Theoretical study of a modified ejector enhanced vapor injection heat pump cycle with hybrid solar-air source for dryer application

A modified ejector enhanced flash tank vapor injection heat pump cycle with hybrid solar-air source (SE-MVIC) for dryer application is present in this paper. The proposed heat pump cycle can enhance the heating perfor-mance because more vapors can be injected into the compressor with the entrainment ability of ejector. The theoretical model is developed to study the SE-MVIC and compare its performance with the conventional flash tank vapor injection heat pump cycle (FVIC) and the solar assisted ejector enhanced flash tank vapor injection cycle (SE-FVIC). In this study, the intermediate pressure of compressor has been investigated to explore the optimum relative vapor injection ratio and further improve the cycle performance. The simulation results show that compared to FVIC and SE-FVIC, the COPh of SE-MVIC with an optimum intermediate pressure are improved by 36.6 % and 2.0 %, respectively. And the optimum intermediate pressure of SE-MVIC is higher than that of FVIC at the same operating condition. Moreover, within the given operating condition, the maximum value of COPh of SE-MVIC is obtained when the relative vapor injection ratio is varied from 0.44 to 0.62, and the cor-responding volume ratio of compressor is varied from 0.55 to 0.72. These results of this paper of the solar assisted ejector enhanced technology show its potential advantages in the heat pump dryer application.

Automated summary

This paper presents a modified heat pump cycle that enhances heating performance using vapor injection technology from both solar and air sources. Simulation results show that compared to traditional cycles, the proposed cycle achieved improvements of 36.6% and 2.0% in performance, and has a higher optimum operating condition.