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 t hrough ventilated packages containing horticultural produce. The technique relies on measurement of the time for CO2 injected in the incoming airflow to reach sampling points throughout the package. This is made practicable b y use of a constant flow gas analyser. Data analysis procedures, including means for their graphical representation, are described, and example result s are given for two pack types. Measured data were applied in a mathematica l model for predicting cooling of fruit in the packs. The in-pack time-temp erature predictions matched measured data thereby indicating that the metho d for characterization of airflow distribution had not been a significant s ource of error. (C) 2000 Silsoe Research Institute.