Comparative performance of air-conditioning systems with different refrigerant circuitries in liquid-separation condenser

Liquid-separation condensation is a novel technology to enhance the condenser performance. Four liquid-separation condensers (LSCs) that had the only difference in refrigerant circuitry were designed, and they were respectively installed to the air-conditioning system and experimentally studied. The capillary tube length and the refrigerant charge were adjusted to achieve the optimum energy efficiency ratio (EER) for each system. The cooling capacity, the system power input and EER were compared at the optimum point. It is found that the four systems are most distinguished in LSCs in terms of condensing pressure and subcooling because of different refrigerant circuitries. The exergy analysis was also carried out. The results show that the refrigerant circuity in LSC has great impacts on the exergetic performance of all system components, and the order of highest exergy efficiency of the four systems is different from that of EER. The detailed characteristics of the four LSCs were further discussed at the designing condition and the practical condition in the tests. The pressure drop of LSC is dominated by the last pass that has serpentine tubes. It is concluded that a low penalty factor (PF) in LSC does not guarantee the good system performance. The optimization of refrigerant circuitry in the condenser to improve the system efficiency should use the system performance as the objective at the system level instead of PF.