Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser Evaluation of classical parametric models for estimating solar radiation in the Eastern Mediterranean region of Turkey H. Başak Yıldırım a, ⁎ , Ahmet Teke b , Fernando Antonanzas-Torres c a Energy Systems Engineering Department, Adana Science and Technology University, Turkey b Electrical and Electronics Engineering Department, Cukurova University, Adana, Turkey c EDMANS Group, Department of Mechanical Engineering, University of La Rioja, Logroño, Spain ARTICLE INFO Keywords: Solar radiation Parametric models Meteorological parameters ABSTRACT Accurate information on global solar radiation is essential to design and operate the systems that are based on solar energy. However, global solar radiation measurement is very rare while the measurements of other meteorological parameters such as air temperature, relative humidity, sunshine duration and precipitation are common in meteorological stations all around the world. Therefore, modelling global solar radiation is an important issue to fill the gaps in database and to estimate global solar radiation in places where global solar radiation measurement is not available. There are many different approaches in the literature for modelling global solar radiation. Two new methodologies are presented in this paper to develop parametric models for estimation of daily global solar radiation based on sunshine duration and relative humidity as well as a review of fourteen different already exist parametric models which are based on air temperature, maximum temperature, minimum temperature, precipitation, sunshine duration and relative humidity. The proposed models improve the estimation results of the other fourteen models with average mean absolute error (MAE) of 0.947 MJ/m 2 for Adana station, 1.086 MJ/m 2 for Göksun station, 1.074 MJ/m 2 for Tarsus station and 1.060 MJ/m 2 for whole study area. Hence, the proposed models which significantly approximate to measurements from pyranometers can be useful for the modelling global solar radiation in Eastern Mediterranean Region. 1. Introduction Global solar radiation is the total amount of solar energy received by the Earth's surface and the principal energy source for life in our planet. Therefore, records of observed solar radiation are required in different fields such as energy planning, climate monitoring and agriculture management. Generally, the best source of solar radiation data comes from on-ground measurements with high-quality and correctly maintained pyranometers. Solar energy maps which show the global solar radiation potential of the country can be useful to determine the most suitable locations to install solar systems and reduce the costs of feasibility studies for such projects [1]. However, due to cost and operational maintenance requirements, it is neither always possible to obtain spherical solar radiation data in such a way, nor to establish pyranometers with sufficient time to make a recording. For these reasons, solar energy planners seek different approaches to obtain long-term accurate solar radiation records. Among these methods, parametric models are widely used in literature because of their simplicity. These parametric techniques model the atmospheric transmittance using other commonly measured meteorological vari- ables that are related to solar radiation [2]. Once trained in a location with a pyranometer, solar radiation can be estimated in stations without pyranometers with the only need of the other input variables, the calculation of the extraterrestrial irradiation and in some cases the calculation of maximum possible sunshine duration [3]. The first parametric model was proposed by Angström [4] using the relation between the measured value of sunshine duration and daily potential sunshine duration under clear-sky conditions. Other re- searchers, such as Swartman and Ogunlade [5] found an excellent agreement with the combination of sunshine duration and relative humidity to explain solar irradiation. The sunshine duration provides information about the cloud cover and the power of solar irradiance that is why models that use sunshine duration as independent variable significantly improve the errors [6]. In this line and for this study, two different models are developed using quadratic and cubic adjustments of the later model. Besides, other models are proposed in the past to estimate solar radiation with another more commonly measured variables such as sunshine duration, temperature, rainfall and humid- http://dx.doi.org/10.1016/j.rser.2017.08.033 Received 19 April 2017; Received in revised form 3 July 2017; Accepted 11 August 2017 ⁎ Corresponding author. E-mail address: byildirim@adanabtu.edu.tr (H.B. Yıldırım). Renewable and Sustainable Energy Reviews xxx (xxxx) xxx–xxx 1364-0321/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Yildirim, H.B., Renewable and Sustainable Energy Reviews (2017), http://dx.doi.org/10.1016/j.rser.2017.08.033