Basic devices of thermodynamics
Below is a list of basic devices in thermodynamics for which you
should know basically what they are and what they do. Remember that
if a device is just a pipe with no moving parts, the power is zero.
Basically just pipes for the substance to flow through:
For the following devices, pressure change of the substance is
essential. So they are never approximated as isobaric. But they are
often approximated as adiabatic (insulated).
- Throttle
- Constriction in a pipe to decrease pressure.
- Valve
- Same as throttle.
- Diffuser
- Convert the kinetic energy of the substance into
pressure by changing cross sectional area.
- Nozzle
- Convert pressure into kinetic energy or measure flow
rate by changing cross sectional area.
Basically just pipes for the substance to flow through:
For the below devices, heat transfer is the primary purpose. So they
are never approximated as adiabatic. But often the pressure changes
accross the device are ignored to first approximation.
- Heat exchanger
- Generic term.
- Boiler
- Heat is used to turn the liquid substance into vapor.
- Evaporator
- Boiler.
- Steam generator
- Boiler.
- Heater
- Generic term.
- Condenser
- Heat is removed from the vapor to make it condense.
- Combustor
- Thermal heat is added to the substance by burning it.
Branching pipes (e.g. Y shaped):
- Mixing chamber
- Two or more streams of substance flow in, to be
combined into a single output stream. Often approximated as isobaric
and/or adiabatic.
Flow devices containing moving components for work out:
- Turbine
- Produces mechanical work from an incoming high-pressure
stream. Often approximated as adiabatic.
- Expander
- Term often used for turbines with nontrivial heat
transfer.
Flow devices containing moving components for work in:
- Compressor
- Turns mechanical work into a pressure increase of the
substance. Often approximated as adiabatic.
- Pump
- Compressor for liquids. Often approximated as adiabatic.
- Fan
- Turns mechanical work into motion of the substance.
- Blower
- Fan.
Composite devices that produce work:
The following device in its simplest form circulates the substance
around.
- Heat engine
- Turns thermal energy into mechanical work. (Note
that your car engine takes in fresh air for each cycle, because it
needs new oxygen to burn the fuel.)
Composite devices that use work to move heat around:
The following devices in their simplest form circulate the substance
around.
- Heat pump
- Uses mechanical work to move heat from cold to hot.
This term is usually used if you are interested in the heat addition
to the hot side, like to your house in winter.
- Refrigerator
- Heat pump for which you are interested in the
removal of heat from the cold side (your milk).
- A/C
- Heat pump for which you are interested in the removal of
heat from the cold side, typically a house or building.