DOCSLIB.ORG

Answers to Four Questions About Carbon Dioxide Sensor Self-Heating

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Answers to Four Questions About Carbon Dioxide Sensor Self-Heating / APPLICATION NOTE Answers to Four Questions about Carbon Dioxide Sensor Self-Heating What Is Self-Heating and Figure 1: Error in relative humidity Why Does It Matter? reading resulting from The self-heating of electronics in +1°C (1.8°F) and +2°C (3.6°F) self-heating carbon dioxide (CO2) instruments usually originates from two main at room temperature sources: the power required to take (20°C, 68°F). the CO2 measurement (sensor infrared source) and the energy required to generate the output signals. Incandescent light bulbs – typical infrared sources in CO2 sensors – consume a significant amount of power and thus generate heat. The heat spreads within the instrument level in the environment and the Also, compensation of humidity enclosure. Because the enclosure vertical axis the error in relative measurements is even more limits thermal exchange with the humidity (%RH) measurement. difficult than that of temperature. In surrounding environment, the The humidity measurement error conclusion, compensating for self- temperature within the instrument rate grows as a function of increasing heating is not recommended. is always slightly higher than the relative humidity. Increased self- ambient temperature. heating also results in a greater Can I Perform Sensor Self-heating is practically irrelevant error. At 50%RH and 20°C ambient Self-Heating Tests? for sensors that only measure CO2. temperature, the error is -3%RH for It is simple and straightforward to However, when the instrument also instruments with +1°C (1.8°F) self- perform self-heating tests, even measures temperature, self-heating heating and -6%RH for instruments without investing in expensive disturbs the measurement by with +2°C (3.6°F) self-heating. equipment: inducing a temperature measurement 1. Install the sensors on the wall error, which is typically around 1°C Can Self-Heating Be along with a passive temperature (1.8°F), or even more. Compensated For? sensor (e.g. Pt100 sensor or similar Sensor manufacturers may consider with minimal self-heating). How Does Self-Heating automatic compensation to correct 2. Turn on the device. Immediately Influence Relative the negative effect of self-heating on Humidity Measurement? compare sensor temperature temperature measurement. In theory, readings with the passive Just like temperature, relative this can be done by subtracting an temperature sensor output. Record humidity can’t be reliably measured average correction factor from the the difference between the two in close proximity to a heat source. measurement results. readings. For a temperature- Relative humidity is a temperature- Compensation may work in some compensated device, the initial dependent parameter, so the conditions; however, the amount readings are often lower than those accuracy of measurement results of self-heating is not constant in all of the passive sensor. will be affected by self-heating. conditions. Instead, it is dependent 3. Leaving the power on, record the Figure 1 shows how +1°C (1.8°F) on airflow and the wall material temperature (and humidity) readings and +2°C (3.6°F) temperature errors behind the sensor. Moreover, from time to time. It can take from distort relative humidity readings at applying a correction factor larger 15 to 40 minutes for the self-heating room temperature (20°C, 68°F). The than the specified measurement effect to fully develop. horizontal axis shows the humidity accuracy is highly questionable. Figure 2: Example of a self-heating test. The transmitter is allowed to reach equilibrium with the surrounding environment. Figure 3: Transmitter temperatures before power-up. Figure 2 shows an example of the Figure 3 shows the thermal images of expected self-heating test behavior. the tested transmitters before power- The relative humidity reading up. All transmitter temperatures (Sp2, decreases as the temperature Sp3, and Sp4) are in equilibrium with increases due to self-heating. the background wall temperature (Sp1). Figure 4 shows the thermal images Self-Heating Test Results of