equation system with time and space derivation

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badia rt on 28 Oct 2020 at 10:36
Commented: Alan Stevens on 29 Oct 2020 at 14:13
hello everyone!
i have an equation system for a solar panel formed by 4 equations 3 of them are depending only on time variation and the last one is depending on time and space variation .could you help me to implement the last equation on matlab .does ode45 works to solve this equation system .
dTfluid/dz i: the variation of temperature in the coil
best regards

Alan Stevens on 28 Oct 2020 at 10:53
You could use the pdepe function (try doc pdepe). Alternatively, explicitly discretise z and use ode45 to solve the time dependence for each section.

Alan Stevens on 29 Oct 2020 at 12:58
In order to get the above curve for G, the sinterm expression needs to be changed to
0.08*(sin(t(j)/tau-pi/2)+1)*950/0.16+50;
or something close to this. The result is then
However, this doesn't improve the remaining calculations, even with an increase in the number of sections and timesteps.
I've just realized that by assuming uniform temperatures along z for all times, there is nothing to make dTfluid/dz change! More information on what makes Tfluid vary with z is required.
badia rt on 29 Oct 2020 at 13:47
thanks a lot Alan Stevens what is the value of "tau" that make this curve for solar flux G .is it the same shape of the curve for the other output??means Tglass Tpvt Twax Tfluid
about dTfluid/dz i didn't have other equations but we can make an assumption that the temperature is uniforme in each section or there is a linear variation
Alan Stevens on 29 Oct 2020 at 14:13
Sorry, I should have noted that tau is just 6000, as in your original expression for sinterm.
There was no sensible solution for the other temperatures, but I didn't try further because of uncertainty in the z dependence. if the temperature is uniform along z then the dTfluid/dT will be zero (as it is in what I've supplied so far). If there is a inear variation then you will need to specity its magnitude.