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Simple Energy Conversion Technologies
Power ProductionSources & Processes
Overview• Mechanisms for energy conversion, power production
– Direct Combustion– Internal Combustion Engines– Electric Generators
• A word about electric circuits and the power grid– Steam Cycle
• Primary “thermal” power sources– Biomass– Coal– Oil– Natural Gas– Nuclear– Geothermal
• Activity: Build Your Own Model Electric Grid
Direct Combustion
• Probably the earliest form of intentional energy conversion by humans
• Breaking chemical bonds and forming new ones • Combustible material + heat volatile gases + residues• Volatile gases + oxygen heat + H2O + CO2 + CO + C + N• Conversion: chemical heat(thermal) energy• Heat can be used for a variety of purposes:
– Directly heating something (air, water)– Heating a gas expansion work can be performed– Heating a liquid boiling steam spin a turbine or perform work
Internal Combustion Engine (I.C.E.)
Electric Motors & Generators
• At its most basic level:
• Motors electric energy kinetic (rotational) energymagnetic field + current‐carrying conductor = motion!
• Generators kinetic (rotational) energy electric energymagnetic field + conductor (wire) + relative motion = electricity!
Electric generators motors• How does a generator motor work?• Requirements
– 1) current‐carrying conductor (a wire with current flowing)– 2) magnetic field
• Current in a coil creates an electromagnet (via RHR)• Magnetic interaction creates a
torque rotation• When rotor is in horizontal pos’n, rotor
current switches direction polarity of theelectromagnet switches
• When rotor is in horizontal position, no net torque relies on momentum
Electric generators• How does a generator work?• Like a motor but in reverse! • Requirements
– 1) conductor (wire)– 2) magnetic field (electromagnets
or permanent magnets)– 3) relative motion between the
conductor and the magnetic field• Magnetic field induces a voltage
on the coil of wire, causing current to flow (Faraday’s Law)
Electric motors & generators
• Convenient memory techniques:– Left hand rule for motors– “Motors drive on the left in England”
– Right hand rule for generators– Generator right– Thumb is now direction of motion
Electric motors & generators
Electric Motors & Generators
• At its most basic level:
• Motors electric energy kinetic (rotational) energymagnetic field + current‐carrying conductor = motion!
• Generators kinetic (rotational) energy electric energymagnetic field + conductor (wire) + relative motion = electricity!
A word about electric circuits
• Ohm’s Law:V=IR where V=voltage(V), I=current(A), R=resistance (ohms)
• Electrical Power:P=IVP=I2R this is why we use transformers for
long‐distance electric transmission lines
A word about electric circuits
• Series: two loads/sources are wired one‐after‐another – current must flow through both of them
• Parallel: two loads/sources are wired such that current can flow through either of them
Current is same through bothVoltages add together
Voltage is same through bothCurrents add together
A word about the electric power grid
• Basically a giant electric circuit with many interconnected sources and loads
• Three Segments:– Generation– Transmission– Distribution
• Direction of power flow is controlled by the laws of physics
• Analogous to a big system of water pipes– Generators = Water pumps– Electric loads = Water faucets/dishwashers/lawn sprinklers– Electric batteries = Water towers
A word about the electric power grid
• Traditionally, power plants divided into baseload and peaking load
• Other considerations:‐ Ramp‐up and ramp‐down rate ‐ Fuel costs‐ Operating costs‐ Location
Steam Cycle
• Rankine Cycle: – ubiquitous!
• Describes the thermodynamic cycleof converting liquid fluidto steam, performing work, and condensingback to liquid… repeat
Questions?
Matt AldemanSenior Energy Analyst
Center for Renewable EnergyIllinois State [email protected](309) 438‐1440