Energiestransport

Energiestransport describes the processes by which energy moves from one location to another within materials, systems, or between systems. It encompasses thermal, electrical, and mechanical energy transfer and is fundamental to thermodynamics, materials science, and engineering.

Thermal energy transport occurs through conduction, convection, and radiation. Conduction transfers energy by molecular interactions and electrons, described at the macroscopic level by Fourier's law and at the microscopic level by phonons and electrons. Convection involves bulk fluid motion driven by temperature differences, and radiation transfers energy via electromagnetic waves, important in vacuum or at high temperatures; the Stefan-Boltzmann law governs radiative exchange.

Electrical energy transport carries energy by electric currents and electromagnetic waves. In conductors, power is transported as P = VI, with resistive losses, while in free space energy propagates as electromagnetic radiation described by the Poynting vector. Long-distance transmission uses high-voltage lines and cables, with insulation and regulation limiting losses.

Mechanical energy transport includes waves and momentum transfer, such as acoustic waves and surface waves, and, in solids, energy carried by lattice vibrations (phonons).

Theoretical descriptions include the energy balance and the heat equation for thermal transport; in electromagnetism, Maxwell's equations with the Poynting vector. At micro- and nano-scales, the Boltzmann transport equation and quantum models describe carriers such as phonons and electrons.

Applications span thermal management in buildings and industry, heat exchangers, district heating, and power distribution networks. Understanding energy transport is essential for efficiency, reduced losses, and the integration of renewable energy and advanced materials.