% Units
bar = 1e5    ; % [Pa]
kJ  = 1000   ; % [J]
min = 60     ; % [s]
m   = 1      ; % [m]
g   = 0.001  ; % [kg]
TT  = 273.15 ; % [K]

% Quantities for mix enthalpy
cp_as  = 1.005 * kJ ; % [kJ/(kg K)]
cp_vap = 1.875 * kJ ; % [kJ/(kg K)]
h_lv   =  2501 * kJ ; % [kJ/(kg)]

% Dry air ideal gas constants
R_bar = 8.314 ;  % [J/(mol K)]
M_as  = 29 * g ; % [kg/mol]
R_as  = R_bar / M_as

% Functions for saturation, absolute humidity, mix enthalpy
p_sat = @(t) 610.5 * exp( 17.269*t / (237.3+t) ) ; % [Pa]
t_sat = @(p) 237.3 / ( 17.269/log(p/610.5)-1 ) ;   % [°C]
w     = @(p_vap, p) 0.622 * p_vap / (p-p_vap) ;    % [kg_vap/kg_as]
p_vap = @(w, p) p / ( 0.622 / w + 1 ) ;            % [Pa]
J     = @(t, w) cp_as * t + w * ( h_lv + cp_vap*t ) ; % [J/kg_as]

% Common pressure
p = 1 * bar ;

% Flow 1
Vp1 = 142 * m^3 / min ;
t1  = 5 ;     % [°C]
w1  = 0.002 ; % [kg_vap/kg_as]

% Flow 2
Vp2   = 425 * m^3 / min ;
t2    = 24 ;   % [°C]
phi2  = 0.50 ; % [-]
p_vap2 = phi2 * p_sat(t2) 
w2    = w(p_vap2, p) 

% Mass flow rates
T1 = t1 + TT ;
mp_as1 = Vp1 * p / ( R_as * T1 ) 
T2 = t2 + TT ;
mp_as2 = Vp2 * p / ( R_as * T2 )

% Mix absolute humidity
w3 = ( mp_as1 * w1 + mp_as2 * w2 ) / (mp_as1 + mp_as2)

% Mix enthalpies
J1 = J(t1, w1)
J2 = J(t2, w2)
J3 = ( mp_as1 * J1 + mp_as2 * J2 ) / (mp_as1 + mp_as2)
t3 = ( J3 - w3*h_lv ) / ( cp_as + w3*cp_vap )
p_vap3 = p_vap(w3, p)
p_sat3 = p_sat(t3) 
phi_3 = p_vap3 / p_sat3