COP-based optimization of accelerated flow evaporators for household refrigeration applications

This paper reports an investigation on the impact of an alternative evaporator design, the so-called Accelerated Flow Evaporator (AFE), on the performance of household refrigerators. In this novel evaporator concept, the air-side cross-section area decreases with the distance from the air flow inlet, accelerating the air as it flows across the tubes and hence improving the air-side local heat transfer coefficient. An AFE heat transfer and pressure drop calculation method proposed elsewhere [1] has been incorporated into an overall system simulation model [2] to assess the impact of the evaporator geometry on the system COP. The results were compared with experimental data obtained in a top-mount refrigerator. The predictions of working pressures, power consumption, cooling capacity and COP agreed with the experimental data to within ±10% error bands. The model was subsequently used in an optimization exercise of the AFE geometry that considered both the system COP and the evaporator mass of material.