Abstract:
Sound is predominantly thought to be made up of pressure and displacement oscillations. In actual effect temperature oscillations are also present and a combination of these oscillations close to a solid surface results in thermo acoustic effect. Even though this effect is not so easily noticeable, with the use of appropriately sized components it can generate strong standing waves and be used to produce refrigerators and heat engines {Swift .G, Wollan. J 2002}. These devices have virtually no moving parts, except the driver (loudspeaker) which can also be eliminated if heat (waste gas or other source) is used to produce the acoustic waves for driving the system. Thermoacoustic process was discovered over a century ago but it’s only in the last few decades that rapid progress in understanding of its working principles and work towards design and development of prototype systems has occurred. Its practical use has still been in niche applications and work is ongoing to extend its use to a wider range of applications. The main limiting factor has been its performance compared to traditional refrigerators. Systems for cooling and air conditioning still rely heavily on vapor compression technology. The commonly used refrigerants in such systems have potential harmful environmental effects, so there is a need to develop alternative systems. The reliability and low operating cost of thermoacoustic systems make them an attractive option to the traditional systems despite their comparative low performance. Along with performance of thermoacoustic systems, their sizing has also been identified as a limiting issue in their widespread use.{Zink,Florian 2010} This experimental study focusses on the need to make these systems compact and the requirement to fit these systems into existing framework of potential applications. In this regard, experiments with straight resonator and other configurations were carried out and results compared. The experiment was divided into two parts. In the first part, resonator made of PVC pipes were arranged in straight, 45 degree, 90 degree and 135 degree configurations. The length of the resonator was kept the same for each configuration. Results for each configuration were compared using FFT analysis. In the second experiment a thermoacoustic refrigerator was built based on Tijani’s model with modifications. The resonator tube was arranged in straight, 45degree, 90 degree and 135 degree orientation and results were compared. In addition computer modeling of the setup was done using DELTAEC (Design environment for low amplitude thermo acoustic energy conversion) program.