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Electricity:Facility [J] and ElectricityNet:Facility [J] are the same for a building with PVWatts solar system added

asked 2024-07-02 16:59:21 -0500

sashadf1's avatar

updated 2024-07-03 14:21:37 -0500

I am modeling the RefrigeratedWarehouse.idf from EnergyPlus example files with a PVWatts System added.

The PVWatts objects are translated from the ASHRAE 90.1 Std 2022 Warehouse.idf (from the PNNL commercial prototype buildings). The model runs successfully without error but I am having issues with reporting the metered outputs related to PV.

The issue is that in the Meter.csv, Electricity:Facility [J] == ElectricityNet:Facility [J] for all timesteps.

ASHRAE 90.1 Metered Electricity: ElectricityNet ASHRAE 90.1 Warehouse

RefrigeratedWarehouse Metered Electricity: ElectricityNet RefrigeratedWarehouse with PVWatts

This occurs for both the ASHRAE 90.1 Warehouse idf and the RefrigeratedWarehouse.idf with PVWatts objects added.

I'm wondering if this is a bug in E+ or an issue with the reporting objects in my idf. If it were a problem with the PVWatts objects, an appropriate error message should have been thrown, so I think an E+ bug or issue with reporting objects is more likely.

I will try calculating Net Electricity following the procedure outlined in the Engineering Reference for Whole Facility Electric Service. For this, I will need to request the following meter variables and ensure that they vary with the DC system capacity input in the PVWatts objects.

  • meter Photovoltaic:ElectricityProduced
  • meter PowerConversion:ElectricityProduced

If someone lets me know a best practice for uploading idfs to an Unmet Hours post, I will add both the ASHRAE 90.1 idf and the Refrigerated Warehouse.idf.

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Starting with the obvious question first... your screenshots occur at night when there is no solar. Do you see the same result for times of the year when there is solar? FWIW, I just ran a file w/ PVWatts and see the expected differences.

shorowit's avatar shorowit  ( 2024-07-03 11:38:06 -0500 )edit

Wow...can't believe I didn't notice that. Thanks Scott. I will remove the bug notice I placed on E+ github right away.

sashadf1's avatar sashadf1  ( 2024-07-03 14:28:07 -0500 )edit

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answered 2024-07-03 14:30:07 -0500

sashadf1's avatar

The issue was looking at design day data at night, not during the day. Very obvious that there is no PV generation at night! There is no problem with the ElectricityNet:Facility variable; though now that I have the data and understand the method necessary to calculate ElectricityNet:Facility manually, I will do so to ensure that E+ is operating under the hood as intended.

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Asked: 2024-07-02 16:59:21 -0500

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Last updated: Jul 11