EAGER: Thermoacoustics: Active Feedback Control Enabling a New Generation of Energy Conversion Devices

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

The objective is to design, optimize and build a new class of thermoacoustic energy conversion devices. The new feature of these devices is the extensive use of active acoustic feedback, and sophisticated controller design that optimizes power conversion efficiency while trading off control effort. The use of such feedback control can overcome two significant challenges in current thermoacoustic devices, namely (a) the narrow range of operating parameters required for high efficiency, and (b) the mechanical design complexity incurred due to acoustic impedance requirements. The use of active feedback control can create virtual acoustics and thus satisfy impedance requirements over a much larger parameter regime than non-feedback devices. In addition, feedback can create new thermoacoustic instabilities in operating regimes where they would not naturally exist. This new device concept moves significant complexity from the mechanical design of the device into the design of the feedback electronics, where it can be much more easily implemented. This is to be done while trading off the additional power required for acoustic control, through optimal feedback control design. The ability to operate over a large parameter regime would enable the use of thermoacoustics in more varieties of energy conversion devices, especially in solar powered ones. Intellectual Merit: Although certain limited types of thermoacoustic energy conversion devices have existed for some time, fundamental limitations have prevented them from being used for more than highly specialized applications. Smart Thermoacoustics has the potential to be a transformative development in this technology, enabling its use for a wide variety of applications. The approach is to investigate control-oriented thermoacoustic modeling together with optimal feedback and learning control design. Broader Impact: Thermoacoustic devices are currently unable to operate using highly variable heat power sources such as solar power, and have therefore not yet been used to harness solar energy. Active feedback control enables thermoacoustic devices to adapt to a wide range of heat power inputs, and could thus enable an entirely new category of solarpowered energy conversion devices. This would be a significant contribution to the renewable and clean energy sector.