the transmitters 30 minutes after of Vaisala GMW90 Series power-up. The temperature readings CARBOCAP® Carbon were taken from the estimated Dioxide, Temperature, location of the temperature sensor Figure 4: Transmitter temperatures and Humidity Transmitters within the instruments. Clear 30 minutes after power-up. Vaisala GMW90 Series Carbon differences between the transmitter Dioxide, Temperature, and Humidity temperatures can be observed. The Vaisala GMW90 transmitter Transmitters were tested for The test results are collected in Table outperforms the competition due the tendency to self-heat. The 1. To conclude, there are significant to its unique low-power microglow results were compared with two differences in the self-heating infrared source. Its power competitors’ instruments (Devices tendency of the three transmitters. The consumption is only 25% that of 1 and 2, marked as Sp2 and Sp3). highest self-heating device (Device 1) traditional infrared sources. Learn Vaisala’s GMW90 transmitter was was 1.3°C (2.34°F) and the lowest more about microglow technology at marked as Device 3 (Sp4). (Device 3) was only 0.2°C (0.36°F). www.vaisala.com/microglow. Temperature Deviation from Temperature 30 min. Difference to Self-heating, unpowered, background after power-up, background °C (°F) °C (°F) temperature, °C (°F) °C (°F) temperature, °C (°F) Background 23.6 (74.5) 23.2 (73.8) temperature (Sp1) Device 1 (Sp2) 23.5 (74.3) -0.1 (-0.2) 24.4 (75.9) 1.2 (2.2) 1.3 (2.3) Device 2 (Sp3) 23.4 (74.1) -0.2 (-0.4) 23.9 (75.0) 0.7 (1.3) 0.9 (1.6) Device 3 (Sp4)* 23.4 (74.1) -0.2 (-0.4) 23.2 (73.8) 0 (0) 0.2 (0.4) Table 1: Self-heating test results. * Vaisala GMW90 transmitter Ref. B211384EN-A ©Vaisala 2014 Please contact us at This material is subject to copyright protection, with all copyrights retained by Vaisala and its individual partners. All www.vaisala.com/requestinfo rights reserved. Any logos and/or product names are trademarks of Vaisala or its individual partners. The reproduction, transfer, distribution or storage of information contained in this brochure in any form without the prior written consent of Vaisala is strictly Scan the code for prohibited. All specifications — technical included — are subject www.vaisala.com more information to change without notice..
Load more

Recommended publications
  • Model AIR 2000 Carbon Dioxide Sensors Consist of a Patented Solid State Infrared CO2 Monitor Housed in an Attractive Plastic Case
    CARBON DIOXIDE (CO2 ) MODEL AIR2000/ INDOOR AIR QUALITY SENSOR (TOXCO2/ANA) GENERAL DESCRIPTION: Toxalert’s AIR 2000 Carbon Dioxide (CO2) sensors come with a linearized signal output capability of 0 to 10 VDC and 4 to 20 mA over its 0-2000ppm range (other ranges available). It has an accuracy of ± 5% of reading and a repeatability of ± 20ppm. Options available with the Air 2000 are a digital dis- play for reading CO2 concentration in ppm; relay output with field adjustable set point; and duct mounting hardware. The AIR 2000 may input directly to a Toxalert controller, interface directly to any standard direct digital controller (DDC); or be a stand-alone unit for the control of ventilation equipment. SENSING ELEMENT: Model AIR 2000 Carbon Dioxide sensors consist of a patented solid state infrared CO2 monitor housed in an attractive plastic case. The AIR 2000 has a new state-of-the-art lithium tantalite detector, updated digital electronics and unique auto-zero function. This results in very stable calibration and longer trouble-free operation in the field. The new IR source is more rugged, operated at 10X derated power and has life expectancy of 10 yrs. The new lithium tantalite detector enhances stability, has less ambient temperature sensitivity, and faster response AIR2000 SENSOR time. The AIR 2000 space sensor has louvers to allow free passage of air to the sensing cell inside. AIR 2000DM duct sensor has pedo tubes for drawing a sample from the ventilation duct. STANDARD FEATURES: • Relay option available • 10 year sensing element life • Optional duct mounted unit • Low voltage circuits • Interfaces directly to DDC systems • Linear 4 to 20 mA output or 0 to 10 vdc output • Other ranges available • Optional digital display TOXALERT INTERNATIONAL, INC.
