EWB: Smokeless Stove - Assignment Example

1 Design Description This section shall give an overview of the projected EWB smokeless stove design and the solutions that it poses over the existing stove technologies. The design and the manufacturing procedures are described in details with the aid images top help in understanding of this solution. 1.1 Summary of the Design The design of this stove uses a simple approach that is meant to make it easy for assembly thereby reducing the costs involved in its manufacture. Based on the Phillips and ONIL stoves, this technology shall utilize clay slabs that are assembled in the form of rectangles and squares. The typical layout of this design is shown in figure 1 below. Figure 1: Typical EWB smokeless stove design assembly. 1.2 Functional Description There are four major elements of this stove that call for functional description and further clarification. These parts include the combustion chamber, insulation chamber, fuel input opening and the stovetop. 1.2.1 Fuel Input Opening The fuel input opening shall basically be an opening as its names puts it. Agricultural wasted including wood shall be fed through this point. Designed to a size of, this opening is larger than in most of the existing stoves due to the oxidation requirements that are set for this design. This size has been considered since it is an optimal figure between the energy release rate and the required fuel usage efficiency. Therefore, this is the point that majorly determines the sustainability of this stove considering that the energy it uses is nonrenewable. 1.2.2 Combustion Chamber This is the feature that gives room for combustion to take place within the EWB smokeless stove. Fuel shall be placed on gratings that offer access to a consistent airflow thus ensuring that the fuel shall burn completely during the combustion process. Flame efficiency shall be ensured by recirculation of stale smoke in order to avoid oxygen deprivation. Figure 2: Drawing indicating dimensions of vital parts. 1.2.3 Stove Top The stove top capacity is designed to be occupied by two cooking pots at a time. This is enhanced by creating opening that shall allow hoy air and flame to escape a process during which food in the pots is cooked. The first pot, is meant to sit on a direct flame while the second one shall be heat by flame emanating from escaping air. The third opening which can be seen on the left in figure 3 below shall be meant for a chimney for purposes of smoke expulsion. Figure 3: A cross sectional view of the EWB smokeless stove. 1.2.4 Insulation Chamber The insulation chamber is the energy saving mechanism of this stove in that it is designed to reduce thermal conduction that is caused by metallic materials that are paramount to the design of this stove. The main purpose of this stove design is to ensure maximum efficiency from the fuel thus the ash depositing chamber allows more of the escaping heat from the smoke to be conducted to the cooking pot. Figure 4: Exploded view indicating the insulation chamber (purple arrow). 1.3 Manufacturing Procedure 1.3.1 Materials The bill of quantities (BoQ) highlighting all the required materials and their respective prices is indicated below. Although this indicates the materials required for one piece to be successfully fabricated, mass production shall require collective/ bulk procurement of materials. Table 1: Bill of quantities. Section Required Materials Quantity Availability Total Cost (US$) Chimney Galvanized steel pipe 5’ diameter X 4m Local hardware 5.00 Chimney cap Aluminum sheet 0.144m2 Local hardware 1.00 Gratings Cast iron 1.5kg Local hardware 2.50 Stove body Clay 0.0067m3 Local deposits 0.00 Total 8.50 1.3.2 Constructing Molds As the process of molding the main stove body shall require clay molding, it is therefore suggested that wooden pattern be used for ease of construction and adjustment in case of unfavorable results. The figure 5 below shows the basic dimensions that are required for this part to be successfully molded. It is also important to note that other parts that require clay molding shall also utilize the same procedure in order to reach at the final product. Figure 5: Layout of the base mold. 1.3.3 Procedure of Molding the Clay Components Clay meant for the molding the base should be collected from a recommended depth of 400mm in order to avoid the top soil which is definitely saturated with organic content. The clay shall then be passed through filtration screens in order to ensure that all large debris or rocks are eliminated at the earliest opportunity possible. Building sand is then mixed with sand at the ratio of three to one in a briskly manner. Once the mixture becomes smooth, it shall be used to manufacture the stove components accordingly. The procedure of producing the stove components that are made of clay shall be as follows; i. Use wood ash to prevent the clay/ sand mixture from sticking onto the mold. ii. Ensure that clay/ sand mixture is well pressed onto the mold to avoid gapping. iii. After partial drying, cut off the stove top holes i.e. two for pots and one for the chimney. Allow the part to dry completely before withdrawing the mold. iv. Withdraw the part from the mold. v. Bake off or fire the part in order to impart strong mechanical properties. 1.3.4 Constructing the Conical Chimney Cap Since the chimney is to be constructed from thin sheet metal, this procedure will be less tedious as bending it shall not need specialized tools. The procedures are described in figure 6 below which is a step by step process analysis. The first step is to cut a 200mm radius sheet metal with a radial cut to the center. After this, one edge is brought over the other to create an angle of 45˚ and riveted. Three cap support strips of each are cut, bent 20mm from the end and riveted to the cap top. A strip of is then cut and riveted at the end forming a circular ring that is then riveted around the vertical strips fitted to the cone. Figure 6: Layout of procedures involved in manufacturing chimney cap. 1.3.5 Assembly Procedure Taking figure 7 below to be the step by step procedure indication for the installation process, the whole exercise is simple and self-explanatory. The first step shall basically involve setting out the room layout so as the stove shall be at the furthest end of the room. Once the stove position has been determined, the vertical components are put in place while ensuring that the insulation which is half fill of crushed clay and wooden ash is not forgotten prior to placing the stove top. The chimney is the placed in the rightful slot and grating put in its position within the combustion chamber. The stove shall be ready for use once the assembly is counterchecked to ensure nothing was forgotten. Figure7: A step by step layout of the stove assembly. 1.4 Maintenance and Utilization 1.4.1 Utilization Once installed, the stove can be used to the advantage of the owner owing to its improved features and efficiency. Wood to be used in this stove, is split so as to enhance entry into the stove opening and to increase combustion surface area. Fire lit for this kind of stove, needs tending in a bid to maintain high fire efficiencies and temperatures. On depletion of fuel, it shall be necessary to add more for continuity. This shall involve even stacking to allow air flow as opposed to random stacking. During usage, it is advisable to cover a pot hole that is not in use to avoid wastage of fuel due to high air flow. 1.4.2 Cleaning The cleaning process is simple and aids in blockage of air flow channels. This is to be done prior to lighting the fire for the purpose of carrying out cooking processes. During the cleaning process, lids are to be placed at the pot holes to avoid air pollution through ash release to air. Ash resulting from the cleaning process should then be disposed in a wide area to reduce concentration in one zone. The chimney on the other side is to be cleaned periodically i.e. six months to twelve months by scraping the inside using a long stick. 1.4.3 Estimated life span This stove is estimated to have a life span of up to three years after which it shall be scrapped off or broken parts replaced for recycling process. 1.4.4 Fuel Requirements Due to the operational temperatures of this stove, wood and other biomass fuel types are recommended. Wood to be stuffed into the stove shall depend on the food being cooked and the temperatures required. This may also vary from one cook to the other depending on professionalism levels and prowess. 1.4.5 Impacts of EWB Smokeless Stove At 50% efficiency improvement over the preceding technology, the time required for firewood collection shall be reduced thus increasing productive time. Improved health among the populations that are going to use this stove are most likely. This shall therefore increase life expectancy of people within the beneficiary communities. Deforestation and emission impacts shall also be greatly reduced. Read More

