Research On Energy-saving Operation Mode Of Forest Fruit Drying System Based On Solar Energy And Heat Pump

In recent years,with the increasing scale of the domestic forest and fruit industry,the research and development of a reasonable and effective forest and fruit drying technology has become the main demand of the current forest and fruit drying industry.In the process of forest fruit drying,the introduction of renewable energy sources such as solar energy to supply energy to the drying system is already a more recognized technical means in the industry.However,the utilization of solar energy resources is affected by the weather and region.Currently,there is a problem of unstable energy supply.The combined dry energy supply technology of solar energy and heat pump,as an emerging dry technology,can effectively solve the problem of instability of solar energy supply.At present,the structure of the solar energy and heat pump combined drying energy supply system is relatively simple.For different drying conditions,using the same operation mode will cause the system to be mismatched with the actual drying conditions,resulting in a decrease in the thermal efficiency of the system.To solve this problem,this paper proposes a multi-mode solar-heat pump combined drying system from the perspective of energy-efficient utilization technology and the actual demand for forest and fruit drying,which uses a combination of theoretical analysis,numerical simulation,and experimental research.Developed the equipment prototype,constructed the system simulation model,and carried out the corresponding simulation,experiment,and optimization research.The main research work and conclusions of this paper are as follows:1)Taking Camellia seeds as the main research object,the analysis of drying characteristics and the determination of basic physical parameters were carried out.First of all,starting from the actual process requirements,combined with the working principle and operating characteristics of the solar-heat pump combined drying system,the theoretical design calculation of the solar-heat pump combined drying system is carried out.It mainly includes:based on the matching between the heating capacity of the compressor and the wet load of the drying material,the selection of the parameters of the drying medium in the system during the operation of the system,and then the relevant design and selection calculation of the main components of the solar heat pump drying system.Completed the structural design of the drying system prototype and built the prototype to complete the commissioning,laying the foundation for the later tests.2)According to the design plan and equipment selection of the test prototype,a simulation model of each component in the heat pump drying system including the heat pump unit model and the drying material model is established.The actual data collected by the test prototype is compared and verified with the simulation results output by the heat pump simulation model.The verification results show that the deviation between the simulation results of the heat pump simulation model and the actual data is between 5%and 10%.3)Based on the TRNSYS software,the heat pump drying system is simulated and the system operating parameters,system performance,and system energy consumption changes are analyzed,and the energy-saving operation mode and control law of the heat pump drying system suitable for the drying of camellia seeds are obtained.The simulation results show that when the drying temperature is 50℃ and the drying mass is 100kg of Camellia seeds,the total power consumption of the system energy-saving operation mode combined with the split,semi-open,and closed modes is higher than that of the single split The system operating mode has been reduced by 15%.4)Based on TRNSYS software,the system simulation of the solar-heat pump combined drying system is carried out.Based on the energy-saving operation mode of heat pump drying,the changes of system operating parameters,system performance,and system energy consumption are analyzed after the solar collector is added to the system.The simulation results show that when the drying temperature is set to 50℃,the mass of the same batch is 100kg of camellia seeds,the area of the solar heat collector is connected in series with the heat pump and the heat collection area is 6m2,the combined drying system of the solar heat pump is used.The total power consumption is reduced by 20%compared to the heat pump drying system.