Refrigerant mass charge distribution in a domestic refrigerator. Part II: steady state conditions

Experimental results are presented of the refrigerant mass charge distribution in a steady state operating domestic refrigerator at varied thermal loads. It was found that the charge decreased in the evaporator and increased in the condenser and compressor upon increased thermal load. No subcooling or superheat was observed over the range of capacities tested (74-145 W). The combination of a low side accumulator and an expansion device with high capacity (short capillary tube) explained this. The study suggests that a capillary tube throttled cooling system, with a floating condensation temperature, can handle large load variations without becoming destabilised (superheat or subcooling) just like a more sophisticated thermostatic expansion device control system