A beginner has a question regarding the heat transfer area of heat exchangers
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The calculated heat transfer area of the heat exchanger is often 30% larger than the estimated value. Why is there such inaccuracy? Will the heat exchanger produced as a result meet the production requirements? (For example, can a water cooler accurately reduce the temperature of a hot fluid from one level to another?) ? ）
The heat exchanger produced can meet the production requirements at first, but after scaling occurs after a few days, it can no longer meet these requirements; if cooling is needed, the desired temperature cannot be achieved. This post was last edited by sus321 on 2009-4-14 15:34]
Sure. . . It should be big. It might not work after a while
The calculated heat transfer area of the heat exchanger is 30% larger than the estimated value; I’m curious to know what the basis for your calculations and estimates was. If based on the same, they should be pretty similar.
1. A margin is generally applied to the heat exchange area of heat exchangers (usually 10%-50%), with equipment costs needing to be taken into consideration. Over time, as the heat exchanger is used, issues such as scaling and shell-side short circuits can occur, leading to a decrease in its heat exchange capacity. 2. To control the temperature, the opening degree of the control valve can be adjusted to change the flow rate of the cooling water.
Well, I think the same way. But I always feel that many things keep changing during use, which is annoying. Last edited by jia717 on 2009-4-14 22:30]
The value you calculated is higher than the estimate, so it should be fine! Generally, it’s better to have a larger heat exchange area for the heat exchange gas! It needs to be practical, but costs must also be taken into account!
Heat exchange calculations are inherently approximate; you won’t find any book that claims to enable precise calculations. The vast majority of the calculation formulas are empirical ones. Taking into account manufacturing errors, scaling, and various other uncertainties, a margin of 25 to 30% is usually applied to ensure that the actual area is larger than the required area. Water coolers can be adjusted to within about 1°C through precise control, but a significant area margin is still necessary.
The design should allow for some flexibility to account for factors such as scaling.
The 30% increase for the larger size is mainly to account for the fact that the efficiency of the heat exchange tubes declines over time; therefore, an additional amount is needed to ensure stable operation of the process
The estimated heat exchange area is not accurate to begin with; it should be the calculated heat exchange area plus some margin. As parameters change over time during use, this is normal, and the additional margin serves as a safety factor.
The issue of considering a margin for heat exchange area should be taken into account.