[GDL] Scheduling area of Solar Photovoltaic objects

[Jim Allen]

One thing I have to do on every single project here in the UK is add solar PVs, and Archicad does have a Library object that is pretty good.

However, what is always useful is the ability to quickly calculate the entire area of panels, and calculate an approximate output. Obviously output varies on angle orientation and location, but the range of output within a small geographical area is not that big, enabling a meaningful approximate calculation to be derived.

The benefit of this is that it allows us to roughly work out what sort of PV area we need for any given project. The building services engineers will be able to provide estimates of heating/cooling load and energy requirements, so at an early stage in design we can get an idea of whether net zero carbon is likely to be achievable, and if so, whether we need PVs in places other than the building roof.

The current object Solar Photovoltaic Panel 25 is pretty good, but seems to be a derivation of the Solar Collector Flat Plate 25 object. These are some of the object properties:

 

Note the FM_HeatOutput property. This is what you would expect with a solar collector. With a PV panel you would expect a power output property.

I would also expect to see a functioning area parameter that allows us to calculate the output in a schedule.

There is one there:

but it has no data.

the Parameter script includes this:

if FM_HeatOutput_unit = `Btu/hour` then
	hideparameter "FM_HeatOutput"
else
	hideparameter "FM_HeatOutput_btu"
endif

if FM_RefrigeratingOutput_unit = `Btu/hour` then
	hideparameter "FM_RefrigeratingOutput"
else
	hideparameter "FM_RefrigeratingOutput_btu"
endif

if FM_PowerConsump_unit = `W/ft2` then
	hideparameter "FM_PowerConsumption"
else
	hideparameter "FM_PowerConsumption_feet"
endif

That's clearly not right for a photovoltaic panel.

I've tried to open it to see if I could modify it to add an area calculation but the 2D and 3D script dialogs are blank.

We can wait for GS to update this (I reckon it's maybe 10 minutes for someone like Peter 😉) or we can do it - assuming it isn't locked.

Comments, suggestions?

[Jim Allen]

Thanks Peter, I thought I was missing something, all it needed was a small tweak to my script line:

PARAMETERS ac_collector_area = (panelWidth*panelHeight) * (nPanelHorizontal*nPanelVertical)

and a couple of others

PARAMETERS ac_collector_area = (panelWidth*panelHeight) * (nPanelHorizontal*nPanelVertical)

PARAMETERS FM_HeatOutput = ac_collector_area * FM_PowerConsumption

! FM_HeatOutput parameter renamed as Output per panel (m2) parameter and used for indicative PV output in W/m2

! FM_PowerConsumption renamed as Indicative electricity output (W/m2) and used to enter estimated electricity generated

I have repurposed and relabelled some of the other parameters to calculate the indicative panel output (based on an estimated input parameter for the output in terms of W/m2 for a particular locality) which is really useful as a rule of thumb.

I have looked at property expressions, but they only work with properties and a very limited set of parameters. I started to do this, but I needed to use some trigonometry to calculate the area of the inclined panel because the only accessible relevant parameters are the 2d footprint and overall height.

These tweaks work perfectly in a schedule, and I can just add objects and with an estimated figure for electricity consumption from engineers for the building (to meet climate change targets in Northern Europe we are going to be moving to reducing consumption with electric heating with renewables) and get a rough idea of how close we can get to net zero at an early design stage.

It's much easier to change parameters in the GDL script.