Portable Emissions Monitoring System (PEMS)

Nordica MacCarty, Damon Ogle, and Karl Walter developed the Portable Emission Monitoring System (PEMS) at Aprovecho to provide stove projects with a simple, effective, and less expensive emissions hood for both laboratory and in-field emissions collection and measurement.

The PEMS consists of:
• Light-weight hood structure
• Blower and flow measurement system
• Sampling system for the emissions
• Real-time data acquisition system
• Logging and analysis software

The PEMS displays emission levels in real time. It also calculates total emissions of carbon monoxide, carbon dioxide, and particulate matter released during a cooking task. Analysis provides total emissions, specific emissions, emission factors, and pollutant/CO2 ratios that highlight the various factors of combustion efficiency.

Available add-on options for the PEMS include:
• Filter system for OCEC particle analysis
• Tedlar bag system for analysis of greenhouse gases

The PEMS analysis software is compatible with Windows XP and Vista and can process data from either a Water Boiling Test (WBT) or a Controlled Cooking Test (CCT) using the automated data processing spreadsheets.

Personnel with reasonable computer experience can run the PEMS, which comes with a comprehensive instruction manual.

The PEMS can be used for various testing procedures:
WBT – the standard laboratory test for optimizing cooking stove designs.  See Link.
CCT – Testing what happens when a local cook prepares common meals using both the traditional and improved stoves for comparisons.
QUALITY CONTROL – When many stoves are produced, a random sample can be selected and tested to ensure performance is up to specifications.
CARBON CREDITS – With CO2 measurement built-in, and a Methane add-on available, actual emission factors can be measured and used in place of the IPCC defaults when carbon credits are being used.  Gold standard has accepted measurements from the PEMS as an excellent alternative to IPCC defaults – which can help to provide higher carbon credits due to more accurate measures of improved stoves.  
USER-DEFINED TESTS – The software can be adapted to suit any test that is desired.  

In addition to the standard WBT and CCT, additional emissions outputs include important measures such as:
Emission Factors (per kg or MJ of fuel)
Total Emissions
Emission/CO2 Ratio
Benchmark performance level

Also, a carbon balance is automatically calculated to ensure that measured emissions are in the proper range with respect to the carbon burned in the fuel.

Brochure (PDF)
Instruction Manual (PDF)

Specifications --
Weight: Collection Structure Suitcase 23kg (50lb).  Sensor Case 9kg (20lb)
Dimensions: Collection Structure Suitcase ~ 77 x 46 X  40 cm (30 X 18 X 16 inches).  
Sensor Case ~ 39 X 28 X 17 cm (13 X 16 X 7 inches).
Power: 120 VAC, 220 VAC with provided transformer, 12 VDC with inverter

Software –
Data Acquisition software consists of a simple data streaming program and graphing software in Java, provided.  Processing software is written in Visual Basic for Microsoft Excel 2003 for Windows and consists of a simple spreadsheet that incorporates and processes data.  A Windows laptop with Microsoft Excel must be available for running the system.  Macros must be enabled in the Security settings for software to function.