Power density

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Power density
SI unit W/m3
In SI base units kg·m−1s−3
Derivations from
other quantities
P/V

Power density (or volume power density or volume specific power) is the amount of power (time rate of energy transfer) per unit volume.

In energy transformers including batteries, fuel cells, motors, etc., and also power supply units or similar, power density refers to a volume. It is then also called volume power density, which is expressed as W/m3.

Volume power density is sometimes an important consideration where space is constrained.

In reciprocating internal combustion engines, power density—power per swept volume or brake horsepower per cubic centimeter —is an important metric. This is based on the internal capacity of the engine, not its external size.

Power densities of common materials[edit]

Storage material Energy type Specific power (W/kg) Power density (W/m3)
Hydrogen (in star) Stellar fusion 0.00184 276.5
Plutonium Alpha decay 1.94 38,360

See also[edit]

References[edit]