Energy fundamentals Flashcards
Define energy and power and explain their difference.
Energy is the capacity to perform work (Joules). Power is the rate of energy transfer (Watts). E = P × t.
What are the units for measuring energy and power?
Energy: Joules (J), kWh, BTU. Power: Watts (W), kW, MW.
What is the formula for energy efficiency?
η = Useful Output Energy / Input Energy.
Explain the First Law of Thermodynamics.
Energy cannot be created or destroyed, only transformed.
Explain the Second Law of Thermodynamics.
Energy conversion always involves losses, often as heat.
What is the Law of Conservation of Energy?
Energy in a closed system remains constant.
Define kinetic and potential energy.
Kinetic: Energy of motion. Potential: Stored energy.
What is specific heat capacity?
The energy required to raise the temperature of 1 kg of a substance by 1°C.
Explain the concept of power density.
Power output per unit area of an energy source.
What is energy density?
Energy stored per unit volume or mass (e.g., fossil fuels have high energy density).
How is heat transferred in energy systems?
Conduction, convection, radiation.
What is thermal efficiency?
Ratio of useful work output to heat input in a heat engine.
What is the Carnot efficiency limit?
The theoretical maximum efficiency of a heat engine: η = 1 - Tc/Th.
What are primary and secondary energy?
Primary: Raw forms (coal, sunlight). Secondary: Converted forms (electricity).
Define base load and peak load power.
Base load: Constant demand. Peak load: High demand periods.
What is energy conversion efficiency?
Ratio of useful energy output to input energy.
Define capacity factor in power generation.
Ratio of actual output to maximum possible output over time.
What is a heat rate in power plants?
The energy input required to produce 1 kWh of electricity.
What is mechanical energy?
The sum of kinetic and potential energy.
What is exergy?
The usable portion of energy after accounting for losses.
How do you calculate electrical power?
P = VI (Power = Voltage × Current).
What is power factor in AC systems?
Ratio of real power to apparent power in AC systems.
What is the principle of energy balance in a closed system?
Energy entering the system equals energy leaving the system plus stored energy.
Define thermal conductivity.
The ability of a material to conduct heat.
What is entropy?
A measure of energy disorder or energy not available for work.
