Design Project II: Shell® Cooking System

1. Design Project II: Shell® Cooking System Prepared by: Luke Safko, Kate Bossar, Andrew Neal, and Hannah ErtzgardEngineering Design 100 Selecting the Final Design EMS Model for Final Design Background & Problem Statement Benefits of Design Currently, most Kenyan households use biomass briquettes made from hay, wood and waste products, which can be burned for fuel. A single briquette costs roughly 3 US cents, according to bioenergylists.org, and a typical family would burn through over 30 cents worth of briquettes per day. For a family which makes only $2/day, 30 cents is a large portion of their daily income. Additionally, the burning of the briquettes gives off CO2, which can be harmful in high doses and is also a greenhouse gas. The solar cooker not only eliminates the need to buy biomass briquettes, and therefore saves the family money, but also eliminates all emissions, creating a safer environment. • Many people in underdeveloped or developing countries have an income of $2 per day or less. While they may not earn a lot of money, they still need an inexpensive way to cook food. There are two models of cook stoves currently used in Kenya specifically: the Jiko and the Envirofit. They are around $20, which is an expensive price for Kenyan’s salaries of about $2 a day. The Jiko and Envirofit both run on biomass, so they have to pay for fuel. They also create fuel emissions which is one thing we are trying to improve with our cooker. • In order to do this, a problem statement was formulated for this project. It reads: • In order to provide people in developing nations, like Kenya, with a cooking stove, a design needs to be created that is inexpensive, efficient at cooking the food, and culturally appropriate. It should also aim to reduce the emissions created by burning biomass fuel and stimulate the local economy in the hopes that it becomes self-sustaining. Lower Emissions Fuel Source Cost Efficient Concepts compared based on: Concept Selection Process Final Design: Solar Cooker In order to select the final design, we compared our ten concepts based on certain criteria, three of which were the amount of emissions created, how much it cost, and the fuel source used. Using concept scoring, we chose the one concept that best met those criteria and continued with it. In this case, the best concept was the solar cooker with four angled sides with reflective material that would direct the energy from the sunlight to the rocks in the bottom of the cooker. The problems as you can see on the EMS model are the cost of the fuel and production materials.  The major problem with the cooker is the emissions though.  As you can see by the solar cooker’s EMS model the only problems occur with cost.  These costs are actually lower than the cost of the current cookers they have.  The sun lets off no emissions and there is only a cost of a fuel source on days without sunshine.  The EMS also describes the two options the solar cooker has.  It can either heat rocks that become the energy source to cook the food, or it can directly cook the food in the solar cooker. Model of Final Design Concept Generation In order to address the problem presented by this project, the team generated preliminary concepts that would eventually be evaluated to determine the final design. A sampling of the concepts are described or pictured below: How Final Design Solves Problem Cost Analysis The final design implements solar power stored within a material that can be transferred into a household’s already existing cooker in place of biomass fuel. The solar cooker will be placed outside to heat the material (a stone, brick, etc.) and will be ready for use when needed. By simply removing the cooker’s reflective panels, the chef can use the built-in handles to transport the heated material to the stove of their choice. This concept reduces cost by eliminating the need to purchase biomass fuels from local companies or foraging for grasses and branches. Additionally, it eliminates all emissions, keeping the home smoke and pollutant free. This concept involves having a solar cooker outside the house and having a chute that would take the heated stones from the solar cooker to the cook stove inside the house where the food would be cooked. Description of Model We came up with a final design that solved the problems we were looking to solve initially.  Our solution combined a low cost system, a free fuel source, and the use of an existing cooker.  We accomplished this task using solar power.  The aluminum flaps of our design reflect the sun’s rays onto rocks.  These rocks will take in the solar energy for the sun and become very hot.  Once the rocks are hot, the aluminum flaps can detach from the cooker.  The bottom of the cooker is made out of a stone that holds in heat well.  This stone is the proper size so that it can fit into the current cooker.  The hot rocks and stone base will be the new energy source for the families’ current cooker (Envirofit or Jiko).  The handles of the stone are also flame resistant and can withstand heat so they make a good gripping surface.  The solar cooker will also have the ability to cook food without the current cooker if the family would like to use it in that respect.  Our solution does depend on the sun so when there is no sun the families’ would have to cook from their current stoves.  Our solution has no emissions, no fuel cost, and is cost efficient. Another one of our concepts was another solar cooker that had four angled sides with reflective material attached to them. The reflective sides would transfer the solar energy from the sun to stones in the bottom in the bottom portion of the cooker. References www.googlepatents.com www.edp.psu.edu/design_projects/edsgn100/fa09/index.html https://www.cia.gov/library/publications/the-world-factbook/ http://www.envirofit.org/ http://www.infoplease.com/ipa/A0107678.html One of our concepts was an emission- controlling cook stove. The bottom of the stove is where the food would be cooked and the emissions would be collected and expelled by the dual chimney system.