The Monitoring Of Humiture And CO₂ Concentration And Its Distribution In Closed Henhouse In The Winter And Spring

With the rapid development of layer breeding industry in China,the efficiency breeding and healthy breeding has become the theme of the laying hens industry.Traditional breeding methods have been unable to meet the needs presently,China's layer breeding industry is transforming from the traditional small feeding to large-scale intensive feeding mode,closed henhouse is one of the most prominent types of chicken houses,the external environment of the henhouse had little effect on the efficiency and quality of laying hens,however,the temperature,relative humidity,CO2 concentration and NH3 concentration were the main factors affecting the health and egg quality of laying hens,so it is necessary to adjust the environmental factors based on appropriate control strategies in the henhouse.The establishment of a reasonable control strategy is mainly to comprehend the distribution of environmental factors in the henhouse.This paper took a closed henhouse in Jiangning Qinglong forest farm in Nanjing city of Jiangsu Province as the research object,the boundary condition and size were measured,and the physical model was established,and the wind speed and temperature field were simulated by Fluent software,a set of environmental monitoring system was designed to monitor the temperature,humidity and CO2 concentration in different locations in the spring and winter,finally,the experimental results were used to verify the simulation results,which could provide accurate theoretical basis and guidance for the establishment of a reasonable control strategy.The main research contents and results are as follows:(1)The design of monitoring system for henhouse.Selecting the appropriate sensor and wireless module,and taking the STM32 minimum system as the core,the system measurement nodes were designed to measure the temperature,relative humidity and CO2 concentration in the henhouse in spring and winter;The gateway node using the Tiny6410 core board and expansion board as hardware platform,porting Android system programming,composing human-computer interaction applications based on multithreading and serial port operation,which realized the fuctions of sending commands,collecting environmental factor and transmitting to PC.PC server using VC++6.0 as the development environment,the host computer program was compiled,which achieved the general situation of the chicken house,inside and outside environmental data,alarm information display,input,storage and other functions;Database server was set up based on MySQL,to manage the monitoring data.(2)Based on the study of a closed henhouse in Jiangning District of Nanjing City,Fluent software was used to simulate the temperature field and wind field,simulation results shows:In the horizontal plane,the temperature of A and C aisle is very stable,which changes between 20?22?,B aisle is in the inlet,the temperature is low,about 18?.The wind speed of A,B,C aisle horizontal plane increases with the distance from the door,The temperature of the A and C aisle on the three vertical surfaces varies between 20?22 ?,B aisle temperature in the X= 14m plane changes between 18?22?,X=44m,X=74m plane,the temperature varies between 19?22?.The wind speed of A and C in X=14m is the largest,X=74m is the minimum,B aisle wind speed in the X=14m plane is the largest,in X=44m,X=74m plane of the wind speed showed high at both ends,low in the middle,but the the wind speed of X=74m plane is greater than the X=44m plane.(3)The distribution the temperature and humidity,CO2 concentration in the henhouse in spring and winter was analysed,results shows that:In spring and winter,the temperature and humidity inside the henhouse are suitable for the growth of layers,during the period from 6 am to 9 am,the concentration of CO2 in the chicken house increased dramatically,however,the highest concentration of CO2 in spring was 2285ppm,also within the scope of the hens,the highest concentration of CO2 in winter was 3095ppm,which exceeded the maximum allowable value 2500ppm of CO2 concentration in chicken house,which shows that the regulation strategy is still should to be improved.(4)The influence of the henhouse temperature and humidity on the concentration of CO2 was described,results show that:In winter,the effect of temperature and humidity on CO2 concentration is small,mainly because the temperature is the most important factor in the regulation,in winter,in order to stabilize the temperature inside the henhouse,reduce the ventilation in the henhouse,so that the CO2 concentration in the henhouse is less,resulting in the accumulation;In spring,the relative humidity has little effect on the CO2 concentration,because the water solubility of CO2 is weak.The correlation coefficient between temperature and CO2 concentration is-0.941,which indicates that the temperature has a great influence on CO2 concentration in spring.In this paper,the distribution of temperature,relative humidity and CO2 concentration in closed house in spring and winter were summarized,having a certain significance to study the environmental factors of modernization of our country farming house temperature and humidity,CO2 concentration etc.,also providing a theoretical basis and guidance for the establishment of a reasonable control strategy.