low-cost sensors for co2 monitoring: calibration ... · 2 monitoring: calibration, characterization...

GGMT | Switzerland | 27 – 31 August 2017

Low-cost sensors for CO2 monitoring: calibration, characterization and assessment

Lukas Emmenegger, Michel Müller, Antoine Berchet, Jonas Meyer, Peter Graf, Christoph Hüglin, Dominik Brunner


www.talentsoft.career.de

GGMT | Switzerland | 27 – 31 August 2017 3 Lukas Emmenegger

Context & motivations

November ‘16 – October ‘17


Sensors in Carbosense

3 units ~100 kCHF

Picarro CRDS 30 (2) units ~3 kCHF

SenseAir HPP 300 units ~0.5 kCHF

SenseAir LP8


SenseAir HPP / Decentlab Low Cost CO2 Instrument

Price (incl. integration): 2-4 k€ NDIR (Non Dispersive Infrared) Temperature stabilized Includes T, RH, P sensor Grid Power

~ 10 W, incl. pump and data transmission Pump (~ 0.5 l/min) CO2 absorption unit for zero-CO2-air Data transmission by LoRaWAN (1 min) Precision*: < 1 ppm

(manufacturer documentation)

Decentlab Sensor Unit

Zero-CO2-Unit


SenseAir LP8 / Decentlab Low Cost CO2 Sensor

Price (incl. integration): 0.2-0.6 k€ NDIR (Non Dispersive Infrared) Temperature not stabilized Includes T sensor/correction Battery powered (> 3 years lifetime)

< 1 mW incl. data transmission Sensirion SHT21 for T and RH Data transmission by LoRaWAN Transmission interval 10 min

Accuracy ±50 ppm, ±3 % of reading (manufacturer specifications)

Sensair LP8



Delivery of 300 LP8 units


Exposition to outdoor environment


LP8 – a first glance

Data filtered to exclude data during high humidity periods. Data gaps due to pressure and temperature calibrations performed in the lab.

CO2: 447 ppm P: 767 hPa


LP8 – a first glance

Factory calibration Empa calibration


LP8 – Calibration and performance: approach

LP8 CO2 sensor response depends on temperature, pressure (and RH) Determination of (nonlinear) multifactor prediction model for sensor

calibration

CO2 (350 – 1000 ppm) T (-5°C – 50°C)

CO2, T CO2 (400 – 900 ppm) P (770 – 1050 hPa), T

Field calibration at DUE site Climate chamber Pressure chamber at METAS


factory settings

factory calibration range T: 10°C – 40°C

LP8 – Calibration / concentration and temperature

Raw IR data

climate chamber CO2: 350, 450, 700, 1000 ppm T: -5°C – 50°C

Empa calibration

-5°C

– 5

0°C


LP8 – Calibration / pressure chamber

𝐼𝐼𝐼𝐼 = 𝑓𝑓(𝐶𝐶𝐶𝐶2 ∙𝑃𝑃𝑃𝑃0∙𝑇𝑇0𝑇𝑇24°𝐶𝐶

, 𝑆𝑆𝑇𝑇=24°𝐶𝐶 ,𝑃𝑃 − 𝑃𝑃0)

𝐼𝐼𝐼𝐼 = 𝑓𝑓(𝐶𝐶𝐶𝐶2 ∙𝑃𝑃𝑃𝑃0∙𝑇𝑇0𝑇𝑇24°𝐶𝐶

, 𝑆𝑆𝑇𝑇=24°𝐶𝐶 ,𝟎𝟎)

P0

METAS Pressure Chamber


LP8 –RH dependence

calibrated data (CO2,T, P) Apr-July


Single measurements vs. 10 minute mean

Single measurement

10 minute mean

t

Last measurement transmitted

t

10 min average transmitted


LP8 – (sudden) drift

Sensor units 1304, 1305, 1306

LP8 CO2

SHT21 RH

LP8 T

NABEL site RIGI

May 6-7, 2017.


Database infrastructure

Webinterface visualization, data access / export

Data access through API including connectors for R-Script and Python

Network analysis

Sensor analysis Data processing • Sensor calibration • CO2 computation • …

database infractructure

Applications

Complete list of available features: www.decentlab.com


HPP – Field tests and evaluation

see also: • Kunz et al., 2014. COCAP - A compact carbon dioxide analyser for airborne platforms. EGU, Vienna. • Arzoumanian et al., 2017. Developing a lower-cost medium precision urban GHG monitoring system

using commercial NDIR sensors. GGMT, Dübendorf.


