OPTIMIZATION OF HEAT EXCHANGE IN MAGNETIC REFRIGERATORS AND THERMOMAGNETIC MOTORS

The power and efficiency of magnetic refrigerators and thermomagnetic motors depend on their operating frequencies. To improve the efficiency of these machines, it is necessary to design the regenerators/heat exchangers so to present heat transfer as high as possible, allowing higher operational frequencies. In several machines, a fluid flowing through internal channels promotes the heat transfer. In such cases, as the temperature difference governing heat transfer decreases along the channels length, the heat transfer also decreases. One solution for this problem is the use of non-linear heat transfer area increase along the channels. That can be done by changing the cross section area or the profile of the channels. This study presents an experimental analysis that shows the effectiveness of this technique by comparing heat exchangers with cylindrical, conical and non-prismatic shaped internal channels using infrared thermography.