Optimisation Design of a Plastic Heat Exchanger Core

Abstract

This thesis details a project to develop a computer based mathematical model of an air to air crossflow heat exchanger system made of common plastic sheets. It is explained how the model was developed to simulate the energy transfer and calculate the relative parameters. A realistic heat exchanger experimental rig is designed and put into testing. The heat exchanger experiment rig and the exchanger cores are made to testing the performance of the material. The projects done by prior studies have also been reviewed, in order to make comparison and evaluation. The explanation is given as how the effectiveness (ε) and number of transfer unit (NTU) method is used to calculate required temperature and pressure drop values, for a given set of initial conditions. This method was also extended by using interactive loop, in order to calculate the energy emitted or released by a given fixed exchanger core geometry. It is explained how the important calculations within the model support one another. The experiment rig testing outcomes are collected by using extensive electronic measuring devices, which including temperature and pressure readings. Most of the acceptable results are produced by the computer model as the experimental data matches. However, due to errors and uncertainties, were most likely to be contributing significantly to a large part of the inconsistency of the results. It is concluded that, the experimental data could be expected with higher precision to match the programme results. Due to the highly similar results between experimental and predicted results, the performance of the plastic made crossflow heat exchanger could be optimised by considering both material and operational costs.