Honeybee Generation Release



Hi Mohamed

Good point about the Sandia model. I’ll see if I can find some time tomorrow to look at the code if not I’ll see if I can implement this functionality on the weekend.

I’ll let you know how I go.



Ahh that sounds very promising for all of us Anton thanks!

May I suggest no work on the weekends though :slight_smile:


Hi guys,

I got started hoping to have something functional for Sandria by the end of the work week.


Thanks a lot Anton,

This will be a masterpiece, all other Parametric solar generation models are non temperature dependent so far, and this could produce over/under estimated results by up to 30% according to latest publications.


Hello Mohamed, was wondering about a couple of things.

Do you have any idea of commercial software that is using Sandia (or equivalent algorithm that takes into account module temperature)? I mean is it something common? I’ve been trying to google Sandia around but not much info.

Finally, are you aware if such a calculation is included in the NREL algorithm? I seem to remember smth related but its been a while I used it.

Kind regards,



Hello Theodoros,

Both the Sandia and Equivalent One Diode models in EnergyPlus, predict the efficiency of PV panels by calculating the back of the panel temperature, however, Sandia model consists of a series of empirical relationships with coefficients that are derived from actual testing. Arguably, it is one of the most accurate prediction models for solar panel generation.

I know for sure Greg Barker in 2003, working for the NREL implemented the Sandia model in FORTRAN77 as a custom type (Type101) for the TRNSYS computer program. so i guess TRNSYS has this algorithm.




The functionality to add sandia models is now available as soon as Mostapha approves it.


Please use it like below. I am in the middle of moving continents and jobs but will try to polish it up and add the one diode model next week.


Thanks Anton. It’s merged into the master branch now.


Hi Anton

Sorry to piggy back on this. Cool tool btw.

Just a very basic question I guess - if using your pv tools do I need to provide an epconstruction to account for the pv - thinking in terms of reflectance - or does E+ determine this from the HBGenerator inputs?



Hi Duncan,

You will need to use one of the three PV models that Energy Plus offers, the Simple model the EquivalentOne-Diode model and the Sandia model. Please see the links to the models below.


Hi Anton,

The tool seems very useful and has great potential for scalability! I am trying to use it on a small box model as you have demonstrated in your post but seem to persistently run into an error. From my understanding EnergyPlus is not recognizing my the inverter and generator (called ‘inverter1’ and ‘generator1’) created and returns that:

  1. The simulation has not run correctly because of this severe error:
    ** Severe ** GetPowerManagerInput: ElectricLoadCenter:Inverter:Simple=“INVERTER1”, invalid entry.

  2. The simulation has not run correctly because of this severe error:
    ** Severe ** GetPowerManagerInput: ElectricLoadCenter:Generators=“SYSTEM1”, invalid entry.

I have attached the file I used. Any ideas what might be causing this? Thank you!

unnamed.gh (540 KB)


Hi Antoine,

Thank you for your interest in these components, unfortunately they haven’t been given the love and attention that they deserve as I have been so busy these past few months.

The issue here is that the schedule Always On is not being written to the IDF file so the generators can’t find it and it the simulation crashes.

I’ll talk to Mostapha about this as I believe he has changed some code, this is why this problem is occurring.

Find the working model attached. You will need to use the Run E+ component in this Grasshopper file for now.

There is a lot more functionality that I want to add with these components and they still need to be clean up a fair bit, let me know if you have any suggestions or questions!

PV HB AS 5.31.2016.gh (538 KB)


Hi Anton,

That’s great for now thanks! Will look forward to seeing what else you get the tool to accomplish in the future. Small note however, the financial analysis tool based on the LB 3D plotter tool isn’t working for some reason (no worries it’s not really why I’m using this tool for now).

Thanks again!


Hi Guys. I have a question regarding the PVGen component.

> The old component had the surface area input, the current version doesn’t have it. How do I input/check the SA of each component?

> I’m not sure if I understood NoParallel and NoSeries correctly. Do they refer to the number of components x-axis and y-axis (respectively, or the other way around?). Since I don’t know the SA for each component, how do I calculate the number of components to be placed on the x and y-axis?

>Regarding the power output per module, is it in Watts/m^2?



I’m also having some problems with the Generators when they’re plugged in into the EP Simulation…

(1) Using the same setup from the tutorials for PV Generators, the EP Simulation gave me this.

(2) When I ran the simulation using either the Old or New version (see .gh file) of the ‘Generator:Wind Horizontal Axis’ component, the simulation gave me this warning.

I have another question by the way. The old ‘Generator:Wind Horizontal Axis’ component only required 2 inputs (boolean for size, and the name). The new component though, even though I already set those two values was still asking for the specs from simpleOranalytical to turbinecost. Is this a bug?

WindGenerator_error.gh (566 KB)


Hi Pin,

Apologies for the delay in my reply, I was away over the weekend

  1. This is indeed a bug and one I am aware of I need Mostapha’s help to fix this since you are using the component. See: https://github.com/mostaphaRoudsari/Honeybee/issues/487

Do you need this functionality ASAP?

  1. This is also a bug, however that one is a quicker fix, see a working component attached, please use the newer version of the component and check out the E+ wind turbine guide for the difference between analytical and simple turbines


WindGenerator_error AS 20.06.2016.gh (495 KB)


Hi Anton,

It’s not urgent as of the moment but I might need it the next weeks or so.

You might have missed my other post regarding the PVGen Component (http://www.grasshopper3d.com/xn/detail/2985220:Comment:1549495). I’m having trouble understanding some of the workings behind the component.



Dear Anto,

I posted a question about the absence of the “percentage of surface area” option in the latest Generator PV component:


Hope you can kindly advise.

Thank you very much!


Hi Anton,

I posted an issue about Honeybee Generation without Lighting Output:


Hope you could give me a hand.

Thank you in advance.