一种新型自然光气体熏蒸平台:系统结构与控制精度

System Structure and Control Accuracy of a Solar-illuminated Gas Fumigation Platform

研制新建自然光气体熏蒸平台主要用于开展大气环境变化对作物影响的研究。该平台采用分布式拓扑结构,通过监测系统实时探知温度、湿度、光照、压力以及目标气体浓度的变化,利用温度、湿度调控系统和布气系统实现对外界环境的动态模拟,使气室内的气象因子与室外基本一致,并使气体浓度达预定目标要求。平台设置室外对照(Ambient)、室内对照(CK)、高浓度臭氧([O3])、高浓度二氧化碳([CO2])和高浓度O3和CO(2[O3×CO2])5个处理,其中室内对照实时模拟室外环境,[O3]处理为Ambient的1.6倍,[CO2]处理比Ambient高200ppm。2011年水稻生长季气室运行结果表明,[CO2]和[O3]控制精度在90%以上的时间占总布气时间的比例分别达95%和80%以上,温度、湿度和大气压力控制精度在90%以上的时间均占总运行时间的95%以上,平台光照控制精度在90%以上的时间占总运行时间的75%以上。整个布气期间,CO2和O3浓度平均控制目标完成比(target achievement ratios,TAR)分别为1.01和1.00,温度、湿度、光照和大气压TAR分别达1.01、0.99、0.96和1.00。稳态熏蒸测试结果表明,气室内O3、CO2、温度和湿度的水平分布和垂直分布均匀,控制稳定。

A sunlit fumigation system was developed to study the influence of atomospheric changes on crop growth and development.The system adopted distributed topology and real time monitors to control environmental factors inside chambers such as temperature,humidity,illumination and atomospheric pressure,as well as carbon dioxide concentration [CO2] and ozone concentration[O3].The real time simulation of ambient conditions through temperature control unit,humidity control unit and gas distribution system enabled meteorological factors inside chambers close to the open-air conditions,while trace gases such as [CO2] and [O3] concentration reached target levels.The target [CO2] for the elevated CO2 plots was controlled to 200 ppm above ambient and the elevated [O3] was 60% higher than the ambient [O3] in the control plots.We had tested the performance of the system by identifing the spacial and temporal distribution of meteorological factorsand target gas concentration.The control performance of the chamber system in 2011 rice growing season showed that,with1-min average value across 2011 rice growing seasons,the elevated [O3] and [CO2] was within 10% of the target for more than 95% and 80%,respectively.The temperature,humidity and atmospheric pressure were within 10% of the target for more than 95%,whereas the frequency within ±10% of the target illumination intensity was more than 75%.Across the 2011 rice season,the target achievement ratios（TAR）of CO2,O3,temperature,relative humidity,illumination intensity,atmospheric pressure were 1.01,1.00,1.01,0.99,0.96 and 1.00,respectively.The constant fumigation test inside the chamber showed uniform distribution of CO2,O3,temperature and humidity inside the chamber in both horizontal and vertical directions.