Performance Of Cookstoves Research Articles

Laboratory and Field Performance of Two In-House Developed Metal Biomass Cookstoves

Present work reports thermal and emission performance of in-house developed natural and forced draft metal biomass cookstoves. Laboratory as well as field tests are performed on the cookstoves. Experiments are performed on natural draft metal cookstove in laboratory at different air supply hole openings. Decrease in average input power and average thermal efficiency is observed between 3.74-3.43 kW and 31.14-29.45% respectively. Variation in average emission factor for carbon monoxide (CO) is found to be between 3.5-9.9 g/MJd. Emissions of Oxides of Nitrogen (NOx) are found to be varying between 1 ppm to 13.5 ppm without any specific trend. Experiments are performed on forced draft metal cookstove in laboratory on two fan speeds. The average input power and average thermal efficiency vary between 3.4-3.0 kW and 36.9-42.5% respectively. Variation in average emission factor for CO is found to be between 1.8-4.5 g/MJd and that of average NOx emissions between 16.8-2.5 ppm.During field tests, amount of fuel consumption and emissions of CO for both the cookstoves is compared with traditional cookstoves used by two families. In case of Family A, there is a saving in fuel consumption by 19% and 40% with natural draft and forced draft metal cookstoves respectively. The corresponding values for Family B are 5 % and 24% respectively. In case of Family A, there is decrease in CO emissions by 89% and 86% with natural draft and forced draft metal cookstoves respectively. The corresponding values for Family B are 76% and 82% respectively.

Design, Fabrication and Testing of a Forced Draft Biomass Cook Stove

An approach towards an Improvement in performance of cook stoves has been a great challenge to scientists and researchers as biomass cook stoves are one of the basic needs of people living in rural areas. But due to household pollution by Traditional Cook stoves causes illness to people preparing for their regular meals near it. So, taking an initiative for Designing, Fabricating and Improvisation in the performance of Forced Draft cook stoves by placing proper Primary and Secondary holes in combustion chamber which gives better air distribution for proper combustion to get Lower Emission rates. Various experimentations are being performed on the basis of standard protocols i.e. BIS (Bureau of Indian Standards), VITA (Volunteer in Technical Assistance), EPTP (Emission Performance Test Protocol), WBT (Water Boiling Test) amongst which BIS had an upper hand and had very less uncertainty of errors due to which it is mostly being used in checking and improving emission performance of cook stoves for more efficient use with less chances of health issues. This paper consists of Design, Calculations and Constructional working of Forced Draft Biomass Cook stove and also the Burning rate Calculations were carried out to check fuel burnt rate.

Design and experimental analysis of an improved burner with natural gas

This research aimed to improve the thermal performance of industrial cookstoves using natural gas in Metropolitan Lima to promote good use of energy and reduce the impacts of climate change. The methodology was to use an appropriate test bench under the international standards of fuel gases; the appropriate instrumentation was used to record the variables such as temperature, pressure, mass flow, and relative air humidity. The burner was installed in the prototype cookstove and test bench to perform the experimental part. After that, the powers and performances of several industrial cookstoves in the Peruvian market were determined for comparison with the design of the prototype cookstove following the experimental methodology of 02 international standards, one Latin American and one Asian. The burner designed and manufactured in previous research gave a wide range of natural gas power according to the working pressure used and high efficiency of approximately 57% compared to the cookstoves that are sold nationwide, which on average is 53%. The advantage of this prototype cookstove is that it uses operating pressures between 23 and 34 mbar compared to stoves in the Peruvian market that do not have a standard of the maximum gas pressure.

