CAE methods for plate heat exchanger design

The heat recovery can substantially reduce energy consumption needful for heating or air conditioning of buildings. The aim of work is to develop a simple CAE method for rapid design and optimization of the dimensions of plate heat exchangers for heat recovery. Flow and heat transfer in an air-to-air recuperative counter-flow plate heat exchangers were investigated numerically. Pressure drop and effectiveness were evaluated as functions of inlet velocity for three sizes of real heat exchangers. Obtained data were analyzed, inlet/outlet cross-flow and middle counter-flow parts were investigated independently and data were substituted by suggested functions for Nusselt number and loss coefficients. These functions were used to illustrate the effect of heat exchanger dimensions. It proved that bigger heat exchangers provide higher effectiveness and lower pressure drop for the same flow rate, but also the heat transfer surface is larger. Derived equations which also take the effect of material thickness and plate pitch into account represent a useful tool for design and optimization of recuperative heat exchangers for use in HVAC systems.