energydissipation

Energy dissipation refers to the irreversible loss of usable energy from a system, typically converted into less useful forms such as heat, but also radiated or dissipated as light or sound. It arises from irreversible processes that destroy the ability to extract work from energy transfers, including friction, viscosity, electrical resistance, radiation, and phase changes. In most physical contexts a portion of input energy is transformed into heat, raising the temperature of the system and its surroundings.

In mechanical systems, dissipation occurs through damping forces that convert kinetic energy into heat, reducing vibrations and motion over time. In electrical circuits, resistors dissipate electrical energy as heat, described by P = I^2R. In fluids, viscous dissipation and turbulent cascades convert kinetic energy into thermal energy. Radiative losses, such as emission of photons, also contribute to energy dissipation in various environments. At the microscopic level, dissipation is tied to irreversibility and entropy production in thermodynamics.

From a thermodynamic viewpoint, dissipation reduces the useful work potential of a system and is associated with exergy destruction. In quantum and open-system contexts, energy exchange with the environment leads to dissipation and decoherence, often modeled by non-unitary dynamics.

Quantities used to characterize dissipation include the damping coefficient, the damping ratio, and the quality factor (Q). The dissipation rate is the rate at which energy is irreversibly lost, for example via heat generation P = I^2R in circuits or damping forces in mechanical systems. Engineers manage dissipation to balance stability, efficiency, and thermal limits.