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how do we make a net-meter (PV generation - loads)?

asked 2015-02-25 12:22:24 -0500

tropo's avatar

updated 2015-07-11 16:57:28 -0500

As an HVAC engineer I see a massive opportunity to design building integrated PV to match the demand side. I suggest "west is best" outlook for facade PV to reduce demand late afternoons in summer.

OpenStudio's results-viewer is very powerful in partially answering my question ... just select the two meters and right-mouse options appear to subtract as required.

But how do we make a net-meter (PV generation - loads) measure to write a report on export to the grid?
That is what a homeowner gets paid for if they have a good contract from the power network.

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Tropo I just retagged your question to include the modeling software you are using.

Benjamin's avatar Benjamin  ( 2015-02-25 12:37:03 -0500 )edit

@Benjamin I might have simultaneously re-re-tagged.

MatthewSteen's avatar MatthewSteen  ( 2015-02-25 12:38:37 -0500 )edit

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answered 2015-02-25 16:14:39 -0500

EnergyPlus has a built-in way to get the net metered values: Output:Meter,ElectricityNet:Facility;. There are a few other meters you can request, such as ElectricityPurchased, and ElectricitySurplusSold. See the documentation for Meters in EnergyPlus for more details.

In OpenStudio, you can request these meters via a Reporting Measure. Here is what the energyPlusOutputRequests section of the measure.rb file should look like:

  def energyPlusOutputRequests(runner, user_arguments)
    super(runner, user_arguments)

    result = OpenStudio::IdfObjectVector.new

    # use the built-in error checking
    if !runner.validateUserArguments(arguments(), user_arguments)
      return result
    end

    result << OpenStudio::IdfObject.load("Output:Meter,ElectricityNet:Facility;").get

    return result
  end
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I'm running into a problem using PVWatts to add rooftop PV to a model where Electricity:Facility = ElectricityNet:Facility even though PV is "supposedly" successfully added to the model.

I think this may be a problem with the meter output variables in the idf or a bug in E+.

sashadf1's avatar sashadf1  ( 2024-07-01 17:38:48 -0500 )edit

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Asked: 2015-02-25 12:22:24 -0500

Seen: 264 times

Last updated: Feb 25 '15