Variation of moisture content in cabbage seeds with heat pump intermittent drying

Aimed at studying the moisture diffusion mechanism inside the seeds during heat pump drying, a nonhomogeneous dynamic mass transfer model was set up for cabbage seeds analyze the moisture diffusion in the cabbage seed under conditions of continuous drying with constant temperature and intermittent drying with on/off pulsating of air velocity. Results showed that the simulation results coincided well with experimental data with correlation coefficient of 0.9974 and relative deviation being less than ±10%. With the heat pump intermittent drying, the moisture distribution inside the cabbage seed was more uniform. With intermittency ratio of 1/3 and on-time in the intermittent drying cycle of 400 s, nearly 50% energy conservation for the heat pump equipment could be achieved during the drying process. This research can provide a reference for application of heat pump drying technique.