%  function [PSIa] = calc_Psia(Ts1,Ts2)
%
    function [Psia] = calc_Psia(Ts1,Ts2)
 
 %Read parameters
 TwoBox_Param
   
% Evaporation
 if Ts1-Ts2>DTcrit_circ
   Psia = BIGONE * (Ts1-Ts2-DTcrit_circ) * SV; %mass transport in kg/s 
 else
   Psia = 0;
 end
