Performance optimization of thermoelectric and vapor compression hybrid refrigeration system by allocating power

Abstract

To enhance the refrigeration efficiency of the thermoelectric and vapor compression hybrid refrigeration system and optimize the allocation of power during system operation, a dimensionless parameter, the power allocation ratio coefficient (θ), is proposed. It represents the ratio of the input power of the thermoelectric refrigeration system to the total input power. A mathematical model of the hybrid refrigeration system is established to investigate the impact of θ on the cooling temperature (Tc), cooling capacity (Qc), and coefficient of performance (COP) of the system. An experimental platform is constructed to validate the mathematical model and explore the relationship between the optimal θ and system operating parameters. The findings demonstrate that, under a constant total input power, as the θ increases, the cooling temperature initially decreases and then increases, whereas the Qc and COP first increase and then decrease. There exists an optimal power allocation relationship for the two-stage refrigeration system, which maximizes the refrigeration performance of the hybrid refrigeration system. When the total input power is 100 W, the optimum θ is 0.52, resulting in a cooling temperature of −55.23 °C and a COP of 0.13. As the total input power increases, the optimal θ decreases. The cooling temperature rises, the optimal θ increases. The ambient temperature increases, the optimal θ also increases. An optimized relationship equation is obtained by fitting the calculated results of the operating parameters and the optimal θ, providing a theoretical basis for the control of power allocation in practical operation of the two-stage refrigeration system within the hybrid refrigeration system.