Externally Calculated Renewable Energy as Input to EnergyPlus

asked 2016-09-06 17:39:29 -0600

updated 2016-09-07 14:29:07 -0600

Hi Modeling Community,

I am calculated the amount of electrical and thermal energy collected from a renewable energy system externally to EnergyPlus. I would like to input the amount generated into EnergyPlus' energy balance but I'm not sure how.

Is there an electrical component that can read values from a schedule or actuator that can subtract energy? I found ElectricalLoadCenter:Generators but it seems to be overly complex and the Photovoltaic:Simple also requires specifications of a PV array.

What about a thermal energy input, maybe a heat exchanger or thermal storage tank? Edit: As a point of clarity, the thermal energy would be best added to an HVAC system input to reduce the load on a boiler.

Thank you for your time,

Justin

Edit 2: Still looking for a way to add renewable energy or subtract energy from the total building consumption.

Edit 3: Providing a negative value to ElectricEquipment does not appear as though it will work because it returns the below fatal error.

   ** Severe  ** Out of range value Numeric Field#1 (Design Level), value=-456.00000, range={>=0}, in ELECTRICEQUIPMENT=SPACE2-1 ELECEQ NEGATIVE
   ** Severe  ** IP: Out of "range" values found in input
   ** Severe  ** IP: Out of "range" values and/or blank required fields found in input
   **  Fatal  ** IP: Errors occurred on processing IDF file. Preceding condition(s) cause termination.

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I've never tried this but can you set a schedule with negative values for an ElectricEquipment object?

Jamie Bull ( 2016-09-07 13:56:22 -0600 )edit

@Jamie Bull I'll give it a try.

JustinShultz ( 2016-09-07 14:01:52 -0600 )edit

@Jamie Bull, no luck. I receive a fatal error regarding the Equipment Level being out of bounds. I have edited my question to include the full error message.

JustinShultz ( 2016-09-07 14:29:57 -0600 )edit

Ah well. It was a long shot. Another one - how about if you set the negative value in the schedule rather than the design level?

Jamie Bull ( 2016-09-07 16:26:25 -0600 )edit

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@Jamie Bull, I gave it a try and receive a very similar error. The schedule is checked for values >=0.0 as well. No luck.

JustinShultz ( 2016-09-08 09:35:18 -0600 )edit

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answered 2016-09-19 13:30:39 -0600

Archmage

7185 ●3 ●11

There is an example file called MicroCogeneration.idf that uses the Generator:CombustionTurbine to fake a wind turbine. The performance curves are set up so that it uses no fuel to make the electricity. In that file it is just a flat baseload power production, but the ElectricLoadCenter:Distribution object could be setup to track a prescribed schedule for renewable production.

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Apologizes for the delay but I have implemented the solution you provided and found it to work excellently. Thank you for provided a great example to get me started.

JustinShultz ( 2016-11-10 15:07:13 -0600 )edit

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answered 2016-09-06 18:41:30 -0600

MatthewSteen

10147 ●1 ●19 ●26 https://www.nrel.gov/b...

For thermal, take a look at the PlantComponent:TemperatureSource.

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Oh yes! I've used this component on a river cooling project but overlooked it for this application. Excellent suggestion, thank you.

JustinShultz ( 2016-09-07 09:53:49 -0600 )edit

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answered 2016-09-07 16:59:44 -0600

shorowit

11931 ●203 ●9 https://www.nrel.gov/b...

Not sure you necessarily want to go down this path, but you could use, e.g., Photovoltaic:Simple with default inputs and then overwrite its output by using an EMS actuator.

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Hello @shorowit, I would absolutely be willing to use an EMS Actuator. The root of my question stems from finding the connectivity points for an ExternalInterface:FunctionMockupImport. However, I'm not sure how I would write an actuator that would overwrite the generated energy. What would the Actuated Component Type and Actuated Component Control Type key words be? Do you have an example of EnergyPlus code that you can share?

JustinShultz ( 2016-09-08 09:30:05 -0600 )edit

Hi @shorowit, do you have any examples you can provide or should I start a new question to see if others can provide assistance? Thank you for your time.

JustinShultz ( 2016-09-09 11:42:44 -0600 )edit

I don't offhand. Maybe @Archmage can chime in with some guidance.

shorowit ( 2016-09-09 12:11:59 -0600 )edit

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answered 2016-09-06 18:22:54 -0600

Thierry Nouidui
1507 ●14 ●7 https://nouidui.com/in...

Hi Justin,

I will suggest to consider the OtherEquipment object in E+: http://bigladdersoftware.com/epx/docs....

Thanks!

Thierry

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So how would this work with an electric energy source generated by a renewable system? I'm assuming the Fraction Lost field would be set to 0, but if that was the case I would not expect this configuration to affect the results.

MatthewSteen ( 2016-09-06 19:13:52 -0600 )edit

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OtherEquipment

Other Equipment object is provided as an additional source for heat gains or losses directly to the zone. That is to say, a loss can be entered by putting a negative value into the Design Level field(s). Note, too, that this object does not have an end-use component – gains or losses do not show up in the bottom energy lines (except as influencing overall zone gains or losses).

MatthewSteen ( 2016-09-06 19:14:11 -0600 )edit

Hi Thierry, thank you for your answer. I believe @MatthewSteen is correct, I've used OtherEquipment to add or subtract heating to a zone but I'm looking more specifically how to subtract electrical energy from the building. Additionally, the thermal energy would be best added to an HVAC system, not the zone directly.

JustinShultz ( 2016-09-07 09:33:25 -0600 )edit

You are both right. I had heating/cooling in mind.