    [Show full text]
  • Probes Facilitate Rollout of Environmentally Friendly Refrigeration
    CO2 PROBES FACILITATE ROLLOUT OF ENVIRONMENTALLY FRIENDLY REFRIGERATION Supermarkets all over Australia and New Zealand are benefiting from advanced carbon dioxide monitors as new natural refrigeration systems are installed in the fight against climate change. Introduction Over the last 8 years, Vaisala carbon dioxide probes have been employed widely across Woolworths Group stores, delivering a The Woolworths Group employs over 205,000 staff and range of benefits and helping the group to achieve its strategic serves 900 million customers each year. As a large and goals. diverse organisation, Woolworths knows that its approach to sustainability has an impact on national economies, communities and environments, and this is reflected in the Group’s Corporate Global move to natural refrigerants Responsibility Strategy 2020. Synthetic refrigerant gases have been utilised in a wide variety The strategy is built around twenty key targets which cover of industries for many decades. However, Chlorofluorocarbons Woolworths’ engagement with customers, communities, supply (CFCs) caused damage to the ozone layer and were phased chain and team members, as well as its responsibility to minimise out following the Montreal Protocol in 1987. Production of the environmental impact of its operations. One of the twenty Hydrochlorofluorocarbons (HCFCs) then increased globally, commitments within the strategy is to innovate with natural because they are less harmful to stratospheric ozone. However, refrigerants and reduce refrigerant leakage in its stores by 15 per HCFCs are very powerful greenhouse gases so Hydrofluorocarbons cent (of carbon dioxide equivalent) below 2015 levels. (HFCs) became more popular. Nevertheless, most HCFCs and HFCs have a global warming potential (GWP) that is thousands of times Carbon dioxide (CO2) is commonly regarded as the ideal natural refrigerant.
    [Show full text]
  • US5345830.Pdf
    |||||I||||||||US005345830A United States Patent (19) 11 Patent Number: 5,345,830 Rogers et al. 45 Date of Patent: ck Sep. 13, 1994 54 FIRE FIGHTING TRAINER AND APPARATUS INCLUDING A OTHER PUBLICATIONS TEMPERATURE SENSOR "Fire Trainer T-2000” manual, AAI corporation, un dated. 75) Inventors: William Rogers, Hopatcong; James "Trainer Engineering Report for Advanced Fire Fight J. Ernst, Livingston; Steven ing Surface Ship Trainer', Austin Electronics, Jan. Williamson, Haledon; Dominick J. 1988 (excerpt). Musto, Middlesex, all of N.J. Primary Examiner-Hezron E. Williams 73) Assignee: Symtron Systems, Inc., Fair Lawn, Assistant Examiner-George M. Dombroske N.J. Attorney, Agent, or Firm-Richard T. Laughlin * Notice: The portion of the term of this patent 57 ABSTRACT subsequent to Jan. 8, 2008 has been A fire fighting trainer for use in training fire fighters is disclaimed. provided. The fire fighting trainer includes a structure (21) Appl. No.: 80,484 having a plurality of chambers having concrete or grat ing floors. Each chamber contains one or a series of real 22 Filed: Jun. 18, 1993 or simulated items, which are chosen from a group of items, such as furniture and fixtures and equipment. The Related U.S. Application Data trainer also includes a smoke generating system having 60 Division of Ser. No. 873,965, Apr. 24, 1992, Pat. No. a smoke generator having a smoke line with an outlet 5,233,869, which is a continuation of Ser. No. 625,210, for each chamber. The trainer also includes a propane Dec. 10, 1990, abandoned, which is a continuation-in gas flame generating system having at least one propane part of Ser.
    [Show full text]
  • Sensor Suite Sensors Overview
    Sensor Suite Sensors Overview Sensor Suite Sensors: Overview Sensor Suite Sensors enable OptiNet® to cost effectively monitor and control a breadth of environmental parameters throughout a facility. Located within a Sensor Suite, the sensors evaluate an array of environmental conditions using a shared sensing architecture. In lieu of locating individual discrete sensors in each space, OptiNet gathers air samples from the spaces and multiplexes them across the OptiNet network back to the Sensor Suite for analysis. OptiNet’s centralized sensor platform affords a more robust, cost effective approach to monitoring many parameters at many locations. A “virtual” sensor function is created as if the sensors were actually located in the environment being monitored. A shared platform additionally negates sensor errors through a true differential measurement (comparing outside to inside conditions via a common shared FEATURES sensor); while minimizing calibration and maintenance costs. • Sensor Suite Sensors are tailored to match specific monitoring and Sensor Suite Sensors have unique performance specifications and product features control needs. to meet specific applications, such as demand controlled ventilation, differential • Calibration and maintenance enthalpy economizer control; or for monitoring only purposes. The ability to sense of sensors is automatically and a variety of conditions, combined with a specific level of sensor performance, routinely scheduled through optimizes an application’s potential energy savings, control or monitoring capacity. Aircuity’s calibration depot and Assurance Services program. OptiNet’s Assurance Services plan assures that the sensors will continue to perform • Flexible architecture for future today, tomorrow, and in to the future. Aircuity’s Calibration Depot services routinely sensor enhancements and refresh all sensors within the Sensor Suite with factory calibrated and serviced units technology updates.
