Thermodynamics and Mechanics Flashcards
Thermodynamics..
the science of heat
Energy
entity of nature that is transferred
between parts of a system in the production of physical change within the
system and usually regarded as the capacity for doing work.
Entropy
Entropy change is
caused by heat transfer, mass flow and irreversible processes
degrading energy from higher to lower order
Three types of systems (in energy)
- open
- Closed
- Isolated
Open energy system
mass and energy exchange occurs
Closed energy system
energy exchange occurs, there is no mass exchange
Isolated system
No energy or mass exchange occurs
First law of thermodynamics
Conservation of energy.
Energy can be moved and transformed but not created and destroyed.
Second law of thermodynamics
Entropy S of an isolated system can never
decrease, tending towards a maximum in an
equilibrium state.
Energy has
work potential.
Quality of energy
is determined by how much you can do with it, low temperature heat has few uses and is therefore considered as low quality.
High quality energy is either direct conversion into work or high temperature heat.
Exergy
maximum potential work that can be extracted from the energy under conditions
Example, exergy of a boiler
strong knowledge
Knowledge that is proven multiple times like air pollution.
It should be verifiable.
Most issues on climate change stem
from uncertainties due to inability to perform experiments.
