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Peltier Solar Concentrator. By: Michael Forrest Kyle Fifield Evan White. The Problem. To demonstrate that a thermoelectric device can efficiently converted solar energy into electricity. The goal is to create a system at least as efficient as PV panels. The Solution.
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Peltier Solar Concentrator By: Michael Forrest Kyle Fifield Evan White
The Problem • To demonstrate that a thermoelectric device can efficiently converted solar energy into electricity. • The goal is to create a system at least as efficient as PV panels.
The Solution • Satellite Dish Solar Concentrator • Hi-Z HZ-20 Thermoelectric Module • Aluminum Collector Plate • Time-Based Solar Coordinate Tracking • Battery Storage • LCD User Interface
What is a Thermoelectric Device? • In a thermoelectric device, a voltage is created when a difference in temperature exists across the device. • By heating one side of the device and sinking heat from the other side, an electric voltage will be created.
Sun System Diagram Solar Rays Solar Concentrator Motor Controller Motor Controller Horizontal Tilt Microcontroller Thermoelectric Device Collector Plate Dc/Dc Step-up Azimuth Rotation
Solar Tracking Subsystem • Real-Time Clock (DS1307) • User interface with Buttons and LCD Screen • Microcontroller (Coldfire) • Motor Controller (H-Bridge) • DC Motor with Potentiometer (Azimuth) • Linear Actuator with Accelerometer (Altitude)
H-Bridge Circuit H-Bridge Circuit Motor Linear Actuator Coldfire Microcontroller Time of Day Sensor Potentiometer Accelerometer LCD Display and User Interface Solar Tracking System Diagram
Solar Tracking Positioning Equations Altitude Angle = Azimuth Angle = • Inputs • Date and Time • Longitude and Latitude
Sun System Diagram Solar Rays Solar Concentrator Motor Controller Motor Controller Horizontal Tilt Microcontroller Thermoelectric Device Collector Plate Azimuth Rotation
Elevation Tracking Highest Sun Elevation (70⁰) Lowest Sun Elevation (12⁰) 70⁰ 12⁰ 6 inch Stroke Solar Concentrator Linear Actuator
Thermoelectric Collector Plate Mount • Purpose: • Maximize Performance and Power Efficiency of HZ-20. • HZ-20 Module Around 5% Efficient. • Design Aspects: • Minimum Load of 200 psi on HZ-20. • Thermal Expansion of HZ-20. • Efficient Heat Transfer • Keeping Cold Side of HZ-20 Cool.
Subsystem Diagram of Thermoelectric Mount Belleville Springs Heat Sink Cool Side Hot Side Thermoelectric Device Collector Plate Solar Rays
Loading on HZ-20 Module • Ensures Module Remains in Compression to Maximize Heat Transfer. • Solution: • Belleville Springs. • Apply Large Amount of Force in Compact Area. • Also Allows for Thermal Expansion.
Load and Thermal Expansion Calculations Thermoelectric Device Dimensions Force Calculation Load Required: 200 psi* Thermal Expansion Calculation Where: = Change in Length = Thermal Expansion* = Change in Temp. = Initial length *Information Given from Specification Sheets
Efficient Heat Transfer • Thermal Grease: • Ensures Efficient Heat Transfer from Mount to HZ-20 and HZ-20 to Heat Sink. • Overhang of 0.5 Inches and 0.25 Inches of Thickness on Mount: • Ensures Uniform Heating on HZ-20.
Thermal Resistance Diagram TBar Temperature of Bar TH Temperature of Hot Side Thermal Resistance of Thermal Adhesive Thermal Resistance of Thermoelectric Junction ∆T TC Temperature of Cold Side THS Temperature of Heat Sink Thermal Resistance of Heat Sink TA Temperature of Ambient
Energy Gain B AreaEclipes= πAB A Area of Dish = 0.303077m² Area of FP = 0.003488m² Energy Gain = Area of Dish / Area of Focal Point Energy Gain = 87
Efficiency Strategies 85% Reflectivity Dish Covered with Reflective Tape Absorbs 90% of light Aluminum Collector Plate Painted Black
Efficiency Diagram Sunlight to Usable Energy Sun Reflective Tape 85% Efficient 5% Heat to Electricity Efficiency 90% Absorption Efficiency Wasted Heat Step-up Dc/Dc Converter 95% Efficient 12v Lead Acid Total Efficiency = 3.34% 92% Storage Efficiency
Power Diagram Sun 8 mins to heat up Collector Concentrator 1000W/m² Heat Sink Thermoelectric Device 303.1W 232W 220W 3V, 6.67A, 20W Dc/Dc Step-up 12V, 1.6A, 19W
Dc/Dc Step-up Convertor 1.8V to 5.5V
User Interface • Displays: • Time of Day • Date • Azimuth Angle • Altitude Angle • Pushbuttons: • Up/Down Selection Arrows • Menu Option • Enter Button
Areas of Responsibility Evan Kyle Mike Solid Modeling / Thermoelectric Device Mounting / Altitude Tracking Mechanical Energy & Power Calculations/ Thermal Design/ Dc-Dc Step-Up Circuit/ Azimuth Tracking Mechanical / Base Design Solar Tracking Programming/ Real Time Clock Programming/ Angle Calculations/ LCD User Interface Programming and Design