面向药材贮藏的热泵干燥系统实验研究

目的 针对药材贮藏前传统干燥处理方法效率低，药材易变质，处理能耗高，不利于药材高品质贮藏等问题，优化药材干燥处理方法至关重要。方法 采用真空低温干燥技术，设计一套以真空干燥箱为传质系统进行低温干燥的热泵干燥处理系统。系统包含基于热泵压缩机驱动的真空低温干燥系统、真空泵、变频风机等设备，通过对其进行干燥性能实验研究，分析获得热泵冷凝温度、空气入口风速以及空气入口温度对该系统干燥性能的影响。结果 在环境真空压力-40～0 kPa实验条件下，热泵真空低温干燥系统的干燥量、干燥效率、传质系数及传热系数最大值分别为3.96 kg/h、44.19%、3.75 g/(m²·s)、3.25 W/(m²·℃)，析湿过程传质系数及传热系数最大值分别为44.51 g/(m²·s)及36.03 W/(m²·℃)，热泵系统最大能效为6.08。对实验数据进行回归分析，得到热泵真空低温干燥系统干燥效率模型，模型计算值与实验值的最大偏差在±21%以内，平均偏差为9.18%，预测效果较好。结论 相较于常压下热泵低温干燥技术，基于真空...

Experimental Research on Heat Pump Drying System for Medicinal Herbs Storage

Aiming to solve the problems of low efficiency, easy deterioration, high energy consumption and unfavorable conditions for high-quality storage in the drying process of medicinal herbs, it is crucial to optimize the drying method. By vacuum low-temperature evaporation drying technology, a heat pump drying system was designed with a vacuum drying chamber as the mass transfer system to conduct low-temperature drying. The system was composed of equipment such as a vacuum low-temperature drying system driven by a heat pump compressor, a vacuum pump and a variable-frequency fan. The performance of the system was studied through experiments, and the effects of heat pump condensation temperature, air inlet velocity, and air inlet temperature on the drying performance of the system were analyzed. Under experimental conditions with environmental vacuum ranging from −40 to 0 kPa, the maximum values of drying capacity, drying efficiency, mass transfer coefficient, and heat transfer coefficient for the heat pump vacuum low-temperature drying system were 3.96 kg/h, 44.19%, 3.75 g/(m2.s), and 3.25 W/(m2.℃) respectively. The maximum values of mass transfer coefficient and heat transfer coefficient in the dehumidification process were 44.51 g/(m2.s) and 36.03 W/(m2.℃) respectively. The maximum coefficient of performance (COP) for the heat pump system was 6.08. Regression analysis was conducted on the experimental data to obtain the correlation equation for the drying efficiency in the heat pump vacuum low-temperature drying system. The maximum deviation between the calculated values and experimental values was within ±21%, and the average deviation was 9.18%, indicating a good predictive performance. Compared with the heat pump low-temperature drying technology at normal pressure, the heat pump drying system based on vacuum low-temperature drying technology effectively improves the efficiency of herb drying and reduces energy consumption in the herb drying process, ensuring the high-quality storage of medicinal herbs.