CONSTRAINTS AND CHALLENGES IN THE DEVELOPMENT OF THERMOACOUSTIC REFRIGERATORS (original) (raw)

Thermoacoustic refrigerators create a refrigeration effect using a pressure wave confined in a resonator filled with air or inert gases. The pressure wave is supplied by a loudspeaker and can also be supplied by a thermoacoustic heat engine. However, such devices have not been widely-commercialized yet because of their low efficiencies and power densities, compared to vapor compression cycles. This work analyzes all components of the loud-speaker driven thermoacoustic engine in order to highlight the constraints and the challenges associated with each component. This is critical to further develop these devices. This work analyzes the constraints and the challenges in the loud speaker (dimensions, power, efficiency, frequency response, position, frequency matching, and enclosure volume); amplifier (power, fidelity, impedance matching); cone (length and cone angle); resonator (shape, length, and cross sectional area); stack (material, dimensions, porosity, geometry and position) and hot and cold heat exchanger design (blockage fraction, porosity, length, material, heat transfer resistances and heat transfer fluid). A prototype of a thermoacoustic refrigerator is currently being built at the American University in Cairo and some of the experiences gained are shared.