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Can EnergyPlus output report chiller energy consumption associated with a process chilled water load?

asked 2017-01-23 13:26:32 -0500

Molly Curtz gravatar image

updated 2017-01-23 14:34:58 -0500

In EnergyPlus, we are using LoadProfile:Plant to apply a process chilled water load to a chilled water system. (It represents chilled water loading associated with water-cooled refrigeration racks.) Is there a way to report the (approximate) chiller energy consumption associated with this process load?

In DOE2.2 (eQuest) this was reported as chiller energy with an end use category of "Misc. Equip". I assume the reported value was determined by allocating a portion of the total chiller energy at each hour using the ratio of the process load to the total chilled water load for each hour. We can run the simulation with and without the process load applied to get a better answer, but I wondered if there is a similar approximate answer available in EnergyPlus.

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answered 2017-01-24 12:41:56 -0500

updated 2017-01-24 23:16:21 -0500

You could use the Output Variables for the LoadProfile:Plant to output the heat transfer rate to the refrigeration load, use the Output Variables for the PlantLoop to output the total load on the plantloop, and calculate the percentage of the load that refrigeration load represents. Then, you could report the total chiller energy and multiply by the percentage to estimate the total chiller energy used to serve the refrigeration loads.

Update:

To automate this, you could:

  1. Make an EMS Actuator for each output variable
  2. Make an EMS Program to do the math to calculate the result
  3. Make an EMS Output Variable to report out the resulting timeseries.
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Good idea. Thanks very much for this suggestion. I think you are suggesting this would be done in post-processing. Is there a way within EnergyPlus to create a custom, calculated, report variable? Still, your suggestion will be easier & faster than running the simulation twice.

Molly Curtz gravatar image Molly Curtz  ( 2017-01-24 14:03:36 -0500 )edit

Yup, see update.

aparker gravatar image aparker  ( 2017-01-24 23:16:29 -0500 )edit

Great! Thank you!

Molly Curtz gravatar image Molly Curtz  ( 2017-01-25 12:40:35 -0500 )edit

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Asked: 2017-01-23 13:26:32 -0500

Seen: 188 times

Last updated: Jan 24 '17