CO2-FACE Enhancement Scheme

I. Overview

The scientific community has made long-term efforts to predict and respond to the consequences of changes in atmospheric composition. the last centuryBefore the 1980s, a large amount of research was conducted in greenhouses, incubators, or open top gas chambers. Due to the significant differences between the corresponding experimental conditions such as temperature, wind speed, humidity, rainfall, and natural conditions, especially the isolation of plants from insects and disease sources in the system, the research results obtained from this simulated environment have a lot of uncertainty in predicting the impact of atmospheric composition and climate change on ecosystems. In view of this, it is necessary to develop an experimental platform system that raises a specific component and/or temperature of the atmosphere under free air conditions, in order to study the response and adaptation of ecosystems to changes under conditions as close as possible to the natural ecological environment.

Regulation in the open system designed by Beijing Huayirei Technology Co., LtdThe automatic control system for CO2 component concentration and temperature, namely the "Carbon Dioxide and Temperature FACE (Free Air Gas Concentration Enrichment)" system platform. The system has no isolation facilities in the target area in the wild, and gas can flow freely. The ventilation, lighting, temperature, humidity and other conditions in the area are very close to the natural ecological environment. This system platform can meet the control accuracy requirements for target gas concentration in a relatively wide range of wind speeds (exceeding similar systems internationally). Control software with independent intellectual property rights, including system control, data acquisition control, analysis and processing software packages, remote monitoring and data management, provides an ideal means for studying the response of ecosystems to changes in atmospheric CO2 concentration and temperature, making China's FACE platform technology the most advanced internationally.

2、 Scheme introduction and performance indicators

Changing and regulating specific gas components in free air over a large area is a highly challenging technological research task. There are multiple excellent teams in the world researching ways to increase air quality in open systemsAutomatic control technology for the concentration of multiple components such as CO2 and O3, as well as changing factors such as temperature and precipitation. The FACE systems that have been and are currently in operation in the world are mostly dryland systems. For example, the system developed in the United States was designed with the goal of increasing the concentration in the experimental area by 50% compared to the atmosphere, but the actual target achieved was an average increase of 20% (Schroeder, 2006). Due to the limitations of this platform technology, it affects the academic and practical value of related research results.

Remote control of the computer to manage the operation of the entire platform, setting the air distribution experiment time, meteorological conditions, etc., can be carried outThe CO2 concentration/temperature setting value or enhancement ratio/amplitude setting is used to control the sample plot data collector to obtain reference data from the control plot data collector. The control quantity is calculated and implemented through various controllers, mass flow meters, pressure regulators, etc. Then, the temperature and gas concentration in the sample plot are measured by controlling the sensors and analyzers in the sample plot to achieve feedback and closed-loop control.

The platform architecture system diagram is as follows:

The control core components of this system are usedCampbell Scientific, Inc's data collector, compared to the international FACE system, some use Campbell's data collector, while others use PLC for control. Compared to using computer control, using a collector has the following advantages.

CO2 enhanced PID automatic calculation control regulation, PID equation proportional calculus equation (PID equation) is a commonly used method in process control, and its flowchart is as follows:

Sampling air inlet waterproof vapor condensation scheme, anti dust filtration

The CO2 intake component (pn 27693) includes an orifice for setting the flow rate, a filter for removing atmospheric dust, and a rainwater distributor, which allows ambient air to be freely used without reducing energy intake. The rainwater diverter is heated to prevent condensation. The intake component includes a balance chamber to suppress fluctuations in the environmental concentrations of CO2 and H2O.

3、 Software Platform and Mobile Monitoring

1. Computer monitoring interface

O3-FACE monitoring and control circuit display, the following figure shows the FACE experimental monitoring interface of the Ecological Environment Research Center.

The O3-FACE monitoring and control circuit display shows the monitoring interface of the ozone production and destruction control system. In order to enhance O3 without damaging nature and the surrounding environment, this system adopts an ozone destruction device.

2. Mobile APP application monitoring

View data and curves（Android and iOS versions

(1)Directly click on the mobile app: Linker to enter the interface that displays all online circle names, as shown in the following figure:

This interface displays all online enclosure names and allows for the modification and addition of new names. You can also directly enter the enclosure number and click to search.