Sizing tool

[judymin88]

When editing the HVACSizingControl section in the hpxml model (https://github.com/NREL/OCHRE/blob/main/ochre/defaults/Input%20Files/sample_resstock_properties.xml) and changing the field AllowIncreasedFixedCapacities from false to true, we noticed that the simulated indoor temperature didn't change and it had no impact in the simulation results (please see attached photo for more information:

). It is also triggering a bunch of warnings because the indoor temp is 30 plus degrees C. I ended up changing the CoolingCapacity manually to resolve the issue.

We were wondering what might be causing this issue? Coud it be improper configuration of the sizing tool?

Thank you!

FYI,
@yuyi-d

[mnblonsky]

OCHRE doesn't do any HVAC sizing calculations, it just takes the capacity values from the HPXML file. So the fix that you made is the recommended approach. I'd recommend using OS-HPXML if you want to resize the HVAC.

There are also some known issues with the current sample files. We're updating our example code and will hopefully have a new release in the next 1-2 months. In the meantime, you are welcome to look at this branch for updated example scripts and files.

[jmaguire1]

https://openstudio-hpxml.readthedocs.io/en/latest/workflow_inputs.html#id166 might be helpful. "AllowIncreasedFixedCapacities" is only used if a user manually entered an HVAC size in ResStock or BEopt when generating an HPXML.

OS-HPXML (which underpins ResStock/BEopt) natively do sizing calculations according to ACCA Manual J/S. Users can also enter fixed sizes (say if your replacing an existing 2 ton system). This field is only used if you enter a fixed size less than the ACCA calculations. Reproducing those ACCA calculations in OCHRE would be a lot of work, so most sizing inputs in HPXML are ignored (it's on our TODO list to give warnings is you specify an input in HPXML that OCHRE ignores, see #21).

Manually entering fixed capacities is your best bet for changing HVAC sizes at the moment.

@judymin88