Evaluation of CAE Methods Used for Plate Heat Exchanger Design

Flow and heat transfer in a plastic recuperative counter flow plate air-to-air heat exchanger were investigated experimentally and numerically using Ansys Fluent software. It was employed previously developed methods to generate a computational mesh and assumed nonzero thickness of the plates to calculate the flow in an air-to-air heat exchanger. Pressure drop and effectiveness were evaluated as functions of inlet velocity. Obtained numerical data were substituted by suggested functions dependent on the Reynolds number and later modified to take change in plate pitch and material thickness into account. It was found that change in plate pitch influence only friction losses due to change of turbulence of the flow. The shape of mini-channels, which are defined by the shape of pressing molds that are constant during our investigation, determines local loses. Increasing the plate pitch has the same effect on Nusselt number as increasing the Reynolds number. Modified functions were used to illustrate the effect of material thickness, plate pitch and heat conductivity of material on pressure drop and effectiveness. Derived equations witch take the effect of material thickness and plate pitch into account represent a useful tool for design and optimization of recuperative heat exchanger for use in HVAC systems in sustainability buildings.