Energy & Green Tech

How to have an all-renewable electric grid

The main solution to climate change is well known—stop burning fossil fuels. How to do this is more complicated, but as a scholar who does energy modeling, I and others see the outlines of a post-fossil-fuel future: We ...

Engineering

How roads can help cool sizzling cities

Special permeable concrete pavement can help reduce the "urban heat island effect" that causes cities to sizzle in the summer, according to a Rutgers-led team of engineers.

Engineering

AI-designed heat pumps consume less energy

In Switzerland, 50 to 60 percent of new homes are equipped with heat pumps. These systems draw in thermal energy from the surrounding environment—such as from the ground, air, or a nearby lake or river—and turn it into ...

Energy & Green Tech

Pioneering 3-D printed device sets new record for efficiency

A new 3-D printed thermoelectric device, which converts heat into electric power with an efficiency factor over 50% higher than the previous best for printed materials—and is cheap to produce in bulk—has been manufactured ...

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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