Feasibility of Innovative Solar-Thermo-Acoustic Power Conversion Cycles

The techno-economic assessment of the concentrating solar power thermo-acoustic power conversion systems is carried out to identify the optimum conditions, under-which the solar thermo-acoustic might be competitive to the current commercial solar thermal power technologies. The thermal and economic performance of a thermo-acoustic engine integrated to five different solar collectors including Compound Parabolic Collector, Linear Fresnel, Parabolic Trough, Central receiver, and Solar Dish is compared to the current commercial solar thermal power technologies as well as to their corresponding Carnot-cycle. To do so, a modular modeling approach is used to consider all the available commercial technologies, through combining a modular energy model with a simplified economic model. Jeddah city (Saudi Arabia) has been chosen as a reference site for the present study. The results indicate that the integration of compound and dish solar collectors to a thermo-acoustic engine might offer competitive solutions. Compound collectors might be more suitable for integration with the thermo-acoustic engine than linear Fresnel collectors, if the exergy efficiency of the engine reaches 40%. Besides, dish-thermo-acoustic system becomes more competitive than current dish-mechanical Stirling engine, if the investment costs of the thermo-acoustic engine are reduced to 3500 $/kWe, but the operating temperature should be above 700°C. Improving the exergy efficiency of the thermos-acoustic engines, from 35% to 40%, could make the dish-thermo-acoustic system more competitive than current dish-mechanical Stirling engines at a working temperature of 500°C. The study concludes that more efforts must be focused on reducing the costs of the TA devices rather than on improving efficiency.