Design And Optimization Of A Row Tube Cold Storage With Cold Storage Plate

Cold storage is an important part of cold chain logistics,is an indispensable link in the cold chain.Cold storage consumes a large amount of electricity,and the electrical charge is an important part of its operation cost.In the cold storage refrigeration system,the adoption of cold storage technology and reasonable utilization of grain electricity can stagger the production and release of cold capacity,effectively reduce the electricity cost of cold storage,and easy to keep the temperature of the warehouse stable.The core of cold storage technology is the material responsible for the storage and release of cold.This paper mainly uses computational fluid dynamics and numerical simulation techniques to simulate the internal temperature field of small cold storage and verifies it with experiments.The verified calculation method is applied to the simulation study of small and medium-sized cold storage,and the influence of different layout schemes of cold storage plates,different sizes of cold storage plates,different stacking heights of goods,and switch doors on the internal temperature field of small and medium-sized cold storage is analyzed.To provide some theoretical reference for the design and optimization of cold storage,the main research content and conclusions of this paper are as follows:(1)Take small cold storage as the experimental object,calculate the required heat load,select the cold storage agent,and determine the dosage.It is concluded that the heat load of a small prefabricated cold storage(5 m×4 m×3.2 m)within 6 h is 1333.9 W.By selecting the cold storage material suitable for the operating temperature of-18℃(30%(NH4Br+NH4Cl)+ 1%Sr Cl2 + 5%xanthan glue),129.3 kg of cold storage material is required.(2)Taking small and medium-sized cold storage as the research object,a numerical model is established for simulation calculation to analyze the internal temperature field changes of small cold storage refrigeration units after shutdown.The numerical calculation was carried out for the cold storage of the top and side storage,and the distribution of temperature field in the two types of storage was studied.The results showed that the temperature distribution in the top storage was more uniform,and the temperature remained at-17.316 ℃ after6 h,while the temperature in the side storage fluctuated greatly after 6 h,and the temperature stratification was obvious.The temperature ranges from-14.758 ℃to 3.461 ℃.The temperature distribution in the warehouse also has an impact on the goods.After 6 h,the average temperature of the goods in the warehouse with the top storage plate is-17.462 ℃,while that with the side storage plate is-16.795 ℃.(3)The numerical model of small and medium-sized cold storage is established,and the size of the cold storage plate is taken as the research object.The influence of three sizes(1.5m × 1m × 0.1m),(3m × 2m × 0.1m)and(7m × 2m × 0.1m)on the temperature field in the storage was studied.In the simulation study,the quality of the storage agent was consistent,and the quantity of the storage plates of different sizes was different.The results show that the smaller the size of the cold storage plate,the temperature distribution in the warehouse is more uniform,with an average temperature of-18.213℃,and the temperature of the goods in the warehouse is more stable,with an average temperature of-17.303 ℃.(4)The numerical model of small and medium-sized cold storage is established,and the stacking height of goods is taken as the research object.The simulation calculation is carried out,and the simulation analysis is carried out on the stacking height of goods(1.5m,2.5m,3.5m,and 5m).After the refrigeration unit is shut down,the size of the cold storage plate is(1.5m × 1m × 0.1m),and the low temperature can be maintained at-18℃ in the area below the height of the goods after 6 h.The temperature stratification phenomenon still exists in the area above the height of the goods,with the highest temperature reaching-12℃.When the cargo height is too low(1.5m and 2.5m),there will be a large vortex centered on the center of the whole cold storage,and the speed can reach 0.183m/s.The high-temperature area appears in the spiral arm region of the vortex.When the height of goods reaches more than 3.5m,the distribution of shelves will block the formation of vortices and maintain good temperature uniformity in the warehouse.(5)The numerical model of small and medium-sized cold storage is established.Taking the cold storage door opening as the research object,the simulation calculation is carried out to analyze the temperature field and the temperature changes of goods in the cold storage room within 60 s of opening the door.There is a violent heat transfer process near the upper part of the warehouse door.The invaded high-temperature fluid mainly gathers at the top of the cold storage room and generates a vortex in the lower part.It spreads inside the warehouse against the top wall of the warehouse and reaches half of the length of the warehouse at the farthest.However,large temperature changes only occur in the top corner of the goods,and the temperature on the surface of the goods reaches nearly 20℃.However,the range of temperature changes is small,and it has no great influence on other goods in the warehouse.