Optimization of Performance of Bio-ethanol Gel Cookstove

Abstract

Approximately one-third of the world’s population uses traditional biomass for cooking using inefficient cookstoves. The use of these forms of energy is associated with environmental as well as human health impacts. The inefficient combustion results to high levels of indoor air pollution from solid fuel use. These emissions have been responsible for more than 1.6 million annual deaths and 2.7% of the global diseases. The major health ailments are lower respiratory infection deaths among children and chronic obstructive pulmonary diseases deaths among adults. The alternative to indoor air pollution from inefficient combustion is use of clean cooking fuels such as liquefied petroleum gas (LPG), biogas, ethanol and kerosene with efficient cookstoves. LPG and kerosene are fossil fuels derivative from finite resources. The storage and scrubbing of biogas to remove hydrogen sulphide is also a challenge. The other clean fuels that can be utilized are ethanol and ethanol gel. Therefore, this research focuses on bio-ethanol gel combustion in cookstoves as an alternative fuel to traditional biomass. The combustion behaviour of the bio-ethanol gel was evaluated through the design of an improved cookstove. Provisions were made for measurement and evaluating its performance in terms of fuel efficiency, indoor emissions and heat transfer in comparison to the moto poa and moto safi cookstoves that use the same gel fuel. The research also involved determination of the physical-chemical properties of gel fuel as factors that may affect combustion. The fuel efficiency and indoor air emissions were determined using the water boiling test (WBT), version 4.1.2 procedure. The indoor concentration of three major pollutants: carbon monoxide, carbon dioxide and particulates; were monitored and recorded using xvii EasyLog CO data logger, Telaire 7001 CO2 data logger and UCB particle monitor respectively. The tests were conducted in a simulated kitchen as the cookstoves boiled water to local boiling point under controlled settings in which every effort possible was made to minimize sources of variability. The results obtained from this study show that by using the improved cookstove CO emissions were reduced by 38.6% and 55.7% in comparison to the moto safi and moto poa cookstoves respectively over the entire water boiling test. Besides characterizing the three cookstoves using their pollutant generation, the study also highlighted the fuel efficiency of the improved cookstove in comparison to moto poa and moto safi cookstoves. The results show that the improved cookstove increased thermal efficiency by 9% and 13% and reduced the cookstoves fuel usage by 8.9% and 11.6% for the entire water boiling test in comparison to moto safi and moto poa cookstoves respectively. The high fuel efficiency and reduction of indoor air pollution by the improved bioethanol gel cookstove over the moto poa and moto safi cookstove showed that it is the most appropriate cookstove for application in low income