can someone assist I am struggling to convert the DHI DNI and GHI from W/m^2 to kWh/m^2

% solar irradiation on a HORIZONTAL SURFACE

Cn = 0.7; % Clearance index

I0 = 1353; % Solar constant

latitude = -34.005133; % Latitude of the location

days =1; % Number of days in the month

hours = 24; % Number of hours in a day

% Initialize matrices to store results

dec_deg = zeros(days, 1); % Declination angles in degrees

DNI = zeros(days, hours); % Direct Normal Irradiation

DHI = zeros(days, hours); % Diffuse Horizontal Irradiance

GHI = zeros(days, hours); % Global Horizontal Irradiance

for n = 1:days

% Calculate declination angle for the day (in degrees)

dec_deg(n) = 23.45 * sind((360/365) * (n + 284));

% Convert declination angle from degrees to radians

dec_rad = deg2rad(dec_deg(n));

for time = 1:hours

% Calculate hour angle

h = (12 - time) * 15; % Hour angle in degrees

h_rad = deg2rad(h); % Hour angle in radians

% Calculate diffuse factor (Cs)

Cs = 0.095 + 0.04 * sin(deg2rad(360/365) * (n - 100));

% Calculate extraterrestrial solar irradiation (I)

I = I0 * (1 + 0.034 * cos(deg2rad(360 * n / 365.25)));

% Calculate atmospheric optical depth (k)

k = 0.174 + 0.035 * sin(deg2rad((360/365) * (n - 100)));

% Calculate solar altitude angle (alt)

Lat = deg2rad(latitude); % Latitude angle in radians

alt = asin(cos(Lat) * cos(dec_rad) * cos(h_rad) + (sin(Lat) * sin(dec_rad)));

alt_deg = rad2deg(alt); % Daily Solar Altitude Angle

% Ensure the solar altitude angle is non-negative

if alt_deg < 0

alt_deg = 0;

end

% Calculate air mass (AM)

AM = 1 / sin(deg2rad(alt_deg)); % Air Mass

% Calculate Direct Normal Irradiation (DNI) for the current hour

DNI(n, time) = Cn * I * exp(-k * AM);

% Calculate Diffuse Horizontal Irradiance (DHI) for the current hour

DHI(n, time) = Cs * DNI(n, time);

% Calculate Global Horizontal Irradiance (GHI) for the current hour

GHI(n, time) = (DNI(n, time) + DHI(n, time)) ; % Convert to W/m^2

end

end

% Display matrices

disp("Direct Normal Irradiation (DNI) for 1 day (24 hours each): ");

disp(DNI)

disp("Diffuse Horizontal Irradiance (DHI) for 1 day (24 hours each): ");

disp(DHI)

disp("Global Horizontal Irradiance (GHI) for 1 day (24 hours each): ");

disp(GHI)

% Sum up the values in DNI and DHI matrices (which are 1x1 matrices)

sum_DNI = sum(DNI(:))

sum_DHI = sum(DHI(:))

GHI_per_year = (sum_DNI + sum_DHI)

Answer 1

[VBBV]

% solar irradiation on a HORIZONTAL SURFACE
Cn = 0.7;           % Clearance index 
I0 = 1353;          % Solar constant
latitude = -34.005133;  % Latitude of the location
days =1;          % Number of days in the month
hours = 24;         % Number of hours in a day
% Initialize matrices to store results
dec_deg = zeros(days, 1);  % Declination angles in degrees
DNI = zeros(days, hours);      % Direct Normal Irradiation
DHI = zeros(days, hours);      % Diffuse Horizontal Irradiance
GHI = zeros(days, hours);      % Global Horizontal Irradiance
for n = 1:days 
    % Calculate declination angle for the day (in degrees)
    dec_deg(n) = 23.45 * sind((360/365) * (n + 284));
    
    % Convert declination angle from degrees to radians
    dec_rad = deg2rad(dec_deg(n));
    
    for time = 1:hours
        % Calculate hour angle
        h = (12 - time) * 15; % Hour angle in degrees
        h_rad = deg2rad(h); % Hour angle in radians
        
        % Calculate diffuse factor (Cs)
        Cs = 0.095 + 0.04 * sin(deg2rad(360/365) * (n - 100));
        
        % Calculate extraterrestrial solar irradiation (I)
        I = I0 * (1 + 0.034 * cos(deg2rad(360 * n / 365.25)));
        
        % Calculate atmospheric optical depth (k)
        k = 0.174 + 0.035 * sin(deg2rad((360/365) * (n - 100)));    
        
        % Calculate solar altitude angle (alt)
        Lat = deg2rad(latitude); % Latitude angle in radians
        alt = asin(cos(Lat) * cos(dec_rad) * cos(h_rad) + (sin(Lat) * sin(dec_rad)));
        alt_deg = rad2deg(alt); % Daily Solar Altitude Angle
        
        % Ensure the solar altitude angle is non-negative
        if alt_deg < 0
            alt_deg = 0;
        end
        
        % Calculate air mass (AM)
        AM = 1 / sin(deg2rad(alt_deg)); % Air Mass
        
        % Calculate Direct Normal Irradiation (DNI) for the current hour
        DNI(n, time) = Cn * I * exp(-k * AM);
        
        % Calculate Diffuse Horizontal Irradiance (DHI) for the current hour
        DHI(n, time) = Cs * DNI(n, time);
        
        % Calculate Global Horizontal Irradiance (GHI) for the current hour
        GHI(n, time) = (DNI(n, time) + DHI(n, time)) ; % Convert to W/m^2
    end
end
% Display matrices
disp("Direct Normal Irradiation (DNI) for 1 day (24 hours each): ");

Direct Normal Irradiation (DNI) for 1 day (24 hours each): 

disp(DNI)

  Columns 1 through 18

         0         0         0         0    1.3470  517.8201  700.6739  776.4273  814.9176  835.8280  846.4561  849.7305  846.4561  835.8280  814.9176  776.4273  700.6739  517.8201

  Columns 19 through 24

    1.3470         0         0         0         0         0

disp("Diffuse Horizontal Irradiance (DHI) for 1 day (24 hours each): ");

Diffuse Horizontal Irradiance (DHI) for 1 day (24 hours each): 

disp(DHI)

  Columns 1 through 18

         0         0         0         0    0.0746   28.6642   38.7861   42.9795   45.1101   46.2676   46.8559   47.0372   46.8559   46.2676   45.1101   42.9795   38.7861   28.6642

  Columns 19 through 24

    0.0746         0         0         0         0         0

disp("Global Horizontal Irradiance (GHI) for 1 day (24 hours each): ");

Global Horizontal Irradiance (GHI) for 1 day (24 hours each): 

disp(GHI)   

  Columns 1 through 18

         0         0         0         0    1.4216  546.4842  739.4600  819.4068  860.0277  882.0956  893.3120  896.7677  893.3120  882.0956  860.0277  819.4068  739.4600  546.4842

  Columns 19 through 24

    1.4216         0         0         0         0         0

% Sum up the values in DNI and DHI matrices (which are 1x1 matrices)
sum_DNI = sum(DNI(:))/(24*1000)  % in kWh/m^2

sum_DNI = 0.4099

sum_DHI = sum(DHI(:))/(24*1000)  % in kWh/m^2

sum_DHI = 0.0227

GHI_per_year = (sum_DNI + sum_DHI)% in kWh/m^2

GHI_per_year = 0.4325

[VBBV]

@Gihahn Assuming, the sum of DNI, DHI and GHI are in W/m^2