Use of Carbon Dioxide as a Tracer Gas for Determining In-package Airflow Distribution

A methodology was developed to characterize the relative rates of airflow through ventilated packages containing horticultural produce. The technique relies on measurement of the time for CO2injected in the incoming airflow to reach sampling points throughout the package. This is made practicable by use of a constant flow gas analyser. Data analysis procedures, including means for their graphical representation, are described, and example results are given for two pack types. Measured data were applied in a mathematical model for predicting cooling of fruit in the packs. The in-pack time-temperature predictions matched measured data thereby indicating that the method for characterization of airflow distribution had not been a significant source of error.