Figure 3: A cross sectional view of the EWB smokeless stove. 1.2.4 Insulation Chamber The insulation chamber is the energy saving mechanism of this stove in that it is designed to reduce thermal conduction that is caused by metallic materials that are paramount to the design of this stove. The main purpose of this stove design is to ensure maximum efficiency from the fuel thus the ash depositing chamber allows more of the escaping heat from the smoke to be conducted to the cooking pot. Figure 4: Exploded view indicating the insulation chamber (purple arrow). 1.3 Manufacturing Procedure 1.3.1 Materials The bill of quantities (BoQ) highlighting all the required materials and their respective prices is indicated below.

Although this indicates the materials required for one piece to be successfully fabricated, mass production shall require collective/ bulk procurement of materials. Table 1: Bill of quantities. Section Required Materials Quantity Availability Total Cost (US$) Chimney Galvanized steel pipe 5’ diameter X 4m Local hardware 5.00 Chimney cap Aluminum sheet 0.144m2 Local hardware 1.00 Gratings Cast iron 1.5kg Local hardware 2.50 Stove body Clay 0.0067m3 Local deposits 0.00 Total 8.50 1.3.2 Constructing Molds As the process of molding the main stove body shall require clay molding, it is therefore suggested that wooden pattern be used for ease of construction and adjustment in case of unfavorable results.

The figure 5 below shows the basic dimensions that are required for this part to be successfully molded. It is also important to note that other parts that require clay molding shall also utilize the same procedure in order to reach at the final product. Figure 5: Layout of the base mold. 1.3.3 Procedure of Molding the Clay Components Clay meant for the molding the base should be collected from a recommended depth of 400mm in order to avoid the top soil which is definitely saturated with organic content.

The clay shall then be passed through filtration screens in order to ensure that all large debris or rocks are eliminated at the earliest opportunity possible. Building sand is then mixed with sand at the ratio of three to one in a briskly manner. Once the mixture becomes smooth, it shall be used to manufacture the stove components accordingly. The procedure of producing the stove components that are made of clay shall be as follows; i. Use wood ash to prevent the clay/ sand mixture from sticking onto the mold. ii. Ensure that clay/ sand mixture is well pressed onto the mold to avoid gapping. iii. After partial drying, cut off the stove top holes i.e. two for pots and one for the chimney.

Allow the part to dry completely before withdrawing the mold. iv. Withdraw the part from the mold. v. Bake off or fire the part in order to impart strong mechanical properties. 1.3.4 Constructing the Conical Chimney Cap Since the chimney is to be constructed from thin sheet metal, this procedure will be less tedious as bending it shall not need specialized tools. The procedures are described in figure 6 below which is a step by step process analysis. The first step is to cut a 200mm radius sheet metal with a radial cut to the center.

After this, one edge is brought over the other to create an angle of 45˚ and riveted. Three cap support strips of each are cut, bent 20mm from the end and riveted to the cap top. A strip of is then cut and riveted at the end forming a circular ring that is then riveted around the vertical strips fitted to the cone. Figure 6: Layout of procedures involved in manufacturing chimney cap. 1.3.5 Assembly Procedure Taking figure 7 below to be the step by step procedure indication for the installation process, the whole exercise is simple and self-explanatory.

The first step shall basically involve setting out the room layout so as the stove shall be at the furthest end of the room. Once the stove position has been determined, the vertical components are put in place while ensuring that the insulation which is half fill of crushed clay and wooden ash is not forgotten prior to placing the stove top.

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