Solar Stirling Generators
Clean and renewable energy for Glenforest
Bringing Tomorrow's Technology Today
Benefits of Renewable Energy
- Clean, no pollution apart from manufacturing the materials
- Decreases dependence on fossil fuels
- Provides free energy
- Governments offer tax rebates
- Leaves a sustainable land for future generations
Why Stirling Generators at Glenforest?
- Glenforest is not located near a source of water
- The project would require government approval
- It may disrupt the local ecosystem
- Glenforest is not located in a particularly windy area
- The land surrounding Glenforest is not flat and open
- Glenforest does not have the land area to support such a project
Photoelectric Solar Panels
- The initial setup cost is far too expensive for a public school ($20-30K for a residential house)
- The technology is relatively inefficient compared to other options
- Electricity is expensive to store in large quantities when the sun doesn't shine
Solar Stirling Generators
- Glenforest has a flat roof with a large surface area that would be perfect for a solar stirling generator
- Stirling engines operate on heat, not light, which is much cheaper to store
- They are more efficient than solar panels
- Stirling engines operate on a temperature difference, so they will actually be more efficient during winter
- The initial setup cost is cheaper than photoelectric solar panels
- They're very reliable and require little maintenance
- A single dish can produce 25kW, which is enough to power about 10 homes
How Everything Works
What is a Solar Stirling Generator?
It's essentially made up of three basic components:
- A parabolic reflector to concentrate the heat
- A stirling engine to convert heat into motion
- A generator to convert motion into usable electricity
It utilizes a parabolic reflector to focus the Sun's rays onto a stirling engine, which transforms the heat energy into mechanical energy, and a generator coverts the mechanical energy into electrical energy.
How a Parabolic Reflector Works
How a Stirling Engine Works
The hot air expands, pushing the top piston upwards, generating kinetic energy
The hot air moves to the cool end of the cylinder where its pressure drops
The pressure drop allows the cool air to be compressed by the pistons
How Electricity Is Generated
- The flywheel of the stirling engine is connected to the driving axle of the generator
- The rotor, which has several magnets on it, spins
- Electric current is induced in the solenoids according to the Faraday-Lenz laws
- The alternating north and south poles of the spinning magnet produces AC current
- Load can be added or taken off the circuit to adjust the resistance
- The resistance is changed to keep the rotor spinning at a constant rpm to maintain the electricity at 60 hertz
- The electricity is converted to 120 volts via a transformer
- Now the Solar Stirling Generator can be used to power anything that runs off of a wall outlet!
Making Dreams a Reality
Implementing the Solar Stirling Generator
- The size of the dish used - is it better to use a single large dish or an array of smaller ones?
- The location - would the roof be able to support the dish or will it need to be placed in the field?
- Funding - how will the school pay for this project? Will it come from the school board or the city?
- The amount of electricity needed - how much electricity will need to be produced? Will this take into account future needs as well? Will the generator supply all of the school's needs or simply supplement them?
These are all important and practical questions that would need to be solved in order for this project to be feasible. Despite the difficulties, the rewards of a solar stirling generator, if successfully implemented, should repay the costs several times over.