The plate heat exchanger is a high-efficiency heat exchanger made up of a series of metal sheets with a certain corrugated shape. Various heat exchanger plates form thin rectangular channels for heat exchange. Plate heat exchangers are ideal equipment for liquid-liquid and liquid-vapor heat exchange. In the process of daily use, the water-water plate heat exchanger unit has low heat transfer efficiency due to various reasons. When this phenomenon occurs, we must think about how to improve the heat transfer of the water-water plate heat exchanger unit effectiveness.
(1) Reduce the thermal resistance of the dirt layer of the heat exchanger.
The key to reducing the thermal resistance of the fouling layer of the heat exchange unit is to prevent fouling of the plates. When the fouling thickness of the plate is 1mm, the heat transfer coefficient is reduced by about 10%. Therefore, we must pay attention to monitoring the water quality on both sides of the heat exchange unit to prevent fouling of the plates and prevent debris in the water from adhering to the plates. If there are viscous impurities in the water, special filters should be used for treatment. When choosing a drug, it is better to choose a non-sticky drug.
(2) Use heat exchanger plates with high thermal conductivity.
The plate material can choose stainless steel, titanium alloy, copper alloy. Stainless steel has good thermal conductivity, with a thermal conductivity of about 14.4W/(mK), high strength, good stamping performance, not easy to be oxidized, and lower price than titanium alloy and copper alloy. It is most used in heating engineering, but its ability to resist chloride ion corrosion is poor.
(3) Reduce the thickness of the plates of the plate heat exchanger.
The thickness of the plate has a great influence on the heat transfer coefficient, the thickness is reduced by 0.1mm, the total heat transfer coefficient of the symmetrical plate heat exchanger unit is increased by about 600W, and the asymmetrical type is increased by about 500W. Under the premise of meeting the pressure-bearing capacity of the heat exchange unit, the thickness of the plate should be as small as possible.