COMPARISON AND ANALYSIS ON THE PERFORMANCE OF R404A DIRECT CONTACT CONDENSATION REFRIGERATION CYCLE FOR LOW TEMPERATURE
A new refrigeration cycle for low temperature called R404A direct contact condensation refrigeration cycle is proposed. The performances of this cycle are analyzed and the following conclusions are obtained. It has an optimum saturated liquid temperature at which the COP of the cycle has the maximum value and the condenser heat load has the minimum value when the evaporating temperature, condensation temperature and the super cooling degrees of supercooled liquid keep constants. With the decrease of the super cooling degrees of the supercooled liquid, the COP of the cycle increases, the condenser heat load reduces and the
optimum saturated liquid temperature decreases. The mass flow ratio of the supercooled liquid to the high
temperature gas increases slightly with the decrease of the saturated liquid temperature and the evaporation
temperature of the main cycle, however this mass flow ratio increases evidently with the decrease of the
super cooling degrees of the supercooled liquid. Furthermore, compared with that of a conventional R404A
two stage compression refrigeration cycle and a R404A/ CO2 cascaded refrigeration cycle under the same
conditions of which the super cooling degrees are 2 ° , the maximum COP of this new cycle improves 10.2% and 69.1% respectively, while the minimum condenser heat load cuts down 3.5% and 5.3% respectively. And the mass flow rate of the refrigerant in evaporator of this new cycle reduces by about 2.1% compared with that of a conventional two stage compression refrigeration cycle.