Performance Characteristics of a Cooking Stove Improved with Sawdust as an Insulation Material

Abstract

In developing countries, energy demand from biomass has increased due to exponential population growth. This has translated into voluminous quantities of wood being used. The situation is exacerbated by the popular use of inefficient stoves with low thermal insulation, hence contributing to deforestation. In this study, the performance of a cooking stove improved with sawdust as an insulation material was assessed. An insulated fire stove prototype of 26 cm saucepan diameter was designed, constructed, and cast with sawdust and clay in a ratio of 1 : 1 (as the first layer) and sawdust alone as the second layer. The developed stove was tested using a water boiling test to establish its operating performance. The thermal efficiency of the stove was assessed using indigenous wood fuels used in rural Uganda (Senna spectabilis, Pinus caribaea, and Eucalyptus grandis). Computational fluid dynamics was used to simulate the temperature and velocity fields within the combustion chamber and for generating temperature contours of the stove. Obtained results indicated that S. spectabilis had the highest thermal efficiency of 35.5 ± 2.5%, followed by E. grandis (25.7 ± 1.7%) and lastly P. caribaea (19.0 ± 1.2%) in the cold start phase when compared with traditional stoves. The stove remained cold as hot air was restricted to the combustion chamber with decreasing temperature contours toward the outer wall up to the ambient temperature. The velocity flow remained constant as the chamber was colored green throughout due to the shielding of the stove with sawdust as insulation. The heat flux generated indicated that a thick layer of 6 cm or more could ensure good insulation, and this could be further reduced by introducing more sawdust. The designed stove has the potential to reduce biomass consumption and emissions when compared to traditional cookstoves. The inclusion of a chimney draught in the fire stove prototype could reduce smoke and increase thermal efficiency. Further studies should focus on minimizing the thickness of the clay-sawdust (first) layer and increasing the thickness of the sawdust layer to reduce the weight of the fire stove.

Reuse of Sawdust in Developing Countries in the Light of Sustainable Development Goals

“…In developing countries, using open flames for cooking consumes more energy than any other end-use service [45]. When compared to upgraded biomass cooking stoves [46], the traditional open-fire (three-stone) stove has a lower efficiency (approximately 15.6%) and greater fuel consumption [47]. The traditional three-stone cooking arrangement exerts enormous demand on natural vegetation.…”

“…Sustainable biomass fuel use and improved cooking stove thermal efficiency can be achieved by using good insulating materials, clean fuel, or adopting innovative designs that facilitate better fuel combustion [49,50]. Improving the combustion chamber design of biomass cooking stoves reduces heat loss through the walls of the stove, resulting in high combustion chamber temperature, improved combustion efficiency, and overall thermal efficiency [46][47][48][49][50][51].…”

“…Both researchers and entrepreneurs have developed various versions and designs of the sawdust stove. In Uganda, Okino et al [46] developed a hybrid stove made of 1:1 mixture of clay and sawdust as an insulator to improve the cooking stove's thermal efficiency. A water boiling test was conducted to assess the new design's performance using indigenous wood fuels commonly found in rural Uganda.…”

Performance characterization of a traditional wood‐fired pizza oven

“…Obviously, such an efficiency is to be regarded as overestimated, since it accounts for the only combustion energy freed during the baking tests and neglects the energy supplied by firewood during the preliminary 6-h prelighting step needed to put the oven in quasi pseudo-steady state conditions. In the circumstances, despite the high quality of baking provided by such equipment, its use results not only in excessive consumption of biomass fuels, leading to natural forest degradation and deforestation, especially in a few areas of Africa (Okino et al, 2021) but also in high indoor levels of air pollutants (i.e., carbon monoxide, polycyclic aromatic hydrocarbons, sulfur dioxide, nitrogen oxide, black carbon, and particulate matter), as observed in several metropolitan areas (Apurva, 2016;Kumar et al, 2016) and in a study dealing with the environmental profile of a few household cooking systems, including firewood ones (Cimini & Moresi, 2022).…”

Development and performance analysis of top lit updraft: natural draft gasifier stoves with various feed stocks

“…An updraft forced gasifier built and manufactured to produce gas at an equivalent ratio of 0.5 using a mixed feedstock of rice husk-sawdust had a thermal efficiency of 17.6 % while using a bluff body B, upper burner type (Susastriawan et al, 2021). When compared to traditional stoves, in a paper by (Okino et al, 2021), has obtained a thermal efficiency of 35.5 AE 2.5% using Senna spectabilis as a feed stock, followed by Eucalyptus grandis 25.7 AE 1.7%, and finally Pinus caribaea 19.0 AE 1.2%.…”