Performances assessment of the first grid-connected photovoltaic micro power in Africa: The PVGIS approach

In this paper, a novel trimeric chain approach to organometallic ferrimagnetics is proposed. The inter and intratrimer exchange interaction has been determined to be antiferromagnetic from a theoretical model magnetic susceptibility.The Curie law observed at very low temperature (q = 5.764 K l0) contrasts with significant ferromagnetic behaviour. The magnetic data were fitted with the IDC model. The compounds interestingly exhibit ferrimagnetic interactions with gCu1 =1.81, gCu2 =2.04 and gCu3 =2.43; J1 =-89.93K and J2 = -2.68 KIn this paper, a novel trimeric chain approach to organometallic ferrimagnetics is proposed. The inter and intratrimer exchange interaction has been determined to be antiferromagnetic from a theoretical model magnetic susceptibility.The Curie law observed at very low temperature (q = 5.764 K l0) contrasts with significant ferromagnetic behaviour. The magnetic data were fitted with the IDC model. The compounds interestingly exhibit ferrimagnetic interactions with gCu1 =1.81, gCu2 =2.04 and gCu3 =2.43; J1 =-89.93K and J2 = -2.68

Comparison of Predictive Models for Photovoltaic Module Performance under Tropical Climate

This paper examines four models which are used to estimate the performance of photovoltaic (PV) modules when the irradiances and PV cell temperatures are known. The models were simulated and the operating temperature and irradiance dependence of PV electrical efficiency and power output were studied. The models accuracy was obtained by comparing the models and the measurements of maximum power for a polycrystalline typical MXS 60 PV module under tropical climate. The evaluated models for estimating the maximum power are the single diode, the Photovoltaic geographical information system (PVGIS), the Borowy and Salameh, and the Hatziargyriou model. The analysis of the error curves shows that the single diode and Hatziargyriou model have better accuracy. The PVGIS and Borowy approach are not appropriate as the module performance prediction in Sudanese sahelian climate

Estimating evapotranspiration in the Segura River Basin from remote sensing data

[SPA] Este trabajo presenta y valida una metodología operacional, basada en el análisis del espacio temperatura de superficie (LST) vs índice de vegetación (IV), para la estimación y la cartografía de evapotranspiracion real (ET) a partir de imágenes satelitales (Landsat 5 TM) en la Cuenca del Segura. El método ha sido validado con observaciones llevadas a cabo con la técnica de covarianza de remolinos en dos parcelas del Campo de Cartagena (España). El ajuste alcanzado (R2 >0.80, y RMSE ± 50 W/m2), demuestra la validez de la información satelital para la estimación de ET a nivel de parcela. [ENG] This paper presents and validates an operational methodology, based on the use of land surface temperature (LST) and vegetation index (IV), for estimating and mapping actual evapotranspiration (ET) from satellite imagery (Landsat5 TM) in Segura river basin. The method was validated with measurements of ET realized by the eddy covariance technique in two citrus orchards of Campo de Cartagena (Spain). The good fit (R2>0.80, RMSE of ± 50 W/m2) demonstrates the usefulness of satellite observations for estimating ET at the farm level.Se agradece la financiación recibida de los siguientes proyectos de I+D: EC-DG ENV ref. 241559. REDSIM, EU FP7-245159 SIRRIMED, y CGL2012-39895-C02-01 HYDROCLIM

BIM-based surface-specific solar simulation of buildings

Photovoltaic (PV) solar energy is rapidly growing as an attractive alternative to fossil fuels. PV panels can harvest the solar power and turn it into a clean source of electricity. Traditionally, PV panels are only used on the rooftops of buildings. However, with the emergence of building-integrated solar panels in recent years, other surfaces on the building façade can be considered for the installation of PV panels. Given that different panels have different cost and performance profiles, it is of a cardinal importance to properly design the PV panels on the building facades to ensure a maximum benefit-cost ratio. Existing simulation and optimization methods do not discriminate between different types of surfaces of the building and treat the building envelope as a set of polygons. This can result in under- or over- design since there is a strong relationship between the type of the surfaces and the type of PV panels that can be attached to them or integrated with them. The advent of Building Information Modeling (BIM) in recent years has provided a rich platform for object-based evaluation and analysis of buildings. Nonetheless, currently, BIM is not used for a detailed and surface-specific simulation of building surfaces. In this research, a BIM-based method is developed for a detailed simulation of a building envelope using its surface properties. A prototype is developed using Dynamo visual programming platform to demonstrate the feasibility of the proposed method, and a case study is presented for a building in Montreal, Canada. In the light of the result of the case study, it can be concluded that the proposed method is promising in terms of providing the input for a comprehensive planning of the solar panel layout

