IMPROVED BIOMASS COOKING STOVES

This study investigates the impact of increased levels of indoor air pollution (IAP) caused due to biomass burning in the rural households of Northern India. A comparative assessment of the impact of traditional cookstoves (TCS) and improved cookstoves (ICS) coupled with the characteristics of kitchen was conducted to estimate the PM (PM 10 , PM 2.5 , PM 1), CO/CO 2 concentrations in the micro-environments of kitchen and living area of the households. The study incorporated both extensive and intensive real-time indoor air quality (IAQ) monitoring during the two cooking sessions of the day. The pollutant concentrations were reported in terms of 24-h as well as 8-h (cooking hours including morning and evening meal) averages. Influence of the three types of kitchen characteristics, i.e., enclosed, semi-enclosed and open was also comprehensively analyzed to measure its impact on the IAQ. In addition to this, the IAQ was further used to evaluate the particle size distribution (PSD), respiratory tract deposition and exposure index to assess its impact on health status of the exposed group including women involved in cooking practices. The results of the study highlighted that deployment of ICS would help in improving the IAQ of the kitchen area by resulting in reducing the concentrations of PM 10, PM 2.5, PM 1 and CO by 21-62%, 20-80%, 24-87% and 19-93%, respectively. It was also highlighted that the kitchen characteristics significantly influence the accumulation of air pollutants, demonstrated by the results that the IAQ being worst in the case of enclosed kitchen, resulted in the highest exposure index values. Multivariate regression models to predict PM 1 concentration were also developed for three kitchen categories for both TCS and ICS. Thus, the current study concludes that usage of ICS coupled with efficient designing of the kitchen can improve the overall IAQ of the household along with immense health benefits. Overall, the study emphasized the need of more comprehensive studies to fully assess the association of household air pollution (HAP) and health of individual in the rural settings by considering the toxicity of PM.

Biochar is a black carbonaceous material produced from waste biomass using efficient pyrolysis technologies that is used as a soil amendment. There have been many studies and researches on biochar technology in different parts of the world but very few studies have been carried out in the context of Nepal. This study is intended to explore the scope, feasibility, drawbacks, and future study areas of biochar in the context of Nepal.
In this study, Padali village, Lamatar 7, Lalitpur was taken for the study. The study was performed to produce biochar from locally available waste biomass like rice husk, wheat husk, pine needles, etc. using biochar stoves and to evaluate the effect of thus produced biochar on the fertility of soil and plant nutrient uptake along with the comparison of the performance of the biochar stove for cooking purpose with traditional cooking stoves. The design of the biochar stove was adapted from the DK-T3M model.
The average rate of biochar production from the biochar stove was recorded to be 26% using pine needles. The field trials on leaf mustard showed that the pH value, N, P, K and OM content of the soil was higher in the biochar incorporated plot than in the control plot where no fertilizers were used. Similarly, the Nutrient Uptake Analysis of Leaf mustard showed that the addition of biochar enhances the nutrient uptake by plants and ultimately improves the plant health and plant yield. The thermal efficiency of the stove was recorded to be 12% at cold start, 17% at hot start and 4% in simmering. The stove showed better performance when dry biomass was used. The biochar stove consumed more fuel but took less time to cook than the traditional stove during controlled cooking test.

Charcoal stoves have widespread use among the poorer households and outdoor food vendors in Nigeria. In order to improve the efficiency of charcoal stoves, various researches have tried integrating a thermoelectric module in the charcoal stove. The researches, however did not exploit the performance of the thermoelectric modules at different ambient temperatures. To evaluate the performance of thermoelectric integrated charcoal stoves in the sub-Saharan Africa, a self-powered, forced air induced thermoelectric charcoal stove experiment was carried out at five different ambient temperatures of 36ºC, 33ºC, 32ºC, 30ºC and 29ºC and an average fuel hotbed temperature of 1023.75ºC. The thermoelectric charcoal stove generated a maximum voltage of 5.25V at an ambient temperature of 29ºC. The least maximum voltage was generated at the highest ambient temperature of 36ºC. It was observed that the maximum voltage increased with decreasing ambient temperature, this could be attributed to the ambient air being used to cool the thermoelectric generator. Therefore, it could be said that the performance of a forced draft thermoelectric charcoal stove increases with decrease in ambient temperature.

This study aimed at making and testing a portable wood stove, which presented an average efficiency of 12.3%. This percentage was higher than the 2.9 to 4.6%. range found in residential stoves in the city of Irati/PR. The fuel used in the experiment was wood from the Mimosa scabrella tree, with 13% moisture content. The thermal power of the portable stove was 241.3W; the fuel consumption was 0.2 kg for each 20-minute of operation, and the levels of volatiles were 0.1 Nm3 CO2/kg, 0.01 Nm3 CO/kg and 9.610-6 Nm3/kg for SO2. These results show that the wood stove presents very promising results.

The proliferation and use of charcoal stoves is on the increase even in urban locations in Africa despite the environmental
hazard associated with charcoal production. The rising cost of fossil fuel, the smokeless nature of charcoal combustion and
probably inexistent or ineffective legislation against deforestation could be the reasons for this. This study aims at more
efficient use of the energy available from the use of common charcoal stoves. A common slightly improved charcoal stove
was placed in an enclosure with openings for air inflow and heating of the pot, and linked to a heat receiver through a duct
all made of burnt brick. The stove enclosure, heat receiver inlet and outlet, and the ambient temperatures were measured
during the boiling of water for 3 periods/stages of 22 minutes per day for 6 days. The quantity of heat generated in the
enclosure, the percentage reaching the heat receiver and the total heat losses from the system were computed under steady
state conditions. A mean value of 93.85 kJ/kg of heated air was generated in the enclosure with about 34.33% reaching the
heat receiver. The mean temperature within the heat receiver was 70.4 °C and the mean total heat loss from the system was
about 6.4 kJ/kg of air. There was a significant difference between the thermal energy lost and trapped within and amongst
the three stages; (p ≤ 0.05) and significant also with time for the three stages and within the stages of operation (p ≤ 0.05)
with positive correlation of total heat lost and the heat trapped for conservation. This significantly indicates great potentials
for utilising part of the thermal energy generated from the use of charcoal stoves for cooking as losses for other alternative
uses such as drying and other forms of preservation of foodstuff thereby improving their utilisation efficiency and probably
compensating in part for the adverse effect on the environment as a result of sustained charcoal production. This is an
eye-opener situation in the quest for total energy conservation and conversion in any energy system.