Lab Monitoring

How much are the stoves being used and how efficiently are the cooks feeding the firewood?

Efficiency tests allow researchers to understand how much firewood the stoves can save under ideal lab conditions; however, it’s also important to measure efficiency and use in the field.

Berkeley Lab is studying small devices called Stove Use Monitors (SUMs) and plans to mount these small self-contained devices on Berkeley-Ethiopia Stoves to monitor and log stove temperature over several months of use. Periodically, a researcher in the field using a PDA or laptop computer will retrieve this information. The SUMs will enable the Cookstoves team to have a better understanding of how cookstoves are used. Information collected will be used to analyze the frequency of stove use, the “burn time” for each use, and the rate at which cooks are feeding firewood into the stove. Likewise, the data will help quantify the reduction in greenhouse gases resulting from the use of improved cookstoves.

The heating rate of the stoves is controlled by many factors. These include the type of wood used to fuel the stove, the size of the pieces of wood used, environmental factors like humidity levels, and how the wood is fed into the stove, among others. Researchers are working towards quantifying how these variables change the heating rates of the stove. These findings will help users of the Berkeley-Darfur Stove and Berkeley-Ethiopia Stove better control heat, make more efficient use of their fuel, and optimize stove functioning.

What portion of the heating energy in the wood is transferred to the pot?

Comparing the total potential heating energy in the wood to the amount of heat affecting the cooking pot ultimately helps researchers determine the efficiency of stoves. This research is being conducted with the help of a Bomb Calorimeter. These devices determine the amount of heat released through combustion of a small amount of wood fuel burning inside a sealed vessel (called the bomb). Oxygen is used to ensure complete combustion of the wood. The heat from this bomb vessel is then transferred to water that surrounds it on all sides. Very sensitive thermometers are used to measure the temperature rise of the water and determine the amount of heat released though the combustion process.