Development Of Data Acquisition System And Study On Its Heating Charact-eristics For Solar Assisted Gas Combinnation System

With the rapid development of production,the acceleration of urbanization and the improvement of people’s living standard,energy shortage and environmental pollution become more and more prominent.Therefore,solar energy as renewable energy is playing an increasingly important role in energy conservation.Although solar energy is endless green energy,but because of the low energy density,and is vulnerable to weather and other factors which people can not control,in the course of the use of a large extent by the restrictions.Especially in the winter conditions of insufficient solar energy in order to achieve the stability of the building heating must be increased auxiliary heat source,and gas is an ideal cleaning auxiliary heat source.Based on the climatic characteristics of Shanghai,this paper studies the solar assisted gas-fired heating system and provides the theoretical basis for the popularization of solar auxiliary gas-fired combinatorial system.First of all,based on the existing experimental platform of our school,we use Simens PLC(Programmable Logic Controller)as the lower machine of the whole complex system,and use Siemens WinCC(Windows Control Center)configuration software as the combined system Of the host computer.The PLC data acquisition and electrical control program and configuration software written by STEP7 programming software are used to complete the data acquisition and monitoring system development of solar auxiliary gas combinatorial system.(Such as water temperature,flow,room temperature,etc.)through the data bus to the PLC and then the serial communication of the collected data transmission and display on the computer to complete the system Data collection,data storage and data display,as well as real-time monitoring.Under the winter climate conditions in Shanghai,the relevant experiments of heating and hot water were carried out,and the experimental data were analyzed in depth.The guaranteed rate of solar energy under different modes and the operating characteristics of the system were studied.(1)In a single hot water supply mode in fine weather(the average amount of radiation is greater than 400(W/m~2),irradiation intensity curve is a parabola with downward opening)under solar guarantee rate is 82%on average;in cloudy to overcast weather conditions(the average amount of radiation is less than 250(W/m~2))under solar energy the guarantee rate of the average value is 54%.In the hot water supply heating mode under good weather conditions guaranteed solar rate is about10.3%;cloudy to overcast conditions guaranteed solar rate is about 5.09%.(2)The instantaneous heat transfer increases with the increase of the solar radiation intensity,and decreases with the increase of the solar radiation intensity.In order to verify the relevant conclusions in the experiment of transient analysis of operating characteristics of the system for the important component in the system of heat collector and the heat storage tank,set up the mathematic model,using MATLAB/Simulink simulation software and tthe conclusions are as follows:(1)The positive correlation between the instantaneous heat of the collector and the solar radiation intensity.(2)In good weather conditions,the heat storage water tank temperature increased linearly during the period from sunrise to sunset.The heat storage tank under the experimental conditions the water temperature increased from 3 to 5 degrees per hour.