The Laboratory Emissions Monitoring System (LEMS)
Aprovecho engineers have been working hard to develop lowest cost and most accurate stove emissions testing equipment. The LEMS (Laboratory Emissions Monitoring System) has gravimetric measurement of Particulate Matter and meets the requirements for the new IWA protocols. The LEMS is a complete emissions collection and measurement system designed specifically for stove laboratories (WBT) and Test Kitchens (CCT).
The LEMS incorporates the same sensor box that’s found in the PEMS, as well as the gravimetric filter system for accurate particulate matter measurement, but the collection system has also been improved to capture a more representative sample and to be more durable. The system is capable of measuring emissions of practically any size of stove. The large blower fan draws enough flow to measure the emissions of institutional stoves, retorts, and gasifiers in the 50 KW range. The blower fan also has a variable speed controller that reduces the flow to measure the emissions of small household stoves in the 1 KW range. The ducting system is equipped with gate valves to adjust the dilution air ratio. The metal LEMS hood is tall enough that chimney stoves can be placed directly under the hood, and the system is also equipped with a chimney cap to collect the emissions from even taller chimneys.

If you are interested in the LEMS, PEMS, or other emissions testing equipment, please visit our website at

ETHOS 2014 and ARC Open House
The annual Engineers in Technical and Humanitarian Opportunities of Service (ETHOS) conference was held over the past weekend in Kirkland, Washington. The Aprovecho staff attended and gave a couple of presentations (‘Tier 4 Stoves: We’re closer than I thought!’ by Dean Still and “A New IAP Hood Concept” by Sam Bentson and Mike Hatfield presented a summary of WBT and CCT studies in Bangladesh. ETHOS is an excellent way for technicians, scientists, students, implementers and others involved in the world of clean cooking technology to come together and share their knowledge and experience in an academic discussion-based environment. Three classroom areas were opened up to presentations from numerous organisations on cookstove research, emissions testing, safety updates, design issues, policy, gasifier advancements, and many other topics. After a full weekend of discussions, presentations, and networking, our staff returned to the laboratory in Cottage Grove accompanied by 23 guests who spent the week here conducting emissions tests on various stoves during the ARC Open House! Many of the guests tested their inventions for the first time and improvements were made! Some of our guests include Christa Roth, Larry Winiarski, Thomas Reed ,Paul Anderson, Alexis Belonio and many others! We were so lucky to learn together and see some really clean rice burning stoves and TLUDs with better turn down ratios. We’re always happy to have fellow stove technicians and enthusiasts visit our laboratory and we look forward to hosting similar testing events in the future!

Bomb Calorimeter TLUD Testing
During the winter open house rice hull burning TLUDs were tested. In the Alliance maintained WBT protocol for continuous fed wood stoves, the fire must be put out when the water boils. To determine the energy remaining at this point one must separate the unburned wood from the charcoal because wood and charcoal have different calorific values. For batch fed TLUD stoves burning pellets, the separation is possible, but tedious. When the fuel is rice hulls, the separation is practically impossible, and an alternative method must be used to measure the energy remaining after the boil. At Aprovecho the Alliance maintained WBT has been adapted to work with TLUDs with the aid of an industrial herb grinder, a desiccator, a manual pellet press, and a bomb calorimeter. After the water boils the fire is put out. The remaining wood and charcoal is mixed. A sample of the mixed fuel is ground to a fine dust. The dust is mixed with water until a paste consistency is achieved. The wetted sample is pressed into a 1 g pellet. The wet pellet is desiccated overnight. The following day the energy content of the dry pellet is determined using the bomb calorimeter. The method being developed at Aprovecho involves the addition of steps, delays, and cost to the current Alliance maintained WBT, but it makes possible the testing of rice hull burning TLUDs, and improves the accuracy of testing other TLUD stoves.