| This study was concerned with the thermal modelling of plate heat exchangers used in micro-flow natural convection SDHW systems. The investigation included three sections: an experimental analysis to determine the performance characteristics the development of a numerical model and parametric analysis for a typical heat exchanger and the verification of an empirical model for SDHW system simulation.The experimental analysis of commercially-available plate heat exchangers was performed with a test apparatus designed to simulate the actual micro-flow SDHW system. Through the analysis of the experimental data, it was determined that, for a specific geometry, a NCHE can be characterized by two simple relationships, To more closely examine the heat transfer and fluid flow characteristics of a representative natural convection plate heat exchanger, a finite element model of the heat exchanger was created. Various system parameters were evaluated to assess their effects on heat exchanger performance. Parameters such as system temperatures and velocities, the size of the heat exchanger, and the plate thermal conductivity were examined.Based on the results of the empirical model and the finite element analysis, a model was created for the simulation of the heat exchanger in a SDHW system, or any other comparable application.The numerical results, used in conjunction with the empirical model allow the determination of the effect of heat exchanger parameters, such as plate width and channel width, without the expense of running a full set of experiments for the new heat exchanger. |
