mm=(10^(-3));
cm=(10^(-2));

r=10mm;
l=10;
alfa=10;
σ=5.67*(10^(-8));
ϵ=0.5;
γ=5.7*(10^7);
teplmax=60;
teplokol=20;
podstava=6*((r^2)/4)*(Sqrt[3]);
plast=6*r*l;
odpor=(l/(γ*podstava));
vykel=odpor*(proud^2);
vykkon=alfa*plast*(teplmax-teplokol);
vykrad=σ*ϵ*plast*((((teplmax+273))^4)-(((teplokol+273))^4));
maxproud=proud/.Solve[vykel==vykkon+vykrad,proud];
Print["Spodstava = ",podstava//N," (m^2), ","Splaste = ",plast//N," (m^2), ","Odpor = ",odpor," Ω, ","Proud = ",maxproud[[2]]//N," A "]

ser[list_]:=Plus@@list;
par[list_]:=(((Plus@@((list^(-1)))))^(-1));
Rokno=1.2;
λzed=0.8;
alfa=10;
d=40cm;
stena=6*3;
pomer=(2/5);(*(2/5)steny jsou okna*)
T1=25;
T2=-5;
Rsteny=par[{ser[{(1/(alfa*stena*(1-pomer))),(1/(alfa*stena*(1-pomer))),(d/(λzed*stena*(1-pomer)))}],(Rokno/(stena*pomer))}];
ztraty=((T1-T2)/Rsteny)

Tvlakna=2200;
dT=200;
Tokoli=Tsteny=20;
Svlakna=1(cm^2);
ϵzarovka=0.8;
σ=5.67*(10^(-8));
p1=σ*ϵzarovka*Svlakna*((((Tvlakna+273))^4)-(((Tsteny+273))^4))
p2=σ*ϵzarovka*Svlakna*((((Tvlakna-dT+273))^4)-(((Tsteny+273))^4))
Δp=p1-p2;
Print["Δp = ",Δp," W"," , pomer= ",(p2/p1)*100," %"]