Electronics & Semiconductors

Finding the exact location of a power fault in minutes

Some of Victoria's worst bushfires have been started by power lines. So, power distribution companies have installed devices that limit the energy flowing to the fault to cut the fire risk. However, in networks equipped with ...

Energy & Green Tech

New approach may help extract more heat from geothermal reservoirs

Geothermal heat offers a promising source of renewable energy with almost zero emissions, but it remains a relatively expensive option to generate electricity. A new technique proposed by Penn State scientists may help prevent ...

Energy & Green Tech

Study finds heat pumps more efficient than gas or oil

As the year 2030 approaches, governments and industry leaders are actively studying ways to meet a European climate law aiming to reduce greenhouse gas emissions by at least 55%. The European Green Deal initiative has set ...

Energy & Green Tech

IEA sees 'beginning of the end' of fossil fuel era

For the first time, world demand for oil, gas and coal is forecast to peak this decade due to the "spectacular" growth of cleaner energy technologies and electric cars, the International Energy Agency's chief said Tuesday.

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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