consequences of field sizing and behavior of optimization curves

Hello Paul,

first of all I would like to say thank you for this great tool and the ambitious support.

I am modelling a utility scale CSP trough (oil) with storage. (280 MW gross el. output and 8h TES)
There are a couple of connections between parameters in SAM and results that I can't properly figure out. I have read the help sections for sizing the solar field and did some additional reading in the manual.

- From what I understand, the irradiation at design is used by SAM to do a first sizing of the needed field.

- There is a connection between the solar multiple (SM) and the 'field thermal output [MW]'. SM=1 would result in a field size (with a given Irr@design) needed to run the power block at its rated capacity. Augmenting the SM will primary lead to a higher 'field thermal output'. SAM then calculates a new resulting actual apperture size to fit this field output.

- If we want to choose the Irr@design correctly, Help file offers us two options. 1: take a value close to the maximum effective DNI from the hourly data. 2: minimize the dumped energy.
Using to low Irr@design should lead to a oversized field, producing to much energy the powerblock cant handle. BUT: when using a big storage, dumped energy is not augmenting.
I am experiencing the opposite: when changing Irr@design from 600 to 800 to 900W/m2, apperture size, energy from solar field, dumped energy and annual energy are augmenting. is this normal?
In consequence, using higher Irr@design leads to allways lower LCOEs. Picture1 in this post shows the different LCOE minima in a parametric simmulation (marked in yellow)
--> So how should I chose the Irr@design, as it can significantly influence the overall LCOE (the maximum effective DNI at the site is arround 950W/m2)?

- If I focus on one Irr@design and do a SM+TES parametrics optimization, --> how should I make the decision what SM and resulting field size to choose? my curves sometimes have two local minimum for LCOE. --> why does this happen?
Picture2 gives an example:
for 8h TES the yellow marked point offers just 0.6% lower LCOE but a 14% bigger apperture size than the light blue one.
--> is there a reasonable trigger where to stop augmenting the field size?

So, thats a couple of questions where I would be very glad if anybody would take a minute to help me out. (especialy the Irr@design issue and the shape of the LCOE curves)
Thank you very much

Phil