Page 490 - Design and Operation of Heat Exchangers and their Networks

Appendix 473

function f = multi_stream_plate_heat_exchanger (x, area)
persistent n0 f0
if isempty(n0)
n0 = 1;
f0 = 1E100;
end

L = 1; % effective length of plate, m. It can be an arbitrary value
T_in = [420; 300; 280]; % K
T_tar = [370; 350; 320]; % K
C_H1 = -8; % kW/K
C_C1 = 4; % kW/K
C_C2 = 5; % kW/K
k = 1.1; % kW/m2K
U_L = k ∗ area / L; % heat transfer parameter, kW/mK

M_C1 = floor(x(1));
M_C2 = floor(x(2));
M_H1 = M_C1 + M_C2 + 1;
M = M_H1 + M_C1 + M_C2; % total number of channels
N1 = 3; % number of entrances: H1, C1, C2
N2 = 3; % number of exits: H1, C1, C2
x_in = zeros(M, 1);
x_out = zeros(M, 1);
C = zeros(M, 1); % heat capacity flow rate in channel, kW/K
G = zeros(M, M); % There is no interchannel connection, i.e. G = 0
G1 = zeros(M, N1);
G2 = zeros(N2, M);
A = zeros(M, M);
for i=1:M
if (mod(i, 2) == 0) % even channel number for cold streams
x_in(i) = 0;
x_out(i) = L;
if (i <= 2 ∗ M_C1) % channels for cold stream C1
C(i) = C_C1 / M_C1;
G1(i, 2) = 1;
G2(2, i) = 1 / M_C1;
else % for cold stream C2