Accession Number : ADA301717

Title :   Improved Efficiency and Power Density for Thermoacoustic Coolers.

Descriptive Note : Annual summary rept. Jun 94-May 95,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS

Personal Author(s) : Hofler, Thomas J.

PDF Url : ADA301717

Report Date : 27 JUL 1995

Pagination or Media Count : 16

Abstract : A new design for a thermoacoustic heat driven cooler is proposed and has been analyzed via a numerical model. The engine layout incorporates a half wavelength or can be run in a full wavelength with dual prime movers and dual coolers coupled thermally in parallel. Both simplified models and more physically realistic models have been constructed and adjusted for good performance. Simplified models indicate an overall COP of 0.48, which means that the total cooling power is a factor of 0.48 smaller than the total heat input. More detailed and realistic models indicate an overall COP of 0.43. Geometry numbers have been finalized and much of the drafting for an experimental unit has been completed. We hope that high power densities can be achieved with this engine. We also believe that overall COP's in the range of 0.6 to 0.7 may be possible with further improvements. Additionally, we have numerically studied issues of achieving acoustic onset with this engine and the sensitivity of the onset condition to the model parameters. We have also developed a new heat exchanger fabrication method which will allow us to achieve the smallness of geometry scale that was discussed in the previous report. The practical result is better thermal coupling with less acoustic dissipation. The fabrication method is also considerably simpler than our previous method.

Descriptors :   *HEAT EXCHANGERS, *ACOUSTIC RESONATORS, THERMAL PROPERTIES, HEAT TRANSFER, MATHEMATICAL MODELS, COUPLING(INTERACTION), OPTIMIZATION, PARAMETERS, ACOUSTIC WAVES, EFFICIENCY, DISSIPATION, COOLING, TEMPERATURE GRADIENTS, THERMAL ANALYSIS, ACOUSTIC MEASUREMENT, SOUND PRESSURE, ACOUSTIC IMPEDANCE, REFRIGERATION SYSTEMS, ENGINE PRIMERS.

Subject Categories : Air Condition, Heating, Lighting & Ventilating
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE