Effects of heat reservoir temperatures on the performance of thermoelectric heat pump driven by thermoelectric generator

摘要

On the basis of the model of the thermoelectric heat pump driven by thermoelectric generator device with external heat transfer, this paper analyzes the effects of generator heat source temperature and heat pump heating temperature on the optimal performance and optimal variables of the combined system for typical thermoelectric element properties using the combination of finite time thermodynamics and non-equilibrium thermodynamics by detailed numerical examples. For fixed total number of thermoelectric elements and fixed total thermal conductance of heat exchangers, the allocations of thermoelectric elements between the thermoelectric generator and the thermoelectric heat pump, and thermal conductance among the four heat exchangers, are optimized for maximum heating load and coefficient of performance (COP), respectively. The change features of optimal design variables are obtained. The results of numerical simulation show that optimization is necessary and effective. By optimization, the heating load, COP and extreme heating temperature are improved. When the thermoelectric generator and the thermoelectric heat pump work at a difference of 150 and 20 K, respectively, a COP of ～0.15 could be reached that is considerable for application in a wide scale for specific purposes. The maximum heating load and maximum COP of the irreversible model and exo-reversible model are compared. The difference between the two models show the effects of external heat transfer irreversibilities on the performance of the combined device.