Inputs and outputs from large parametric analysis

I would like to use SAM to run a large parametric analysis. Specifically, I want to model similar PV arrays at roughly 550 individual sites and obtain time series outputs of the DC and AC energy production for input to other simulations.

I know I can implement this sort of study via the SDK (likely the way I will do it), but I am also wondering if it is possible to do efficiently from within the SAM GUI. The relevant questions seem to be:

1. Can I import (or copy/paste) a list of which TMY3 files I want to run in the parametric analysis, to avoid needing to manually select all ~550 of them?

2. For time series output, I see that if I save a CSV I can get time series as CSV string entries that are semicolon ; delimited. However, this makes a really giant CSV file when I run 550 simulations, each with DC and AC power as time series output. Is there a way to instead automatically pipe the time series output to individual results files for every simulation that I can later parse?

Incidentally, when I run so many parametric simulations within SAM and include time series as outputs, the plots it automatically generates (in the beta version) take a very long time to display. I don't really need the plots to auto-display and would like to turn them off to save time, if possible. Is there an option for that?

SAM's Parametrics feature works well for parametric studies involving a relatively small number of values, and is particularly useful when you want to use SAM to create graphs to show the relationship between an output and one or two inputs, or to find a minimum or maximum for optimization.

For larger studies involving more than one or two dozen values, it is probably more efficient to use a script (SamUL in SAM 2014.1.14 and older, LK in SAM 2014.9.30 Beta and later). My answers assume that you would implement a solution via script.

1. Yes. You can put the weather files in a single folder, and then use the script to step through them.

2. You can write a script to write time series data to a separate file for each simulation run.

In SamUL, you can use the Simulate() function with the 'false' parameter to prevent SAM from generating the graph data. In LK, by default the Simulate() function does not generate graph data. There is not a way to turn off graphs with the Parametrics feature.

Best regards,
Paul.

Thanks. I will check out the scripting features.

Hi Paul,

I'm making good progress but stuck on efficiently extracting time series outputs from each simulation. Can you provide an example of how to generate a multi-column CSV using the new LK script?

Here's what I have so far:
// Get time series output
output = [
get('dc_gross'),
get('dc_net'),
get('ac_gross'),
get('ac_net')
];

// Write time series output
csvwrite(cases + '_' + locs[j], output);

The downside is that (a) there are no headers, and (b) the outputs are transposed from the usual layout (timestamps are by column but should be by row).

EDIT: Never mind! It was as simple as switching to a table structure...

// Get time series output
output = {
'dc_gross' = get('dc_gross'),
'dc_net' = get('dc_net'),
'ac_gross' = get('ac_gross'),
'ac_net' = get('ac_net')
};

// Write time series output
csvwrite(cases + '_' + locs[j], output);

Output looks like...
dc_gross,dc_net,ac_gross,ac_net
0,0,-0.0012,-0.001188
0,0,-0.0012,-0.001188
...