Energy performance of cookstoves and emission factors in rural areas of Eastern Indo Gangetic Plains (EIGP)

Biomass consumption, energy performance of cookstoves and emission factor of cattle dung cake, used as a main source of energy, in EIGP was evaluated. Average biomass consumption was recorded as 2.46 kg/capita/day indicating 1.5-fold higher fuel consumption in the region compared to other parts of the country. Use of improved cookstove could, however, save 13% biomass use compared to traditional stove besides 32.5 kJ of energy for cooking of one kg of food. On average, 56.70–67.75 kJ of human energy is required to prepare one kg of cattle dung cake. Of the total energy requirements, women folk contribute the maximum (>45%), followed by male counterpart (>30%) and rest is shared by children of 9–12 years of age. Labour energy expenditure was, however, significantly low for cattle dung cake preparation compared to energy involved in firewood collection. Emission factors for hazardous gaseous pollutants ranged from 464.30–548.80, 19.1–34.30 and 0.981–1.455 g/kg, respectively, for CO2, CO and HC. With increasing ratio of crop biomass, the emission factor for CO2 decreased, irrespective of biomass used. Based on the biomass consumption and emission factors for pollutants, lentil stalk and paddy straw have been found suitable substrate for cattle dung cake preparation.

Assessment of clean cooking technologies under different fuel use conditions in rural areas of Northern India

The study was conducted to assess the performance of improved and traditional cookstoves using wood as a fuel and three combinations of other fuel mixes – (i) wood and cow dung, (ii) wood and mustard stalks, and (iii) cow dung and mustard stalks). Energy and emission parameters such as specific energy consumption (SEC), emission factors (EFs) of carbon monoxide (CO), particulate matter (PM) and black carbon (BC) were used to compare four different types of cookstoves. These included top-feed forced draft (TF-FD), top-feed natural draft (TF-ND), front-feed natural draft (FF-ND) and front-feed traditional (FF-TR) cookstoves. Controlled cooking test (CCT) was used as the test protocol. The results showed the performance of improved cookstove technologies can vary based on the fuel used for cooking. It was observed that emission factors for PM and CO increased by 67–96% and 45–90% respectively when all three improved cookstoves were tested with three fuel combinations against wood as cooking fuel. Among the tested cookstoves, a marked difference was observed between performance of forced draft and natural draft cookstoves. Forced draft cookstoves emitted higher amount of all pollutant emissions compared to natural draft cookstoves when used with mustard stalks in combination with either wood or cowdung. The results are of critical importance given that forced draft cookstoves have been promoted in geographical regions where fuel mix use is prevalent. Therefore, forced draft cookstove might not be the right choice when the goal is climate mitigation and reduction in impact on human health. It is imperative to study comprehensively the influence of various field variables on performance of cookstoves, which have severe implications on the performance of cookstoves.

Predicting and analyzing the performance of biomass-burning natural draft rocket cookstoves using computational fluid dynamics

Nearly three billion people in the world today rely on biomass for their cooking needs. Indoor cooking using biomass has been identified as a major cause of respiratory illnesses, resulting in four million premature deaths every year. Improved biomass cookstoves may help mitigate this challenge. This paper presents a two-dimensional axisymmetric steady-state computational fluid dynamics (CFD) model of a biomass burning, natural draft rocket cookstove. The CFD model includes coupled sub-models representing combustion, turbulence, and heat transfer. The model is validated against experimental data and used to predict temperatures and flow inside the cookstove, including the airflow rate through the cookstove and heat transfer to the cookpot. We find that the excess air is typically many times stoichiometric air during standard operating conditions and is sensitive to flow field obstructions. We analyze the effects of geometric and operational features such as the pot support height, secondary air entrainment, cone-deck shape, and baffle placement within the cookstove on the flow, airflow rate, mixing, and stove thermal efficiency. The model shows that secondary air entrainment, though ineffective by itself, increases turbulent mixing when used in conjunction with a central baffle but reduces thermal efficiencies due to enhanced heat transfer to the walls. We find that a lower pot support height decreases the airflow rate and increases thermal efficiency. We model thirty-six cone-deck configurations and find that the cone-deck shape primarily affects the airflow rate through the stove, with more constricted designs leading to higher thermal efficiencies.

