BIOGAS LAMP

Biogas Lamps
The lighting efficiency of biogas lamps is generally quite low, averaging between 3% and 5%. Nonetheless, a good biogas lamp can illuminate a room far better than a wick kerosene lamp, and produces a light intensity comparable to that which can be obtained with a pressure kerosene lamp or an electric light bulb in the power range of 25-75 W.

Many parts of rural Kenya still have no access to electric power. In such areas, biogas makes it possible for farm households to improve their work areas for longer periods every day. This in turn enhances the overall quality of farm families' lives, for example by enabling women to do their housework - and children to do their school work - during the evening hours (after 6.30 pm) under good lighting conditions.

High-quality, "modern" household lighting is also a status symbol among rural people and, as a result, biogas lamps contribute significantly to the attractiveness of the biogas technology among the relevant target groups.

KIE began development work on biogas lamps in 1984, and the first model produced by the firm was based on a standard commercial LPG lamp that had been modified for biogas operation. Unfortunately, however, this prototype did not perform satisfactorily because of the nature and scope of the modifications that had been undertaken. Consequently, another lamp was developed.

To date, more than 120 lamps of this second type have been produced and distributed, and a number have also been supplied to users in Tanzania. The lamps have performed satisfactorily. Some users have complained about flickering, or noted that the light was yellow rather than white, or that black spots had developed on the mantle. However, such problems are not attributable to design flaws in the lamp, but rather to insufficient gas pressure in the biogas plant or to the presence of water in the gas piping.

Recently it was decided to modify this design in order to eliminate certain manufacturing problems which had had an adverse effect on the overall quality of the output:

The mixing chamber was assembled from three separate parts. The bores were not of a uniform diameter, which meant that in some cases the gas did not flow properly and extensive threading was required to join the parts.

In some lamps the injector jet was not in line with the axis of the mixing chamber. Unfortunately, the new KIE lamp is not yet on the market. However, with demand for biogas lamps increasing rapidly in Kenya, and in view of the crucial role of improved domestic lighting in promoting the dissemination of the technology, it is important to ensure that adequate supplies of these suitable appliances are available to consumers. With this in mind, the SEP/Kenya initiated the importation of Brazilian "Jackwal" brand biogas lamps. The importation and distribution of the units is now being handled by private merchants.

Like other gas or pressure lamps, the "Jackwal" lamp employs a gas mantle. The lampshade reflects the light downwards and the lamp-glass helps maintain the operating temperature at the required high level. Both the gas and the air inlet can be regulated. The specific biogas consumption of the "Jackwal" lamp works out at about 100 litres/hour. Its retail price in Nairobi is KSh 820. The new KIE design should be every bit as good as the "Jackwal" lamp - if not better - and it is not expected to be any more expensive than the Brazilian import.

[top] [end]Contents: Boiling Point 22: Stoves - other uses
.
BP22: Stoves other uses - BP22: Other uses of stoves - BP22: Puffing Rice - BP22: Biogas Properties, Stoves and Lamps - BP22: Bellerive Develops Bakery Oven for Kenya - BP22: The Bakery Programme - BP22: Expanded Coal Utilization Project - BP22: Household Cooking Fuel - BP22: Company House Kitchens - BP22: Keep your wood dry - BP22: Self-help for Forests - BP22: The Clay Testing Centre - Sudan - BP22: Duma Institutional Stove - BP22: "REDI" Stove Trials - BP22: Solar Box Cooker - BP22: The Kelly Kettle - BP22: Extentionists' Blue! - BP22: Stove Profiles - Thai Bu