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Improved quality control procedures and models for solar radiation using a world-wide database.

Younes, Serge (2006) Improved quality control procedures and models for solar radiation using a world-wide database. PhD thesis, Edinburgh Napier University.

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    Abstract/Description

    This thesis deals with- various aspects of broadband horizontal solar
    irradiance. Quality control of measured datasets are identified and analysed. It
    was found that solar irradiance datasets may contain significant errors. These
    sources of errors were divided in two categories, the inherent instrument
    errors and operation related errors. Methods of assessing the quality of the
    datasets were evaluated and found to be unsatisfactory. A new method was
    hence developed to quality control the solar irradiance data.
    The quality control procedure consists of two tiers of tests. The first tests are
    physical tests that identify and remove data points that are physical
    impossibilities. The second tier tests consist of the creation of a mathematical
    envelope of acceptance in a sky clarity index domain. This envelope of
    acceptance is based on multiples of standard deviations of the weighted
    mean of clearness index to diffuse ratio. The available datasets in this study
    were thus quality controlled to remove any obvious outliers.
    Modelling the solar resource is an important tool for engineers and scientists.
    Such models have been developed since the second half of the 20th century.
    Some models rely on one or two meteorological parameters to estimate the
    solar irradiance, while other models are more complex and require a far
    greater number of points. Two of these models have been analysed and
    evaluated. The two models are all-sky, broadband solar irradiance models.
    The first model analysed is the Meteorological Radiation Model, or MRM. This
    model is in fact a sunshine based model, with atmospheric turbidity taken into
    account as well. The beam irradiance component was found to be acceptable
    given the number of inputs required by the model. Any extra parameters
    would increase the complexity of the model, without noticeable improvements.
    The regressions were modified to take into account sunshine fraction banding.
    However the diffuse irradiance was identified as one which had the potential
    III
    for improvement. Thus, in the present work an attempt has been made to
    develop improved models. The new model was found to be far superior to the
    older, original model, thus the name Improved Meteorological Radiation
    Model, IMRM.
    The second type of model investigated is the cloud based radiation model.
    This type of model is simple to use and rely on regressions between
    irradiation, solar altitude angle and the cloud cover. Careful analysis of the
    cloud distribution reveals certain flaws in the current regressions. New
    regressions were formulated and the result was a model superior to all its
    predecessors.
    Clear-sky modelling is important for maximum load calculations; however,
    there is no method of extracting with accuracy clear-sky broadband data.
    Clear-sky identification techniques were evaluated and a new method was
    devised. These new datasets were used on four clear-sky models, MRM,
    Page's Radiation Model, PRM, Yang's radiation model and Gueymard's
    REST2 model. It was found that using this new method of extracting extremeclear-
    sky data, the models performed better than when using quasi-clear-sky
    data.
    Solar radiation modelling is not an end by-itself, it must serve a purpose for
    engineers in their applications. Napier University has installed a 160m2
    photovoltaic facility in 2003. A 27 -year solar radiation dataset was available
    for Edinburgh, to do feasibility calculations for the project; however this
    dataset contained gaps in the data. The cloud radiation model developed in
    this study was utilised to this end. In addition a complete life cycle analysis
    was performed on the project, and it was found that with an average efficiency
    at around 12%, the facility will payback its embodied energy in eight years,
    and based on a relatively conservative forecast of energy prices, the financial
    payback is set at under 100 years.

    Item Type: Thesis (PhD)
    Uncontrolled Keywords: Braodband horizontal solar irradiance; sky clarity index domain; standard deviations; Meteorological Radiation Model; IMRM;
    University Divisions/Research Centres: Faculty of Engineering, Computing and Creative Industries > School of Engineering and the Built Environment
    Dewey Decimal Subjects: 500 Science > 550 Earth sciences & geology > 551 Geology, hydrology & meteorology
    Library of Congress Subjects: T Technology > TD Environmental technology. Sanitary engineering
    Item ID: 4282
    Depositing User: Mrs Lyn Gibson
    Date Deposited: 11 Mar 2011 11:59
    Last Modified: 11 Mar 2011 11:59
    URI: http://researchrepository.napier.ac.uk/id/eprint/4282

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