Inverse Design of Spectrally Selective Thickness Sensitive Pigmented Coatings for Solar Thermal Applications

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Refet A. Yalçın ◽  
Hakan Ertürk
Keyword(s):  
Radiative Transfer ◽  
Effective Medium Theory ◽  
Collection Efficiency ◽  
Radiative Properties ◽  
Solar Thermal ◽  
Inverse Design ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Spectrally Selective ◽  
Pigmented Coatings

Inverse design of thickness sensitive spectrally selective pigmented coatings that are used in absorbers of solar thermal collectors is considered. The objective is to maximize collection efficiency by achieving high absorptance at solar wavelengths and low emittance at the infrared (IR) wavelengths to minimize heat loss. Radiative properties of these coatings depend on coating thickness, pigment size, concentration, and the optical properties of binder and pigment materials, and a unified radiative transfer model of the pigmented coatings is developed in order to understand the effect of these parameters on the properties. The unified model (UM) relies on Lorenz–Mie theory (LMT) for independent scattering regime in conjunction with extended Hartel theory (EHT) to incorporate the multiple scattering effects, T-matrix method (TMM) for dependent scattering, and effective medium theory (EMT) for very small particles. A simplified version of the UM (SUM) ignoring dependent scattering is also developed for improving computational efficiency. Through the solution of the radiative transfer equation by the four flux method (FFM), spectral properties are predicted. The developed model is used in conjunction with inverse design for estimating design variables yielding the desired spectral emittance of the ideal coating. The nonlinear inverse design problem is solved by optimization by using simulated annealing (SA) method that is capable of finding global minimum regardless of initial guess.

scholarly journals Thermodynamic and Radiative Structure of Stratocumulus-Topped Boundary Layers*

2015 ◽  
Vol 72 (1) ◽  
pp. 430-451 ◽  
Author(s):  
Virendra P. Ghate ◽  
Mark A. Miller ◽  
Bruce A. Albrecht ◽  
Christopher W. Fairall
Keyword(s):  
Radiative Transfer ◽  
Boundary Layers ◽  
Great Plains ◽  
Potential Temperature ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Cloud Base ◽  
Transfer Model ◽  
Flux Divergence ◽  
Liquid Water Path

Abstract Stratocumulus-topped boundary layers (STBLs) observed in three different regions are described in the context of their thermodynamic and radiative properties. The primary dataset consists of 131 soundings from the southeastern Pacific (SEP), 90 soundings from the island of Graciosa (GRW) in the North Atlantic, and 83 soundings from the U.S. Southern Great Plains (SGP). A new technique that makes an attempt to preserve the depths of the sublayers within an STBL is proposed for averaging the profiles of thermodynamic and radiative variables. A one-dimensional radiative transfer model known as the Rapid Radiative Transfer Model was used to compute the radiative fluxes within the STBL. The SEP STBLs were characterized by a stronger and deeper inversion, together with thicker clouds, lower free-tropospheric moisture, and higher radiative flux divergence across the cloud layer, as compared to the GRW STBLs. Compared to the STBLs over the marine locations, the STBLs over SGP had higher wind shear and a negligible (−0.41 g kg−1) jump in mixing ratio across the inversion. Despite the differences in many of the STBL thermodynamic parameters, the differences in liquid water path at the three locations were statistically insignificant. The soundings were further classified as well mixed or decoupled based on the difference between the surface and cloud-base virtual potential temperature. The decoupled STBLs were deeper than the well-mixed STBLs at all three locations. Statistically insignificant differences in surface latent heat flux (LHF) between well-mixed and decoupled STBLs suggest that parameters other than LHF are responsible for producing decoupling.

scholarly journals Seasonal variations in brightness temperature for central Antarctica

1993 ◽  
Vol 17 ◽  
pp. 300-306 ◽  
Author(s):  
C.J. Van Der Veen ◽  
K. C. Jezek
Keyword(s):  
Radiative Transfer ◽  
Brightness Temperature ◽  
Scattering Theory ◽  
Rayleigh Scattering ◽  
Source Term ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Temperature Model ◽  
One Dimensional

The radiative-transfer model developed by Zwally (1977) is modified and coupled to a one-dimensional time-dependent temperature model, to calculate the seasonal variation in brightness temperature. By comparing this with observed records, the radiative properties of firn can be determined. By retaining scattering as a source term in the radiative transfer function, agreement between model-derived scattering and absorption coefficients and those calculated from the Mie/Rayleigh scattering theory can be obtained. The horizontal brightness temperature is not linked to the vertical one through a constant power reflection coefficient.

