Thermoacoustic refrigerators have typically been designed to cool an isolated working fluid, necessitating a heat exchanging device to draw heat from the outside target fluid into the cooled working fluid. For example, a thermoacoustic refrigerator designed to chill air might utilize argon as an isolated working fluid, necessitating a heat exchanger to draw heat from the air to the argon. A second heat exchanger would be required to draw heat from the argon to a cold sink. A design team at Utah State University has created a thermoacoustic refrigerator which uses air at atmospheric pressure as its working fluid. By selecting an open-open tube design with pressure nodes at both ends, the design team was able to impose airflow directly through the thermoacoustic stack. In this way, atmospheric air is cooled directly, obviating the need for a heat exchanger to operate between the air and an isolated working fluid.