Friday, January 20 th Team P12472 : Solar Stirling Generator Room AM – 12 PM

Team P12472 Phil Glasser – Lead Engineer, Electrical Engineer William Tierney – Mechanical Engineer Bryan Abbott – Mechanical Engineer Mike Scionti– Mechanical Engineer Dr. Alan Raisanen – Faculty Guide and Customer

 Overview of the project  Confirm Engineering Specifications and Customer Needs  Review concepts  Propose a design approach and confirm its functionality  Cross-disciplinary review: generate further ideas

 Project Description  Work Breakdown Structure  Project Plan  Customer Needs  Engineering Specifications  Concept Development  Proposed Design  Risk Assessment

 We wish to demonstrate a small portable Stirling cycle electrical generator system that can be used to power small portable USB electronics.  Stirling generators can use any heat source to produce power including geothermal, waste heat and in our case solar energy.  Although mechanically more complex than photovoltaic systems, stirling generator system efficiency can out perform photovoltaic system efficiency.  Our system will require the design of a solar collector component, a stirling engine component, and an electrical generator, power conditioner and power storage component.

The Beta Type Stirling Engine consists of one cylinder containing a displacer piston and a power piston, coupled to a flywheel. The working fluid on the far side of the cylinder is heated by some external heat source and the opposite side is cooled by a heat sink or some method of heat rejection. As the working fluid on the hot side expands, it pushes the power piston towards the cold end of the cylinder. On the cold end the gas contracts, pulling the power piston back towards the hot side. The displacer piston acts as a shuttle, moving hot gas towards the cold side and vice versa. The power piston and displacer piston rods are linked to the flywheel 90 degrees out of phase, producing output power.

Solar Powered Stirling Generator Stirling Engine (Bryan, Mike, Will) Cylinder (Will) Power Piston (Will) Displacer Piston (Bryan) Heat Sink (Mike) Rods and Linkages (Mike) Seals (Bryan) Generator (Phil) Motor Power conditioning Battery Charge Circuit USB output Parabolic Mirror (Will, Bryan, Mike) Mounting structure Mirror attachment place Engine and generator attachment place Base Many Small Mirrors

Power Small Electronics Output electrical power to USB Store electrical power Condition electrical power Generate electrical power Convert solar energy to thermal energy Convert thermal energy to mechanical energy Protect SystemCorrosion resistantWeather proofing

Convert solar energy to thermal energy Collect solar energy Focus sunlight on an object Place the hot side of a Stirling engine in the focal point of the sunlight Mount Stirling engineMount solar collector

Convert thermal energy to mechanical energy Create a temperature difference Heat the working fluid in a Stirling engine Cool the working fluid in a Stirling engine Seal fluid in a chamber Convert linear motion to rotational motion Convert rotational motion to electricity

Design Engine parameters and 3D Cad modeling Design Mirror and mount Electrical design Week 5-8 Refine and tweak designs In depth analysis and seek the aid of professors to look over design Final simulations, artwork, and design parameters Week 8-11

 USB Charger: Stirling generator must output power through a USB port.  Stirling Engine: Generator component must be powered by a heat engine utilizing the stirling cycle.  Solar Power: Stirling engine must obtain its heat energy from the sun.  Self Start: Stirling engine must start autonomously.  Low Maintenance: Stirling generator system must operate for one year, maintenance free.  Inexpensive: Project may not exceed the project budget.  Light Weight: Stirling generator assembly must be relatively portable and need exceed the weight requirement.  Safe: Stirling generator must not cause any damage to people or surroundings when operated.

 Power: Stirling generator must output at least 10 Watts of power when operating.  Voltage: Generator component must provide a nominal voltage of 5 Volts when operating.  Budget: Stirling generator assembly must be within the budget of $500.  Weight: Stirling generator assembly must be within the weight requirement of 20 pounds.  Mean Time Between Failures: Stirling generator system must operate for one year before requiring maintenance.  Weatherproof: Stirling generator must be able to withstand all weather conditions.

Decision Matrices:  Engine Configuration – Alpha, Beta, Gamma, Free Piston, Rotary, Ringborn  Linkage – Standard 90 degree offset, Rhombic Drive  Motor – Brushless DC, Stepper, Handwound Flywheel  Battery – Nickel-Metal Hydride, Rechargeable Alkaline, Lithium Ion, Lead-Acid

We are continuing with the Beta Type Stirling Engine

We are continuing with the 90 Degree Offset Crankshaft

We are continuing with the AC Stepper Motor

We are continuing with the Nickel-Metal Hydride Battery

Parabolic Mirror and Mount Beta Type Stirling Engine Crank Shaft and Gearing Stepper Motor Power Conditioning Battery Charge Circuit USB Output 5V 10W Soft start Mechanism Temp sensor with comparator Stepper Driver Chip Arduino with temp sensor Power FETs

 5 Volt Output, 2 Amps, 10 Watts  Assuming ~60% efficiency of the generator, 18W motor needed  Rectify ac stepper voltage to DC by mixing all the phases through diodes  Linear regulator or buck/boost to desired V for charge circuit and USB output  Drive motor to overcome generator torque