Entries by Kim Still

The swirl creating fan blade: How it works in a ND-TLUD

by Kirk Harris Blade cross sectional shapes: There are several main physical principles that can be used to make a functional cross-sectional shape. The gas enters the stationary fan vertically from below, and should leave the fan at as flat an angle as possible. Deflection:  The side of the blade that faces the oncoming gas […]

Turbulence: Swirl, Squish, Tumble

learnmech.com/importance-of-turbulence-swirl-squish-tumble-related-to-ci-engine Turbulence is very important for close to complete combustion. Swirl, Squish, and Tumble are used to create turbulence in internal combustion engines. Kirk Harris discovered that a static fan shape with overlapping 70 degree blades creates lots of fast moving swirl at the approximately one to two meter per second velocities found in TLUDs. […]

Jet-Flame Paper, Simplified

In the last Newsletter, we announced the publication of Aprovecho’s recent research on the Jet-Flame, “Retrofitting stoves with forced jets of primary air improves speed, emissions, and efficiency: Evidence from six types of biomass cookstoves” Here is a simplified summary of the findings: When the goals for biomass cook stove interventions were raised to include protecting […]

Jet-Flame Research Results From Six Types of Biomass Cookstoves

The Journal “Energy for Sustainable Development” has just published Aprovecho’s most recent research paper, “Retrofitting stoves with forced jets of primary air improves speed, emissions, and efficiency: Evidence from six types of biomass cook stoves.” It was authored by Samuel Bentson, David Evitt, Dean Still, Dr. Daniel Lieberman and Dr. Nordica MacCarty (Energy for Sustainable Development 71 […]

Is Forced Draft Really Needed in the TLUD?

The Rocket stove requires forced draft to create sufficient mixing in the flame to achieve Tier 4 for PM2.5. In addition, when sticks are pushed too fast into the Rocket, too much wood gas enters the combustion zone and a lot of smoke is emitted. Metering of the fuel is necessary to keep the Rocket […]

SupaMoto Forced Draft TLUD: Good, Better, Best!

Before starting to develop cleaner burning cook stoves in the 2013-2015 DOE project, ARC researchers completed a survey of best performing existing stoves. Improving combustion efficiency to protect health (and climate) has continued as various cook stove organizations have worked tirelessly to meet the WHO 2015 PM2.5 Intermediate Emission Rate Target of 1.75mg/minute, calculated to […]

A Recent History of the Rocket Stove: 2022

How can smoke, extremely dangerous for health and climate change, be ignored in carbon credit equations? Carbon dioxide and methane are counted but not smoke. Carbon dioxide is reduced when heat transfer is improved resulting in less wood being burned. Wood doesn’t make appreciable amounts of methane.  Because smoke is not counted to earn carbon […]

A Recent History of the Rocket Stove: 2016-2021

The investigation of how to reduce emissions and fuel use in biomass stoves continued with support from an EPA SBIR award. Two products were manufactured by our Chinese partner SSM, a heating/cooking stove and the Jet-Flame, a $12 insert that has made stoves 67% cleaner burning in field tests. https://www.jet-flame.com/ The Gates funded Global Health Labs […]

A Recent History of the Rocket Stove: 2011-2015

In 2011, Dr. Samuel Baldwin at the Department of Energy (who wrote the Bible on cook stoves in 1987) organized a two-day 100 person conference to identify how cook stoves could be improved and manufactured. Key recommendations were:  At least 90% emissions reduction and 50% fuel savings are appropriate initial targets for biomass cook stoves.  Multiple […]