Development of a ptototyp of a sustainable magnetocaloric cooling device
Fatima Muhammed Husain Al-Battat
فاطمة محمد حسين البطاط
Magnetic Refrigeration (MR) is a new cooling technology using a solid refrigerant instead of a gaseous refrigerant used in conventional cooling technics. The solid refrigerant is magnetocaloric material (MCM), its temperature increases when exposed to an external magnetic field causing magnetization of MCM, and the demagnetization happens to MCM by removing the external magnetic field which decreases the temperature of MCM. The magnetocaloric effect (MCE) is the phenomenon that describes the change of temperature of an MCM which is considered the basis of magnetocaloric refrigeration technologies. Compared to the conventional vapor compression cycle, the magnetocaloric cooling cycle is more energy-efficient and more environmentally friendly because it does not make use of greenhouse gases. In this thesis, we develop a prototype of a sustainable magnetocaloric cooling device. A suitable design for the prototype was chosen and performed using the Autodesk inventor professional 2021 3D design program. The components of our magnetic refrigeration device were selected and divided into four sub-systems: Magnetic Field Generator (MFG) consisting of the magnet and its mechanism, Active Magnetic Regenerator (AMR) containing the Magneto-Caloric Material, Fluid flow/heat transfer system, and the Control system. An initial magnetic field generator was selected, which consists of two concentric 90 mm long Halbach cylinders, made of 16 permanent magnet segments, which were integrated with a support structure in optimized orientation, the outer cylinder is fixed and the inner one rotates with respect to the outer one producing two areas of maximum (1.3 T) and minimum (0.0002 T) magnet flux densities used to magnetize and demagnetizing the MCM to produce the cooling cycle. The greatest effort expended in this master's thesis was to design an MFG at a low price. Various designs of the MFG were implemented on Autodesk inventor and simulated on Faraday simulation software. We decrease the number of segments to half (8 segments) and replaced the other 8 with soft magnetic low-carbon steel. The simulation results showed that the new design can generate a 0.8 T magnetic field, and thus the price of the magnet was halved, but its price remained very expensive we were limited by budget money.Magnetic Arrangement for Novel Discrete Halbach Layout (Mandhalas)consisting of the final MFG. The final Mandhalas MFG produced a magnetic field of 0.82 T at the center of the magnet fined by simulation results and 0.6 T calculated by equations. The support structure for the magnet circuit was designed with the program Autodesk inventor and the components were subsequently manufactured at the JCNS2 workshop. The housing was designed for the final mandhala magnet by the Autodesk Inverter program, then these designs were printed at the JCNS2 Institute, and the strong magnets were purchased and arranged in a certain way according to the simulation results.The Mandhala produced a magnetic field of 0.6 T at the center of the magnet measured by the axial Hall probe and transverse flowmeter.The magnet design was improved and developed, as we were able to reduce the price of the magnet by 90%, while the decrease in the magnetic field of the magnet circuit was 36%.The AMR was selected by choosing the type and the geometry of the MCM used to place into the inner magnet cylinder. We used Calorivac material from Vacuum schmelze company. A mixture of 80% water and 20% ethylene glycol is used as heat transfer fluid.The control system was planned and relies on individual components which are easily accessible and are already available. The fluid flow/heat transfer system was also designed and the components were ordered.