4. Conclusion
A model of two-stage thermoelectric cooler (TEC) system driven by two-stage thermoelectric generator (TEG) with
external heat transfer, Joulean heat inside the thermoelectric device, and the heat leakage through the thermoelectric couple
leg is proposed.
The results show that the external heat transfers affect the performance of combined thermoelectric device strongly.
Moreover, for fixed total number of thermocouples and fixed total thermal conductance, allocations of number of
thermocouples and allocations of thermal conductance have an important effect on cooling capacity and COP. In detail, the
two-stage TEG needs more thermocouples than the two-stage TEC to obtain high performance. In the optimal selection
range, more thermocouples in the TEG can lead larger cooling capacity, and more thermocouples in the TEC can lead
larger COP. The permissible range of thermal conductance ratios is about 0.20.8. The basic criteria of thermal conductance
allocations are f > 0:5; f1 D 0:5, and f2 > 0:5. In the permissible range, thermal conductance ratios have little influence on
the performance of the system. Note that, the allocations of thermal conductance are strict between the two-stage TEG and
the two-stage TEC, and between the hot side and the cold side of the two-stage TEG.
When the total thermal conductance of heat exchangers extends to infinity, the results of this paper approach the non-
equilibrium thermodynamic results obtained by Meng et al. [13], i.e. the external heat transfer losses are ignored. The
results obtained herein may provide guidelines for the design and application of practical combined thermoelectric devices,
especially for the design of heat exchangers. As those obtained in Refs. [3749] by using finite time thermodynamics, the
results obtained herein can provide some guidelines for the design and optimization of practical thermoelectric devices.
4. Conclusion
A model of two-stage thermoelectric cooler (TEC) system driven by two-stage thermoelectric generator (TEG) with
external heat transfer, Joulean heat inside the thermoelectric device, and the heat leakage through the thermoelectric couple
leg is proposed.
The results show that the external heat transfers affect the performance of combined thermoelectric device strongly.
Moreover, for fixed total number of thermocouples and fixed total thermal conductance, allocations of number of
thermocouples and allocations of thermal conductance have an important effect on cooling capacity and COP. In detail, the
two-stage TEG needs more thermocouples than the two-stage TEC to obtain high performance. In the optimal selection
range, more thermocouples in the TEG can lead larger cooling capacity, and more thermocouples in the TEC can lead
larger COP. The permissible range of thermal conductance ratios is about 0.20.8. The basic criteria of thermal conductance
allocations are f > 0:5; f1 D 0:5, and f2 > 0:5. In the permissible range, thermal conductance ratios have little influence on
the performance of the system. Note that, the allocations of thermal conductance are strict between the two-stage TEG and
the two-stage TEC, and between the hot side and the cold side of the two-stage TEG.
When the total thermal conductance of heat exchangers extends to infinity, the results of this paper approach the non-
equilibrium thermodynamic results obtained by Meng et al. [13], i.e. the external heat transfer losses are ignored. The
results obtained herein may provide guidelines for the design and application of practical combined thermoelectric devices,
especially for the design of heat exchangers. As those obtained in Refs. [3749] by using finite time thermodynamics, the
results obtained herein can provide some guidelines for the design and optimization of practical thermoelectric devices.
การแปล กรุณารอสักครู่..