Hi Modellers,

In EnergyPlus, we are attempting to model the part load performance of an air cooled chiller by generating custom performance curves using the E+ HVAC curve fit tool. We are unsure exactly what performance data to request from the manufacturer to do so.
For the biquadratic CAP_FT and EIR_FT, we plan to request data at various Leaving CHW Temperature (say 44-54?F) and Outdoor Air Dry Bulb Temperatures (~55-105?F). However, to define the load on the chiller at these points, we need to specify more information.

? Should CHW flow rate be held constant at 2.4 GPM/ton (AHRI)?

? Should Entering CHW Temperature be held constant (~54?F)? I imagine not because there would be no Delta T when you reset leaving CHW Temperature up higher. So, should the CHW delta T be held constant instead?

For the quadratic EIR_FPLR, at 100% load, the ratings would be at AHRI conditions: 2.4 GPM/ton, 54/44?F Entering/Leaving Chilled Water Temperature, 95?F Outdoor Air Dry Bulb Temperature. For part load ratios:

? Should CHW flow rate be varied with a fixed Entering CHW Temperature? Or vice-versa?

We would appreciate insight from anyone who has run into this before!

Thanks,
Kyle