4186*80
((%)/(2*60.))

res=DSolve[{λ*D[T[x],{x,2}]==0,T[0]==T1,T[d]==T2},T[x],x][[1]][[1]]//FullSimplify

-λ*D[T[x]/.res,x]

ro=2400;
Cp=1011;
Tout=5+273;
Tin=20+273;
lambda=0.3;
tloustka=0.3;
tMax=400000;

rce=ro*Cp*D[T[x,t],t]==lambda*D[D[T[x,t],x],x];
pocPodminka=T[x,0]==Tout;
okrVlevo=T[0,t]==Tin*Tanh[t]+Tout*(1-Tanh[t]);
okrVpravo=T[x,t]==Tout/.x->tloustka;

res=NDSolve[{rce,pocPodminka,okrVlevo,okrVpravo},T,{x,0,tloustka},{t,0,tMax}]

Plot3D[T[x,t]-273/.res,{x,0,tloustka},{t,0,tMax}]