Intern’l Conference on the Performance of Renewable Energy Systems (PRES 2017) July 11, 2017 Oldenburg, Germany

1. University of Oldenburg
Department of Physics
Energy and Semiconductor
Research Laboratory (EHF)
Postgraduate Programme
Renewable Energy
Motivation
Acknowledgements:
The authors gratefully acknowledge the guidance from Dr. Robin Knecht, Dr. Christiane
Stroth, and PPRE colleagues Kshitij Goyal and Apoorv Pareek (PPRE1618) for their cordial
help during the experiment.
Gasifier stove under testing utilized wood efficiently compared to the
rocket stove.
Stove efficiency may differ under real-life scenarios.
WBT does not take climatic conditions, sizes and material of cooking
pots into consideration.
Testing procedures other than WBT can be conducted to validate the
findings.
Aspect Rocket
Stove
Gasifier
Stove
Calculated
Efficiency [%]
19.6 (±0.3) 25.2
(±0.4)
Reported
efficiency[5]
[%]
~20-40 ~20-50
Rate of
temperature
rise [ºC/min]
4.8(±1.6) 7.7(±3.0)
Wood
consumption
[% of initial
mass]
70.2(±0.02) 63.3(±0.01)
Key findings:
Gasifier stove showed 5.6% higher efficiency than the Rocket stove.
Rocket stove consumed 7% higher wood compared to the gasifier
stove.
Gasifier stove took 67% of the time needed for the rocket stove
while boiling approximately double amount of water.
Low efficiency of rocket stove can be attributed to the air-fuel ratio
during cooking which is difficult to control.
Gasifier stove has better air control through primary and secondary
air supply along with ‘Top-lit Updraft’ approach [3].
Temperature profile based on WBT
Methodology:
Conclusions & Outlook
[1] World Health Organization,”Household air pollution and health”, February 2016.
[Online]. Available:http://www.who.int/mediacentre/factsheets/fs292/en/ .[Accessed 6
July 2017].
[2] United Nations, “Photo Story: Sustainable Energy for All 2015 -Converting
commitments to kilowatts”. May 2015, [Online].
Available:http://www.un.org/apps/news/story.asp?NewsID=50933#.WVpSC4iGPIU.[Acc
essed 6 July 2017].
[3] R. Knecht, C. Stroth, “Cookers” in Performance of Renewable Energy Systems: Carl
von Ossietzky University of Oldenburg,2017,pp 75-96
[4] Global Alliance for clean cookstoves, “The Water Boiling Test, Version 4.2.3”,
March,2014.
[5] Berkley Air Monitoring Group, “Stove Performance Inventory Report,” October,
2012.
Performance Comparison of Improved Cooking
Stoves using Water Boiling Test
Ahmed Altaif, Dipta Majumder
University of Oldenburg, Department of Physics, Energy and Semiconductor Research Laboratory
Carl-von-Ossietzky Str. 9-11, 26129 Oldenburg, Germany
Around 3 billion people depend on biomass for heating and
cooking, while 4.3 million die each year due to indoor air
pollution from inefficient cooking [1].
Collecting fuel is time consuming, mostly done by women
and children in developing countries [2].
Improved cooking stoves could reduce fuel consumption.
Efficiency of improved cooking stoves could be investigated
through standardized Water Boiling Test (WBT).
Two well known improved cook stoves i.e. Rocket and
Gasifier Stove were tested as per WBT procedure.
Measurement of initial mass of
water and wood to be used.
Recording of temperature and
time during the water boiling
Simmering for 30 minutes after
reaching the boiling point.
Final mass measurement of the
remaining water, wood and
charcoal.
Rocket stove Gasifier stove
Sources-Authors
Theory
The efficiency of a cook stove ( ) refers to the transferred heat
energy in comparison to the consumed heat energy [3].
Where,
1
! 100%
Para-
meter
Details Para-
meter
Details
Specific heat
capacity of water
(4187 J/kg/K)
Combustion value of dry
wood(16.3 MJ/kg)
, Mass of the water
at the end and at
the beginning of
experiment
, Combustion value of
charcoal (29.6 MJ/kg)
and mass of char.
, Initial and final
mass of the wood
used
Moisture content ratio
(0.12, experimentally
found by authors)
Heat of water
vaporization (2257
kJ/kg)
Temperature difference of
water between initial and
final condition
Water Boiling Test (WBT): A simple laboratory test procedure to
find out the stove efficiency. In this work, cold start high power phase
along with 30 minutes of simmering has been conducted to calculate
stove efficiency [4].
Results and Discussion:
Key References