The goal of this study was to determine whether extruded aluminum tubing could be usedin the manufacture of a condenser and evaporator for a domestic refrigerator that would becompetitive with conventional technology. A variety of tube geometries were examined.Condenser and an evaporator models were constructed using two-phase flow correlations toaccount for "refrigerant-side pressure drop. The duct size and airflow rate were held withinconventional limits for comparison. Constraints on the tube spacing insured that there would beroomfor cleaning the condenser coil and that the evaporator would not become blocked by frost.An analysis of base case tube geometries showed that using two parallel circuits substantiallyreduced the amount of aluminum. Optimal condenser and evaporator designs were found byminimizing component cost. The best condenser design used a tube with 10 sub-millimeter portswith 6 mm lateral fins to increase heat transfer. The optimal evaporator design also incorporatedlateral fins, but had only one relatively large port. A model of a refrigerator system wasconstructed and used to determine the effect of pressure drop on COP for a 150 W evaporator.The optimal component designs were used as initial guesses for the system analysis. The resultsshowed that a feasible design does exist that is comparable in cost to conventional heat exchangers.Further, the extruded aluminum exchangers reduce refrigerant charge and can provide a higherCOP than the current technology.
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