Initial Product Temperature Research Articles

Forced-Air Cooling of Bell Peppers in Bulk

ABSTRACT TEMPERATURE response, as a function of air velocity and position in load, was determined during cooling of bell peppers in bulk with 1.7 C (35 F) air. Data were analyzed to provide graphs and equations that can be used to predict mass average tempera-tures during cooling for any desired initial product temperature or cooling air temperature, and at any air velocity from 0.02 to 2.0 m/s (4 to 400 ft/min). Informa-tion is also presented on moisture loss during cooling and on static pressure drop through the load as a func-tion of airflow.

Heat Transfer During Aircooling and Storing of Moist Food Products — II. Spherical and Cylindrical Shapes

ABSTRACT HEAT transfer characteristics during aircooling of moist food products are analyzed taking into account the effects of the evapora-tion of the moisture film that usually exists on the product surface. The one-dimensional transient heat con-duction equation in spherical and cylindrical coordinates is solved. Charts useful in predicting the time-temperature histories and cool-ing loads are presented for the fol-lowing values of dimensionless parameters: Biot number, Bi: 0.1 to 10, Initial product temperature, tj : 2.5 (a 21 C) to 4.0 (~ 43 C) in increments of 0.5, Cooling air temperature, t^~: 1.25 (~ 2 C) to 2.25 (~ 15 C) in in-crements of 0.5, Relative humidity, $ : 0.0 to 1.0 in increments of 0.2. Relative humidity of the cooling air is an important parameter which decides the cooling rates. Surface evaporation effects are significant, particularly at low air humidities. The present analyses yield much better agreement with the experi-mental results compared to existing conventional methods.

Simultaneous heat and mass transfer during the cooling of a deep bed of biological products under varying inlet air conditions

The cooling and dehydration of a deep bed of high moisture content cherry pits was investigated experimentally and the data were analysed by writing three heat and mass transfer balances. The inlet air conditions were changed continuously during the test period; the initial product temperature distribution within the bed was not uniform. The set of coupled equations resulting from the transfer balances were solved numerically with the aid of a digital computer. The empirical and theoretical heat and mass transfer agreed well.