May I ask, is a plate heat exchanger or a spiral plate heat exchanger better for air cooling water?
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Compressed air at around 25 degrees; water cooled from 60 degrees to 40 degrees, with a flow rate of 3.8 tons per hour； Please ask an expert to help answer
It is naturally a finned tube heat exchanger, and I can design it precisely if necessary.
For cases like this, where heat is exchanged between air and water, what are the heat transfer coefficients of finned tubes and spiral plates?
Low-pressure air: finned tube, K can be increased to around 300 W/(m2.K)； For spiral plates, around K 50 is sufficient.
What about plate heat exchangers? Is their heat transfer coefficient higher or lower than that of finned tubes? Also, is the heat exchange area of finned tubes the area of the outer surface of the tubes, including the fins as well? Thank you for the reply: handshake
https://bbs.hcbbs.com/thread-862673-1-1.html I saw in this post that spiral plates are used for heat exchange between oil and steam, with a heat transfer coefficient of 300; it was also said that this value is somewhat conservative
Generally speaking: for finned tubes, the heat exchange area is calculated based on the bare tube, with the heat transfer from the fin part being attributed to the bare tube. Only then can it be compared. Of course, it can also be calculated based on the fin area plus the area of the light tubes that are exposed (not covered by the fins). In this case, the heat transfer coefficient is low, but the total area is large. The effects of the two are the same. In my software, both types of areas are available.
Additionally: during heat transfer, both sides and the top of the fins are considered heat transfer areas, while the bottom part in contact with the base tube is not counted as an area. The heat transfer area cannot be used to calculate the volume or weight of fins: the two are fundamentally different.
Compared to finned tubes, the performance of plate-type ones is inferior. But the plate type has its advantages: it performs well when the temperature difference is low.
Does low temperature refer to the logarithmic mean temperature?