Monitoring impacts of clean cookstoves and fuels with the Fuel Use Electronic Logger (FUEL): Results of pilot testing

Objective, affordable, and unobtrusive monitoring tools are needed to quantify in-field performance and increase user acceptance rates of clean cookstoves and fuels. To meet this need, researchers have developed the Fuel Use Electronic Logger (FUEL), a sensor-based system that monitors the mass of a household fuel supply and cookstove temperature over time to quantify cookstove adoption and use, fuel consumption, and extrapolate to air quality and climate emissions. Following proof-of-concept studies in Honduras and Uganda, a pilot study was conducted in 44 rural Ugandan households monitoring over an average of 45 days. The purpose of these studies was to evaluate sensor usability and technical performance, inform algorithm development, and demonstrate how FUEL data can be used to quantify key stove performance metrics. Usability results indicated that the FUEL accurately monitored fuel consumption 88% of monitoring days, and 78% of households continued to use the fuel holder without the sensor 8 months after the monitoring period. Fuel consumption was reported per cooking event, day, monitoring period, household, and per capita. Results showed high daily variability in each household, suggesting that longer monitoring durations are needed, with estimation error decreasing from 72% at 4 days to 6.5% relative to a 25-day monitoring period. Cooking duration paired with fuel consumption also provided indicators of average firepower and therefore operational practices across households. Use of emission factors with fuel consumption data estimated carbon savings, showing that stacking of an improved and traditional stove will contribute to higher fuel consumption and carbon emissions per capita than households using a single improved stove. These results highlight the potential of the FUEL system to aid in more effective and accurate quantification of long-term technical performance and adoption, while increasing the transparency and impact of improved cookstove projects.

In-Home Emissions Performance of Cookstoves in Asia and Africa

This paper presents results from eight field studies in Asia and Africa on the emissions performance of 16 stove/fuel combinations measured during normal cooking events in homes. Characterizing real-world emissions performance is important for understanding the climate and health implications of technologies being promoted as alternatives to displace baseline cooking stoves and fuels. Almost all of the stove interventions were measured to have substantial reductions in PM2.5 and CO emissions compared to their respective baseline technologies (reductions of 24–87% and 25–80%, for PM2.5 and CO emission rates, respectively), though comparison with performance guidance from the World Health Organization (WHO) and the International Organization for Standardization (ISO) suggests that further improvement for biomass stoves would help realize more health benefits. The emissions of LPG stoves were generally below the WHO interim PM2.5 emissions target (1.75 mg/min) though it was not clear how close they were to the most aspirational ISO (0.2 mg/min) or WHO (0.23 mg/min) targets as our limit of detection was 1.1 mg/min. Elemental and organic carbon emission factors and elemental-to-total carbon ratios (medians ranging from 0.11 to 0.42) were in line with previously reported field-based estimates for similar stove/fuel combinations. Two of the better performing forced draft stoves used with pellets—the Oorja (median ET/TC = 0.12) and Eco-Chula (median ET/TC = 0.42)—were at opposite ends of the range, indicating that important differences in combustion conditions can arise even between similar stove/fuel combinations. Field-based tests of stove performance also provide important feedback for laboratory test protocols. Comparison of these results to previously published water boiling test data from the laboratory reinforce the trend that stove performance is generally better during controlled laboratory conditions, with modified combustion efficiency (MCE) being consistently lower in the field for respective stove/fuel categories. New testing approaches, which operate stoves through a broader range of conditions, indicate potential for better MCE agreement than previous versions of water boiling tests. This improved agreement suggests that stove performance estimates from a new ISO laboratory testing protocol, including testing stoves across low, medium, and high firepower, may provide more representative estimates of real-world performance than previously used tests. More representative results from standardized laboratory testing should help push stove designs toward better real-world performance as well as provide a better indication of how the tested technologies will perform for the user.

