Champion (2021) average energy emission factors (g/MJ) from ISO high, medium, and low tests. Lab testing can quickly compare emissions from stoves. The EPA and ARC labs now measure the climate emission factors, not just PM2.5 and CO. It has been proven that only field tests show real world performance. Together, lab and field tests help […]
Primary air usually controls the rate of reactions: How fast the solid biomass changes into wood gas. Jets of primary air into the charcoal beneath the biomass add mixing while raising temperatures. Secondary air jets into the side of the flame can also supply needed mixing but tend to lower temperatures. Metering the gas supply […]
Dr. Sam Baldwin describes the use of a pot skirt in his book “Biomass Stoves: Engineering Design, Development, and Dissemination (1987).” Changes in the length and diameter of the channel gap (between the pot and the interior of the skirt) result in dramatic changes in heat transfer efficiency. “In fact, the channel efficiency, defined as […]
That the days are shorter is easy to attest to here at Blue Mountain. Our campus is wedged between parallel rows of 100-foot tall Fir trees. Yesterday, the rare sun fell down below the celestial horizon at 2PM. We envy the valley farmers whose day lasts until around five. On the other hand, being surrounded […]
“The concept of black boxes has been around since the early days of systems theory though some attribute the first use to the field of electrical engineering. It is a simple concept and has a straightforward definition: we know the inputs and subsequent outputs to a system but the internal workings of the system are […]
The great and upsetting thing about YouTube videos is that they don’t go away! A lot of this old video now seems incomplete: Our understanding of how to come closer to complete combustion has changed and includes details missing before. The following describes a hopefully less wrong set of design principles. David Evitt is currently deep […]
The U.S. Department of Energy (DOE) Bioenergy Technologies Office (BETO), in collaboration with Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL), and the Alliance for Green Heat, today announced the winning teams for the Wood Heater Design Challenge (WHDC). Aprovecho Research Center, from Cottage Grove, Oregon, came in second place and won $25,000 with a novel burn pot, airflow configuration, and sensor package for pellet heaters. […]
A few years ago, on another series of hot summer days, Aprovecho hosted a seminar on biochar. About twenty enthusiasts from all over the US joined us for a biochar summer camp, lighting a lot of stoves and scaring the safety advisors. We needed more spark screens. At the closing event, we created a list […]
Following the COP26 international climate conference, Senator Susan Collins (R-ME) and Senator Dick Durbin (D-IL), have introduced a bill to accelerate access to clean cooking. Here is the opening text of the section defining the activities directed in the bill. H.R.6316 has been referred to the Subcommittee on Energy: SEC. 5. CLEAN COOKING PROGRAM. (a) Department Of […]
The Problem with Metal It’s great to start making stoves and testing ideas with tincanium (cut up tin cans). Making new prototypes from tin cans is a quick, inexpensive way to start the design process but tin cans only last for a limited amount of time, depending on the temperature of the combustion chamber. At […]