Ovrednotenje spektrometra za merjenje koncentracije ogljikovega dioksida v zraku

Janežič, Andraž (author), Begeš, Gaber (mentor)

V tem delu bom govoril o merjenju koncentracije ogljikovega dioksida v zraku. Predstavil sem osnovne lastnosti omenjenega plina in njegovo uporabo v industriji ter vplive na ljudi. Bežno se bom dotaknil tudi izpustov ogljikovega dioksida kot enega izmed toplogrednih plinov v zemeljski atmosferi. Za merjenje koncentracije ogljikovega dioksida imamo na voljo široko paleto merilnih inštrumentov, ki uporabljajo različne tehnike merjenja. V delu sem predstavil najpogosteje uporabljene merilnike, njihova področja uporabe in prednosti ter slabosti posameznih inštrumentov. S pomočjo standarda ISO/IEC SIST 17025 sem preveril zahteve za akreditirane postopke kalibracij in sledljivost referenčnih etalonov do osnovnih SI enot. Opisal sem pripravo certificiranih referenčnih plinov za izvedbo kalibracij na primarnem in sekundarnem nivoju ter kalibracijske postopke s standardnimi prispevki negotovosti. V zadnjem delu sem izvedel ovrednotenje merilnega sistema, ki temelji na nedisperzivnemu infrardečemu (NDIR) merilniku ogljikovega dioksida. Opisal sem izdelavo merilnega sistema in odpravljanje pomanjkljivosti, katere sem spoznaval pri izvajanju meritev. Pisal sem o uporabi certificiranih referenčnih plinov in o tehničnih referenčnih plinih. Nazadnje sem opisal prispevke standardne negotovosti, ki so sestavni del vsake opravljene meritve. Navedel sem ključne prispevke merilne negotovosti in jih ovrednotil ter na koncu podal skupno standardno merilno negotovost sistema.

• Language: Slovenian
• Keywords: merjenje koncentracije CO2, nedisperzivni infrardeči merilnik, standardna negotovost merilnega sistema in postopka umerjanj, kalibracijski postopki.
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2023
• PID: 20.500.12556/RUL-153184
• COBISS.SI-ID: 181936643
• Publication date in RUL: 20.12.2023

Secondary language

• Language: English
• Title: Evaluation of a spectrometer for measuring the concentration of carbon dioxide in air

Abstract

In this paper, I will talk about measuring the concentration of carbon dioxide in the air. I have outlined the basic properties of said gas, its use in industry and its effects on humans. I will also briefly discuss carbon dioxide emissions as a greenhouse gas in the Earth's atmosphere. To measure the concentration of carbon dioxide, we can choose from a wide range of measuring devices that use different measurement techniques. In this article, I have presented the most commonly used measuring devices, their areas of application and the advantages and disadvantages of each technique. Using the ISO/IEC SIST 17025 standard, I have reviewed the requirements for accredited calibration procedures and the traceability of reference standards to basic SI units. I describe the preparation of certified reference gases for performing primary and secondary level calibrations and calibration procedures with standard uncertainty contributions. In the last part, I evaluated the measurement system based on the non-dispersive infrared (NDIR) carbon dioxide spectrometer. I presented the setup of the measuring device and the solutions to eliminate obstacles I encountered when carrying out the measurements. I also talked about the use of certified reference gases and technical reference gases used in calibration procedures. Finally, I described the contributions to standard uncertainty, which is an essential part of any measurement. I listed the most important contributions to measurement uncertainty, evaluated them and finally stated the total standard uncertainty of the measurement system.

• Keywords: CO2 concentration measurements, non-dispersive infrared spectroscopy, standard uncertainty of the measurement system, calibration procedures