Comparative Study of Using R-410A, R-407C, R-22 and R-134a as Cooling Medium in the Condenser of a Steam Power Plant

A step-by-step technique has been implemented in the analytical study of heat transfer and pressure gradient characteristics of refrigerants R-410A, R-407C, R-22 and R-134a used as cooling media in the condenser of a steam power plant. Refrigerants are optimized to replace water/air as coolant in the condenser of a steam power plant. Refrigerants have much lower temperatures and much higher heat transfer rates than water or air. The thermal resistances that affect heat transfer characteristics and surface condenser performance are included. The effect of inlet refrigerant temperature and mass flow rate are reported for the four refrigerants. Calculations are performed at two inlet refrigerant temperatures −21 °C and −30 °C and mass flow rate ranging from 92.905 to 132.905 kg/s. The results revealed that the overall heat transfer coefficient, heat transfer rate and condensation rate increased with refrigerant mass flow rate, with higher values at lower inlet refrigerant temperatures. For a given refrigerant mass flow rate and inlet temperature, the analytical study indicated that R-410A has higher values of overall heat transfer coefficient, heat transfer rate and condensation rate than R-407C, R-22 and R-314a, respectively. Moreover, it is found that R-410A, at −30 °C and 132.905 kg/s, is superior in condensing all steam entering the condenser than the other refrigerants; this corresponds to higher exergy efficiency. The condenser pressure was observed to be slightly higher for R-410A than the other refrigerants.