Atmospheric transmission loss in mirror-to-tower slant ranges due to water vapor

Gueymard, Christian A.; López, Gabriel; Rapp-Arrarás, Ígor

doi:10.1063/1.4984518

Cited by 11 publications

(3 citation statements)

References 10 publications

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“…Usually, meteorological data sets, including irradiance measurements or typical meteorological years, are acquired within the planning phase for a CSP project. As it is not always possible to also perform on-site measurements of the atmospheric extinction additionally to the standard measurement setup during the resource assessment process, the need of according modeling methods arose during the last few years, and different methods have been presented [12][13][14][15][16][17][18]. The different models use, for example, the aerosol optical depth (AOD) of, e.g., the AERONET network, remote sensing data of MODIS, or water vapor data sets.…”

Section: Introductionmentioning

confidence: 99%

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

Hanrieder¹,

Ghennioui

Wilbert³

et al. 2020

Energies

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Attenuation of solar radiation between the receiver and the heliostat field in concentrated solar power (CSP) tower plants can reduce the overall system performance significantly. The attenuation varies strongly with time and the average attenuation at different sites might also vary strongly from each other. If no site specific attenuation data is available, the optimal plant design cannot be determined and rough estimations of the attenuation effect are required leading to high uncertainties of yield analysis calculations. The attenuation is caused mainly by water vapor content and aerosol particles in the lower atmospheric layer above ground. Although several on-site measurement systems have been developed during recent years, attenuation data sets are usually not available to be included during the plant project development. An Atmospheric Attenuation (AATTENUATION) model to derive the atmospheric transmittance between a heliostat and receiver on the basis of common direct normal irradiance (DNI), temperature, relative humidity, and barometric pressure measurements was developed and validated by the authors earlier. The model allows the accurate estimation of attenuation for sites with low attenuation and gives an estimation of the attenuation for less clear sites. However, the site-dependent coefficients of the AATTENUATION model had to be developed individually for each site of interest, which required time-consuming radiative transfer simulations, considering the exact location and altitude, as well as the pre-dominant aerosol type at the location. This strongly limited the application of the model despite its typically available input data. In this manuscript, a look-up table (LUT) is presented which enables the application of the AATTENUATION model at the site of interest without the necessity to perform the according complex radiative transfer calculations for each site individually. This enables the application of the AATTENUATION model for virtually all resource assessments for tower plants and in an operational mode in real time within plant monitoring systems around the world. The LUT also facilitates the generation of solar attenuation maps on the basis of long-term meteorological data sets which can be considered during resource assessment for CSP tower plant projects. The LUTs are provided together with this manuscript as supplementary files. The LUT for the AATTENUATION model was developed for a solar zenith angle (SZA) grid of 1°, an altitude grid of 100 m, 7 different standard aerosol types and the standard AFGL atmospheres for mid-latitudes and the tropics. The LUT was tested against the original version of the AATTENUATION model at 4 sites in Morocco and Spain, and it was found that the additional uncertainty introduced by the application of the LUT is negligible. With the information of latitude, longitude, altitude above mean sea level, DNI, relative humidity (RH), ambient temperature (Tair), and barometric pressure (bp), the attenuation can be now derived easily for each site of interest.

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Section: Introductionmentioning

confidence: 99%

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

Hanrieder¹,

Ghennioui

Wilbert³

et al. 2020

Energies

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“…constitutes one major cause of visibility reduction. Water vapor and aerosols close to the surface are the main atmospheric constituents contributing to the slant-path solar transmission losses occurring between the heliostats and the receiver in a solar tower power (STP) plant [1]. This has prompted the use of horizontal visibility as one key input parameter in computer codes that have been developed for the design and operation codes of STP plants [2].…”

Section: Introductionmentioning

confidence: 99%

Visibility Estimates From Atmospheric and Radiometric Variables Using Artificial Neural Networks

López¹,

Bosch²,

Pulido‐Calvo³

et al. 2017

WIT Transactions on Ecology and the Environment

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Visibility is traditionally needed for air quality monitoring or air traffic control, and has become a key input to determine the transmission losses of solar radiation propagating between heliostats and the receiver of solar tower power (STP) plants. Recent studies suggest that haze can reduce visibility and increase these losses up to 25% compared to clear conditions. Monitoring visibility would thus be needed for proper design and operation of STPs, but this is usually not done at all potential sites. Here, visibility's magnitude and variability are analyzed in terms of more common atmospheric variables: temperature, humidity, pressure, wind speed and precipitable water. To that effect, 1-min observations from a visibility meter located in Huelva (southwestern Spain) are analyzed over a 2-month period. Relative humidity is linearly correlated with visibility and explains 40% of its variability. This correlation is strongest under cloudless and daytime conditions. Using standard statistical techniques, no significant correlation is found between visibility and other atmospheric variables. Artificial neural networks (ANN) are thus investigated here for mapping the complex and non-linear relationships between visibility and multiple atmospheric inputs. This improves results significantly, increasing the explained visibility variability up to 72% and reducing RMSE from 40% to 30%. Moderate improvements in visibility estimation are further obtained when radiometric information (direct and diffuse solar irradiances) are added as ANN predictors. These findings show that visibility can be estimated from local atmospheric and radiometric observations using ANN, despite the complex and non-linear relationships between them.

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“…They established a correlation between temperature and protective paint lifetime for the three temperatures.The atmosphere plays an important role in the degradation of mirrors. Suspended water vapour causes small reductions in heat transmission depending on the humidity[97]. Aerosols are also relevant in this aspect, according to the study by Sengupta and Wagner[98].…”

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confidence: 97%

A review of the application performances of concentrated solar power systems

2019

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The global energy production model is changing from fossil fuels to renewable and nuclear energies. Concentrated solar power is one of the growing technologies that is leading this process. This growth implies the sophistication and size of the systems and, therefore, it requires an increase in maintenance tasks to ensure reliability, availability, maintainability and safety. The aim of this paper is to describe the current context of concentrated solar power, to summarise and analyse the main degradation mechanisms and the main techniques to detect, prevent and mitigate these faults. An exhaustive literature study is presented, considering the most advanced techniques and approaches. A novel qualitative and quantitative analysis of the literature is provided. Finally, the current trends and the future challenges in this field are gathered from this study.

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Atmospheric transmission loss in mirror-to-tower slant ranges due to water vapor

Cited by 11 publications

References 10 publications

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

Visibility Estimates From Atmospheric and Radiometric Variables Using Artificial Neural Networks

A review of the application performances of concentrated solar power systems

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