Influence of condenser pressure drop on the thermodynamic efficiency of a single-stage vapor-compression cycle using different refrigerants: entropic and statistical method of analysis

BACKGROUND: Conventional evaluation of refrigeration system performance based solely on the coefficient of performance (COP) fails to identify localized irreversible losses, particularly those arising from pressure drops in heat exchangers. This limitation is critical in applications demanding high temperature stability, such as pharmaceutical refrigeration.

AIM: To perform a comparative thermodynamic analysis of a single-stage vapor-compression cycle using refrigerants R134a, R410A, R507A, and R717, explicitly accounting for the effect of condenser pressure drop on entropy production distribution across cycle components.

METHODS: The entropic and statistical method of thermodynamic analysis (ESMA) was applied. Simulations were conducted at a fixed cooling capacity of 1 kW, evaporation temperature of –10 °C, and condensation temperature of +42 °C. Condenser pressure drop was varied from 0 to 2 bar in 0.2-bar increments.

RESULTS: Increasing the pressure drop to 2 bar reduced thermodynamic efficiency by 8–13%, depending on the refrigerant. R410A demonstrated the highest resilience: its COP decreased by only 8%, and additional power required to compensate for entropy generation amounted to 3.8% of total compression power.

CONCLUSION: The entropic and statistical method of analysis (ESMA) allows for losses in different refrigeration plant components to be calculated and compared to determine the elements that need measures to increase their operation efficiency.