A study was conducted to examine the impact of pipe sizes on freshwater production and heat transfer rates in a simple air-water harvester (AWH). The pipe sizes used for the evaporator construction varied from 3.00mm, 4.00mm, 6.35mm, 8.00mm, to 10.00mm. The AWH was powered by a refrigeration system and operated under environmental conditions. The evaporator was placed inside an open box with dimensions of Due to the low temperature of the evaporator walls, water vapor condensed and collected in a bucket. The cooling process relied on natural convection, with no fan to assist the airflow, so the air flowed passively due to gravity. The heat transfer rate from the air to the evaporator was evaluated using an energy balance equation. This study built upon previous research on the effect of channel sizes on the heat transfer coefficient, but specifically focused on AWHs, as no similar studies had been conducted on the effect of pipe sizes in such systems. It was found that as the pipe size decreased, both freshwater production and heat transfer rates increased. The smallest pipe size yielded 381g of freshwater and a heat transfer rate of 53.54W, while the largest pipe size produced 256g of freshwater and 43.56W. The highest COP of 8.7 was achieved with the smallest pipe size.

pipe size, freshwater, heat transfer rate, COP, air water harvester, evaporator