# Heat Flow

## heat flow

[′hēt ‚flō]
(thermodynamics)
Heat thought of as energy flowing from one substance to another; quantitatively, the amount of heat transferred in a unit time. Also known as heat transmission.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Heat Flow

the amount of heat transferred across an isothermal surface in a unit time. Heat flow has the same dimensions as power and is measured in watts (W) or kilocalories per hour (kcal/hr); 1 W = 0.86 kcal/hr.

The amount of heat transferred across an isothermal surface of unit area in a unit time is called the heat flux. It is usually designated

Figure 1. Designs of recuperative heat exchangers: (a) coiled tubular heat exchanger, (b) double-pipe heat exchanger, (c) shell-and-tube heat exchanger, (d) tubular air heater, (e) plate-fin heat exchanger

by q and is measured in W/m2 or kcal/(m2·hr). Heat flux is a vector. The magnitude of any component of this vector is equal to the amount of heat transferred in a unit time across a surface of unit area perpendicular to the direction of the component. In English, the term “heat flux” is sometimes used in the sense of “heat flow.”

## heat transfer

The flow of heat from one body at higher temperature to another body at a lower temperature, until the two temperatures are equal.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Scientists can measure the depth and temperatures at which metamorphic rocks form, and thereby constrain heat flow at different places in Earth's crust.
An experimental plan was developed to measure the heat flow capabilities of various resin percentages and ratios using differential scanning calorimetry (DSC).
There is also a heat-flow probe, which is known as the Heat Flow and Physical Properties Package or HP3.
During the Apollo 15 and 17 missions in 1971 and 1972, astronauts placed Heat Flow Experiment (HFE) monitors a few meters into the lunar surface to measure the temperature of soil undisturbed by the month-long day/night cycle.
Using deuterium for estimating heat flow is safe for the environment and has no visual impact to distract from the park visitors' experience.
"And we're going to go and observe it with our seismometer and with our heat flow probe for the very first time." The launch was originally to have taken place in March 2016, but a delay occurred due to a leak in the suite of seismometers' vacuum container.
[4], two factors pose dangers to photovoltaic systems, namely, temperature and heat flow density.
The influence of temperature fluctuation on the operation of PHP is analyzed by studying the variation of heat flow and heat flux as well as the amplitude and phase of temperature wave.
A An "R" rating or value such as 19, 22 or 30 is the resistance to heat flow the insulation material is capable of maintaining.

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