05-10-2012, 05:32 PM
Staircase Power Harvesting
Staircase Power.doc (Size: 58 KB / Downloads: 73)
Introduction
Energy has always been an issue for sustainability. The coal reserve, which is the main fossil fuel to generate electrical power, is estimated to last only for about 200 years more. In regarding this problem, all sorts of sustainable energy sources like solar, wind and hydro power emerge. We would like to investigate an alternative energy source: human power. We would like to convert the kinetic energy of people walking stairs into electricity.
Objective
Think about the forces you exert when you are walking down the stairs. The staircase power harvesting system intends to turn this energy that was long gone originally into electrical power using a generator. The system will be able to use gears and flywheels to rotate the generator once a staircase is stepped on. The electricity that is generated will be able to be stored and extract anytime. In addition we will be able to monitor and control the amount of electricity generated.
Block Description
Mechanical Movement
• This part mainly involves the staircase itself and the gears inside the staircase that are used to rotate the generator. The staircase has to be specially designed that can achieve a small displacement when being stepped on. The gears ratio and flywheel are optimized to get the maximum possible power out by driving the micro-generator. Alternatively, we can use a spring action with magnets and coils triggered by the staircase action to generate electricity.
Micro-generator
• The generator is the main component to convert mechanical movement into electricity. It works by induction, which means that when a conductor moves through the magnetic field, electricity is generated and stored in the next stage.
Storage Capacitor
• At the end of the line is the storage capacitor which explains itself very much. Electricity generated by the micro-generator can be stored by charging up the capacitor, which can be stored for a period of time and extract anytime.
Sensors
• Sensors are needed to monitor the speed of the gears and flywheel of the mechanical movement in order to avoid wear and tear and to ensure proper engagement of the gears.
Digital Controller
• Information from the sensors is processed here and feedback control is executed under certain conditions such as the rotation speed of the flywheel. It will control the engaging and disengaging of the gears to control the speed to avoid overheating of the circuit.
Performance Requirements
• Be able to generate about 1W of power for each step of staircase
• Be able to store significant power that can be used for basic lighting for at least one day
• People should not spend too much energy in order to activate the system
• Be able to fit into small compartments like under the stairs
Verification
Testing Procedures
To ensure proper operation that meets the performance requirement, we will:
• determine the voltage the micro-generator can generate from various rotation speeds.
o This can be done by using a motor to drive the generator and using a multimeter to measure the voltage
o At the same time we will need to use sensors to determine the rotation speed of our gears and flywheel and adjust them in order to obtain optimum speed
• determine the capacitance and number of capacitors we will use for the storage.
o An oscilloscope can be used to see how long does average traffic charges up different capacitors
• monitor the temperature of the circuit to set the speed limit of the flywheel
o We can use a temperature sensor and input the data to the microprocessor as well, then we can use the data to control the engagement of the gears