VENTILATION CONTROL TO REDUCE AIRBORNE CONTAMINANTS

研究结论表明，空气中的污染物水平 猪的圈养通常达到足够的水平， 对该职业的工人造成危害。除了一种微粒 成分，可达到26毫克/立方米的水平，气体中存在的 高含量的限制物包括甲烷，硫化氢，氨， 和二氧化碳。 猪农的公认呼吸道疾病 包括上呼吸道炎症、哮喘样综合征和慢性 气流限制。与猪相关的通风系统 禁闭室的设计主要是为了提供一个舒适的气候， 猪。然而，由于禁闭是以营利为目的的， 与运行通风系统相关的成本为 通常通过最小化风扇使用而保持在最低限度， 保持空气中污染物的高水平。 本研究提案 涉及应用反馈控制理论来设计 自动密闭通风系统，将操作该系统 以这样的方式，同时最大限度地减少竞争的需要， 最小化成本和污染物水平。在设计之前， 测试了这种控制方法，分析了时变特性 两种污染物（总粉尘浓度和氨水平）， 两个气候因素（温度和湿度）将在 一年中的猪圈。 这项工作将导致 确定所用实时传感器准确性所需的信息 来衡量这四个“输出”变量，并指出 测量信号的噪声质量。连续测量 在风扇速度变化期间的这种类型也将用于确定， 并建立数学模型， 输出变量和风扇速度的变化。 从知识的 噪声质量和输出变量的动态行为，设计 并对几种可能的反馈控制方法进行仿真， 使用专门为此目的开发的软件执行。一 拟议研究的最后一个方面将涉及一系列测试， 最好的候选控制方法与使用的全面 通风测试设施。 今后的工作将涉及 开发和测试最佳控制方法， 设施;开发其他工程控制方法， 最大限度地减少空气中污染物的产生和迁移 限制;以及通过以下方式验证控制方法的效用： 测量污染物水平和肺功能的变化， 工人

Studies have shown conclusively that airborne contaminant levels in swine confinements are typically of a sufficient level to pose a health hazard to workers in that occupation. In addition to a particulate component that can reach levels of 26 mg/m3, gases present in confinements in high amounts include methane, hydrogen sulfide, ammonia, and carbon dioxide. Recognized respiratory diseases of swine farmers include upper airway inflammation, an asthma-like syndrome, and chronic airflow limitations. Ventilation systems associated with swine confinements are largely designed to provide a comfortable climate for the pigs. However, because confinements are operated on a for-profit basis, costs associated with operating the ventilation system are typically kept to a minimum by minimizing fan usage which results in maintaining high airborne contaminant levels. This research proposal involves the application of feedback control theory to design an automated confinement ventilation system that will operate the system in such a way as to simultaneously minimize the competing needs to minimize both costs and contaminant levels. Prior to the design and testing of such a control method, an analysis of the time-varying nature of two contaminants (total dust concentration and ammonia levels) and two climate factors (temperature and humidity) will be performed over the course of year in a swine confinement. This work will result in information needed to ascertain the accuracy of real-time sensors used to measure these four "output" variables as well as to indicate the noise qualities of the measurement signal. Sequential measurements of this type during a change in fan speed will also be used to determine, and mathematically model, the dynamic relationship between a change in output variable and a change in fan speed. From a knowledge of the noise qualities and dynamic behavior of the output variables, the design and simulation of several possible feedback control methods will be performed using software specifically developed for this purpose. A final aspect of the proposed research will involve a series of tests of the best candidate control methods with the use of a full-scale ventilation-testing facility. Future work would then involve the development and testing of the best control method in an actual facility; the development of other engineering control methods to minimize the production and migration of airborne contaminants in a confinement; and a verification of the control method's utility by measuring the change in contaminant levels and the lung function of workers.