| Abstract: | A mathematical model is developed to analyse the performance of a vacuum cooler. The model is based on the mass conservation of air and vapour in the vacuum chamber. In the chamber, the vapour evaporated from foods under the vacuum and the vapour removed by the vapour-condenser and vacuum pump contribute to the variation in the vapour partial pressure, and the ingress air and the air released by the pump cause the change of air partial pressure. Experiments were carried out on vacuum cooling of water to validate the model. The predicted vacuum pressure and temperature histories are compared with the measured values. The maximum deviation between the predicted and measured vacuum pressure is within 110 Pa (for the chamber pressure between 12,000 and 2200 Pa), while the maximum deviation between the predicted and measured temperature of water is less than 2 °C. The model can, therefore, be used to predict the transient vacuum pressure profiles for analysing the vacuum cooling process of foods such as cooked meat. |
