Power density is the amount of
power
Power most often refers to:
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power
* Power (social and political), the ability to influence people or events
** Abusive power
Power may a ...
(time rate of
energy transfer
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat ...
) per unit
volume
Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). Th ...
.
In
energy transformers including
batteries,
fuel cells, motors,
power supply
A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a ...
units etc., power density refers to a volume, where it is often called volume power density, expressed as W/m
3.
In
reciprocating internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal c ...
s, power density (power per
swept volume
Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. It is commonly used as an expression of an engine's size, and by extension as a loose indicator of the ...
or
brake horsepower per cubic centimeter {{Unreferenced, date=May 2019, bot=noref (GreenC bot)
Brake horsepower per cubic centimeter or (bhp/cc) is a figure of merit that is used to indicate the ' state of tune' of an internal combustion engine. It is defined as the ratio of the engine's n ...
) is an important metric, based on the ''internal'' capacity of the engine, not its external size.
Examples
See also
*
Surface power density
In physics and engineering, surface power density is power per unit area.
Applications
* The intensity of electromagnetic radiation can be expressed in W/m2. An example of such a quantity is the solar constant.
* Wind turbines are often compared ...
, energy per unit of area
*
Energy density, energy per unit volume
*
Specific energy
Specific energy or massic energy is energy per unit mass. It is also sometimes called gravimetric energy density, which is not to be confused with energy density, which is defined as energy per unit volume. It is used to quantify, for example, sto ...
, energy per unit mass
*
Power-to-weight ratio/specific power, power per unit mass
**
Specific absorption rate Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field. It can also refer to absorption of other forms of energy by tissue, inc ...
(SAR)
References
Power (physics)
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