Review of Thermoacoustic Refrigeration. Description of a Simple Thermoacoustic Refrigerator for Demonstration Purpose.

Abstract

It is possible to build refrigerators using acoustic waves to pump heat. This technique is called thermoacoustic refrigeration and is based on the interac¬tion between pressure oscillation and temperature oscillation of a gas. A quantitatively accurate theory was developed in the 1970s and the first thermoacoustic refrigerator was built in 1985. Hence, this technique is relatively new. It benefits from being environmentally safe, having no sliding parts and predicted low fabrication cost. A disadvantage is the efficiency, which today is below its vapor-compression counterparts, but efficiencies of the same order have been predicted by theoretical studies. Further development is still needed in order to get commercially marketable devices. But already today, we can find thermoacoustic refrigerators in special applications. This thesis work contains a review of the field of thermoacoustics in general and thermoacoustic refrigerators in particular. The history of thermoacoustic refrigerators is presented and future research, development and commerciali¬zation is predicted. The physical explanation is presented as well as the equations describing the phenomena. Design choices are discussed. A simple thermoacoustic refrigerator has been built in order to demonstrate the thermoacoustic phenomena. The refrigerator was built using a tube of transparent plastic to allow visualization of the inside. A temperature differ¬ence of about 20°C was achieved. A detailed description of this refrigerator is presented and results from measurements are discussed.