Premium
Parametric study on the thermoelectric conversion performance of a concentrated solar‐driven thermionic‐thermoelectric hybrid generator
Author(s) -
Xiao Lan,
Wu ShuangYing,
Yang ShiLing
Publication year - 2018
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.3849
Subject(s) - thermoelectric generator , materials science , anode , thermoelectric effect , energy conversion efficiency , radiator (engine cooling) , maximum power principle , thermodynamics , thermionic emission , nuclear engineering , optoelectronics , electrical engineering , mechanical engineering , power (physics) , chemistry , electrode , physics , engineering , quantum mechanics , electron
Summary A concentrated solar‐driven thermionic‐thermoelectric hybrid generator composed of solar heat collector, thermionic generator (TIG), thermoelectric generator (TEG), and radiator is introduced in this paper. A theoretical model of thermoelectric conversion performance for the hybrid generator is built up based on the heat source of the concentrated solar radiation rather than isothermal heat source. Based on the model, the impacts of related parameters on the internal temperature distributions, output power, and efficiency have been discussed. Moreover, the optimal operating conditions of the TIG‐TEG hybrid device at its maximum output power and efficiency have been determined. Results show that when cascading the TEG with the TIG, there is very little change of the TIG cathode temperature in most conditions, namely, T C ≈ T C ′. Meanwhile, the anode temperature becomes higher, and the TEG cold end temperature T 2 is close to the anode temperature T A ′ for the single TIG system, ie, T A > T A ′ ≈ T 2 . In theory, the optimal concentrated solar radiation I 0 for the maximum output power P max and the maximum efficiency η max differs, which are I 0, P = 2.5 × 10 6 W/m 2 and I 0, η = 2 × 10 6 W/m 2 , respectively, whereas the output power and efficiency of the TIG‐TEG hybrid system simultaneously reach their maximum values when the optimal TIG anode temperature T A,opt = 1025 K, the optimal TIG output voltage V opt = 2 V, and the optimal ratio of load resistance to internal resistance ( R 2 / R ) opt = 2. However, in practice, the parameter values of I 0 , Φ A , and T A should be strictly controlled under 1.8 × 10 6 W/m 2 , 1.4 eV, and 660 K, respectively. Generally, the maximum output power and efficiency of the hybrid TIG‐TEG system are, respectively, 35% and 4% higher than that of the single TIG.