Study On The Application Of A New Type Of Heat Pump In Drying Of Dried Noodles

In this paper,a new type of heat pump drying system is proposed to overcome the shortcomings of the traditional closed heat pump drying system.By using the switch of four-way directional valve,the system meets the two requirement s of accelerating the temperature rise rate of the drying house and ensuring the oven to maintain the constant temperature required by the process.In order to study the performance of the new heat pump drying system used in the drying of noodle.In this paper,the drying process of 500 kg wet noodle is taken as an example to design the drying system of drying house and heat pump and to analyze the performance of heat pump system.Because of the shorter drying time,the storage of enclosure structure and the effect of exothermic characteristics on the load of drying house.Therefore,the transient heat transfer model of the enclosure structure is established by using the ANSYS software thermal analysis module,and the load through the enclosure structure in winter and summer is analyzed.At the same time,the heat and moisture load of the whole oven is analyzed.In order to ensure the requirements of the drying process for the air velocity of the drying house,this paper carried out the design of the local orifice plate of the drying house and simulated it with FLUENT software.The main components of heat pump drying system are designed on the basis of load analysis and air distribution calculation.Finally,each part of the new heat pump drying system is modeled by using MATLAB software,and each component model is solved by the coupling parameters of each component.The variation of desiccant energy consumption ratio(SMER)in different drying stages in winter and summer,as well as the power consumption of compressor,auxiliary electric heating power and auxiliary heat exhaust / heat absorption in different stages were simulated.Through the analysis,it is concluded that when the heat pump drying house is preheated or precooled within 0-30 min,the winter load is heat load and the maximum value is 13.1kW.the summer load is cooling load and the maximum value is 4.8kW.after preheating or precooling,the heat pump dryer enters the formal drying stage.The heat load of drying house in winter is higher than that in summer.The maximum load in winter predrying stage is 3.12 kW,the maximum heat load is 15.46 kW in the main drying stage and the temperature reaches45 ℃,the maximum heat load in the complete drying stage is 5.17 kW.the cooling load in the pre-drying stage in summer is the highest.The large cooling load is 1.14 kW.the main drying stage is heat load and the temperature reaches 45℃,the maximum heat load is 13.5kW.and the complete drying stage is the cooling load and the maximum value is 6.88 kW.In the heat pump drying process,the average SMER of pre-drying stage is higher than that of main drying stage in winter or summer.The average SMER of pre-drying stage and main drying stage was higher in summer than that in winter.The average SMER in summer was 2.51 in summer and 2.18 in winter.The average SMER in summer was 15% higher than that in winter.In winter,the predrying stage and the main drying stage have a large heat load,so the system needs to make up part of the load by auxiliary electric heating.In the main drying stage,the outdoor heat can be extracted from the auxiliary heat exchanger to compensate for the lack of heat.In winter and summer,the auxiliary radiators are in the auxiliary heat removal condition.The power consu mption in the dry stage is higher than that in the predrying stage,and the sum of the main power consumption,compressor power consumption and electric heat ing energy consumption in winter is higher than that in summer.The average main energy consumption in winter is 28.5 higher than that in summer.