For heat exchangers, which is more effective: good convection or co-current flow?
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Is better cooling performance achieved at the same end where the heat exchange material inlet and the condensate water inlet are located, or at the other end?
I also wonder; the few projects I did before seemed to be of no particular importance
Could you explain to me the principle behind high convective efficiency? What is the difference between convection and advection?
What you want to ask is about counterflow and co-flow (co-flow is also a form of convection, right?). For heat transfer between two fluids without phase change, counterflow certainly yields better results, and this is mainly reflected in the logarithmic mean temperature of the two fluids; under the same temperature difference, the logarithmic mean temperature is higher in counterflow compared to co-flow. For the case with phase change on one side, counterflow and co-flow are the same.
Based on overall experience, convection yields better results; this depends on your requirements regarding the heating temperature of the material and the heat exchange medium, as well as taking into account heat loss. If the heat transfer medium is steam, hot oil, or superheated material, convective heat transfer is highly effective. If the heat transfer medium is something like hot water with a not-too-high temperature, the co-current flow pattern will yield better results!