4. Results and discussions
Fig. 6a and b compare the three working fluids for the MT refrigeration system. The condenser inlet air temperature is set to Tc_in = 25_C. Both Qf and the COP values are shown. R404a fluid (red bars) allows a lower cooling capacity and COP respect to both R407f (blue bar) and R410a (green bar) fluids for all scenarios. In addition, R407f and R410a fluids present opposite behaviours. The former provides a higher cooling capacity, the latter presents a higher efficiency (COP).
Such results are confirmed in the case of the condenser inlet air temperature increase. Fig. 7a and b show the cooling capacity and the COP for Tc_in equal to 25 _C, 35 _C and 45 _C and Tchamb equal to 0 _C.
Refrigerant R407f generates higher cooling capacity, ranging between 1215Wand 1520 W, while R410a has a higher COP, ranging between 1.2 and 2.0, for all scenarios. Finally, for the higher condenser inlet air temperature (Tc_in = 45_C), the performances of the refrigerant R404a overcome the R407f and R410a fluids for the generated cooling capacity and the COP, respectively.