Link Sizing for SWHC005 Water Cooled Chiller

[behzadsalimian]

Attempts to run models for SWHC005 water-cooled chiller using the link sizing approach as follows:

• Implemented linked sizing (sizing_case) so that the measure case follows baseline case capacity.

• Disabled EMS per PR #60.

• Still receiving sizing errors for some building types (e.g., ESe, EUn, ECC). These appear tied to missing Sizing:System objects (SZ-VAV Unitary).

This was achieved by adding the sizing_case column to the case files. In addition, we set the parameter “disable_ems = True” (per Pull Request #60) to disable EMS and ensure proper linked sizing. (See screenshot below)

Despite these adjustments, we continued to encounter errors for some building types (ECC, Ese, Eun), specifically:
“No Sizing:System objects were entered,” which appears related to SZ-VAV Unitary systems.
See error for ESe building type:

To re-run the simulation and review the bug related to link sizing we've created a pull request PR#41

[behzadsalimian]

Attempts to run models for SWHC012 HVAC occupancy sensor using the link sizing approach per CPUC comment as follows:

https://www.caetrm.com/measure/SWHC012/measure-log/2025-08-11-36739/#reply

• Implemented linked sizing (sizing_case) so that the measure case follows baseline case capacity.

• Disabled EMS per Disable EMS to fix linked sizing #60.

Still receiving sizing errors for some building types (ESe, EPr and ERC). These appear tied to missing Sizing:System objects (SZ-VAV Unitary). Attached is the simulation error regarding the link sizing approach for review.

[nfette]

Solaris Technical team worked on resolving the issue with the following:

1. Modelkit lacks a sizing map file for EnergyPlus 22.2
2. Errors seem to be triggered mostly by building types with Coil:Cooling:DX:Multispeed object
3. We focused on outputs from Coil:Cooling:DX:Multispeed which is present by default in a subset of commercial building types. We observed a possible bug in EnergyPlus that the Speed 2 coil capacity output is being mislabeled as evaporator pump power. Per example outputs below (ESe), the evaporator pump power column = 2 * speed 1 capacity, so it is likely actually speed 2 capacity (which is the missing output we need for linked sizing to work with that component)

commercial measures\SWHC012-05 Occupancy Sensor\SWHC012-05 Occupancy Sensor_Ex\runs\CZ01\ESe&0&cDXGF&Ex&HV_Tech__OccSens\NE-HV_Tech-OccSens-cDXGF-NoOccSens\instance-size-tbl.htm

[nfette]

I have developed a workaround to the EnergyPlus output field labeling bug by using the "incorrect" field names in the sizing map file. After some additional debugging to QC the sizing map file, I am able to get linked-sizing to work in commercial models with SWHC012. See simularis#45.

To apply the new sizing map file:

1. Copy the sizing map file into modelkit, e.g. "C:\Program Files (x86)\Modelkit Caboodle\lib\rubygems\gems\modelkit-energyplus-0.3.0\resources\sizing-map\22-2.csv"
2. Update the rakefile:

_, count, output_file = Modelkit::EnergyPlus.size(sql, input_file, {json: size_json_path, version: "22-2"})

If you try this for another measure and get an error, there may be additional object types and output fields in building types and HVAC variations that I did not test. To debug, look for any input fields in the measure case model file ('instance-hardsize.idf') with a value of 'Autosize', and determine the input field index number (1 = name, 2 = next input field, ...). Then, open the base case HTM output file and find the corresponding "input field description" from component sizing summary. Add a row to the sizing map file for the given object class, input field description, and input field index number. Please share any missing rows here.