Peat Peeps

Project undertaken in course year 2022-23 with the Stanford Precourt Institute for Energy

Project Goal

Design an automated floating flux chamber for collection of data on concentrations of carbon dioxide and methane gases emitted from the water surface of peatland environments.

Project Motivation

The current lack of suitable instrumentation requires the development of a low-cost, easily deployable sensing device for greenhouse gas (GHG) emissions.

An automated floating flux chamber would enable the large-scale collection of GHG emissions data to better understand Earth's changing climate and inform actions for environmental sustainability.

Background

The rise in greenhouse gas (GHG) emissions is correlated with the rise in global temperatures, worsening global disasters like wildfires, droughts, and storms and ultimately threatening life. The current methods of collecting GHG emissions data are expensive, non-portable, or not suitable for large-scale production.

Methane emissions from tropical wetlands, such as peatlands, are thought to contribute 20-30% of the total global GHG budget, yet the challenge of effectively measuring these emissions causes it to remain a major uncertainty.

Peatlands contain large amounts of water, low pH, low oxygen supply and low nutrient content. These conditions slow down plant decomposition and, as a result, cause a buildup of partially decomposed plant remains

High Priority Requirements

Water line must not rise above half the height of the chamber
The chamber must equilibrate when tilted 30 degrees from horizontal
Keep GHG concentrations from leaking over 3% over 5 minutes
After collecting gases, the chamber must reset to ambient GHG concentrations within 5% of steady state values within 5 minutes
User must be able to access data chip and batteries within 2 minutes
Sensors must be fully operational in conditions of 80%+ humidity, IP4
Material needs to be able to resist deformation over temperature range of 2C - 57C.
Chamber must be tethered to a stationary object
Max dimensions of45 x 46 x 35 inches.

Ethical Considerations

Environmental Impact
Helicopter Research
User Accessibility

Solution

Designed and built PEAT: the Peatlands Environmental Assessment Tool, an automated floating flux chamber that collects methane and carbon dioxide emissions data from the water surface of peatland environments.

Working system

The chamber includes a foam ring and counterweights around the base for flotation and stability.

The side features a metal mount for the user to attach a tether to keep the chamber locatable after deployment.

CAD back view

Back view of the PEAT CAD model, showing the flotation device (pink), housing for sensor system, and door

The sensor housing protects the sensing unit from water and humidity using desiccant.

CAD front view

Front view of the PEAT CAD model, showing the sliding door mechanism that seals the chamber when closed and vents the chamber, with the help fo a fan, when opened.

Sensor housing

Exploded view of components comprising the sensor housing within PEAT.

Door mechanism

Exploded view of the door mechanism compoennts within PEAT

Water testing

PEAT being subjected to water testing in one of the Fountains on campus

Results for Closed Door CO2 vs Time

Decay of CO2 over a 6 minute time period, in which CO2 concentration measurements were taken by the sensor every 5 seconds. With PEAT's door closed and sealed, PEAT was able to prevent >3% of CO2 from leaking. After 5 minutes, 98% of the initial CO2 remained

Open Door with Fan testing

Decay of CO2 over a 6-minute time period, in whihc CO2 concentration measurements were taken by the sensor every 5 seconds. Witht he fan on and door open, PEAT was able to return CO2 concentrations to ambient conditions within 2 minutes

Student team

PEAT

Future Work

Create pictorial instructions for users who don't read English
Assess impact of outgassing of materials in chamber
Design for manufacturing depending on quantities needed
Test in the field

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