Engineering

A pocket cooling device based on a cascade mechanism

Recent technological advances have enabled the development of increasingly compact and flexible devices. This includes wearable or portable technology, such as smart watches, earphones or other smart accessories, which can ...

Energy & Green Tech

Study measures Switzerland's potential geothermal heating capacity

An EPFL Ph.D. student has calculated the maximum amount of geothermal energy that could theoretically be extracted using ground-source heat pumps in the Cantons of Vaud and Geneva. In a study combining data on the area available ...

Energy & Green Tech

Making a case for organic Rankine cycles in waste heat recovery

A team from City, University of London's Department of Engineering believes that a new approach to generating energy through waste heat could yield important insights into delivering environmentally-friendly power.

Energy & Green Tech

Talc improves pipe performance in geothermal heat pump systems

Geothermal energy is an energy source of increasing importance. In the pursuit of energy efficiency to achieve set climate goals, it is important to get to understand the technical challenges in detail. The plastic pipes ...

Business

Airbnb requires hosts to commit to enhanced cleaning

Airbnb said Thursday it will require hosts to comply with enhanced cleaning procedures as part of its effort to reassure guests and local officials during the coronavirus pandemic.

page 1 from 12

Heat

In physics and thermodynamics, heat is the process of energy transfer from one body or system to another due to a difference in temperature. In thermodynamics, the quantity TdS is used as a representative measure of the (inexact) heat differential δQ, which is the absolute temperature of an object multiplied by the differential quantity of a system's entropy measured at the boundary of the object.

A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature. Heat is also loosely referred to as thermal energy, although many definitions require this thermal energy to actually be in the process of movement between one body and another to be technically called heat (otherwise, many sources prefer to continue to refer to the static quantity as "thermal energy"). Heat is also known as "Energy".

Energy transfer by heat can occur between objects by radiation, conduction and convection. Temperature is used as a measure of the internal energy or enthalpy, that is the level of elementary motion giving rise to heat transfer. Energy can only be transferred by heat between objects - or areas within an object - with different temperatures (as given by the zeroth law of thermodynamics). This transfer happens spontaneously only in the direction of the colder body (as per the second law of thermodynamics). The transfer of energy by heat from one object to another object with an equal or higher temperature can happen only with the aid of a heat pump, which does work.

This text uses material from Wikipedia, licensed under CC BY-SA