    [Show full text]
  • Technical Specification
    • 1.09.280E • 5.3.2007 © VALLOX Code 3486 SE TECHNICAL SPECIFICATION DIGIT SED ELECTRONIC CONTROLLER WITH LCD DISPLAY TECHNICAL SPECIFICATION • For dwelling-specific ventilation Input power 230 V, 50 Hz, 11 A in large detached houses (+ post-heating unit 4.3 A) • Supply and extract air ventilation Class of protection IP34 with heat recovery Fans alternating Extract air 300 W 1.31 A 205 dm3/s 100 Pa • Heat recovery efficiency of the 3 counter-current cell up to 80% current (AC) Supply air 300 W 1.31 A 185 dm /s 100 Pa Fans, direct Extract air 2 x 90 W 0.6 A 180 dm3/s 100 Pa • Electronic control panel with LCD display current (DC) Supply air 2 x 90 W 0.6 A 165 dm3/s 100 Pa • Week clock control as a standard feature Heat recovery Counter-current cell, ␩> 80% • Humidity control (option) Heat recovery bypass Summer / winter automation • Carbon dioxide control (option) Electric preheating unit 2.0 kW 8.7 A • Maintenance reminder Electric post-heating unit (option) 1.0 kW 4.3 A • Fireplace / booster switch function Water post-heating radiator (option) ca 3 kW at the controller Filters Supply air G3, F7 • Silent operation Extract air G3 Weight / basic unit 146 kg • Good filtering Ventilation adjustment options – control via control panel • Summer / winter automation – CO2 and %RH control • Fixed air flow measuring outlets – remote monitoring control (LON converter) – remote monitoring control (voltage / current signal) Options – electric post-heating unit – water post-heating unit – CO2 sensor – %RH sensor – pressure difference switch – LON converter – Silencer TECHNICAL SPECIFICATION © VALLOX • We reserve the right to make changes without prior notification.
    [Show full text]
  • Carbon Dioxide Sensors GG-VL2-CO2
    VENT LINE GG-VL2-CO2 CARBON DIOXIDE SENSOR Key Features • Carbon dioxide-selective infrared sensor technology prevents false alarms • Continuous monitoring of refrigeration system relief valves • Rugged, long life, and low power catalytic-bead sensor • Designed for harsh environments (-40°F to +140°F) • Sensor and preamp in one assembly • 0-5% CO2 (0-50,000 ppm) detection range • Ability to detect “weeping valves” to prevent refrigerant loss over time Carbon Dioxide sensors Carbon Dioxide • Sensor housing allows for easy sensor replacement and calibration • 316 stainless steel 18 gauge enclosure • Industry standard 24 VDC, linear 4/20 mA output From unlikely high-pressure releases to the inevitable “weepers”, the CTI Vent Line sensor will notify you … before your neighbors do. The GG VL2 utilizes a rugged infrared High concentrations of carbon diox- The GG-VL2-CO2 provides an industry sensor technology for fast leak detec- ide gases in your vent line are usually standard linear 4/20 mA output signal tion and long life. The standard 0-5% indications of a leaking valve or system compatible with most gas detection CO2 detection range of the GG-VL2- overpressure. This could mean costly systems and PLCs. Expect long sensor CO2 provides real-time continuous repairs or plant downtime, not to men- life and no zero-signal drift over time. monitoring of carbon dioxide concen- tion loss of refrigerant and regulatory trations in your high-pressure relief fines. Early detection can save money vent header. while also protecting equipment, prod- uct,
    [Show full text]
  • 6 Cumulative and Growth Inducing Impacts
    6 CUMULATIVE AND GROWTH INDUCING IMPACTS This section includes a detailed analysis of the cumulative impacts that would be anticipated with the proposed project with a specific focus on the project’s cumulative traffic impacts. In addition, this section includes a detailed discussion of the proposed project’s growth-inducing impacts, the project’s significant and irreversible commitment of resources, and the project’s effects on global climate change. 6.1 CUMULATIVE IMPACTS OF THE PROPOSED PROJECT This draft environmental impact report (Draft EIR) provides an analysis of overall cumulative impacts of the project taken together with other past, present, and probable future projects producing related impacts, as required by Section 15130 of the California Environmental Quality Act Guidelines (State CEQA Guidelines). The goal of such an exercise is twofold: first, to determine whether the overall long-term impacts of all such projects would be cumulatively significant; and second, to determine whether the Rocklin Crossings project itself would cause a “cumulatively considerable” (and thus significant) incremental contribution to any such cumulatively significant impacts. (See State CEQA Guidelines Sections 15130[a]-[b], Section 15355[b], Section 15064[h], Section 15065[c]; Communities for a Better Environment v. California Resources Agency [2002] 103 Ca1.App.4th 98, 120.) In other words, the required analysis intends to first create a broad context in which to assess the project’s incremental contribution to anticipated cumulative impacts, viewed on a geographic scale well beyond the project site itself, and then to determine whether the project’s incremental contribution to any significant cumulative impacts from all projects is itself significant (i.e., “cumulatively considerable” in CEQA parlance).