Effect of Height, Shape and Air Supply in the Performance of Wood Burning Cookstoves

Effect of Height, Shape and Air Supply in the Performance of Wood Burning Cookstoves

Experimental investigation on thermal performance of three natural draft biomass cookstoves

Testing the performance of biomass cookstoves is an important task in front of cookstove researchers. Different cookstove testing protocols are being used across the world for laboratory testing of the cookstoves. Most of the protocols recommend testing the stove at a fixed input power (kW) which is the product of fuel burning rate (kg/s) and calorific value (kJ/kg) of the biomass fuel. In actual field, the operator may operate the cookstove at any suitable input power. This causes difference in laboratory and field performance of the cookstove. Thus, single value of efficiency is not sufficient to describe the performance of a particular cookstove. To simulate actual cooking process through laboratory experiments, it is proposed to generate input power versus thermal efficiency characteristics of the cookstove. The present work involves detailed laboratory experiments on three natural draft biomass cookstoves viz. three stone fire, Panval rocket stove and Berkeley-Darfur stove. The experiments were performed on each cookstove according to modified Bureau of Indian Standards (BIS) Protocol. Each stove was operated at four different fuel-burning rates. Each test was repeated four times and uncertainty analysis was carried out using student’s t test. Input power versus thermal efficiency characteristics were plotted for the three cookstoves. These characteristics help the users to compare the performance of the cookstoves at a given fuel-burning rate.

A simplified combustion model integrated with a particle growth dynamic model for top-lit updraft cookstoves

Solid fuel stoves are used by over a third of the world's population for cooking and space heating. Efforts are being made to develop cookstoves with higher combustion and thermal efficiencies, but these efforts lack support of numerical models for predicting emissions that can be used in the design process. This work presents a simplified steady-state model to simulate combustion in a top-lit updraft (TLUD) cookstove integrated with a model for particle growth dynamics. The model incorporates the effects of cookstove operating parameters, specifically primary and secondary air fluxes and their temperatures and fuel composition (moisture, char, and volatile content) on various emissions and thermal characteristics of the cookstove, such as emission factors (EF), emission rates (ER), and size distribution of particulate matter. The results demonstrated that EF and ER do not necessarily follow the same trends, and therefore a lower EF might lead to a higher personal exposure. This raises serious concern over the high reliance on EFs as a metric to assess the performance of cookstoves. Emissions trends obtained from the model matched with the trends reported in previous studies. Sensitivity analyses demonstrated that a small variation in the cookstove operating parameters or fuel properties drastically changes emission.

Energy performance of biomass cookstoves using fuel briquettes

ABSTRACTIn this study, the energy performance of an improved cookstove (ICS) is evaluated and compared with the performance of a charcoal stove and the three-stone fire using two biomass fuel – rice husk and sawdust briquettes. The performance of the cookstoves is evaluated based on the standard testing protocol of water boiling test in three phases – cold start, hot start and simmering. The energy performance of the cookstoves is compared using analysis of variance (ANOVA). The results of the study show that the ICS performed better in the cold and hot starts as opposed to the simmering phase. ANOVA shows that the thermal efficiency, firepower, specific fuel consumption, time to boil, burning rate and the turndown ratio of the three cookstoves are significantly different (p < 0.05) from one another for each of the fuel types. In the high power phase, the ICS offered superior energy performance over the two conventional cookstoves with the use of rice husk briquette as fuel. However, the performance of the ICS is low compared to that of the two conventional cookstoves in the simmering phase. The ICS offered better thermal efficiency over the traditional cookstoves and some other ICSs in the literatures.

Lessons learned from a comparison study of charcoal stoves for Haiti

Biomass is the predominant cooking fuel in Haiti, where it creates burdens on both the environment and the Haitian people. Following the 2010 earthquake in Port-au-Prince, the need for fuel-efficient cookstoves was acute. Although several organizations were quite interested in dissemination of fuel-efficient stoves in the relief effort, there was little knowledge about the performance and usability of the proposed stoves. To help fill the knowledge gap, stove researchers from Lawrence Berkeley National Laboratory evaluated and compared the performance of several cookstoves intended for dissemination in Haiti. This paper discusses the decisions made throughout the course of that work, from project identification and approach through the dissemination of results. It identifies the challenges faced and how they were addressed, while briefly presenting the data from stove performance evaluated using Water Boiling and Controlled Cooking Tests. It also highlights the importance and benefits of evaluating technologies such as cookstoves prior to dissemination, even in urgent disaster relief situations.

