Water Carryover Characteristics From Evaporator Coils During Transitional Airflows

In this paper, the results from an experimental investigation to determine the water carryover characteristics from the evaporator coil during transitional airflows is presented. The tests were conducted at the following transitional operating conditions: blower speed low to medium; and blower speed low to high. For both of these tests the system operated at low blower speed for an extended period of operation before switching to either medium or high speeds. A laminate (plate type) evaporator with louvered fins with hydrophilic coating was used for this investigation.

Tests were also conducted with a screen at the downstream face of the core to prevent water carryover. This test was conducted for the worst case scenario, i.e., when the blower speed was increased to high from an extended period of operation at low speed.

This study reveals that the accumulated water in the evaporator core during extended low blower speed is carried over to the downstream side (i.e., heater unit side) in approximately 15 seconds. Photographs of the progression of the water from the evaporator core is also presented in this paper.