טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentGonen Eran
SubjectInvestigation of a Thermo-Acoustic Stirling Engine
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Emeritus Gershon Grossman
Full Thesis textFull thesis text - English Version


Abstract

Thermoacoustic oscillations are the outcome of interactions between heat and sound, yet it took two centuries until the first commercial product based on thermoacoustic effects appeared in the market. In parallel, Stirling cycle engines have been investigated for almost 150 years, until they found their use in solar powered systems, setting the world record for the highest reported conversion efficiency from solar to electrical power. These engines operate at high temperatures and high pressures, are externally heated, and generally employ inert working gas. In the past, several companies have built successful prototypes but have failed in their industrialization, mainly due to reliability issues.

An electricity generating Thermo Acoustic Stirling heat Engine (TASE) has no moving parts other than the alternator magnet, hence it has great potential for a reliable and efficient engine. However, no such device is commercially available yet, and only very few laboratory models have been fabricated and tested so far. Moreover, only two publications of solar powered TASE have been reported so far. Despite its conceptual simplicity and high reliability, the overall efficiency of a complete system based on TASE needs further improvements in order to be become a dominant player in today's fast growing solar market.

The main advantages of TASE are found in its inherently simplified structure and lack of hot moving parts, leading to highly robust operation under extreme conditions, which enhance the value for customers by forming a safe and sustainable power generating unit.  Additionally, as stringent environmental regulations are forcing ultra-low emissions, the adaptation of commercial heater heads conforming to environmental regulations seems relatively straightforward in such systems.

Higher efficiencies could be attained through proper implementation of specific elements, complemented by precise determination of the main physical variables existing in actual conditions. Improved configurations as well as practical designs, based on the considerations explored in this dissertation, may increase public awareness, and eventually lead to enhanced system performance, mostly in terms of the product overall cost per Watt, in the envisaged higher power levels, suitable for home appliance. 


The objective of this work is to study the performance of TASE, identify barriers to its efficient performance and recommend ways for improvement.