Improvement of the Domestic LPG Cooking Stoves: A Review

Objectives: The objective of this review was to study various works that have focussed on the improvement of the efficiency and emission features of the LPG (Liquified Petroleum Gas)cook-stoves. Methods: The major focus of the review was on the LPG cook-stoves, though a variant in the form of Biogas was also studied. Parameters like performance, efficiency and emission features of various cook-stoves were taken into account. The design factors of the burners used in these cook-stoves was also one of the major factors that was strongly emphasized in this study. Findings: It was found that if the efficiency of a stove needs to be improved, the focus must be on the improvement of the specifications, design and material of the burner. For better efficient burners, the air preheating can be considered as a factor. As in the case of porous media, the thermal efficiency of the burner increases and the CO and NOX emissions reduce drastically. Application: Material of the burner also plays a pivotal role in the performance of the stove. Burners made up of have been found to be more efficient than their counterparts iron burners. Also, the shape of the burner is one factor that can help improve the performance of the stove.

Laboratory based assessment of cookstove performance using energy and emission parameters for North Indian cooking cycle

The study was conducted to evaluate the performance of cookstoves using controlled cooking test (CCT) with cooking cycles of Northern India, i.e., Uttar Pradesh (UP) and Uttarakhand (UK). Cooking time, specific energy consumption (SEC), and emission factors (EFs) of carbon monoxide (CO) and particulate matter (PM) were monitored for three improved and one traditional cookstoves. Cooking was conducted by residents of the study area. The findings from the study showed that the difference in thickness of roti baked in UP and UK resulted in a significant change in emission and energy performance in all the four cookstoves. The low-power inputs required for baking thinner roti resulted in higher CO and PM emissions in case of CCT-UK. The results of CCT were also compared to Water Boiling Test (WBT) for all the four cookstoves. The percent reductions in terms of energy and emission parameters in the three improved cookstoves compared to traditional cookstove were found to differ in CCT and WBT. Large variations were also observed during the emission performance (40% decrease in CO EF) of the fan cookstove with change in fan speed, which was usually unreported in previous studies. Overall, results show significant influence of cooking cycles on cookstove performance, which was found to alter the cookstove rankings. Therefore, the study thrusts upon the inclusion of user centric cookstove testing protocols in order to identify actual benefits for targeted rural communities.

A laboratory based comparative study of Indian biomass cookstove testing protocol and Water Boiling Test

The study was carried out to compare the cookstove performance using Water Boiling Test (WBT) and the Indian Standard on Solid Biomass Chulha Specification developed by the Bureau of Indian Standards (BIS) for testing cookstove. Additionally, the testing guidelines pertaining to feeding interval and ignition material were also tested in the BIS and WBT, respectively. Two cookstoves manufactured by Phillips, Philips Natural Draft (PN) and Philips Forced Draft (PF) were selected for assessing their performance. The thermal efficiency (TE), emission factors (EFs) of carbon monoxide (CO) and particulate matter (PM) were used as performance indicators to compare the cookstove performance. It was observed that both the cookstoves gave comparable TE with no significant difference (p>0.05) using both protocols; whereas, CO EFs were ~39% and ~47% higher in BIS test due to dominance of smoldering conditions compared to WBT in PF and PN cookstoves, respectively. On the contrary, PM emissions were found to be ~55% lower in BIS test compared to WBT in PN cookstove, which could be due to the oven dried wood recommended in the BIS test. Inclusion of emissions of ignition phase was found to increase the total PM and CO emissions during cold start by 45–70% when mustard stalks were used as kindling material compared to wood chips and kerosene. Average CO emissions were found to increase by ~68% and ~48% in PF and PN cookstoves, respectively, with 15minute fuel feeding interval in BIS test. The result shows that change in combustion conditions during the two different test protocols did not affect the energy parameters; however, the effect on CO and PM emissions was significant. It can be concluded that multiple testing methods might yield different information of cookstove performance leading to difficulty in assessing the actual performance of cookstoves.

