Carbon dioxide is one of the raw materials for photosynthesis in green plants, and 95% of crop dry weight comes from photosynthesis. Therefore, using carbon dioxide sensors to control concentration has become an important factor affecting crop yield.

Plastic greenhouse cultivation keeps crops in relatively enclosed areas for a long time, and the concentration of carbon dioxide inside the greenhouse varies greatly within a day. It reaches its maximum value of 1000-1200pp before sunrise, and drops to around 100ppm 2.5-3 hours after sunrise, which is only about 30% of the atmospheric concentration. It continues to rise until 2 hours after noon and returns to atmospheric levels around 4 pm. Vegetables generally require a carbon dioxide concentration of 1000-1500ppm. Therefore, the carbon dioxide deficit in plastic greenhouses is quite severe, becoming an important factor affecting the yield of vegetables in plastic greenhouses. Installing carbon dioxide sensors in plastic greenhouses can ensure timely alarm in case of insufficient carbon dioxide concentration, thus enabling the use of gas fertilizers. Ensure that vegetables, edible mushrooms, flowers, traditional Chinese medicine, and other products are launched early and of high quality and yield.

Infrared carbon dioxide sensor: This sensor uses the principle of non dispersive infrared (NDIR) to detect CO2 present in the air, with good selectivity and no oxygen dependence. It is widely used in various occasions where flammable and explosive gases exist.

Catalytic carbon dioxide sensor: It converts the detected carbon dioxide concentration on site into a standard 4-20mA current signal output and is widely used in industries such as petroleum, chemical, metallurgy, refining, gas transmission and distribution, biomedicine, and water treatment.

Thermal conductivity carbon dioxide sensor: made based on the principle that the total thermal conductivity of the mixed gas changes with the content of the gas to be analyzed, it consists of two arms of a bridge composed of a detection element and a compensation element. When encountering flammable gases, the resistance of the detection element decreases, and when encountering non flammable gases, the resistance of the detection element increases (air background). The bridge circuit outputs a voltage variable, which increases proportionally with the increase of gas concentration. The compensation element plays a reference and temperature compensation role. It is mainly used in the concentration detection of flammable gases such as natural gas, liquefied gas, coal gas, alkanes, and organic solvent vapors such as gasoline, alcohols, ketones, and benzene in civil and industrial sites.