# 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.

## 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.
References in periodicals archive ?
The latent heat flow associated with the process of condensation shows minimum values of -90 W [m.
The DSC sensor measures the heat flow of a sample and the reference side separately, so it does not require a homogeneous sensor temperature.
The third element, the insulator, consists of a larger-pored material that wicks liquid upward while resisting heat flow downward.
K-12 students can slip this portable data logging device into a Tablet PC's Compact Flash expansion slot to capture and analyze science data such as heart rate, heat flow, temperature and voltage.
They also account for the effect of insulated or exothermic sleeves, which increase the modulus of a riser by blocking heat flow from the riser surface into the mold.
Transformation of Fe-Ti gabbro to coronite, eclogite, and amphibolite in the Baie du Nord segment, Manicouagan Imbricate zone, eastern Grenville province: evidence for high heat flow in the lower crust during orogenesis
Knowing the length of the heat flow path, the thermal gradient and the perpendicular area, as shown in Figure 4, makes it possible to determine the thermal resistance [theta].
Comments on efficient air and heat flow, and the use of pyrometric cones is of value in this worthwhile video.
Whereas heat flow from point to point depended on the temperatures of the two points and the heat conductivity of the material between, so electric flow from point to point might depend on the electrical potential of the two points and on the electrical conductivity of the material between.
The vertical insulation inhibits heat flow from the floor slab to the ground surface outside the house; it directs heat into the ground underneath the foundation.
The latter results in a high transferred heat flow as well as the heat efficiency.
Thermal resistance is measured by R-value which represents the ability of a product to resist heat flow, the primary function of insulation.

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