Improved test method for evaluation of bio-mass cook-stoves

More than two-thirds of the world's population is relying on biomass fuel to meet their cooking and heating energy-requirements. Traditional biomass stoves operate at low efficiency and cause severe health problems and pollute the environment. Due to higher quantity of fuel use, these cookstoves increase the burden on fuel management. Several test protocols are being used across the world for evaluating the performance of cookstoves. One of the major challenges of existing protocols is to narrow down the gap between the test results obtained under lab conditions and actual cooking conditions. Hence, there is a need to evolve an improved test method that can reflect the stove performance under field conditions. This paper is aimed to reduce the gaps in test methodology in such a manner that the test results obtained in the lab are comparable with the results of actual cooking carried out in the kitchen. An improved test method, which includes a residual heat recovery phase, is proposed to evaluate the performance of cookstoves. Design parameters related to technical, social and economic aspects were identified. Common errors that occur during the water boiling test were identified and methods to minimize such errors were also proposed.

Metrics to evaluate use, adoption and field performance of advanced-combustion cookstoves in a fuel-device stacking context.

Metrics to evaluate use, adoption and field performance of advanced-combustion cookstoves in a fuel-device stacking context.

Computational Heat Transfer Analysis of the Effect of Skirts on the Performance of Third-World Cookstoves

In many developing countries, natural gas, wood, or biomass fired cookstoves find prolific usage. Skirts, placed around the cookpot, have been proposed as a means to improve the thermal efficiency. However, use of skirts has shown conflicting results, and the role of skirts is poorly understood. In this study, a computational heat transfer analysis of a generic third-world cookstove is conducted with the goal to understand the effect of various skirt-related parameters on the overall heat transfer characteristics and thermal efficiency. A computational fluid dynamics model, including turbulence and heat transfer by all three modes, was created. The model was first validated against the experimental data, also collected as part of this study. Unknown parameters in the model were calibrated to better match the experimental observations. Subsequently, the model was explored to study the effects of several skirt-related parameters. These include the vertical position of the skirt, the width of the gap between the skirt and the cookpot, and the thermal conductivity of the skirt (insulating versus conducting material). The computational predictions suggest that the skirt must either be made out of an insulating material or insulated on the outer surface by a backing insulating layer for it to provide maximum benefits. It was also found that it must be placed at an optimum distance away from the cookpot and aligned with the mouth of the cookstove chimney for maximum thermal efficiency. An optimum set of conditions obtained through this computational analysis resulted in an increase in the thermal efficiency from 20.7% to 28.7%.

Energy performance of wood-burning cookstoves in Michoacan, Mexico

There have been few detailed assessments of the actual impacts of improved stove interventions in rural communities, although many improved stove projects have reported overall efficiencies from tests in simulated kitchens using water-boiling tests (WBTs). This paper presents an integrated energy evaluation of the Patsari cookstove, an efficient wood-burning cookstove developed in Mexico that has recently obtained international recognition, in comparison to traditional cookstoves in rural communities of Michoacan, Mexico. The evaluation uses three standard protocols: the WBT, which quantifies thermal efficiency and firepower; the controlled cooking test (CCT), which measures specific energy consumption associated with local cooking tasks, and the kitchen performance test (KPT), which evaluates the behavior of the stoves in-field conditions and estimates fuel savings. The results showed that the WBT gave little indication of the overall performance of the stove in rural communities. Field testing in rural communities is of critical importance, therefore, in estimating the benefits of improved stoves. In the CCT for tortilla making, the main cooking task in Mexican rural households, Patsari stoves showed fuelwood savings ranging from 44% to 65% in relation to traditional open fires ( n=6; P<0.05). These savings were similar in magnitude to the average energy savings from KPT before and after Patsari adoption of 67% ( n=23; P<0.05) in rural households exclusively using fuelwood. Similar energy savings of 66% for fuelwood and 64% for LPG, respectively, were also observed in households using mixed fuels. With sound technical design, critical input from local users and proper dissemination strategies, therefore, improved stoves can significantly contribute to improvements in the quality of life of rural people with potential benefits to the surrounding environment.