How to Measure CO2 and Why?Webinar May 4, 2017

Meet the presenters

Lars Stormbom. Product Manager at Vaisala with over 30 years of experience of industrial and HVAC measurements.

Maria Uusimaa. Product Area Manager for Vaisala’s Industrial Instruments. She has over 10 years of experience in CO2 measurements in various measurement applications.

Covered Topics

What is CO2 and why measure it? Vaisala CARBOCAP® technology and why it’s unique?Why measure and what are the benefits in Demanding HVAC Agriculture Greenhouses Safety CO2 incubators

Carbon Dioxide

What is CO2?

A colorless gas soluble in water A greenhouse gas A solid material called "dry ice" below -79 °C Formed in combustion of carbon-containing materials respiration and metabolism of living organisms Non-combustible and inert Used by plants in the photosynthesis

CO2 molecule

GREENHOUSE

700 ... 800 ppmCO2

GARAGE

Elevated ppm (exhaust gases produce up to 20 %CO2)

CO2 INCUBATOR

5 %CO2; 37 °C; >90 %RH

AMBIENT

400 ppmCO2

INDOOR

<1000 ppmCO2

What are typical

CO2concentrations?

Vaisala CARBOCAP® Technology and why it’s unique?

Optical Infra-Red CO2 Measurement Technology Light source, filter and detector CO2 measurement at 4.26 µm Attenuation in intensity gives the CO2 concentration (e.g. 1000

ppmCO2) Changes in sensor structure cause drift: Light source intensity change Dirt in optical cuvette Any mechanical changes!

One IR source, one filter CO2 absorption wavelength

Ways to Overcome Drift: Different Optical Measurement TechnologiesWays to compensate for drift adding components using software tricks, such as so-

called ABC (Automatic background calibration)

Two IR sources, one filter reference source

One IR source, two filters CO2 and reference wavelengths

The CARBOCAP® - It´s unique

Vaisala CARBOCAP® sensorOne IR source, one tunable filter CO2 and reference wavelengths = true referencing!

Tunable bandpass filter

0102030405060708090

100

3.5 4 4.5 5

Transmission

Wavelength (micrometers)

CO2 absorption

FPI chipAir gap

Upper mirrorLower mirrorSilicon substrate

Absorption measurement

Tunable bandpass filter

0102030405060708090

100

3.5 4 4.5 5

Reference measurement

Air gapUpper mirrorLower mirrorSilicon substrate

Transmission

Wavelength (micrometers)

CO2 absorption

The first generation: Traditional filament lamp

• Limited lifetime• Light power decreases over time• High power consumption• Needs manual assembly

The second generation: New lightsourceNow: The Microglow

Emitter

Membrane for thermal insulation

Frame

• Long lifetime• Stable light output• Low power consumption• Automatic assembly

We do everything ourselves

From chips To calibrated measurement modules

..with experience of CO2 measurements since 1997

To a variety of products for different measurement ranges and purposes

Vaisala CARBOCAP® Benefits

Stability

Long lifetime

Continuous CO2 environment

Why measure and what are the benefits?

HVAC – an easy application?Benign conditions

No Service

Why Measure CO2 in HVAC?

Energy savings:

Buildings use 40% of global energy Demand Controlled Ventilation can

save:– Auditoriums and schools: 50-60%– Offices: 10-25%

Why Measure CO2 in HVAC?

Human wellbeing and productivity:A recent Harvard study finds that cognitive perfomance is directly impacted by CO2 level:

– Baseline levels measured at 550 ppm CO2– At 945 ppm scores decrease by 15%– At 1400 ppm scores decrease by 50%

CARBOCAP® Benefits in HVAC Good measurements =

money saved on energyDesired indoor air qualityTrouble-free operation for

at least 15 yearsWorks in constantly

occupied spaces Immediate verification of

operation

Benefits in HVAC: Excellent stability

at 1000 ppm at 2000 ppm

CEC-400-2008-001-CMF

Specified drift: ±15 ppm + 2% of reading over 5 years

Largest value

smallest value25% fractileMedian75% fractile

Legend

Why Measure in Demanding HVAC, for example in a Poultry House? High CO2 and humidity levels in poultry houses cost time

and money – Birds are lost to diseases– Feed conversion is decreased– Fewer fully developed birds

By monitoring CO2, and humidity levels, improved growth rate has been observed

Typically measurements up to 3000 ppmCO2 are needed

CO2 in Agricultural Applications

<7000 ppmCO2

Setters and Hatchers

Typically 3000...10 000 ppmCO2

Storage of Fruit and Vegetable

Depends on fruit, %CO2 level

Breweries, Wineries

Safe levels – both ppm and % used

Greenhouses

800...1000 ppmCO2

Mushroom farms

Why Measure in a Greenhouse? Plants need CO2 in order to grow

– Carbohydrates are formed from CO2 and H2O– Plants use carbon dioxide in photosynthesis:

6 CO2 + 6 H2O + light energy ⇒ C6 H12O6 + 6 O2

Optimal conditions:– 800 … 1000 ppm CO2 – ~ 70 %RH

Productivity in a greenhouse can be increased with up to 30% with proper CO2 fertilization

Too much CO2 is expensive and can be harmful for the crop

Greenhouses: What are the benefits?

Humidity tolerance Chemical durability Long-term stability CO2 fertilization is expensive, unstable

measurement can cost a lot of money

Why Measure in CO2 Incubators? Special climate chambers used in life science

laboratories to grow biological samples e.g. cell cultures

Pharmaceutical incubators are mostly used at 5 %CO2 37 °C >90 %RH

– Sometimes RH control/measurement is needed

The same condition as in human body, the optimal conditions for cell growth!

Vaisala GMP231 Carbon Dioxide Probe installed in an incubator

CO2 Incubators: What are the benefits?Due to internal reference in constant 5 %CO2and high humidity and temperature: Stability Long lifetime

For CO2 incubator OEM’s and monitoring: Wide range of products available: 2nd generation products: GMP231, GMP251

Heat sterilization durability (GMP231) Fast recovery when opening a door

CARBOCAP®

Stability

Long lifetime

Continuous CO2 environment

Thank you for your interest!

Below you will find some relevant links to our web pages:CO2 web page

HVAC web page

You can also contact us using the contact form or go directly to our online store.