Heat transfer coefficient of shell-and-tube heat exchangers
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Dear experts, I would like to ask what the heat transfer coefficient is for typical shell-and-tube heat exchangers. Some sources say it’s 200, while others mention values ranging from 1000 to 2000, or even 1500 to 2400 – there are many different figures, which is confusing. Some experienced professionals suggest using a value of 500 to 800. I’m curious to know how others determine this value
It is related to the medium; different media result in different empirical ranges for heat transfer in the same heat exchanger
Water is generally used as the cooling medium to condense water vapor; approximately how much can be obtained?
Water is generally used as the cooling medium to condense water vapor; approximately how much can be obtained?
First of all, you need to understand that this heat transfer coefficient is not chosen arbitrarily; it is calculated based on the structure of the heat exchanger. At the beginning of heat exchanger design, an estimated value for the heat transfer coefficient is determined, and once the design of the heat exchanger’s structure is complete, the actual heat transfer coefficient must be calculated accordingly. For general steam heating, a higher value can be used; 400 to 500 should work fine. For condensate water, around 200 should suffice.
First of all, you need to understand that this heat transfer coefficient is not something you can choose arbitrarily; it is calculated based on the structure of the heat exchanger. You can check the manual to find out the typical values used. Chemical Process Handbook, Fourth Edition
The heat transfer coefficient of a heat exchanger should not be the overall heat transfer coefficient. Generally, we need to determine the heat exchange area based on the overall heat transfer coefficients of different media, but carrying out such calculations is practically impossible; therefore, an empirical value has to be used to roughly determine the heat exchange area
It is recommended that the poster use professional heat exchanger calculation software, as such software can automatically calculate the heat transfer coefficient
Answer: It depends on the properties of the fluid and the operating conditions; the K value ranges from several hundred to several thousand. It is necessary to refer to relevant manuals to select an appropriate range of K values based on the actual operating conditions. The range of K values is usually wide, in order to reduce operating costs. A smaller K value can be chosen; if reducing equipment costs is the goal, a larger K value can be selected.