Reshaping building cooling in hot and humid climates with a decentralized personal cooling system

Global warming is driving a rapid rise in cooling demand, especially in hot and humid climates, where substantial number of spaces will soon require mechanical cooling and exert pressure on the electricity grid. The conventional approach of cooling the entire space will become increasingly unsustainable, highlighting the need for hybrid strategies that integrate natural ventilation and personal cooling. Personal cooling systems (PCS) offer a pathway to reduce cooling energy while maintaining comfort, yet their real-world deployment has been limited by the absence of solutions that balance portability, cooling capacity, and energy efficiency. This paper presents a plug-and-play PCS utilizing thermoelectric cooling and phase change material, supported by a novel co-design framework that optimizes system architecture, operational stability, and overall performance. The cooling effectiveness and energy performance of the proposed devices were comprehensively evaluated via prototype experiments and co-simulations under realistic ambient conditions, thereby achieving a state-of-the-art coefficient of performance above 3. The adaptable PCS enables mixed-mode cooling by substantially extending the time window for natural ventilation. Climate sensitivity simulations showed that the estimated cooling energy savings varied across representative tropical conditions, averaging 52% under the standardized simulation assumptions.