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LI-7815 CO2/H2O Trace Gas Analyzer

High precision CO2 monitoring

The LI-COR LI-7815 CO2/H2O Trace Gas Analyzer provides exceptionally stable and precise measurements for long-term atmospheric monitoring measurements. CO2 measurements drift less than 0.2 ppm per 24-hour period with 0.04 ppm precision (1σ, with 5-second averaging) at 400 ppm CO2 in dry air at STP.

LI-7815 CO2/H2O Trace Gas Analyzer

Exceptionally stable and precise measurements

The LI-7815 CO2/H2O Gas Analyzer provides stable and precise CO2 measurements in a rugged, portable, and cost-effective design.

LI-7815 Long-Term Outdoor CO2 Stability

LI-7815 Long-Term Outdoor CO2 Stability
Thirty-day CO2 stability data from an LI-7815 CO2/H2O analyzer. A single instrument was operated outdoors continuously over the entire time period, measuring ambient air between stability checks. During stability checks, the analyzer was flushed for 10 minutes with tank gas (2 ppm CH4, 400 ppm CO2 mixed in air balance, 1% nominal concentration accuracy) and a time series data set was subsequently recorded for 10 minutes every 12 hours. The figure shows the mean value of the 10-minute measurements. Error bars represent a 1σ confidence interval (68%).

LI-7815 24-Hour CO2 Precision with Allan Deviation Plot

LI-7815 24-Hour CO2 Precision with Allan Deviation Plot
Figure 2. 24-hour CO2 stability data from an LI-7815 CO2/H2O analyzer (top). The instrument was operated continuously over a 24-hour period with a continuous flow of tank gas. The blue line shows 1-second measurements; the diamond line shows a 50-minute block average. Allan deviation plot (bottom) of CO2 measurements from an LI-7815 measuring 402.3 ppm CO2 shows precision at 1-second signal averaging, with improved precision as averaging time increases. Error bars represent 68% (±1σ) confidence intervals based on number of averaged time series available at each τ.

Key specifications

  • Response Time (T10-T90): CO2 ≤ 2 seconds, 0 to 400 ppm
  • CO2 Precision (1σ):
    • 0.10 ppm with 1 second averaging
    • 0.04 ppm with 5 second averaging
  • CO2 Max Drift: < 0.2 ppm per 24-hour period
  • Total Weight: 11.4 kg with the batteries
  • Battery Life: 8 hours typical with 2 batteries
See the full LI-7815 specs

Applications

The LI-7815 Trace Gas Analyzer can be used for, but is not limited to, the following applications:

  • Atmospheric monitoring
  • Urban emissions monitoring
  • Mobile emissions monitoring
  • pCO2
  • Sensor networks
  • Large area emissions monitoring
  • Fugitive emissions

Choosing your analyzer

The LI-7815 Trace Gas Analyzer is ideal for applications that require long-term CO2 monitoring, or where precision and stability over time is critical.

In comparison to the LI-7000 CO2/H2O Gas Analyzer, the LI-7815 provides a wider measurement range, low drift characteristics, and more flexibility in its uses and applications. While it does not provide a differential measurement, the LI-7815 still provides sub-1.0 ppm measurements.

The LI-7815 is not designed for eddy covariance applications—which requires higher frequency measurements. If you need higher frequency measurements for the eddy covariance method, consider our eddy covariance solutions.

LI-7815 Specifications

General

  • Measurement Technique: OF-CEAS (Optical Feedback-Cavity Enhanced Absorption Spectroscopy)
  • Measurement Rate: 1 sample per second (1 Hz)
  • Optical Cavity Volume: 6.41 cm3
  • Flow Rate: 250 sccm (nominally)
  • Total Weight: 11.4 kg (including batteries)
  • Case Dimensions: 51 cm L x 33 cm W x 18 cm H
  • Operating Temperature Range: -25 °C to 45 °C (without solar load, under normal operating conditions)
  • Operating Humidity Range: 0 to 85% RH (non-condensing, without solar load, under normal operating conditions)
  • Operating Pressure Range: 70 to 110 kPa
  • Connectivity: Ethernet, Wi-Fi (not available in some countries)
  • Wi-Fi Compatibility: 2.4 GHz, 802.11 a/b/g/n/ac
  • Power Consumption:
    • Steady State Operation: 22 Watts
    • Warmup (10.5 to 33 VDC power supply, pins 3 and 4): Up to 90 Watts
    • Warmup (Universal power supply or 24VDC power supply, pins 1 and 5): Up to 140 Watts with batteries charging
  • Power Supply: Universal Power Adapter (Input: 100 to 240 VAC, 50-60 Hz; Output: 24 VDC)
  • Battery Life: 8 hours typical with 2 batteries

CO2/H2O Measurements

  • Response Time (T10-T90): CO2 ≤ 2 seconds, 0 to 400 ppm

CO2 Measurements

  • Range: 1 to 10,000 ppm
  • Precision (1σ):
    • 0.10 ppm at 400 ppm with 1 second averaging
    • 0.04 ppm at 400 ppm with 5 second averaging
  • Maximum Drift: < 0.2 ppm per 24-hour period

H2O Measurements

  • Range: 100 to 60,000 ppm
  • Precision (1σ):
    • 45 ppm with 1 second averaging
    • 20 ppm with 5 second averaging

Specifications subject to change without notice.

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