HPP – Calibration and performance

CO2: 447 ppm P: 767 hPa

chamber

Field data

Field data


HPP – Calibration and performance


CarboSense Network: planned sites


CarboSense Network: extent as of August 2017

Switzerland

• 21 at Swisscom antennas • 9 at MeteoSwiss observation sites • 8 at NABEL observation sites

Zurich

• 45 sensors in Zurich


CarboSense Network: exemples of locations


First week of data in Zürich


High-resolution simulations of CO2 in the city of Zürich

Anthropogenic Biogenic All

Day

Night

• Few dominating hot spots of anthropogenic emissions • Photosynthesis compensate most anthropogenic emissions during daytime

Waste incinerator

s

Zurich airport

Tunnel portals and highways


Poster on CO2 simulations

Poster P43 Antoine Berchet et al. CarboSense: a low-cost low-power CO2 network for the city of Zurich and Switzerland


Sequence of simulations

Anthropogenic Biogenic

All


Conclusions: Low-Cost Sensor SensAir LP8 / Decentlab

Battery powered, small, rugged, passive sampling Tantalizing approach for high spacial resolution Individual accuracy < 10 ppm can (probably) be achieved Demanding and costly calibration New concepts for QA/QC needed Correction of drift/ageing is mandatory

and requires new approaches in (statistics/transport) modelling To be combined with (on-site calibrated) instruments


Conclusions: Low-Cost Instrument SensAir HPP / Decentlab

c Grid Power and active pumping Promising compromise between low-cost and high-precision Individual accuracy < 2 ppm can (probably) be achieved Demanding and costly calibration Regular (on-site) calibration needed Ideal complement to high-density (low-cost) sensors


Acknowledgements

• Reinhard Bischoff • Jonas Biveroni • Simon Prior • Nico Vonau • Andreas Maggi • Olivier Verscheure • Sofiane Sarni • Christian Félix • Jürg Brunner • Thomas von Allmen • Jörg Sintermann • Carl Bengtsson • Hans Martin • Günter Grossmann • Bernhard Niederhauser


LPN data transmission

Juli - August 2017 Juli - August 2017

• 10 minute transmission interval • Message can be received by multiple LPN gateways. • Data is not resent in case of transmission failure.


LP8 – Pressure at network locations

No pressure sensor integrated in LP8 units

Interpolation of Meteoswiss

observations at Carbosense sites

DUE RIG


SenseAir HPP / Decentlab Low Cost CO2 Instrument

Price (incl. integration): 2-4 kCHF NDIR (Non Dispersive Infrared) Temperature stabilized Includes T, RH, P sensor Grid Power

~ 10 W, incl. pump and data transmission Pump (~ 0.5 l/min) CO2 absorption unit for zero-CO2-air Data transmission by LoRaWAN (1 min) Range: 0 – 1’000 ppm CO2

Precision*: ~ 1 ppm (1 min) Accuracy*: ~ 10 ppm


Zero-CO2-Unit

* estimation Empa based on SenseAir documentation and measurements


SenseAir LP8 / Decentlab Low Cost CO2 Sensor

Price (incl. integration): 0.2-0.6 kCHF NDIR (Non Dispersive Infrared) Temperature not stabilized Includes T sensor/correction Battery powered (> 3 years lifetime)

< 1 mW incl. data transmission Sensirion SHT21 for T and RH Data transmission by LoRaWAN Transmission interval 10 min Range: 0 to 2000 ppm CO2

Precision: 14 ppm (1s, 400 ppm CO2)

Accuracy ±50 ppm, ±3 % of reading

Sensair LP8



Picarro – CRDS

G2401 CO2 (+CO + CH4 + H2O)

NIR Cavity Ringdown Spectroscopy Precision (5 s): <50 ppb Accuracy: <50 ppb *

Price (system): ca. 100 kCHF

*) 1 h average, 2σ, GAW Data Quality Objective


Low Power Network (LPN)

Wireless telecommunication network (LoRaWAN: www.lora-alliance.org)

Developed for the Internet of Things (IoT) Secure bi-directional communication Low energy consumption Low data transmission rate Long range (>15 km)

Swisscom LPN Connectivity service since October 2016 CarboSense as demonstrator and test case

http://lpn.swisscom.ch/e/our-coverage)

http://lpn.swisscom.ch/e/our-coverage/

low-cost sensors for co2 monitoring: calibration ... · 2 monitoring: calibration, characterization...

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