### ASA 126th Meeting Denver 1993 October 4-8

## 2aPAa1. Optimal heat-driven thermoacoustic refrigeration: The beer cooler
revisited.

**W. Patrick
Arnott and par
Anthony A. Atchley
**

**
**
*Atmos. Sci. Ctr., Desert Res. Inst., P. O. Box 60220, Reno, NV 89506
Physics Dept., Naval Postgraduate School, Monterey, CA 93943
*

*
*
The goals of this research are to design and build an optimally efficient
heat-driven thermoacoustic refrigerator to cool a given heat load to a desired
temperature. The system uses heat to drive a thermoacoustic prime mover that
produces sound for a thermoacoustic refrigerator (as originally investigated by
John Wheatley in a device he called a beer cooler on account of the
temperatures and heat loads he was striving to obtain). Here, the first step,
numerical design, is described. A given system configuration is analyzed using
Runge--Kutta integration of three coupled DE's for ambient temperature,
acoustic pressure, and specific acoustic impedance (SAI) in the prime mover and
refrigerator and using pressure plus SAI transition equations elsewhere.
Complex eigenfrequency analysis is used to obtain starting values for a root
finding routine for the systems opening acoustic pressure, hot end temperature,
heat load, and frequency. Optimization is used to find a system configuration
that maximizes overall efficiency. These calculations should shed new insight
into optimal heat exchanger lengths. Progress on meeting these goals is
reported. The basic set of equations used in the Runge--Kutta integration have
intriguing forms and are discussed. Emphasis is placed on investigation of the
coupling between prime mover and refrigerator operation. [Work supported by
ONR.]