temperature of housing 17 Maximum temperature of hot side of TEG 9 9,16 °C 275 300 Importance Scale: 1 – Low Importance, 3 – Moderate Importance, 9 – High Importance System Level Design Subsystem Interfaces Energy Flow Project Interfaces 11462 INTERFACE STOVE INTERFACE DEFINING FEATURES CRITICAL SPECS
INTERFACE 1 Heat Rod Fire Heat rod will take energy from fire. Heat rod will penetrate walls. Diameter of rod Fire Temperature INTERFACE 2 Duct Coupling Stove Housing Ducting will provide air flow at a given pressure. Duct will provide air into stove through square shaped hole in the outer wall of stove. Dimensions of ducting Location of entrance Flow Rate Pressure Drop INTERFACE 3 Device Attachment Housing The fan system will attach to the outside wall of the Location of device on exterior of stove Method of attachment Architecture of exterior of stove
Risk Assessment ID Risk Item Effect Likelihood Severity Importance Action to Minimize Risk Owner Risks Involved with Thermoelectric Generator 1 TEG overheat Total System Failure Inadequate heat transfer control 2 3 6 In-depth heat transfer including FEM, testing Jeff 2 Insufficient TEG cooling Unsustainable operation Heating up of TEG cold side 2 2 4 In-depth heat transfer including FEM, testing Brad 3 Unable to maintain max TEG efficiency TEG capabilities not optimized Transient effect on components 2 2 4 In depth analysis( TEG I-V characteristics), Testing Tom/Jeff 4 Inability to accurately TEG Optimal power not being used TEG changes as heat is consistently applied 2 2 4 In depth analysis(TEG I-V characteristics) / Testing Jeff/Tom 5 TEG power producing capacity too small Underpowered system Unable to meet required ∆T or TEG incapable of producing required power 1 3 3 Design with minimal consumption / Design to required specs using amplifiers. Jeff/Tom
ID Risk Item Effect Cause Likelihood Severity Importance Action to Minimize Risk Owner Risks Involved with /Charging System 6 failure/destruction Total system failure Poor battery sizing, excessive heat 2 3 6 Proper battery sizing, means to bypass battery Fahad 7 Electrical components fail/overheat System Failure Excessive heating to components. Complicated design. 2 3 6 Keep components insulated and distant from heat. Simplify design to incorporate as little components as possible. 8 Faulty design of control system System failure Components not sized properly or break due to overheating from fire 2 3 6 Design system in insulated location / In depth analysis of design requirements. Tom/Fahad 9 doesn’t charge Fan won't start immediately. Aux. device won't charge. Poor battery sizing, too little current to battery, battery malfunction 2 2 4 Size the battery more accurately through better testing. Allow TEG to charge aux device. Fahad 10 is drained Fan won't immediately. Aux. device won't charge. too small and doesn't hold charge well. Excessive user interaction 3 1 3 Test battery many times to ensure charge is held. Incorporate an LED warning system to tell user that battery is drained. Fahad ID Risk Item Effect Likelihood Severity Importance Action to Minimize Risk Risks Involved with Fan 11 Fan produces insufficient pressure drop Forced air unable to reach fire Poor modeling/testing of stove 2 2 4 Increase flow rate, Provide more power to fan. Jared 12 Fan melts Loss of airflow, main system failure Fan placed too close to stove, stove heat estimated 1 3 3 Testing to correctly estimate temperatures at proposed location Jared 13 Fan requires too much power Fan will drain power from battery, overdraw TE Poor fan selection or design, fan failure 1 2 2 Apply margin on battery size or fan sizing Jared
ID Risk Item Effect Cause Likelihood Severity Importance Action to Minimize Risk Owner Involved with Conduction Rod 14 Heat conduction rod melting Possible loss of heat transfer to thermoelectric Inadequate analysis of stove operating temperatures and material properties 2 3 6 Analyze stove operating temperatures. Carefully select material to suit Brad 15 Heat conduction rod conducts too much/not enough heat Possible overheating of thermoelectric/ Insufficient generation Inadequate heat transfer analysis 2 3 6 Complete analysis of heat transfer characteristics of rod/block. Average stove operating temperatures taken into consideration Brad 16 Rod takes too long to heat up Improper system function. Fan may not operate at Inadequate transient heat transfer analysis. Inadequate understanding of transient temperatures in combustion chamber. 2 2 4 Test stove to get understanding of transient temperatures. Model transient temperature characteristics of rod. Brad