[Equest-users] CHW coil model documentation

[Erik Kolderup]

Anyone know where to find documentation of DOE2.2's chilled water cooling
coil model? I see keywords listed in the help system for the CHW model,
such as the CHW-CAP-FEWBEWT curve, but I haven't found any documentation
about how all the curves are used together to calculate coil performance.

I ask because my hourly outputs show physically impossible results. I have
a single CHW coil with 2-way valves. At low load the CHW flow drops, which
is expected. But it drops so much that the reported leaving water
temperature is far higher than the entering air temperature. For example, I
get 80F water leaving the coil when the entering air temperature is only
60F. The heat balance works out when comparing the air-side and water-side
loads based on the hourly outputs. But the leaving water temperature is
much too high, i.e. flow too low.

For reference, the system has 40F CHW entering the coil, 48F air leaving
the coil (hospital operating room), and constant airflow.

Thanks for any insights.

*Erik Kolderup, PE, LEED AP*
erik at kolderupconsulting.com | 415.531.5198 | www.kolderupconsulting.com
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