A Method for Modeling the Mitigation of Hazardous Fire Thermal Radiation by Water Spray Curtains

1997 ◽  
Vol 119 (4) ◽  
pp. 746-753 ◽  
Author(s):  
S. Dembele ◽  
A. Delmas ◽  
J. F. Sacadura
Keyword(s):  
Radiative Transfer ◽  
Thermal Radiation ◽  
Integral Form ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Discrete Ordinates ◽  
Transfer Model ◽  
General Description ◽  
Water Droplets ◽  
Distribution Method

A radiative transfer model describing the interactions between hazardous fire thermal radiation and water sprays is presented. Both the liquid (water droplets) and gaseous (mainly water vapor and carbon dioxide) phases of the spray are considered in the present work. Radiative properties of the polydisperse water droplets are derived from Mie theory. The gaseous phase behavior is handled by the correlated-k distribution method, where the k-distribution function is evaluated for Malkmus narrow-band statistical model. The radiative transfer equation, in its integral form, is solved by a discrete ordinates method. After a general description of the radiative model developed and the experimental task to validate it, some results are discussed on its accuracy and CPU time. A deeper analysis is also carried out to point out the influence of the main parameters involved in the problem.

scholarly journals Application of TRMM PR and TMI Measurements to Assess Cloud Microphysical Schemes in the MM5 for a Winter Storm

2010 ◽  
Vol 49 (6) ◽  
pp. 1129-1148 ◽  
Author(s):  
Mei Han ◽  
Scott A. Braun ◽  
William S. Olson ◽  
P. Ola G. Persson ◽  
Jian-Wen Bao
Keyword(s):  
Radiative Transfer ◽  
Mesoscale Model ◽  
Single Layer ◽  
Radar Reflectivity ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Microphysics Scheme ◽  
Precipitation System ◽  
Simulated Precipitation

Abstract This paper uses observations from Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and microwave imager (TMI) to evaluate the cloud microphysical schemes in the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5; version 3.7.4) for a wintertime frontal precipitation system over the eastern Pacific Ocean. By incorporating a forward radiative transfer model, the radar reflectivity and brightness temperatures are simulated and compared with the observations at PR and TMI frequencies. The main purpose of this study is to identify key differences among the five schemes [including Simple ice, Reisner1, Reisner2, Schultz, and Goddard Space Flight Center (GSFC) microphysics scheme] in the MM5 that may lead to significant departures of simulated precipitation properties from both active (PR) and passive (TMI) microwave observations. Radiative properties, including radar reflectivity, attenuation, and scattering in precipitation liquid and ice layers are investigated. In the rain layer, most schemes are capable of reproducing the observed radiative properties to a reasonable degree; the Reisner2 simulation, however, produces weaker reflectivity and stronger attenuation than the observations, which is possibly attributable to the larger intercept parameter (N0r) applied in this run. In the precipitation ice layer, strong evidence regarding the differences in the microphysical and radiative properties between a narrow cold-frontal rainband (NCFR) and a wide cold-frontal rainband (WCFR) within this frontal precipitation system is found. The performances of these schemes vary significantly on simulating the microphysical and radiative properties of the frontal rainband. The GSFC scheme shows the least bias, while the Reisner1 scheme has the largest bias in the reflectivity comparison. It appears more challenging for the model to replicate the scattering signatures obtained by the passive sensor (TMI). Despite the common problem of excessive scattering in the WCFR (stratiform precipitation) region in every simulation, the magnitude of the scattering maximum seems better represented in the Reisner2 scheme. The different types of precipitation ice, snow, and graupel are found to behave differently in the relationship of scattering versus reflectivity. The determinative role of the precipitation ice particle size distribution (intercept parameters) is extensively discussed through sensitivity tests and a single-layer radiative transfer model.

scholarly journals Seasonal variations in brightness temperature for central Antarctica

1993 ◽  
Vol 17 ◽  
pp. 300-306 ◽  
Author(s):  
C.J. Van Der Veen ◽  
K. C. Jezek
Keyword(s):  
Radiative Transfer ◽  
Brightness Temperature ◽  
Scattering Theory ◽  
Rayleigh Scattering ◽  
Source Term ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Temperature Model ◽  
One Dimensional

The radiative-transfer model developed by Zwally (1977) is modified and coupled to a one-dimensional time-dependent temperature model, to calculate the seasonal variation in brightness temperature. By comparing this with observed records, the radiative properties of firn can be determined. By retaining scattering as a source term in the radiative transfer function, agreement between model-derived scattering and absorption coefficients and those calculated from the Mie/Rayleigh scattering theory can be obtained. The horizontal brightness temperature is not linked to the vertical one through a constant power reflection coefficient.

scholarly journals Assessment of Aerosol Radiative Forcing with 1-D Radiative Transfer Modeling in the U. S. South-East

Atmosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 271 ◽  
Author(s):  
Erica Alston ◽  
Irina Sokolik
Keyword(s):  
Radiative Transfer ◽  
Radiative Forcing ◽  
Global Climate Model ◽  
Regional Scale ◽  
Climate Impacts ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Aerosol Layer ◽  
Potential Implication

Aerosols and their radiative properties play an integral part in understanding Earth’s climate. It is becoming increasingly common to examine aerosol’s radiative impacts on a regional scale. The primary goal of this research is to explore the impacts of regional aerosol’s forcing at the surface and top-of-atmosphere (TOA) in the south-eastern U.S. by using a 1-D radiative transfer model. By using test cases that are representative of conditions common to this region, an estimate of aerosol forcing can be compared to other results. Speciation data and aerosol layer analysis provide the basis for the modeling. Results indicate that the region experiences TOA cooling year-round, where the winter has TOA forcings between −2.8 and −5 W/m2, and the summer has forcings between −5 and −15 W/m2 for typical atmospheric conditions. Surface level forcing efficiencies are greater than those estimated for the TOA for all cases considered i.e., urban and non-urban background conditions. One potential implication of this research is that regional aerosol mixtures have effects that are not well captured in global climate model estimates, which has implications for a warming climate where all radiative inputs are not well characterized, thus increasing the ambiguity in determining regional climate impacts.

scholarly journals Optical Properties and Direct Radiative Effects of Aerosol Species at the Global Scale Based on the Synergistic Use of MERRA-2 Optical Properties and the FORTH Radiative Transfer Model

2020 ◽  
Vol 4 (1) ◽  
pp. 4
Author(s):  
Marios-Bruno Korras-Carraca ◽  
Antonis Gkikas ◽  
Arlindo M. Da Silva ◽  
Christos Matsoukas ◽  
Nikolaos Hatzianastassiou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Transfer ◽  
Surface Albedo ◽  
Global Scale ◽  
Radiative Properties ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Radiative Effects ◽  
Clear Sky ◽  
Strong Surface

The overarching goal of the current study is to quantify the aerosol-induced clear-sky direct radiative effects (DREs) within the Earth-atmosphere system at the global scale and for the 40-year period 1980–2019. To this aim, the MERRA-2 aerosol radiative properties, along with meteorological fields and surface albedo, are used as inputs to the Foundation for Research and Technology-Hellas (FORTH) radiative transfer model (RTM). Our preliminary results, representative for the year 2015, reveal strong surface radiative cooling (down to −45 Wm−2) over areas where high aerosol loadings and absorbing particles (i.e., dust and biomass burning) dominate. This reduction of the incoming solar radiation in the aforementioned regions is largely attributed to its absorption by the overlying suspended particles resulting in atmospheric warming reaching up to 40 Wm−2. At the top of the atmosphere (TOA), negative DREs (planetary cooling) are computed worldwide (down to −20 Wm−2) with few exceptions over bright surfaces (warming up to 5 Wm−2). Finally, the strong variations between the obtained DREs of different aerosol species (dust, sea salt, sulfate, and organic/black carbon) as well as between hemispheres and surface types (i.e., land vs. ocean) are also discussed.

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