3.  We are engaged in construction and production of
various products such as improved Metal Rocket
Stoves. Charcoal Stoves in all different sizes among
these both movable and fixed(non movable)
depending on the market forces of demand and
supply. The organization has Participated in many
Energy efficient activities such as Energy efficient
week Carried out by the Uganda Ministry Of Energy
in effort of Promoting efficiency in the country’s
environment.

4.  Domestic and Institutional Charcoal
Stoves: Our stoves range from size
1(one) to size 7(seven)that is from
domestic size to commercial. these
stove are easy to operate because they
are built with fire insulation materials
which help to save fire and reduce the
consumption of charcoal to almost
70% compared to the ordinary stoves
which are locally made. these stove are
supplied in our sole agents and
supermarkets within Kampala and
surrounding districts.
 Production of charcoal briquettes:
these briquettes are made from waste
products in order to reduce the
consumption made at home. we also
train maids how to conserve the
environment by using efficiency
products by making charcoal
briquettes as away of recycling other
waste products like charcoal leftovers
and banana pods.

5.  Insulated low mass
combustion chamber
 Internal shelf allows sticks
to form a grate.
Stick/air/stick/air
 Small amount of high
velocity air is drawn under
the coals and the wood
‘grate’ which improves air
to fuel mixture
 Stove power is controlled
by regulating the fuel
supply not the air intake
 Horizontal feed chamber is
convenient

6. “Whenever possible,
insulate around the fire
using lightweight, heat-
resistant materials.”
 Insulation around the
fire keeps it hot which
reduces smoke
 Insulation around the
fire keeps the heat from
going into the stove
body instead of pot
 Insulation is light and
full of small pockets of
air

8.  If possible, avoid heavy
materials like sand, clay,
and cement.
 Metal is better than heavy
material above (less
thermal mass) but does not
last very long near hot fire.
 Heat resistant insulated
material are best

9. “Place an insulated short chimney right above
the fire.”
 a short insulated chimney right above fire
forces mixing of flames and smoke which
burns up the harmful smoke.
 The short chimney above the fire increases
the speed of the air drawn into the fire
which helps the fire to burn hotter.
 Forcing the hot gases to scrape past the
pot at a high speed helps to heat up the
food more quickly while using less fuel.

10. “High and low heat are created by how
many sticks are pushed into the fire.”
 Adjust the amount of gas made and fire
created to suit the cooking task. (Wood
gets hot and releases gas. The gas
catches fire and makes heat.)
Low Heat High Heat

11. “Maintain a good fast draft
through the burning fuel.”
 Just as blowing on a fire
and charcoal can make it
hotter, having the proper
amount of draft will help to
keep high temperatures in
your stove.
 A hot fire is a clean fire.
 The wind passing through
the coals helps to raise the
temperature of the fire so
that all the gases become
flame.

12. “Maintain a good fast draft through the
burning fuel.”
 The air should be aimed at the coals
and not above the sticks into the
flame.
 The wind that is drawn into the coals
heats up the fire. Blowing air into the
flames can do the opposite and cool
the fire.

13. “Too little draft being pulled into
the fire will result in smoke
and excess charcoal.”
 If a lot of charcoal is being
made by the fire then there is
too little air entering the
combustion chamber.
 A fire that makes a lot of
charcoal is producing too
much harmful carbon
monoxide.
 A hot clean burning fire will
not make much charcoal as it
is being used. Make sure that
enough air is freely flowing
under the fire into the coals

14.  3 rules for maximizing
heat transfer:
 Maximize the surface
area where the hot flue
gases touch the pot
 Maximize velocity of hot
flue gases to disturb
boundary layer around
the pot
 Maximize temperature
difference between the
hot flue gases and the
pot ( i.e. make a high
temp fire - 1000C

With a heat exchanger,
overall efficiency can be
improved by 50% or more

15.  Ensure the correct gap
between the pot and the
stove body (for average
household pots, 7-10
mm is good rule of
thumb)
 Make the skirt as tall as
feasibly possible
•For a 10cm long
channel, the channel
efficiency drops from
46% for an 8mm gap to
26% for a 10mm gap.

16. “Maximize heat transfer to the pot with properly sized
gaps.”
 Getting heat into pots or griddles is best done with small
channels.
 gap too large: hot flue gases mostly stay in the middle of the
channel and do not pass their heat to the desired cooking
surface.
 Gap too small: the draft diminishes, causing the fire to be
cooler, the emissions to go up, and less heat to enter the pot.