    [Show full text]
  • A Multipollutant Smoke Emissions Sensing and Sampling Instrument Package for Unmanned Aircraft Systems: Development and Testing
    fire Article A Multipollutant Smoke Emissions Sensing and Sampling Instrument Package for Unmanned Aircraft Systems: Development and Testing Kellen N. Nelson 1,2,*, Jayne M. Boehmler 1, Andrey Y. Khlystov 1 , Hans Moosmüller 1 , Vera Samburova 1, Chiranjivi Bhattarai 1 , Eric M. Wilcox 1 and Adam C. Watts 1,* 1 Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, USA; [email protected] (J.M.B.); [email protected] (A.Y.K.); [email protected] (H.M.); [email protected] (V.S.); [email protected] (C.B.); [email protected] (E.M.W.) 2 Department of Natural Resources and Environmental Sciences, University of Nevada—Reno, 1664 N. Virginia St., Reno, NV 89557, USA * Correspondence: [email protected] (K.N.N.); [email protected] (A.C.W.) Received: 4 May 2019; Accepted: 4 June 2019; Published: 7 June 2019 Abstract: Poor air quality arising from prescribed and wildfire smoke emissions poses threats to human health and therefore must be taken into account for the planning and implementation of prescribed burns for reducing contemporary fuel loading and other management goals. To better understand how smoke properties vary as a function of fuel beds and environmental conditions, we developed and tested a compact portable instrument package that integrates direct air sampling with air quality and meteorology sensing, suitable for in situ data collection within burn units and as a payload on multi-rotor small unmanned aircraft systems (sUASs). Co-located sensors collect carbon dioxide, carbon monoxide, and particulate matter data at a sampling rate of ~0.5 Hz with a microcontroller-based system that includes independent data logging, power systems, radio telemetry, and global positioning system data.
    [Show full text]
  • Mass Teacher's Retirement System, 500 Rutherford Ave
    POST-OCCUPANCY ASSESSMENT Massachusetts Teachers’ Retirement System 500 Rutherford Avenue Charlestown, MA Prepared by: Massachusetts Department of Public Health Bureau of Environmental Health Indoor Air Quality Program December 2016 Background Massachusetts Teachers’ Retirement System Building: (MTRS) Address: 500 Rutherford Avenue, Charlestown, MA Paul Burke, Senior Project Manager, Division of Assessment Requested by: Capital Asset Management and Maintenance (DCAMM) Post-occupancy indoor air quality (IAQ) Reason for Request: assessment Date of Assessment: November 17, 2016 Massachusetts Department of Public Health/Bureau of Environmental Health Ruth Alfasso, Environmental Engineer/Inspector, (MDPH/BEH) Staff Conducting IAQ Program Assessment: This office suite is a part of “Hood Park” on the location of the former H.P. Hood and Sons Milk Building Description: factory. It is now an office park containing other office tenants. The building also includes a fitness center and restaurant. Building Population: Approximately 100 Windows: Not openable Methods Please refer to the IAQ Manual for methods, sampling procedures, and interpretation of results (MDPH, 2015). IAQ Testing Results The following is a summary of indoor air testing results (Table 1). • Carbon dioxide levels were below 800 parts per million (ppm) in all areas assessed, indicating adequate fresh air in the space. • Temperature was within the recommended range of 70°F to 78°F in all areas assessed. 2 • Relative humidity was below the recommended range of 40% to 60% in all areas assessed. • Carbon monoxide levels were non-detectable in all indoor areas assessed. • Total volatile organic compounds (TVOCs) were either not detected or below background in the building at the time of assessment.
