1. Thermoacoustic Refrigeration By Jackie Branscomb

2. Motivation Pros – Uses sound for refrigeration –no harmful chemicals (CFC’s, HFC’s, HCFC’s) – Few moving parts—more reliable – Not harmful to the environment Cons – Most efficent is approaching 40% of Carnot limit – 20-30% overall efficiency

3. Parts of Acoustic Refrigerator Two main parts – Driver Houses the Loudspeaker – Resonator Houses the gas (in this case Helium) The hot and cold heat exchangers Houses the Stack

4. How it works Moving coil Loudspeaker – Inside 2 magnets with metal coil between them, current is induced causing coil to move – Creates sound waves up to 200 dB! Resonator—where gas cooling and compression take place – Uses inert gas, commonly Helium Stack – Series of small parallel channels through which pressure and velocity of waves change – In between the heat exchangers Heat Exchangers – Hot heat exchanger to remove excess heat – Cold heat exchanger for refrigeration

5. Acoustic Refrigerator

6. Applications Ben & Jerry’s – Ice cream storage containers – 200 L at 18 degrees Fahrenheit U.S. Navy – Wants acoustic refrigerators for submarines – Refrigerant leaks on subs are a deadly problem – With acoustic refrigerators, no harmful fluids