Abstract
We present a systematic optimization of nighttime thermoelectric power generation system utilizing radiative cooling. We show that an electrical power density >2 W/m2, two orders of magnitude higher than the previously reported experimental result, is achievable using existing technologies. This system combines radiative cooling and thermoelectric power generation and operates at night when solar energy harvesting is unavailable. The thermoelectric power generator (TEG) itself covers less than 1 percent of the system footprint area when achieving this optimal power generation, showing economic feasibility. We study the influence of emissivity spectra, thermal convection, thermoelectric figure of merit and the area ratio between the TEG and the radiative cooler on the power generation performance. We optimize the thermal radiation emitter attached to the cold side and propose practical material implementation. The importance of the optimal emitter is elucidated by the gain of 153% in power density compared to regular blackbody emitters.
Highlights
The rapid growth of world population and industrial development poses a major threat to the global energy supply, causing escalatory environmental degradation and social unrest [1,2,3]
A proof-of-concept experiment [9] developed a device that couples the cold side of a thermoelectric power generator (TEG) to a sky-facing blackbody surface that radiates heat to the cold of space and has its hot side heated by the surrounding air, enabling electrical power generation of 25 mW/m2 at night
For all three cases the maximum power density is achieved with the TEG area less than 1 percent of the radiative cooler area
Summary
The rapid growth of world population and industrial development poses a major threat to the global energy supply, causing escalatory environmental degradation and social unrest [1,2,3]. With typical temperature difference between the ambient and hot side of few degrees K and the free air convection coefficient of 8∼10 W/m2K [9], the input power density provided to the generator is limited to on the order of 10 W/m2 - which, with the typical power conversion efficiency of TEG, cannot provide the desired 1 W/m2 power density, requiring significant enhancement A proof-of-concept experiment [9] developed a device that couples the cold side of a TEG to a sky-facing blackbody surface that radiates heat to the cold of space and has its hot side heated by the surrounding air, enabling electrical power generation of 25 mW/m2 at night This demonstration of nighttime electrical power generation is remarkable, it is not sufficient to fulfill energy demand of many applications mentioned above.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.