rice hulls

Rice husk Gasifier stoves
Rice husk Gasifier stoves
Instruction sheet 1
Instruction sheet 2

From Alexis Belonio:
Good morning!!

Attached are the info on the latest development on rice husk gas stove in India. Just to update you that rice husk gas stove is now being commercialized by Navdurga Metal Industries of India.

From the India Economic Times:

The three-year-old startup based at Faizabad in Uttar Pradesh has created rice husk-powered, smokeless biomass cooking stoves that significantly reduce the cost of household spending on conventional fuel sources such as LPG, electricity, kerosene, wood and wood charcoal. "Rice husks can give about 3,000 kilo calorie of energy, compared with wood that gives between 3,800 and 4,000. These stoves reduce carbon emissions, and cooking costs significantly," said Jaiswal, 31. Nav Durga's first product, aptly named Janta Chulha Smokeless Stove, was launched in 2009 and priced at Rs 500. It has now launched a range under the brand name, Agni, which caters to both domestic and industrial customers. "We currently manufacture up to domestic 10,000 cook stoves and about 50 commercial stoves a month. We want to ramp that up to 20,000 domestic and up to 1,000 commercial stoves soon," Jaiswal said.

According to recent industry data, about 67% of Indian households, adding up to about 166 million households, continue to use solid fuels as their primary source of cooking fuel. While conversion to modern fuels has accelerated in urban areas, rural areas have been slow. Saurabh and the firm's co-founder Arvind Jaiswal, 56, have set up their own distribution and supply chain system. The startup currently has about 50 distributors spread across Uttar Pradesh, Bihar, Assam and Punjab. The company employs about 50, spread across two facilities in Faizabad and Faridabad, in Haryana. "The manufacturing is done by local talent alone," Jaiswal said.

The original news article, and instructions sheets for the stoves are attached as pdf files.

On February 22, 2012 I did three boiling tests.

The first test was carried out on a normal propane gas burner that I have in my kitchen.

http://youtu.be/w8OdW_GEhWo
Here it took 6 minutes and 6 seconds to bring one liter of water to a boil.
The burner shown in this video is a very efficient premix gas burner.
But since it operates solely by means of convection, its performance is not optimal.

The second test was carried out using the 150 gasifier:

http://youtu.be/jK3UTe1Lxqk
Here it took 3 minutes and 42 seconds to bring one liter of water to a boil.
Note that the same pan without a lid was used in these two boiling tests.
Here heat is transferred by both convection and thermal radiation.

The third test was carried out using an insulated electric water kettle, as shown here:
http://dl.dropbox.com/u/22013094/150%20Gasifier/Boiling/IMG_1042.JPG
Here it took 3 minutes and 25 seconds to bring one liter of water to a boil.
In this way I was able to compare the two previous results
with what could be considered to be the fastest way to boil water in a kitchen setting.

I wonder if you have found any technical design literature for this added radiative mesh? (Materials, wire diameters and spacing, etc?)

I have no theoretical understanding with regard to what is happening with the wire mesh dome.
I tried flat wire mesh, and this did not work at all.
The wire mesh has to be in the form of a dome to accommodate the small diffusion tail that you see here:
http://youtu.be/WXZvvoxCm1g

I tried wire meshes of various apertures.
If the aperture of the wire mesh is too big, the flames are not contained properly under the dome.
If the burning of gases takes place above the dome, the dome does not turn red hot.
This week I will experiment with much finer wires and apertures.

Also, if I turn down the primary air to a point where much less gas is produced,
combustion no longer takes place at the burner holes but within the apex of the dome.
Here a most unusual but stable cloud of burning gases is formed.

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