Performance Measurements on a Thermoacoustic Refrigerator Driven at High Amplitudes,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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Since the power density in a thermoacoustic device is proportional to the square of the acoustic Mach number, there is strong motivation to design thermoacoustic refrigerators to operate at larger pressure amplitudes. Measurements are reported of a modified version of the Space Thermoacoustic Refrigerator STAR, driven at pressure amplitudes up to 6. This pressure ratio corresponds to 30 W of cooling power -- five times as large as reported in 1993. The results of these measurements are compared to a DELTAE computer model of the low amplitude linear performance that matches experimental conditions on a point-by-point basis. It is found that there is a small but measurable deviation in heat pumping power from the power predicted with a linear acoustic computer model. This deviation in heat pumping power at 6 pressure ratio is about 15. A large, amplitude independent disagreement in the acoustic power needed to attain a specific pressure ratio is found between measured data and DELTAE results. An overview of the instrumentation, including a measurement of exhaust heat with an absolute accuracy of 65 mW, is also presented.
- Air Conditioning, Heating, Lighting and Ventilating