In this Letter, an N-body theory for the radiative heat exchange in thermally nonequilibrated discrete systems of finite size objects is presented. We report strong exaltation effects of heat flux which can be explained only by taking into account the presence of many-body interactions. Our theory extends the standard Polder and van Hove stochastic formalism used to evaluate heat exchanges between two objects isolated from their environment to a collection of objects in mutual interaction. It gives a natural theoretical framework to investigate the photon heat transport properties of complex systems at the mesoscopic scale.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.107.114301 | DOI Listing |
Micromachines (Basel)
January 2025
School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China.
This study analyzes the impact of slip-dependent zeta potential on the heat transfer characteristics of nanofluids in cylindrical microchannels with consideration of thermal radiation effects. An analytical model is developed, accounting for the coupling between surface potential and interfacial slip. The linearized Poisson-Boltzmann equation, along with the momentum and energy conservation equations, is solved analytically to obtain the electrical potential field, velocity field, temperature distribution, and Nusselt number for both slip-dependent (SD) and slip-independent (SI) zeta potentials.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Energy System Engineering, Faculty of Mechanical Engineering, K.N. Toosi University of Technology, No. 15, Pardis St., Molasadra Ave., Vanak Sq., Tehran, Iran.
The rising global demand for air conditioning systems, driven by increasing temperatures and urbanization, has led to higher energy consumption and greenhouse gas emissions. HVAC systems, particularly AC, account for nearly half of building energy use, highlighting the need for efficient cooling solutions. Passive cooling, especially radiative cooling, offers potential to reduce cooling loads and improve energy efficiency.
View Article and Find Full Text PDFSci Rep
January 2025
Lawrence Livermore National Laboratory, Livermore, CA, USA.
Climate models simulate a wide range of temperatures in the Arctic. Here we investigate one of the main drivers of changes in surface temperature: the net surface heat flux in the models. We show that in the winter months of the dark Arctic, there is a more than two-fold difference in the net surface heat fluxes among the models, and this difference is dominated by the downward infrared radiation from clouds.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Radiative cooling is an excellent strategy for mitigating global warming, by enhancing heat fluxes away from the Earth, thus balancing the Earth's heat flow. However, for randomly particle-dispersed radiative cooling materials, the particle content as high as 94-96 wt % or 60 vol %, far exceeds the critical pigment percentage (40-50%) of traditional coatings, preventing its large-scale application. Here, inspired by particle deposition under gravity in solution, we demonstrate an auto-deposited SiO composite radiative cooling coating (ADRC) which reduces the amounts of particles required and lowers costs.
View Article and Find Full Text PDFACS Environ Au
January 2025
Department of Geography, Hong Kong Baptist University, Hong Kong SAR 999077, China.
Brown carbon (BrC) has been recognized as an important light-absorbing carbonaceous aerosol, yet understanding of its influence on regional climate and air quality has been lacking, mainly due to the ignorance of regional coupled meteorology-chemistry models. Besides, assumptions about its emissions in previous explorations might cause large uncertainties in estimates. Here, we implemented a BrC module into the WRF-Chem model that considers source-dependent absorption and avoids uncertainties caused by assumptions about emission intensities.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!