Solar Stirling Engine Generator P12471 2011-2/3 (Sponsor) Dr. Alan Raisanen (Team Guide) Thomas Gamer (ME) David Volzer (ME) Daniel Thering (EE) Tara Dougherty (ME) Problem Statement To design and construct a portable Stirling cycle engine generator that operates using solar energy Project Background Harvesting energy from renewable sources (solar) offers a way to provide power in remote locations using local sources Photovoltaic systems, which convert sunlight directly into electricity, are commonly used because of the direct conversion of energy to power. Radiation can destroy photovoltaic systems Stirling Cycle engines with an electrical generator can be used to focus sunlight and generate electricity. The advantage of this engine type is that it uses a purely mechanical device to convert energy, and is unaffected by radiation Objectives Generator must produce 10 watts at 5 volts of electrical power Must be weatherproof, and able to last 1 year from the date it is set outside Provide first generation design for further development of higher power applications Engine must weigh less than 20 pounds History Invented by Dr. Robert Stirling in 1816, his design followed attempts at making an air engine Three different types of Stirling Engines: Beta, Alpha, and Gamma Engine Design Electrical Design 3-D Model of Completed Engine Completed Engine Engine Test Results Rectification Power Circuit Charging Circuit Electrical Results Heat Tape used as heat source. Note: At time 0, heat tape was at 70 % max power. At time 20, heat tape power was increased to 90 %. At time 35, heat tape power was increased to 99%. At time 55, fan was added to help cool heat sink 12 V R Vin (V) Iin (A) Vout (V) Iout (A) Pin (W) Pout (W) Efficiency 150 15 0.086 11.953 0.079687 1.29 0.952495 73.8368 75 15.02 0.167 11.958 0.15944 2.50834 1.906584 76.00977 12 V and 5 V working together Effciency Expected 0.029 4.993 0.033287 0.435 0.1662 38.20697   0.041 4.983 0.06644 0.61582 0.331071 53.76092 0.164 4.966 0.331067 2.46328 1.644077 66.74341 64 Power (W) at motor shaft 20 at rectifier 16 at USB port 10.68 Summary & Conclusions The Stirling Engine Generator was successfully built and tested, but unfortunately it was unable run on its own. Despite the engine not functioning as a complete system, each subsystem, thermal, mechanical, and electrical, function successfully as designed. Most design objectives are satisfied and the result is a durable, waterproof, stirling engine with the potential to generate electricity. Possible reasons for non-functioning engine: Excessive friction in the seal of the engine Insufficient compression ratio Lack of counterweights or necessary momentum at the crankshaft for continuous motion