overview

It was reported by a user that in this data set file, the “Reference Condenser Fluid Flow Rate” field seems to be incorrect across multiple (actually nearly all) chiller objects as 0.0011 m3/s. This can be demonstrated in the last line in following snapshot:

According to the Input Output Reference, the autosizing for this field is based on 0.000114 m3/s/W (850 cfm/ton) multiplied by the chiller Reference Capacity. This means that: first, this field should be different for each object based on the Reference Capacity (the first field in the figure above); and further, the current 0.0011 m3/s value for all the objects is based on roughly a 10W Reference Capacity (of the chiller), which seems to be too low.

One way the users can do is to choose the “autosize” field, which would then have the field autosized based on the calculation method above (0.000114 m3/s/W times the Reference Capacity Wattage).

On the other hand, for this data set file, the field values should be revised (e.g. based on the method described above to reflect some realistic value, or more ideally, based on data from actual equipment catalogs) if the values are explicitly supplied there.

Details

Some additional details for this issue (if relevant):

• Platform (Operating system, version): All
• Version of EnergyPlus (if using an intermediate build, include SHA): at least from v8.8 to v9.5
• Helpdesk ticket number: 15769

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)