how to measure co2 and why webinar slides 2017
TRANSCRIPT
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.