Determination of optimum refrigerant charge for domestic refrigerator units

A method is given of assessing the optimum refrigerant (R12) charge for domestic refrigerators employing a capillary tube expansion device. This amound of refrigerant was found to depend mostly on the volumes of the evaporator and condenser in broad accordance with an earlier theoretical analysis which, however, tended to overestimate the optimum quantity. Experimental measurements were made with different charges and it was concluded that ambient air temperature was not a significant factor. The coefficient of performance was shown to be more sensitive to overfilling than underfilling.