If the filter is removed, the analysis parallels that of the previous section with Eq. (9.18) remaining valid. However, the simplification made possible by Eqs. (9.19) and (9.20) no longer apply. Instead, the equivalent of Eq. (9.21) becomes:
Where E h/N h, N c/N h and Ec/E h are given by the same expressions as Eqs. (9.6), (9.7) and (9.8) but where TR is replaced by TH and the argument of the /(-functions equals – (EG – qVH/kTH), while that of the P* functions equals – ( EG – qVC)/kTC. In the most efficient mode of operation, these arguments approach zero, with the ratios approaching, for kTH << EG:
EH/NH “ EG[1 + (kTH/EG)P1 /P0 ] (9.28)
Nc/N h « (Tc/Th)( p0 / P0 )[1 + 2(kTc/Eg в / p0 – 2 kTH /Eg в / P0 ]
Ec/EH = (Tc/Th)(P0/P0)[ 1 + 3(kTc/Eg )p1 /P0 -3(kTH/Eg )P1 /P0]
Again, efficiency close to the Carnot limit is feasible. The main loss is due to the thermalisation of carriers emitted at temperature TH to the temperature Tc on absorption in the cell, although this loss applies only to the net carrier flow.