Impact of Small-scale Storage Systems on the Photovoltaic Penetration Potential at the Municipal Scale

AbstractHigh penetration of grid-connected roof-top photovoltaic power plants (GCRT-PV) is restricted by electric energy grid quality requirements and available storage capacities. This study evaluates how far small-scale storage systems can contribute to increment GCRT-PV penetration at municipal scale. To accomplish this, the GCRT-PV potential of a municipality is calculated in high spatiotemporal resolution and various scenarios of storage systems penetration are evaluated with a series of indicators. The adoption of a low share of storage systems improves energy utilisation, variability and reliability indicators; while an increased penetration of storage systems only marginally improves these indicators

GIS-Based Optimal Photovoltaic Panel Floorplanning for Residential Installations

Shading is a crucial issue for the placement of PV installations, as it heavily impacts power production and the corresponding return of investment. Nonetheless, residential rooftop installations still rely on rule-of-thumb criteria and on gross estimates of the shading patterns, while more optimized approaches focus solely on the identification of suitable surfaces (e.g., roofs) in a larger geographic area (e.g., city or district). This work addresses the challenge of identifying an optimal (with respect to the overall energy production) placement of PV panels on a roof. The novel aspect of the proposed solution lies in the possibility of having a sparse, irregular placement of individual modules so as to better exploit the variance of solar data. The latter are represented in terms of the distribution of irradiance and temperature values over the roof, as elaborated from historical traces and Geographical Information System (GIS) data. Experimental results will prove the effectiveness of the algorithm through three real world case studies, and that the generated optimal solutions allow to increase power production by up to 28% with respect to rule-of-thumb solutions

Performance of a V-trough photovoltaic/thermal concentrator

The idea of concentrating solar energy to increase the output of photovoltaic and solar thermal collectors is an area that has received significant attention. In this study, a design model for a V-trough concentrating photovoltaic/thermal solar collector was theoretically analysed and validated with experimental data. The results showed that the V-trough offered improved electrical yields from both concentrating radiation onto the photovoltaic cells and also by actively cooling them. Also, it was shown that the V-trough could be made of a durable (long life) stainless steel, rather than the more reflective aluminium, while still offering a 25% increase in incident radiation over a typical year. However it was noted that modifications would be needed to improve cooling and to increase the thermal efficiency by reducing heat losses

Improving shadows detection for solar radiation numerical models

[EN]Solar radiation numerical models need the implementation of an accurate method for determining cast shadows on the terrain or on solar collectors. The aim of this work is the development of a new methodology to detect the shadows on a particular terrain. The paper addresses the detection of self and cast shadows produced by the orography as well as those caused by clouds. The paper presents important enhancements on the methodology proposed by the authors in previous works, to detect the shadows caused by the orography. The domain is the terrain surface discretised using an adaptive mesh of triangles. A triangle of terrain will be under cast shadows when, looking at the mesh from the Sun, you can find another triangle that covers all or partially the first one. For each time step, all the triangles should be checked to see if there are cast or self shadows on it. The computational cost of this procedure eventually resulted unaffordable when dealing with complex topography such as that in Canary Islands thus, a new methodology was developed. This one includes a filtering system to identify which triangles are those likely to be shadowed. If there are no self shadowed triangles, the entire mesh will be illuminated and there will not be any shadows. Only triangles that have their backs towards the Sun will be able to cast shadows on other triangles. Detection of shadows generated by clouds is achieved by a shadow algorithm using satellite images. In this paper, Landsat 8 images have been used. The code was done in python programming language. Finally, the outputs of both approaches, shadows generated by the topography and generated by clouds, can be combined in one map. The whole problem has been tested in Gran Canaria and Tenerife Island (Canary Islands – Spain), and in the Tatra Mountains (Poland and Slovakia).Ministerio de Economía y Competitividad del Gobierno de Españ