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As climate change accelerates and global energy consumption grows, scientists are increasingly exploring passive cooling technologies—methods that reduce heat without consuming electricity. Among these, radiative cooling stands out. It works by reflecting sunlight and emitting thermal energy as infrared radiation into outer space. However, its efficiency has been constrained by fundamental physical limits. A new theoretical model could soon change that.
Published in the Journal of Photonics for Energy, recent research introduces a system that combines a thermoradiative diode (TRD) with a heat engine. This novel configuration promises to exceed the long-standing thermal radiation limit set by blackbody physics, potentially revolutionizing passive cooling strategies.
The system’s core innovation lies in manipulating what is known as photon chemical potential. This parameter determines how much thermal energy can be carried away as photons. Typically, increasing photon chemical potential—and therefore radiative cooling power—requires external energy input. But the proposed model achieves this effect internally. By coupling the TRD with a heat engine, the system self-generates the necessary conditions for enhanced infrared emission without relying on continuous external electricity.
Calculations suggest that this integrated approach could deliver cooling power up to 485 watts per square meter, surpassing the blackbody radiation limit at room temperature (about 459 W/m²). This would mark a significant leap forward for passive radiative cooling, which has so far been restricted by that threshold.
The researchers also investigated variations of the system. For instance, substituting the heat engine with a thermoelectric generator, which converts waste heat into electricity, could still enable efficient cooling. Their analysis showed that factors such as the size ratio between components have a substantial impact on the system’s overall performance. With optimized design, the TRD-generator combination could operate effectively even in the absence of active power input.
Though still in the theoretical stage, this concept introduces a promising direction for developing sustainable cooling systems that reduce dependence on energy-intensive technologies like air conditioning. The researchers hope their work will inspire experimental efforts to build and test real-world prototypes for managing heat in buildings, electronics, and other applications.
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Post time 2025-05-19 02:09:59