Lecture

Definition of Energy

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

HUM-123(b): Global issues: energy B

Le cours abordera les grandes problématiques technologiques et socio-économiques liées à la transition énergétique, ainsi que les perspectives et barrières à l'établissement d'un système énergétique durable. ...

Description

This lecture covers the definition of energy as the character of a material system capable of producing work, different forms of energy such as nuclear, chemical, thermal, and kinetic, energy units like calorie and joule, energy conversion, energy density, and power units.

Instructors (2)

Tuong-Van Nguyen

Teaching & PhD Courses Energy conversion and renewable energy ME-409 This course presents an overview of (i) the current energy system and uses (ii) the main principles of conventional and renewable energy technologies and (iii) the most important parameters that define their efficiency, costs and environmental impacts. The Energy Transition : challenges and opportunities HUM-293 This course explores the energy transition from a system based on fossil fuels to a model based o

Selin Yilmaz

Teaching & PhD Past EPFL PhD Students as codirector Matteo Barsanti Courses The Energy Transition : challenges and opportunities HUM-293 This course explores the energy transition from a system based on fossil fuels to a model based on decarbonised energy sources, sobriety and efficiency, and highlights the main technological, socio-economic and geopolitical issues involved.

Official source

Related concepts (32)

Energy density

In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or . Often only the useful or extractable energy is measured, which is to say that inaccessible energy (such as rest mass energy) is ignored. In cosmological and other general relativistic contexts, however, the energy densities considered are those that correspond to the elements of the stress-energy tensor and therefore do include mass energy as well as energy densities associated with pressure.

Energy

In physics, energy () 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 and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).

Power density

Power density is the amount of power (time rate of energy transfer) per unit volume. In energy transformers including batteries, fuel cells, motors, power supply units etc., power density refers to a volume, where it is often called volume power density, expressed as W/m3. In reciprocating internal combustion engines, power density (power per swept volume or brake horsepower per cubic centimeter) is an important metric, based on the internal capacity of the engine, not its external size.

Primary energy

Primary energy (PE) is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw fuels and other forms of energy, including waste, received as input to a system. Primary energy can be non-renewable or renewable. Primary energy is used in energy statistics in the compilation of energy balances, as well as in the field of energetics. In energetics, a primary energy source (PES) refers to the energy forms required by the energy sector to generate the supply of energy carriers used by human society.

Ocean thermal energy conversion

Ocean Thermal Energy Conversion (OTEC) uses the ocean thermal gradient between cooler deep and warmer shallow or surface seawaters to run a heat engine and produce useful work, usually in the form of electricity. OTEC can operate with a very high capacity factor and so can operate in base load mode. The denser cold water masses, formed by ocean surface water interaction with cold atmosphere in quite specific areas of the North Atlantic and the Southern Ocean, sink into the deep sea basins and spread in entire deep ocean by the thermohaline circulation.

Related lectures (64)

Carrier Scattering, Generation, Recombination

Explores carrier scattering, generation, and recombination in nanoscale energy systems.

Conservation of Energy: Pendulum Example

Explores the conservation of energy using a simple pendulum example and discusses various forms of energy.

Renewable Energies: Technologies and Transition

Explores renewable energy technologies, transition dynamics, and storage solutions for a sustainable future.

Conservation of Energy

Discusses the conservation of energy and different forms of energy in various systems.

Energy Systems Overview