Hi

https://www.energymatters.com.au/solar-calculators/solar-battery-calculator.php?utm_source=NewsletterMailingList&utm_medium=email&utm_campaign=EM171101CN

I am trying to find how it calculates how much solar will be exported back to the grid. I thought this could only be estimated  empirically, but apparently not.

Anyway, it depends on three factors, power consumption, power installed, and average hours of sun per day, or hours per day as a function of time of year. For C=4.5kWh/day and S=5kW and H=4 sun hrs per day, means 90% will be exported back to the grid Y. So Y(C,S,H)= a closed form expression.

How to guess the fuction? I tried array interpolation for a numeric solution, but it complains: independent coordinates must be sorted in increasing order

law.mw

Hiya

from this

>with(combinat):
>A:=choose([CPC__h, SIZE__h,CPC__m, SIZE__m,CPC__l, SIZE__l],2): 

where h denotes high, m=medium, l=low

I want to select CPC and SIZE all the combinations w.r.t h, m and l

[[CPC__h, SIZE__h], [CPC__h, SIZE__l], [CPC__h, SIZE__m], [CPC__l, SIZE__h], [CPC__l, SIZE__l], [CPC__l, SIZE__m], [CPC__m, SIZE__h], [CPC__m, SIZE__l], [CPC__m, SIZE__m]]

>nops(A)-3

9

I want to apply the methodology to 
choose([CPC__h, SIZE__h, SH__h,CPC__m, SIZE__m, SH__m,CPC__l, SIZE__l, SH__l],3)
 

This may seem a bit trivial, but I prefer f'(x) to writing diff(f(x),x) in 1D input. How to achieve?

differential.mw

Download differential.mw

Hello

I have an expression which invokes the LambertW function.

LambertW(-ln(1+i)*EP*p*(1+i)^(-(365*EP*hr*kw*p+SC*i)/(365*FIT*hr*i*kw*(-1+p)))/(FIT*i*(-1+p)))

I was trying to import this expression into Excel, but my version doesn't have LambertW.

Does someone know an analagous function in a form Excel can compute?

According to wiki The Lambert W relation cannot be expressed in terms of elementary functions.

I have gotten around the problem using Newton-Raphson method, but it takes a few cells to converge....

This is probably a silly question, but...

given 

GST := AE+AI-ANB-AR-CP

how do i append [i] to each element of the list so I get

AE[i]+AI[i]-ANB[i]-AR[i]-CP[i]

this nearly gets it

(GST@`[]`)~(i);