Short- and long-wave radiation flux densities absorbed by people have a significant influence on their energy balance. The heat effect of the absorbed radiation flux densities is parameterised by the mean radiant temperature. This paper presents the physical basis of the RayMan model, which simulates the short- and long-wave radiation flux densities from the three-dimensional surroundings in simple and complex environments. RayMan has the character of a freely available radiation and human-bioclimate model. The aim of the RayMan model is to calculate radiation flux densities, sunshine duration, shadow spaces and thermo-physiologically relevant assessment indices using only a limited number of meteorological and other input data. A comparison between measured and simulated values for global radiation and mean radiant temperature shows that the simulated data closely resemble measured data.

/pdf/modelling-radiation-fluxes-in-simple-and-complex-g6gth4vara.pdf

Modelling radiation fluxes in simple and complex environments—application of the RayMan model

Concentrated solar power plants (CSPs) are gaining increasing interest, mostly as parabolic trough collectors (PTC) or solar tower collectors (STC). Notwithstanding CSP benefits, the daily and monthly variation of the solar irradiation flux is a main drawback. Despite the approximate match between hours of the day where solar radiation and energy demand peak, CSPs experience short term variations on cloudy days and cannot provide energy during night hours unless incorporating thermal energy storage (TES) and/or backup systems (BS) to operate continuously. To determine the optimum design and operation of the CSP throughout the year, whilst defining the required TES and/or BS, an accurate estimation of the daily solar irradiation is needed. Local solar irradiation data are mostly only available as monthly averages, and a predictive conversion into hourly data and direct irradiation is needed to provide a more accurate input into the CSP design. The paper (i) briefly reviews CSP technologies and STC advantages; (ii) presents a methodology to predict hourly beam (direct) irradiation from available monthly averages, based upon combined previous literature findings and available meteorological data; (iii) illustrates predictions for different selected STC locations; and finally (iv) describes the use of the predictions in simulating the required plant configuration of an optimum STC. The methodology and results demonstrate the potential of CSPs in general, whilst also defining the design background of STC plants.

/pdf/concentrated-solar-power-plants-review-and-design-1vowjo3z7e.pdf

Concentrated solar power plants: Review and design methodology

Review of photovoltaic power forecasting

http://coimbra.ucsd.edu/publications/papers/2013_Inman_Pedro_Coimbra.pdf

Solar forecasting methods for renewable energy integration

Artificial intelligence techniques for photovoltaic applications: A review

Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies

The accumulation of dust on the surface of a photovoltaic module decreases the radiation reaching the solar cell and produces losses in the generated power. Dust not only reduces the radiation on the solar cell, but also changes the dependence on the angle of incidence of such radiation. This work presents the results of a study carried out at the University of Malaga to quantify losses caused by the accumulation of dust on the surface of photovoltaic modules. Our results show that the mean of the daily energy loss along a year caused by dust deposited on the surface of the PV module is around 4.4%. In long periods without rain, daily energy losses can be higher than 20%. In addition, the irradiance losses are not constant throughout the day and are strongly dependent on the sunlight incident angle and the ratio between diffuse and direct radiations. When studied as a function of solar time, the irradiance losses are symmetric with respect noon, where they reach the minimum value. We also propose a simple theoretical model that, taking into account the percentage of dirty surface and the diffuse/direct radiation ratio, accounts for the qualitative behavior of the irradiance losses during the day.

https://www.ep.liu.se/ecp/057/vol11/039/ecp57vol11_039.pdf

Mariano Sidrach-de-Cardona

Papers

Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies

Analysis of Dust Losses in Photovoltaic Modules

Comparative analysis of energy produced by photovoltaic modules with anti-soiling coated surface in arid climates

Energy performance of different photovoltaic module technologies under outdoor conditions

Multiplicative ARMA models to generate hourly series of global irradiation