Relative to $F_{eff}$

Again, from Eq. (30), assuming $F_{eff}$ and $B_{eff}$ are independent,

  $$\frac{1}{Tcal} \frac{\partial Tcal}{\partial F_{eff}} = \frac{1}{F_{eff}} + \frac{1}{\frac{T_{cab}-T_{emi}}{T_{cab}-T_{atm}}-F_{eff}}$$ (44)

which is of the order of 1.4 for the numerical values in Eq. (31). The first term must be omitted if one assumes $B_s$ = $F_{eff}$, and in this case the derivative is of the order of 0.26.