Effect of the condenser subcooling on the performance of vapor compression systems

• As condenser subcooling increases, COP undergoes a maximum.
• The COP maximizing subcooling is not strong function of thermodynamic properties.
• R1234yf benefits more from condenser subcooling than R410A, R134a and R717.
• COP increase due to condenser subcooling is a function of thermodynamic properties.

This paper presents a theoretical study about the effect of condenser subcooling on the performance of vapor-compression systems. It is shown that, as condenser subcooling increases, the COP reaches a maximum as a result of a trade-off between increasing refrigerating effect and specific compression work. The thermodynamic properties associated with the relative increase in refrigerating effect, i.e. liquid specific heat and latent heat of vaporization, are dominant to determine the maximum COP improvement with condenser subcooling. Refrigerants with large latent heat of vaporization tend to benefit less from condenser subcooling. For an air conditioning system, results indicate that the R1234yf (+8.4%) would benefit the most from condenser subcooling in comparison to R410A (7.0%), R134a (5.9%) and R717 (2.7%) due to its smaller latent heat of vaporization. On the other hand, the value of COP maximizing subcooling does not seem to be a strong function of thermodynamic properties.