Refrigerant Circuit

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Figure 1 shows a schematic diagram of the test rig used to determine the performance of a R410A domestic air conditioning system. It includes a refrigerant circuit, a main (evaporator) air duct and a secondary (condenser) air duct. Refrigerant circuit comprises an expansion device, an evaporator, an electrically driven compressor and a condenser followed by a receiver, a sight glass and a filter/drier. Table 2 gives specifications of the main components of the refrigerant circuit. As the refrigerant flows through the evaporator, it absorbs heat that changes its phase. As a result, the superheated refrigerant vapor leaves the evaporator (state point 1) and then goes to the compressor. The compressor increases the pressure of the refrigerant…show more content…
Thus, the refrigerant vapor gets condensed (state point 3) and collected into the receiver, which prevent uncondensed vapor passing through the circuit. After passing through the receiver, the liquid refrigerant passes through a sight glass and filter/drier that absorbs the water vapor that may enter the circuit. Then reducing the pressure of refrigerant by the expansion device and now the phase of refrigerant before entering the evaporator is two phase (state point 4). Low and high pressure-stats are used to protect the compressor from over and under operating pressures. The low pressure-stat is connected to the suction side and high pressure-stat is installed on the discharge side. If the pressure exceeds its limits, the compressor will be automatically switched…show more content…
The system performance are evaluated at two evaporator air flow rates (400 and 550m3 h[-1]), evaporator inlet temperature lies between 28[o]C and 34[o]C and humidity ratio ranges from 8 to 25.5gw kga[-1]. The effects of evaporator inlet air humidity ratio, temperature and flow rate are discussed in the next section. * Effect of evaporator air inlet humidity ratio Effect of evaporator air inlet humidity ratio on the condenser and evaporator pressures can be predicted from Figure 2. It is seen that the evaporator pressure as well as the condenser pressure increase by 9.4% and 3.2%, respectively, as the evaporator air inlet humidity ratio increases from 8 to 25.5gw kga-1 at evaporator air inlet temperature 34[o]C. Figure 3 illustrates variation of measured evaporator and condenser air outlet temperatures and discharge refrigerant temperature with evaporator air inlet humidity ratio. As air inlet humidity ratio increases from 8 to 25.5gw kga-1 the evaporator and condenser outlet temperatures increase by 68.7% and 17.4%, respectively, and discharge refrigerant temperature increases by 6.6% at evaporator air inlet temperature

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