A general calculation method for plate heat exchangers

The possibilities of process stream guidance within plate heat exchangers are very complex. There exist constructional solutions, in which the process-streams are led through stream-passages connected in series or parallel. Other constructions realize the heat transfer between more than two process streams. Known are also constructions, where the stream passages are spirals. All these constructions deviate more or less from the ideal principle of uniflow or counterflow guidance. While the approximate interpretation of plate heat exchangers is solved methodically, the only methods used for the calculation of existing apparatus are either mathematically extremely exacting or not generally valid. To analyse the behaviour of plate heat exchangers, exact and easy to apply calculation methods are required. This article presents a general calculation method for the stationary simulation of plate heat exchangers of any type required. The method allows a mathematically exact determination of the temperature profiles of types of apparatus mentioned above. In a further step the proposed method can also be used for the simulation of the heat flux along the walls of the plates as well as the dispersion in the passages. The basic idea of the presented method is the simulation of a heat exchanger network with generalized operating characteristics. The “classic formulas” of this operating characteristic are given in this method as special cases. The general calculation method for plate heat exchangers can be used without any iteration. Only the consideration of temperature dependent properties as well as phase transitions require iterations. This method is characterized by a great numerical stability.