How to increase plate heat exchanger lmtd

A method for increasing the logarithmic mean temperature difference of a plate heat exchanger:

(1) The flow pattern of the plate heat exchanger has countercurrent, downstream and mixed flow patterns.Under the same working conditions, the logarithmic mean temperature difference is the largest in the countercurrent and the smallest in the downstream flow, and the mixed flow pattern is in between.The method of increasing the logarithmic mean temperature difference of the heat exchanger is to adopt a mixed flow pattern of countercurrent or near countercurrent as much as possible, to increase the temperature of the hot side fluid as much as possible, and to reduce the temperature of the cold side fluid.

(2)For the plate heat exchangers arranged in a single process, for the convenience of maintenance, the fluid inlet and outlet pipes should be arranged on the side of the fixed end plate of the heat exchanger.The greater the temperature difference of the medium, the stronger the natural convection of the fluid and the more obvious the influence of the retention zone.Therefore, the hot medium inlet and outlet position should be arranged top inlet and bottom out, and the cold fluid is placed in bottom inlret and top outlet arrangement to reduce the influence of the retaining zone and improve the heat transfer efficiency.