Basics and Some Theory of AnThermGraphic Representation of Heat FlowSince the heat flow pattern of a thermal bridge is characteristically more complex than the single-direction flow through a planar component, graphic illustrations of bridge flow patterns can provide critical information at a glance. | heat flow diagram | One method of visualising heat flow is to delineate the direction of flow (vector) through the building component with lines drawn at prescribed intervals. The area bounded by two lines in the diagram represents a heat quantity defined by the interval (e.g. given 10 intervals, the heat flow between two lines corresponds to 10% of the total heat flow in one direction through the surface of a given space). The denser the lines in a region of such a diagram, the more heat flows through this region. Thus local peaks of heat loss (and predictably cold surface points) are easily discernible. Due to the two-dimensionality of graphic illustrations, however, three-dimensional heat flow patterns cannot be meaningfully rendered with such a diagram. Therefore the three-dimensional rendering provides one streamline through the arbitrary chosen point.
| | isotherms | The second common method of heat flow representation is to render the temperature distribution in a component with isotherms, i.e. by delineating lines of the same temperature at defined intervals. Isotherms lie normal to the direction of heat flow, thus providing an "inverted" rendering of the heat flow pattern (denser isotherms correspond to regions of increased heat flow). Since isotherms represent a two-dimensional section through a temperature distribution rather than vectors directly, the isotherm method is also suited for (partial) rendering of three-dimensional heat flow situations. |
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