Dual-Controlled Indirect Cooling Refrigerator/Freezer Using Two Capillary Tubes and an Air Flow Switching System

The dual~controlled refrigeration system is devised to enhance the energy efficiency and basic performance of an indirect cooling household refrigerator/freezer. In order to alternately serve the fresh food and freezer compartment with a conventional simple refrigeration cycle, two capillary tubes and on/off valves are adopted. The air flow switching system, which is composed of two fans and dampers, is used to provide air flow for each compartment The motor-driven on/off dampers are employed to switch the circulating path of air flowing through each compartment. The cycle and air flow switching system are controlled on the basis of compartment temperature. In the present investigation, the 510L prototype unit is a modification of a conventional refrigerator/freezer. The cycle matching and performance test is performed at 30 OC ambient temperature. The energy consumption test reveals that compared to the conventional system, the energy consumption of the present refrigeration system is reduced by about 9%. Moreover, the cooling speed test result shows that with the present refrigeration system, the refrigeration and freezing time become about 10 minute shorter than the conventional system. R-12 was used for this research.