IDEA experience in combustion improvements in large scale cooking and rural industries.

R.M.AmerasekeraExecutive DirectorIntegrated Development Associatio(IDEA)

IDEA experience in combustion improvements in large scale cooking and rural industries.

Hotels and Restaurants

Hospitals

Domestic Income generating activitiesCurd MakingTreacle makingSweetmeatLarge scale food preparation

Brick Clamps

Bakeries

Basic improvement in institutional stoves is the introduction of features such as

grate, baffle, chimney, sturdy construction, better insulationfor

improved combustion efficiency, ease of operation, less time consumptionimproved cooking hygieneLess firewood consumption

The stove dimension basically depends on the pot size which guides the grate size and primary air considerations

In general standardised and portable designs are not favoured since cooking tasks differ from place to place due to the varying nature and size of the tasks. Institutional stoves are mostly heavy mass stoves.

Prior to designing, a deep insight of the nature and requirements of the cooking task is required which calls for tailor made solutions and a good rapport with the users.Popularising institutional stoves require dissemination of stovedesigning technology through training of artisans.

Reported Firewood savings 39%

Time savings 42%

Availability of more hot water for the patients

Reported Fuel Savings: 37%

Time Savings: 40%

Making Curd Traditionally

Milk: 12 lts

Traditional Stove:

Firewood: 2.5 Kg

Time: 50 MtsImproved Stove:

Firewood : 1.6kg

Time: 31 Mts

Chimney, Bricks and Mud, Iron GrateNo fly ash contamination. Other biomass could be used

Using improved stove

BEFORE AFTERBiomassWeightTime

12.5 kg155 mts

6.5kg55mts

WoodWeightTime

8.5kg145mts

4.5kg50mts

24 kg of Paddy

Cost savings/week

Fuel Before-Rs

After-Rs

FirewoodLPGKerosene

60097587.50

15010223

High firewood consumption

Low quality bricks

High breakage

Clay improvements:Only clay with moderate sand % is suitable

Mix clay with 20 - 30% of rice husk/sawdust

Keep the mixture at least for 2 days to dry

Make the bricks using the moulds.

Dry the unfired bricks for at least 3 days.

Stacking and firing improvements.Method of stacking bricks modified

Additional Firing channels are provided

The interlayer gaps are filled with rice husk

Firing methods are changed

Fuel Used

Firing with rice husk only.

Firing with firewood. Additional channels used

Firing with fire wood and rice husk

Stacking depends on the method of firing

AdvantagesLow cost of production

Better quality of bricks

Less or no firewood used

Less clay used

Light weight bricks with high porosity

Less labour intensive due to better drying, easy demoulding, less tending of fire and easy handling

Less breakage

Major disadvantage

Ash management and disposal

Improved brick clamps

Transporting rice husk Mixing clay with husk

Improved Kiln with additional channels for combustion

Study tour of brick makers

Modifications

A hopper to feed the rice husk and blower powered with a 1.5 hp motor or with a hand tractor. Additional opening is made opposite the normal opening or on the side.

Two chimneys 16 ft tall are provided above the two openings

Cost USD 800. Subsidy provided: USD 250

To start the oven next day ignite the rice husk settled on the oven floor with a little dry biomass. When it ignites blow the rice husk using the motor/blower or a hand tractor. When the temperature rise to 350oC stop blowing. Remove the ash and the oven is ready for baking again.

After modifications use firewood as usual for the first firing. Bring up the temperature to 3500 C. Remove all ash. Bake the bread at around 3000 C.

After the baking is over remove the bread and allow it to cool to around 200 C. Blow a little bit of rice husk into the chamber. Close it. Leave it overnight.

Blower powered by kerosene water pump engine

Blower powered by a hand tractor

Ash disposal ?Fly ash is an environmental and health hazard. Partly carbonised(black) ash could be used as fertiliser. Water is poured on the hot ash before it cools down and forms white ash.

BEFORE BEFORE BEFORE --- FIREWOODFIREWOODFIREWOODAfter After After --- ElectricityElectricityElectricity

Rice husk Rice husk Rice husk --- No costNo costNo cost

Rs 100 - 200 55%

Rs 200 - 300 35%

Rs 300 - 500 15%

< Rs 25 80%

Rs 25 - 50 15%

Rs 50 - 75 5%

20 bakeries converted