Thermal Insulation Materials And Environment Optimization Of Micro-Plant Factory

In order to improve the uniformity of temperature distribution inside the micro-plant factory and reduce the cost of insulation materials,the thermal insulation properties of thermal insulation materials and the Micro-plant microenvironment was simulated and tested in this paper.The ways to optimize insulation and improve temperature uniformity were proposed.The heat balance of Micro-plant factories was analyzed.The interaction between microenvironment and lettuce growth in plant factories was studied.The thermal insulation materials were simulated and optimized through ANSYS software.In this paper,the computational fluid dynamics（CFD）technique is used to simulate the velocity field and temperature field distribution of micro-plant factories under different cyclic wind speeds.The optimal cycle wind speed combination mode was determined and experimentally verified by planting lettuce in a micro-plant factory.The specific research work is as follows:（1）Micro-plant factory thermal balance and its numerical analysis model.Taking the MPF-700 micro-plant factory of Jiangsu University as the research object,the heat source of the micro-plant factory was analyzed,and the dynamic heat model of the micro-plant factory was established according to the heat expression and heat balance equation of each part of the micro-plant factory.The airflow flow control equation and the turbulent transport equation were selected to provide a theoretical basis for the analysis of the internal flow field in the micro-plant factory.（2）The interaction between microenvironment and lettuce growth in plant factories.The temperatures is set as 3 levels of T₁（18°C）,T₂（22°C）and T₃（26°C）,humidity is H₁（40%）,H₂（60%）and H₃（80%）,and the circulating wind speed is W₁(0 m?s^-1),W₂(0.6 m?s^-1),W₃(1.2 m?s^-1)and W₄(1.8 m?s^-1)4 levels.In this paper,the effects of different temperature,humidity and circulating wind speed conditions on the net photosynthetic rate and transpiration rate of lettuce were studied.The test results show that temperature,humidity and circulating wind speed have significant effects on the photosynthetic characteristics of lettuce.Considering the coupling of temperature,humidity and circulating wind speed,the treatments of seedling,growth and harvesting maximum net photosynthetic rate were W₄H₂T₃,W₄H₂T₃ and W₄H₂T_2,respectively.The maximum transpiration rates were W₄H₁T₁,W₄H₁T₁ and W₄H₁T₁.Optimized design of thermal insulation materials for Micro-plant factories.Through ANSYS finite element analysis,the temperature field distribution and heat flux of single-layer insulation materials with different thicknesses are simulated when the heat transfer to the outside through the heat insulation material and the heat transfer to the room through the heat insulation material.It is determined that the thickness ratio of the two materials is 0.8,the outer material is rock wool insulation board,the inner material is phenolic insulation board,and the total thickness is 20mm,which is the best insulation material for MPF-700 miniature plant factory.Its thermal insulation properties meet the thermal insulation requirements of Micro-plant plants and are less expensive than single-layer materials and other two-layer materials.（4）Microenvironmental optimization design of micro-plant factory.A three-dimensional model of a micro-plant factory was established and simulated by CFD technology.Set upper and lower low(upper wind speed V=1.8 m?s^-1,middle wind speed V=1.2 m?s^-1,lower wind speed V=0.6 m?s^-1),lower high and low(V_上=1.8m?s^-1,V_中=1.2 m?s^-1,V_下=0.6 m?s^-1)and constant velocity(V_上=V_中=V_下=1.2 m?s^-1)Three kinds of air circulation modes for simulation.This paper analyzes the airflow field and temperature field of the micro-plant factory in the upper,middle and lower layers with different circulating wind speeds.It was found that the upper and lower high airflow and temperature uniformity were the best.Three kinds of airflow circulation modes were tested and verified.The test results show that the optimal airflow circulation inside the micro-plant factory is high and low,and the temperature inside the micro-plant factory is more uniform.