How to solve algebraic equations for different values of variables ?

I am new to MATLAB, I want to solve the equation “eqn” to get the values of “Te” for different values of I. How solve thIS equation. I have made the code. But I am not getting the numerical valueS of “Te”.

clear all

close all

clc

% For ETC collector

syms Te

% Read the solar radiation data

filename = '1.xlsx';

T = readtable(filename)

% Convert table to array

T= table2array(T);

% Inpit data

Ac=repelem(2,480)

I=T'

eta_0=0.7

a1=repelem(5,480)

a2=repelem(0.0057,480)

Ti =repelem(30,480)

T_air=repelem(30,480)

m =repelem(0.04,480)

c =repelem(4,480)

% Efficiency of collector

eta=(eta_0-a1.*(((Ti+Te)./2)-T_air)./I-a2.*(((Ti+Te)./2)-T_air).^2./I);

% Solve the equation

eqn = Ac.*I.*eta-m.*c.*(Te-Ti);

S = solve(eqn,Te);

% NOTE: there are 2 roots for above equation so consider positive value only

S=round(S)

S = S( S>=0 )

[Aiden James]

Thanks for quick reply. Please find the data file in the attachment.

Answer 1

[VBBV]

eqn = Ac.*I.*eta-m.*c.*(Te-Ti)==0;

[VBBV]

The input eqn is not an equation. You need LHS and RHS for an equation. Pls attach the data file for more info. Remember output of solve is often a struct variable and logical indexing of struct without direct referencing to struct variable is not recommended

[VBBV]

@Aiden James, you have vector of equations to solve and only one unknown to determine the value for those vector of equations. You can solve them by using a for loop as shown below

clear all
close all
clc
%  For ETC collector 
syms  Te 
% Read the solar radiation data 
filename = 'a1.xlsx';
T = readtable(filename);
% Convert table to array 
T= table2array(T);
% Inpit data 
Ac=repelem(2,480);
I=T';
eta_0=0.7;
a1=repelem(5,480);
a2=repelem(0.0057,480);
Ti =repelem(30,480);
T_air=repelem(30,480);
m =repelem(0.04,480);
c =repelem(4,480);
% Efficiency of collector 
eta=(eta_0-a1.*(((Ti+Te)./2)-T_air)./I-a2.*(((Ti+Te)./2)-T_air).^2./I);

% Solve the equation
eqn = Ac.*I.*eta-m.*c.*(Te-Ti)==0;
for k = 1:numel(eta)
 S{k} = solve(eqn(k),Te);
end
S = S{:}

S = 

% NOTE: there are 2 roots for above equation so  consider positive value only
S = vpa(S,3)

S = 

S = double(S(S>=0))

S = 125.3670

[Aiden James]

Thanks

Answer 2

[Torsten]

% Solve the equation
eqn = Ac.*I.*eta-m.*c.*(Te-Ti)==0
for i=1:numel(eqn)
  s = solve(eqn(i),Te);
  S(i) = vpa(s(s>=0));
end
S

[Aiden James]

Thanks