scispace - formally typeset
Search or ask a question
Topic

Thermal radiation

About: Thermal radiation is a research topic. Over the lifetime, 12290 publications have been published within this topic receiving 197186 citations. The topic is also known as: heat radiation.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the optical properties of the solar module were redesigned to eliminate parasitic absorption and enhance thermal emission to reduce the operating temperature of one-sun terrestrial solar modules up to 10 °C.
Abstract: For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20–30 °C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of photovoltaic (PV) modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of the solar module to eliminate parasitic absorption ( selective-spectral cooling ) and enhance thermal emission ( radiative cooling ). Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool one-sun terrestrial solar modules up to 10 °C. This self-cooling would substantially extend the lifetime for solar modules, with corresponding increase in energy yields and reduced levelized cost of electricity.

89 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the thermogravitational transmission and thermal radiation of micropolar nanoliquid within a porous chamber in the presence of the uniform magnetic influence.

89 citations

Journal ArticleDOI
TL;DR: The Galileo probe net flux radiometer (NFR) measured radiation fluxes in Jupiter's atmosphere from about 0.44 to 14 bars, using five spectral channels to separate solar and thermal components.
Abstract: The Galileo probe net flux radiometer (NFR) measured radiation fluxes in Jupiter's atmosphere from about 0.44 to 14 bars, using five spectral channels to separate solar and thermal components. Onboard calibration results confirm that the NFR responded to radiation approximately as expected. NFR channels also responded to a superimposed thermal perturbation, which can be approximately removed using blind channel measurements and physical constraints. Evidence for the expected NH3 cloud was seen in the spectral character of spin-induced modulations of the direct solar beam signals. These results are consistent with an overlying cloud of small NH3 ice particles (0.5-0.75 microns in radius) of optical depth 1.5-2 at 0.5 microns. Such a cloud would have so little effect on thermal fluxes that NFR thermal channels provide no additional constraints on its properties. However, evidence for heating near 0.45 bar in the NFR thermal channels would seem to require either an additional opacity source beyond this small-particle cloud, implying a heterogeneous cloud structure to avoid conflicts with solar modulation results, or a change in temperature lapse rate just above the probe measurements. The large thermal flux levels imply water vapor mixing ratios that are only 6% of solar at 10 bars, but possibly increasing with depth, and significantly subsaturated ammonia at pressures less than 3 bars. If deep NH3 mixing ratios at the probe entry site are 3-4 times ground-based inferences, as suggested by probe radio signal attenuation, then only half as much water is needed to match NFR observations. No evidence of a water cloud was seen near the 5-bar level. The 5-microns thermal channel detected the presumed NH4SH cloud base near 1.35 bars. Effects of this cloud were also seen in the solar channel upflux measurements but not in the solar net fluxes, implying that the cloud is a conservative scatterer of sunlight. The minor thermal signature of this cloud is compatible with particle radii near 3 gm, but it cannot rule out smaller particles. Deeper than about 3 bars, solar channels indicate unexpectedly large absorption of sunlight at wavelengths longer than 0.6 microns, which might be due to unaccounted-for absorption by NH3 between 0.65 and 1.5 microns.

89 citations

Journal ArticleDOI
TL;DR: In this article, the thermal conductivity and the cellular structure as well as the matrix polymer morphology of a collection of chemically crosslinked low-density closed cell polyolefin foams, manufactured by a high-pressure nitrogen gas solution process, have been studied.
Abstract: The thermal conductivity and the cellular structure as well as the matrix polymer morphology of a collection of chemically crosslinked low-density closed cell polyolefin foams, manufactured by a high-pressure nitrogen gas solution process, have been studied. With the aid of a useful theoretical model, the relative contribution of each heat-transfer mechanism (conduction through the gas and solid phases and thermal radiation) has been evaluated. The thermal radiation can be calculated by using a theoretical model, which takes into account the dependence of this heat-transfer mechanism with cell size, foam thickness, chemical composition, and matrix polymer morphology. A simple equation, which can be used to predict the thermal conductivity of a given material, is presented.

89 citations

Journal ArticleDOI
TL;DR: In this article, a rheological model featuring thermophoretic and Brownian diffusions is introduced to formulate the second-grade nanoliquid flow considering mixed convection and magnetohydrodynamics.
Abstract: These days, the most important requirement of contemporary technological activities is extraordinary performance chilling for standard construction. Weaker thermal transference is meaningful issue to keep the extraordinary performance chilling throughout manufacturing systems. This difficulty can be determined by the nanoparticles submersion. Thus, a rheological model featuring thermophoretic and Brownian diffusions is introduced to formulate the two-dimensional viscoelastic (second-grade) nanoliquid flow considering mixed convection and magnetohydrodynamics. Modeling subject to viscous dissipation, convective conditions, Joule heating, heat absorption/generation, stratifications and radiation aspects is presented. Non-dimensionalization process is performed introducing apposite variables. Homotopy algorithm is opted for nonlinear analysis. Graphs are exhibited for interpretation of distinct variables influence against dimensionless quantities. We found opposing behavior for radiation and thermal stratification variables against thermal field.

89 citations


Network Information
Related Topics (5)
Heat transfer
181.7K papers, 2.9M citations
89% related
Thermal conductivity
72.4K papers, 1.4M citations
87% related
Turbulence
112.1K papers, 2.7M citations
86% related
Reynolds number
68.4K papers, 1.6M citations
83% related
Boundary layer
64.9K papers, 1.4M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023375
2022749
2021575
2020636
2019663
2018618