An airflow enhancing floor cover to improve temperature uniformity in maritime refrigerated containers.

In maritime refrigerated containers air is drawn from just below the ceiling into the refrigeration unit, where it is cooled to the desired temperature and then supplied into 60 mm high longitudinal T-bars, which make up the container floor. Cargo temperatures at the door-end are usually 2 °C higher than the supply air temperature. A better air flow distribution could improve the temperature uniformity. In earlier work four different air flow enhancing floor cover shapes were tested in a climate chamber. The aim of this study is to assess the effectiveness of the best of those four air flow enhancing floor covers in a field experiment with commercial container shipments from South Africa to The Netherlands. Three test containers contained that air flow enhancing floor cover, three reference containers did not. All other parameters were, to the extent possible, the same for all containers. Based on the test results it is concluded that the tested air flow enhancing floor cover reduces the difference between the warmest and the coldest cargo temperature in shipments of precooled grapes by approximately 30%. Keywords: air distribution, air flow, duct, refrigerated container, temperature difference.