17. “Maximize heat transfer to the pot with properly sized
gaps.”
 Optimal Gap:
 size of channel estimated by keeping the cross sectional
area constant
 Using trial and error, start with a small gap, and increase
little by little till fire stays hot and vigorous

18. Gap ‘D’
Gap ‘C’
Gap‘ B’
Gap‘A’

19.  To calculate gap A ( between the top of the combustion gap A = Area of feed chamber
chamber and the pot) Perimeter of feed chamber
 To calculate gap B ( between the pot and the gap B = Area of feed chamber
outer edge of the combustion chamber) Perimeter of outer feed chamber =
[(D+10 cm] *3.14)
 To calculate gap C (under the outer edge of the pot gap C = Area of feed chamber
and the stove body) Circumference Pot
 To calculate gap D (between the sides of the pot gap D = gap C * 0.75
and the stove body)
Gap ‘D’
Gap ‘C’
Gap‘ B’
Gap‘A’

20. Force heat to rub against heat exchanger
 Insulate all parts of the stove body
 Keep exit temperatures low (around 180)
 Chimney can be ½ area of the stove
entrance
 Tapering the manifold
 Exit temps should be 150-180 C
 If lower what happens?

21.  Smoke
coming
out of
the top
of the
stove?
 Too much wood
in combustion
chamber
 The wood is wet
 The gap is too
small between
pot and stove
body which is
resulting in a
reduction of air
flow through
the system
• Encourage
users to reduce
fuel
• Encourage
users to store
fuel for drying
• Check the pot
gaps

22. Troubleshooting a Stove
• Smoke
coming
out of the
front of
the stove?
• Check the pot
gaps
• Clean
combustion
chamber
•The gap between the pot
and the sides of stove are
too too small or uneven
•The gap between the
bottom of the pot and the
combustion chamber is too
small
•The combustion chamber
is clogged with ash

23. Troubleshooting a Stove
• Flames
coming
out of the
front of
the stove?
• We want a
vigorous draft
that draws the
flames up into
the combustion
zone
•The gap between the pot
and the sides of stove are
too too small or uneven
•The gap between the
bottom of the pot and the
combustion chamber is too
small
•The combustion chamber
is clogged with ash

24. Troubleshooting a Stove
Things that can go wrong with a stove
• Slow
cooking
times
• Keep the stove
indoors when
not in use
• Dry the stove
before testing it
• Check gaps
•Is the stove wet? A wet
stove will produce a lot of
smoke and take a long
time to heat up .
•Black soot will appear on
the inside of the bricks if
the stove is wet or damp
•The gap could be wrong
(too big or too small)

25. Material and Design options

26. 1.5-2X
Min 2x
X
Hard fired bricks used at entrance
and at the back of the combustion
chamber . Ground and graded
Pumice (use excel guide) and
cement fondue at other points
Mortar fired bricks together
with a mixture of 20% cement
fondue and 80% < 1mm ground
pumice
Use min water for max.
strength
Thinnest joint possible 3-5
mm Cures in 48 hours
Mortar should NOT be
insulative

27. The fire clay tiles or clay pipe
Very durable: 3 years of success in
East and central Africa
Inexpensive: less than 55000/=
per combustion chamber
Not monolithic: individual parts
‘float’ so they can withstand
greater thermal shock.
Low mass: needs insulation
Can be cut from pre-existing tiles
or made from moulds
Possibly surround with Rock
wool insulation!

28. Material Density
(kg/m^3)
Specific Heat
(J/kg-C)
Thermal
Conductivity
(W/m-C)
Estimated heat
loss
(MJ)
Ordinary Brick 1600 840 0.7 5.7
Guatamalan
Baldosa
1691 812 0.219 3.1
85% pearlite
15% clay
1400 F firing
439 921 0.128 1.4
50/50
sawdust/clay
729 701 0.081 1.2
85%
vermiculite
15% clay
559 698 0.12 1.4
El Coco
Baldosa
1328 835
(estimated)
0.181 2.5
Pumice brick 770 835
(estimated)
0.107 1.5
Glass wool 40 700 0.038 0.37

29.  Can calculate density (g/cc) or test to see if
the mixture floats . Yes? Than less than 1
g/cc
 A very light insulative mixture 4 g/cc (ideal
for top plate)
 .6 -.8g/cc ideal for combustion chamber
above abrasion points ( i.e above feed
chamber)

30.  Step A Grind 2 kg of pumice
 Step B Stack a 4mm and a 2mm screen. Use these to prepare 3
grades of pumice. Be sure to sift very thoroughly
 Step 1 Sift these piles with the full range of screens. Then
Weigh each screen and insert to excel
 Step 2 Change proportions to find true readings . If possible For
larger sieve sizes (4-19mm) choose closer to the ‘least’ , for 0-4
sieves choose closer to the most
 If proportions cant be met , additional grinding may be
necessary

31.  Build a small , 3-5
mm thick wood
shelf . Shelf MUST
include a limiter to
prevent it entering
to far into the stove
 And a hinged wood
support to keep
wood level !

32. Mortar Options