Intelligent control technology of air source heat pump for mango drying

In order to improve the efficiency of mango drying and save energy, the paper analyzes the process flow of mango drying by air source heat pump (ASHP). Aiming at the low energy efficiency of the conventional segmented constant temperature and humidity (SCTCH) drying process, the paper proposes a new method combining segmented variable structure drying rate control with intelligent neural network. To accurately control the dehumidification amount at the drying process transition point (TP) to ensure the drying quality of mango, each drying section is devide to 3 parts and respectively adopt different control methods. According to the mutual coupling characteristics of the temperature and humidity and the fact that the drying process is easily disturbed by the environment and other external factors, the non-linear autoregressive neural network (NARX) with external input is used to intelligently adjust the set values of the temperature and humidity of the drying room to improve the dehumidification capacity of the unit energy consumption. Through the experiment of mango drying with ASHP drying system, compared with the conventional SCTCH drying method, the control method proposed in this paper can ensure the drying quality of mango and save 8.45% of electric energy.