    [Show full text]
  • Data Acquisiton and Transmission System for Carbon Dioxide Analysis
    Revista Brasileira de Meteorologia, v. 36, n. 1, 115À 123, 2021 rbmet.org.br DOI: http://dx.doi.org/10.1590/0102-77863610003 Artigo Data Acquisiton and Transmission System for Carbon Dioxide Analysis Renato Trevisan Signori1 , Samuel Alves de Souza2, Rardiles Branches Ferreira2, Júlio Tota da Silva3, Antonio Marcos Delfino de Andrade3, Gabriela Cacilda Godinho dos Reis4 1Programa de Ciência e Tecnologia, Instituto de Engenharia e Geociências, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil. 2Programa de Pós-Graduação em Recursos Naturais da Amazônia, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil. 3Programa de Ciências da Terra, Instituto de Engenharia e Geociências, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil. 4Programa de Pós-Graduação Doutorado em Sociedade, Natureza e Desenvolvimento, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil. Received: 4 September 2019 - Revised: 17 August 2020 - Accepted: 21 September 2020 Abstract Despite being a minor part of the atmosphere's composition, the so-called greenhouse gases play a crucial role in their thermodynamics. Over the past 200 years, however, human activities have significantly altered the global carbon cycle. Thus, in the current context of global warming, quantifying, with increasingly reliable values, greenhouse gas emissions and the global carbon cycle has become one of scientists’ priorities. This study aims to develop a system for acquisition and wireless transmission of carbon dioxide data from the C-Sense, a sensor manufactured by Turner Designs. As result, a reliable, compact and versatile circuit has been developed that acts as an embedded system for monitoring CO2 con- centration and partial pressure, as well as two temperature variables.
    [Show full text]
  • Test Plan and Procedures
    DEVELOPMENT OF A LOW COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE TOPICAL REPORT For the reporting period: September 2002 – May 2005 Prepared by: E. Kelner D. George T. Morrow T. Owen M. Nored R. Burkey A. Minachi May 2005 Prepared for: U.S. DEPARTMENT OF ENERGY DOE Cooperative Agreement No. DE-FC21-96MC33033 DOE Technical Monitor Anthony Zammerilli Gas Technology Management Division Submitted by: SOUTHWEST RESEARCH INSTITUTE® Mechanical and Fluids Engineering Division 6220 Culebra Road San Antonio, Texas, USA 78238–5166 This page is intentionally blank. ii DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. iii This page is intentionally blank. iv DEVELOPMENT OF A LOW COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE E. Kelner D. George T. Morrow T. Owen M. Nored R. Burkey A. Minachi SOUTHWEST RESEARCH INSTITUTE® Mechanical and Fluids Engineering Division 6220 Culebra Road San Antonio, Texas, USA 78238–5166 ABSTRACT In 1998, Southwest Research Institute® began a multi-year project to develop a working prototype instrument module for natural gas energy measurement.
    [Show full text]
  • Carbon Dioxide Sensor Module Based on NDIR Technology
    micromachines Article Carbon Dioxide Sensor Module Based on NDIR Technology Libing Zhou 1,2, Yaoyi He 1,2, Qing Zhang 1,2 and Lei Zhang 3,* 1 Tiandi (Changzhou) Automation Co., Ltd., Changzhou 213015, China; [email protected] (L.Z.); [email protected] (Y.H.); [email protected] (Q.Z.) 2 CCTEG Changzhou Research Institute, Changzhou 213015, China 3 Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China * Correspondence: [email protected] Abstract: In this paper, a gas detection system with an environmental compensation algorithm based on nondispersive infrared (NDIR) technology was designed. The prepared infrared pyroelectric detector was a dual-channel type based on the lithium tantalate (LiTaO3) wafer. The design of the optical gas chamber adopted a combination of two ellipsoids and a spherical top surface, which not only enhanced the coupling efficiency of the light propagation but also facilitated the miniaturization of the sensor module. In addition to this, a temperature and humidity compensation algorithm based on the least square method was proposed to make the measurement accuracy up to ±0.9% full scale (FS). Keywords: CO2; pyroelectric; lithium tantalate; the least square method; compensation algorithm 1. Introduction Citation: Zhou, L.; He, Y.; Zhang, Q.; In recent years, with the development of industry, the problems of air pollution and Zhang, L. Carbon Dioxide Sensor global warming are becoming increasingly serious, and the gas monitoring system has Module Based on NDIR Technology. obtained a sufficient market for development. CO2 gas sensors are essential in the field Micromachines 2021, 12, 845.
    [Show full text]