Overall heat transfer coefficient
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Devices such as heat exchangers and air coolers have a total heat transfer coefficient. But what exactly is this total heat transfer coefficient? Was it calculated? Or are it the inherent properties of the equipment and materials? Could it be explained in very simple terms? Baidu states that the heat transfer coefficient was previously referred to as the overall heat transfer coefficient. **The current standard specifications uniformly refer to it as the heat transfer coefficient. The heat transfer coefficient K value refers to the amount of heat transferred per unit area per unit time under stable heat transfer conditions, when there is a temperature difference of 1 degree (K or °C) between the air on either side of the building envelope. Its unit is watts per square meter per degree (W/㎡·K; here, K can be replaced by °C). This value reflects the intensity of the heat transfer process; it depends not only on the material used but also on the specific conditions of the process. .
The overall heat transfer coefficient is represented by K in the formula Q = KAΔt, where Q represents the heat transfer rate, in watts； K----total heat transfer coefficient, W/(m2·K) ； A----Heat transfer area, m2 ； △t----temperature difference, K. K can be calculated or obtained through actual measurements. The factors that affect K include the type of medium, the material of the heat exchange surface, its thickness, and fouling; these values can change