Energy & Green Tech

Batteries, community spirit help California fight heat wave

Dire predictions of blackouts in California during a fearsome heat wave this month never came to pass, with technology—and a dose of community spirit—helping the creaking grid through its most testing period ever.

Energy & Green Tech

How does this professor's garden grow? On a Denver rooftop

Colorado State University professor Jennifer Bousselot is growing a garden on top of a building in Denver as part of her ongoing research into "green roofs" and her efforts to educate the public about their many benefits.

Energy & Green Tech

A self-learning algorithm that helps save heating energy

A thermostat that predictively controls the indoor climate and thereby improves energy efficiency and comfort—Empa researchers Felix Bünning and Benjamin Huber came up with this idea while working in Empa's Urban Energy ...

Energy & Green Tech

Californians told not to charge EVs as grid struggles in heat wave

Californians were told Wednesday not to charge their electric vehicles during peak hours, just days after the state said it would stop selling gas-powered cars, as the aging electricity grid struggles with a fearsome heatwave.

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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