The objective of this study is to investigate the effects of hot-wall condenser geometry on domestic refrigerator-freezers (RFs) in terms of refrigerant charge reduction. A transient simulation model for an R600a domestic RF is developed and validated to capture the dynamic performance at various operating conditions. The hot-wall condenser in the domestic RF is determined to store excess refrigerant charge. The effects of the hot-wall condenser geometry on the performance of the RF are analyzed according to the total refrigerant charge. The coefficient of performance (COP) decreases with decreasing hot-wall condenser length and diameter; however, the decrease in the COP of the RF is compensated by the decreased energy consumption. Based on the global minimum energy consumption, the optimum hot-wall condenser design is achieved when the tube length is reduced to 70% of its original size and the tube outer diameter is decreased to 3.75 mm. Furthermore, the total refrigerant charge in the RF corresponding to the optimized hot-wall condenser geometry is shown to be 14% lower compared to the rated charge amount.

这项研究的目的是研究减少制冷剂充注量的热壁冷凝器几何形状对家用冰箱-冷冻机（RF）的影响。开发并验证了R600a家用RF的瞬态仿真模型，以捕获各种工作条件下的动态性能。确定家用RF中的热壁冷凝器可存储过量的制冷剂。根据总的制冷剂充注量，分析了热壁冷凝器几何形状对RF性能的影响。性能系数（COP）随热壁冷凝器长度和直径的减小而减小；但是，RF COP的降低可通过降低的能耗来补偿。根据全球最低能耗，当管长减小到其原始尺寸的70％，并且管外径减小到3.75 mm时，可获得最佳的热壁冷凝器设计。此外，与优化的热壁冷凝器几何形状相对应的RF中的总制冷剂填充量比额定填充量低14％。